News from www.caltech.eduhttps://www.caltech.edu/about/news2023-12-12T04:41:52.220390+00:00The Office of Strategic Communicationswww@caltech.eduCopyright © 2024 California Institute of TechnologyCaltech Science Journeys Program Returns with Physics Presentation: "Bringing Imbalance to the Universe"2023-12-08T19:38:00+00:002023-12-08T23:42:36.574119+00:00Caltech Communicationswww@caltech.eduhttps://www.caltech.edu/about/news/science-journeys-stem-arian-jadbabaie-physics<p data-block-key="en9k9">Everyone's journey into science is unique. For Arian Jadbabaie (PhD '23), it was all over the map: He was born in Iran, grew up in Connecticut, earned his bachelor's degree at Washington University in St. Louis, interned at Brookhaven National Laboratory and Lawrence Berkeley National Laboratory during a gap year, and landed in Pasadena to pursue his doctorate.</p><p data-block-key="3bvsj">Jadbabaie did his PhD work in the lab of Assistant Professor <a href="https://www.hutzlerlab.com/">Nick Hutzler</a>. Outside the lab, he was active in science outreach, seizing opportunities to share his passion for physics with the community. He collaborated with the Caltech Center for Teaching, Learning & Outreach to develop <a href="https://www.youtube.com/watch?v=T46hxSHiOoE">science demonstrations</a> and perform outreach at local <a href="/about/news/caltech-program-fosters-scientific-curiosity-pasadena-unified-students-78504">schools</a> and <a href="/about/news/city-of-stem-outreach">events</a>.</p><p data-block-key="26h8j">One of his final projects was to record a Science Journey presentation that shares the mysteries of the universe with students and science fans.</p><p data-block-key="67pgf">"When I was a young child, I was really mesmerized by spinning things; for example, a ceiling fan," Jadbabaie says in his presentation. "I actually do still work with spinning things today. They don't quite look like ceiling fans. They look like cold rotating molecules. At the end of the day, we use these cold rotating molecules to learn about very deep fundamental questions in physics related to the big bang, the origins of our universe, and how we came to be here today."</p><p data-block-key="bhgi6"></p><embed embedtype="media" url="https://youtu.be/bNrFh-Cd-rc?feature=shared"/><p data-block-key="8add9"></p><p data-block-key="couhr">Jadbabie's video premiere kicks off the 2023–24 season of Science Journeys, which will include in-person field trips that explore topics including fluid dynamics and turbulence, soil microbes and climate change, and neuroscience and decision-making.</p><h3 data-block-key="6015b"><b>About the Series</b></h3><p data-block-key="6fbqh">In Science Journeys, Caltech graduate students and postdoctoral scholars discuss a range of scientific topics that will spark students' curiosity and provide educators with supplemental resources to continue that exploration in the classroom.</p><p data-block-key="f1mfa">"I am delighted to welcome back in-person Science Journeys field trips in 2024," said Mary Herrera, the program's coordinator. "Caltech young researchers have a wealth of STEM knowledge and inspiration to share with students and lifelong learners in our community. We are ready for you—we hope you are ready for us!"</p><p data-block-key="95bas">Each field trip includes a presentation and Q&A. Programs are designed especially for middle and high school students, but everyone is welcome to attend. All events are free through the generosity of the <a href="https://events.caltech.edu/support/fob?utm_medium=web&utm_campaign=science-journeys&utm_source=caltechnews&utm_content=&utm_term=">Friends of Beckman Auditorium</a>, but registration is required.</p><p data-block-key="co3qv">Visit the <a href="https://events.caltech.edu/series/science-journeys#upcoming-science-journeys?utm_medium=web&utm_campaign=science-journeys&utm_source=caltechnews&utm_content=&utm_term=">Science Journeys website</a> to register yourself or your classroom for a future event and to watch past presentations.</p>Caltech's Institute for Quantum Information and Matter (IQIM) Receives New 6-Year Grant2023-09-12T16:28:00+00:002023-09-14T00:07:44.804663+00:00Whitney Clavinwclavin@caltech.eduhttps://www.caltech.edu/about/news/caltechs-institute-for-quantum-information-and-matter-iqim-receives-new-6-year-grant<p data-block-key="endiz">The National Science Foundation (NSF) has awarded Caltech's hub for cutting-edge quantum research, the Institute for Quantum Information and Matter, or IQIM, $13.8 million to support six more years of operations. IQIM is one of several NSF <a href="https://www.nsf.gov/mps/phy/pfc_program.jsp">Physics Frontiers Centers</a>, which bring together a collection of research groups, often across disciplines, and are designed to "foster major breakthroughs at the intellectual frontiers of physics."</p><p data-block-key="2lhce">IQIM, which first became a Physics Frontier Center in 2011, explores innovative topics in quantum science. The center's researchers study physical systems "in which the weirdness of the quantum world becomes manifest on macroscopic scales," according to the <a href="https://iqim.caltech.edu/about-iqim/">center's website</a>. IQIM's work has applications in quantum computing, precision measurement, fundamental physics, and the creation of new quantum materials with potential societal benefits in the areas of health care, cybersecurity, energy production, and the sustainability of the planet.</p><p data-block-key="296nk">"Quantum research centers are springing up all over the world in recent years, but NSF recognizes that IQIM has a unique and valuable role," says <a href="https://pma.caltech.edu/people/john-p-preskill">John Preskill</a>, the Allen V. C. Davis and Lenabelle Leadership Chair of IQIM and the Richard P. Feynman Professor of Theoretical Physics. "We've built a highly interconnected community focused on exploiting quantum technology for scientific discovery. We're proud of our past accomplishments, but more importantly, this new award will enable IQIM to lead further advances in quantum science that lay the foundations for extraordinary future applications."</p><p data-block-key="34bsm">"Research teams at NSF Physics Frontiers Centers have made breakthrough after breakthrough, such as creating remarkable new states of matter and revealing the first evidence for the gravitational wave background of the universe," says NSF Director Sethuraman Panchanathan. "While different in their respective areas of focus, <a href="https://new.nsf.gov/news/4-physics-research-centers-set-their-sights">NSF's newly funded centers</a> are all bold team efforts to punch through to exciting new vistas of scientific exploration. Achieving transformative opportunities requires us to reach those vistas through new technologies and other advances and have a look around."</p><p data-block-key="amt1v">In the coming years, IQIM will continue to probe the quantum realm with the goal of igniting ever-deepening insights into information, matter, and the universe. The center's researchers will study promising hardware platforms for quantum computers, including those based on <a href="/about/news/quantum-innovations-achieved-using-alkaline-earth-atoms">individually controlled atoms</a> as well as superconducting materials, the latter of which are being actively investigated by the <a href="/about/news/caltech-and-amazon-partner-to-create-new-hub-of-quantum-computing">AWS Center for Quantum Computing</a> on the Caltech campus. IQIM researchers will also study exotic types of matter such as topological materials, which may be useful for reducing the errors that are common in quantum computing.</p><p data-block-key="5ed">Another focus of IQIM will be on quantum precision measurements, or quantum metrology. By harnessing the phenomenon of quantum <a href="https://scienceexchange.caltech.edu/topics/quantum-science-explained/entanglement">entanglement</a>, in which particles such as photons are connected and become more cooperative with each other, researchers have been able to make more-precise measurements at smaller and smaller scales. This work may lead to more-accurate optical clocks and more-precise detection of very weak forces, with applications in next-generation gravitational-wave detection. Caltech's new <a href="/about/news/breaking-ground-cqpm">Dr. Allen and Charlotte Ginsburg Center for Quantum Precision Measurement</a> will address many of these topics in tandem with IQIM.</p><p data-block-key="44glg">A major success of IQIM has been the development of an extensive outreach program that includes the <a href="http://quantumfrontiers.com/">Quantum Frontiers blog</a>; <a href="https://iqim.caltech.edu/outreach/film-and-media/">short films</a> that star celebrities such as Paul Rudd, Zoe Saldana, and Keanu Reeves; science advising for movies such as <i>Ant-Man;</i> the development of <a href="/about/news/quantum-in-the-classroom">quantum games</a> such as quantum chess; and several in-depth <a href="https://iqim.caltech.edu/outreach/k-12-programs/">programs for K-12 students</a>.</p><p data-block-key="5f3qc">"I want kids to have the same intuition for quantum physics that they have about gravity," says Spiros Michalakis, a mathematical physicist and the IQIM outreach manager. "When they throw a ball, they intuitively understand gravity, but they haven't had the same exposure to quantum physics. None of us have. I think it's imperative to meet kids where they are at, with games and stories deeply infused with quantum science."</p><p data-block-key="a87o4">The center's <a href="https://magazine.caltech.edu/post/iqim-quantum-john-preskill">roots go back to the late 1990s</a>, when Preskill and <a href="https://pma.caltech.edu/people/h-j-kimble">H. J. "Jeff" Kimble</a>, now Caltech's William L. Valentine Professor of Physics, Emeritus, received a grant from the Defense Advanced Research Projects Agency (DARPA) to study quantum computing's potential applications in cryptography. Later, in 2000, Preskill and Kimble were awarded funding from the NSF for their growing group, which, at that time, was called the Institute for Quantum Information, or IQI.</p><p data-block-key="4kei3">"I wanted to bring in the best young scientists and give them a lot of freedom, to create a community of people who had some common interests, but also complementary backgrounds," said Preskill of the early days of the center in an <a href="https://heritageproject.caltech.edu/interviews-updates/john-preskill">interview with the Caltech Heritage Project</a>. "So, I deliberately would put a computer scientist in the same office with a physicist so [they] would talk.…We had an amazing group of young people in the early 2000s who came through, many of whom are leaders of research in quantum information now."</p><p data-block-key="2lsbe">IQI focused solely on theoretical studies until 2011, when the NSF expanded the center's funding and scope to include experimental work. That's when IQI became the Institute for Quantum Information <i>and Matter</i>.</p><p data-block-key="cu9iu">"All of a sudden, we attach <i>M</i>—matter—and it really mattered because it wasn't just that experimentalists started knocking on our door, we started to have conversations [about] how you can convert some of the theories into experiments that then could advance quantum computing or quantum metrology or quantum anything in the future," Michalakis said in his own <a href="https://heritageproject.caltech.edu/interviews-updates/spiros-michalakis">interview with the Caltech Heritage project</a>. "[IQIM] became a very strong nucleating force for so many different individuals."</p><p data-block-key="9rr1o">Preskill adds, "In each award cycle we've refreshed IQIM by bringing in new ideas and new people who are eager to launch new collaborations. And we encourage people to try risky things. Some of our projects might fail, but you need to take a risk to make a breakthrough."</p>Some Alloys Don't Change Size When Heated. We Now Know Why.2023-07-27T16:59:00+00:002023-07-27T23:19:26.863532+00:00Emily Velascoevelasco@caltech.eduhttps://www.caltech.edu/about/news/some-alloys-dont-change-size-when-heated-we-now-know-why<p data-block-key="mhvmh">Nearly every material, whether it is solid, liquid, or gas, expands when its temperature goes up and contracts when its temperature goes down. This property, called thermal expansion, makes a hot air balloon float, and the phenomenon has been harnessed to create thermostats that automatically turn a home furnace on and off. Railroads, bridges, and buildings are designed with this property in mind, and they are given room to expand without buckling or breaking on a hot day.</p><p data-block-key="e6hqc">Thermal expansion occurs because a material's atoms vibrate more as its temperature increases. The more its atoms vibrate, the more they push away from their neighboring atoms. As the space between the atoms increases, the density of the material decreases and its overall size increases.</p><p data-block-key="4pcsc">There are a few exceptions, but by and large, materials conform strictly to this principle. There is, however, a class of metal alloys called Invars (think <b><i>invar</i></b>iable), that stubbornly refuse to change in size and density over a large range of temperatures.</p><p data-block-key="6htk3"></p><embed alt="Silvery metal blocks rest on a white surface." embedtype="image" format="RightAlignMedium" id="9919"/><p data-block-key="9saug"></p><p data-block-key="9fouu">"It's almost unheard of to find metals that don't expand," says Stefan Lohaus, a graduate student in materials science and lead author of the new paper. "But in 1895, a physicist discovered by accident that if you combine iron and nickel, each of which has positive thermal expansion, in a certain proportion, you get this material with very unusual behavior."</p><p data-block-key="3ijgp">That anomalous behavior makes these alloys useful in applications where extreme precision is required, such as in the manufacture of parts for clocks, telescopes, and other fine instruments. Until now, no one knew why Invars behave this way. In a new paper published in <i>Nature Physics</i>, researchers from the lab of <a href="https://www.eas.caltech.edu/people/btf">Brent Fultz</a>, the Barbara and Stanley R. Rawn, Jr., Professor of Materials Science and Applied Physics, say they have figured out the secret to at least one Invar's steadiness.</p><p data-block-key="acso9"></p><embed alt="A photo of Brent Fultz. He has a beard, mustache, and glasses." embedtype="image" format="RightAlignSmall" id="9920"/><p data-block-key="aiibg"></p><p data-block-key="dk3n9">For over 150 years, scientists have known that thermal expansion is related to entropy, a central concept in thermodynamics. Entropy is a measure of the disorder, such as positions of atoms, in a system. As temperature increases, so does the entropy of a system. This is universally true, so an Invar's unusual behavior must be explained through something counteracting that expansion.</p><p data-block-key="9t7bk">Lohaus says it had been long suspected that this behavior was somehow related to magnetism because only certain alloys that are ferromagnetic (capable of being magnetized) behave as invars.</p><p data-block-key="7sdg8"></p><embed alt="A photo of Stefan Lohaus. In the background is laboratory equipment." embedtype="image" format="LeftAlignSmall" id="9921"/><p data-block-key="4ouhc"></p><p data-block-key="47uer">"We decided to look at that because we have this very neat experimental setup that can measure both magnetism and atomic vibrations," Lohaus says. "It was a perfect system for this."</p><p data-block-key="a1a30">Since the magnetic properties of a material are the result of its electrons' so-called spin state— a quantum measure of angular momentum that can be either "up" or "down"—any magnetic effect counteracting the material's expected expansion must be due to the activity of its electrons.</p><p data-block-key="7qcii">The relationship between entropy, thermal expansion, and pressure, known as the "Maxwell relations" is often presented as a textbook curiosity, but the Caltech group found a way to use it to independently measure the thermal expansion caused by magnetism and by atom vibrations. The experiments were done at the Advanced Photon Source, a source of synchrotron X-rays at the Argonne National Laboratory in Illinois, by measuring the vibrational spectra and magnetism of small samples of Invar at pressures within a diamond anvil cell.</p><p data-block-key="6oaei">The measurements showed a delicate cancellation of the thermal expansion from atom vibrations and from magnetism. Both changed with temperature and pressure, but in a way that maintained their balance. Using a newly developed accurate theoretical approach, collaborators on this work showed how this balance was helped by interactions between vibrations and magnetism, such as where the frequencies of atom vibrations are altered by magnetism. Such coupling between vibrations and magnetism could be useful for understanding thermal expansion in other magnetic materials, as well for developing materials for magnetic refrigeration.</p><p data-block-key="cqdgu">The experimental setup consisted of a diamond anvil cell, which is essentially two precisely ground diamond tips between which samples of materials can be tightly squeezed. In this case, a small piece of Invar alloy was squeezed at a pressure of 200,000 atmospheres. The researchers passed a powerful beam of X-rays through the alloy, and during that process the X-rays interacted with the vibrations (phonons) of its atoms. That interaction changed the amount of energy carried by the X-rays, allowing the researchers to measure how much the atoms were vibrating.</p><p data-block-key="bmkd">They also placed sensors around the diamond anvil cell that can detect interference patterns created by the spin state of the electrons belonging to the sample's atoms.</p><p data-block-key="56bno">The team used their experimental setup to observe both the atomic vibrations of an Invar sample and the spin state of its electrons as they increased the sample's temperature. At cooler temperatures, more of the Invar's electrons shared the same spin state, causing them to move farther apart and push their parent atoms farther apart as well.</p><p data-block-key="57uaj">As the temperature of the Invar rose, the spin state of some of those electrons increasingly flipped. As a result, the electrons became more comfortable cozying up to their neighboring electrons. Typically, this would cause the Invar to contract as it warmed up. But here, the Invar's atoms were also vibrating more and taking up more room. The contraction due to changing spin states and the atomic vibration expansion counteracted each other, and the Invar stayed the same size.</p><p data-block-key="890us">"This is exciting because this has been a problem in science for over a hundred years or so," Lohaus says. "There are literally thousands of publications trying to show how magnetism causes contraction, but there was no holistic explanation of the Invar effect."</p><p data-block-key="blb2p">The paper describing the research, "<a href="https://www.nature.com/articles/s41567-023-02142-z.epdf?sharing_token=Kpp4hAGNnsZZoWfGGlC58dRgN0jAjWel9jnR3ZoTv0MqX9VjZ126twpdHMGPJ2csd8ecvTUNtpPOWfav11pUg8KfLRin8MEsCEPqrW1H3eUuJLV9emiFiAonE5bGA4x2booS9eOVot9ifuWO3VJgjFHYHgKvGP1fovePZwoYCuk%3D">Thermodynamic explanation of the Invar effect</a>," appears in the July 27 issue of <i>Nature Physics.</i> Co-authors are graduate students in materials science Pedro Guzman and Camille M. Bernal-Choban, visitor in applied physics and materials science Claire N. Saunders, Guoyin Shen of the Argonne National Laboratory, Olle Hellman of the Weizmann Institute of Science, David Broido and Matthew Heine of Boston College, and Fultz.</p><p data-block-key="4i53a">Funding for the research was provided by the National Science Foundation and the U.S. Department of Energy.</p>Breaking Ground on the Quantum World2023-06-28T00:33:00+00:002023-07-12T07:00:40.869860+00:00https://www.caltech.edu/about/news/breaking-ground-cqpm<p data-block-key="dg486">This summer, Caltech will break ground on the Dr. Allen and Charlotte Ginsburg Center for Quantum Precision Measurement, the first center to unite researchers in precision measurement, quantum information, and the detection of gravitational waves, or ripples in space-time.</p><p data-block-key="4ut75">These areas each involve incredibly precise measurement aimed at advancing fundamental physics research.</p><p data-block-key="fhe0k">Construction is slated to begin this winter, after the site along California Boulevard is prepared and the design is finalized. The building will open in the fall of 2025.</p><p data-block-key="6sct9">"The Ginsburg Center for Quantum Precision Measurement will bring together researchers from across the Caltech campus—astronomers, biologists, chemists, computer scientists, engineers, physicists—united by their passion to understand the inner workings of Nature," says Caltech president Thomas F. Rosenbaum. "In state-of-the art laboratories and open, interactive spaces, they will develop powerful new quantum devices and educate the next generation of leaders in quantum science and technology."</p><p data-block-key="eemrc">"This building will facilitate discoveries that change our understanding of physics and the cosmos," says Fiona Harrison, Caltech's Harold A. Rosen Professor of Physics and the Kent and Joyce Kresa Leadership Chair of the Division of Physics, Mathematics and Astronomy.</p><p data-block-key="pbdu">"The building will bring together talented people with diverse backgrounds: students and faculty, theorists and experimentalists, people with different life experiences and expertise," she adds. "With that same approach, Caltech researchers have co-developed instruments that detect wavelengths of light our eyes cannot see, gravitational waves, and the quantum interactions of subatomic particles. We anticipate similar advances from the new center."</p><p data-block-key="n220"><b>What is quantum precision measurement?</b></p><p data-block-key="dcq9e">From living cells to black holes, nature is built on <a href="https://scienceexchange.caltech.edu/topics/quantum-science-explained/quantum-physics">quantum physics</a>. At first, scientists observed quantum physics at atomic and subatomic scales; now they are beginning to study and harness quantum phenomena in assemblies of tens of thousands of atoms. Researchers in the Ginsburg Center will explore quantum phenomena across all scales and invent measurement instruments with unprecedented sensitivity. The resulting discoveries are expected to yield insights into natural processes and lead to new technologies.</p><p data-block-key="911o"><b>Building basics</b></p><p data-block-key="33r75">This hub for quantum research will neighbor physics, mathematics, astronomy, and engineering buildings. It will stand on the north side of California Boulevard between the <a href="/map/campus/ronald-and-maxine-linde-hall-of-mathematics-and-physics">Ronald and Maxine Linde Hall of Mathematics and Physics</a> and the <a href="/map/campus/george-w-downs-laboratory-of-physics-and-charles-c-lauritsen-laboratory-of-high-energy-physics">George W. Downs Laboratory of Physics and Charles C. Lauritsen Laboratory of High Energy Physics</a>, on the site of a physics building that was demolished in 2016.</p><p data-block-key="6oo38">The building's four stories of research offices, meeting rooms, and collaboration zones, and a basement level of laboratories will bring together at least a dozen faculty members, 50 postdoctoral scholars, 40 graduate students, and several senior and junior scientists and engineers.</p><p data-block-key="96ku9">The building was made possible by a lead <a href="/about/news/ginsburgs-give-to-create-new-quantum-center-and-building-at-caltech">gift from Dr. Allen and Charlotte Ginsburg</a> of Rancho Palos Verdes, California, by an anonymous gift, and by a <a href="/about/news/new-quantum-measurement-center-launched-by-sherman-fairchild-foundation-grant">grant from the Sherman Fairchild Foundation</a>.</p><p data-block-key="4onug"><b>Architectural innovation</b></p><p data-block-key="55n3b">Caltech selected HOK, which designed the National Air and Space Museum in Washington, D.C., and other notable buildings worldwide, as the new facility's architect. The choice supports Caltech's emphasis on <a href="https://sustainability.caltech.edu/campus/buildings">sustainable design</a>, an HOK specialty. The Ginsburg Center project goal is <a href="https://www.usgbc.org/leed">Leadership in Energy and Environmental Design</a> (LEED) Gold certification.</p><p data-block-key="4k5qp">HOK's preliminary concept features a transparent facade inflected inward on its south and west sides to suggest a prism or the bending of spacetime, an allusion to research that will take place in the building.</p><p data-block-key="f14sr">In the HOK concept, behind that evocative facade, the building's street-facing south side will feature collaboration areas, while offices will line the quiet interior sides. Parts of the ground floor will be recessed to give space to lush plantings and outdoor mingling areas. Glass panel doors and a breezeway, perhaps connecting to an adjacent seminar room, will enable indoor-outdoor flow.</p><p data-block-key="8t0n4"><b>Basement laboratories to explore space, time, and gravity</b></p><p data-block-key="drkim">While much of the new building is conceptualized as a nearly rectangular column proportionate to other campus buildings and made of similar materials, the basement will be expansive, stretching west under the historic campus entrance on the north side of California Boulevard.</p><p data-block-key="3t346">With amenities such as a shared space for laser experiments, this scientific playground will include the Kip Thorne Laboratories, which the Sherman Fairchild Foundation named in honor of Nobel laureate Kip Thorne (BS '62), Caltech's Richard P. Feynman Professor of Theoretical Physics, Emeritus. Thorne co-founded <a href="https://www.ligo.caltech.edu/">LIGO</a> and developed ideas central to the use of quantum precision measurement to study space, time, and gravity.</p><p data-block-key="8nskf">Researchers in the Thorne Laboratories will develop advanced instruments to probe the nature of space and time, will research how to make the most precise measurements of time, and will conduct basic experiments to understand the behavior of controlled quantum systems. The Thorne Laboratories will provide state-of-the-art space for several future hires.</p><p data-block-key="2klda">"The best physics happens in basements. Things are quiet, which we like," says physics professor Rana Adhikari. "Even better, the new building has the promise of putting people together in one place. We realized over the past few years that science progresses best when we're together in person. We rely on chitchat. A lot of our good ideas come from this kind of casual, informal interaction."</p><p data-block-key="4v8ea">Adhikari says the building will help researchers gain insight into space and time. "We think it's possible that there's a microscopic description of spacetime that comes from quantum entanglement or some kind of mysterious thing that we don't understand yet," he says. "Why is the speed of light what it is? What happens at the edge of the black hole? Why does empty space behave the way it does? The fact that you can curve space and that it has energy when you curve it means it's not really empty. All these things are wrapped up in the microphysics of space and time."</p><p data-block-key="b7clh">"To push forward that idea," he adds, "you need to have people who are working on the theory and thinking about experiments. But we have been on opposite sides of the campus. I can't predict what will come out of it, and that's a good thing. Putting people together, who are passionate about fundamental physics; I'm sure that, whatever happens, it will be wondrous."</p><p data-block-key="54b8j"><b>Next steps</b></p><p data-block-key="2970e">Pasadena's Charles Pankow Builders will serve as general contractor for the project's pre-construction phase. Trusted with the construction of such treasured properties as Grand Park in Los Angeles, Pankow stood out from the field for another project: the San Francisco Conservatory of Music Bowes Center, an acoustically impeccable space. Pankow's experience with that project will help ensure the Ginsburg Center's facilities will have the silence and stability needed in the world's most advanced quantum measurement laboratories.</p><p data-block-key="9cspe">This year, Caltech will prepare the building site, hold a groundbreaking celebration, conduct informational and listening sessions with the campus community and Pasadena neighbors, and finalize the building design.</p><p data-block-key="cf292">Caltech sought the City of Pasadena <a href="https://www.cityofpasadena.net/commissions/design-commission/">Design Commission</a>'s comments on the center's proposed design at a preliminary consultation meeting on Tuesday, July 11.</p><p data-block-key="evu4n">As site preparation and construction progress, further updates will be shared <a href="http://local.caltech.edu/construction">here</a>.</p>New Device Opens Door to Storing Quantum Information as Sound Waves2023-06-22T16:50:00+00:002023-12-12T04:41:52.220390+00:00Emily Velascoevelasco@caltech.eduhttps://www.caltech.edu/about/news/new-device-opens-door-to-storing-quantum-information-as-sound-waves<p data-block-key="5s1f0">Quantum computing, just like traditional computing, needs a way to store the information it uses and processes. On the computer you're using right now, information, whether it be photos of your dog, a reminder about a friend's birthday, or the words you're typing into your browser's address bar, has to be stored <i>somewhere.</i> Quantum computing, being a new field, is still working out where and how to store quantum information.</p><p data-block-key="aipbe">In a paper published in the journal <i>Nature Physics</i>, <a href="https://www.ee.caltech.edu/people/mohmir">Mohammad Mirhosseini</a>, assistant professor of electrical engineering and applied physics, shows a new method his lab developed for efficiently translating electrical quantum states into sound and vice versa. This type of translation may allow for storing quantum information prepared by future quantum computers, which are likely to be made from electrical circuits.</p><p data-block-key="55ks5"></p><embed alt="A portrait of Mohammad Mirhosseini. He wears a collared shirt and stands outside." embedtype="image" format="RightAlignSmall" id="9841"/><p data-block-key="67jrn"></p><p data-block-key="c6av1">This method makes use of what are known as phonons, the sound equivalent of a light particle called a photon. (Remember that in quantum mechanics, all waves are particles and vice versa). The experiment investigates phonons for storing quantum information because it's relatively easy to build small devices that can store these mechanical waves.</p><p data-block-key="5lqmn">To understand how a sound wave can store information, imagine an extremely echoey room. Now, let's say you need to remember your grocery list for the afternoon, so you open the door to that room and shout, "Eggs, bacon, and milk!" and shut the door. An hour later, when it's time to go to the grocery store, you open the door, poke your head inside, and hear your own voice still echoing, "Eggs, bacon, and milk!" You just used sound waves to store information.</p><p data-block-key="acj0b">Of course, in the real world, an echo like that wouldn't last very long, and your voice might end up so distorted you can no longer make out your own words, not to mention that using an entire room for storing a little bit of data would be ridiculous. The research team's solution is a tiny device consisting of flexible plates that are vibrated by sound waves at extremely high frequencies. When an electric charge is placed on those plates, they become able to interact with electrical signals carrying quantum information. This allows that information to be piped into the device for storage, and be piped out for later use—not unlike the door to the room you were shouting into earlier in this story.</p><p data-block-key="dnb7k">According to Mohammad Mirhosseini, previous studies had investigated a special type of materials known as piezoelectrics as a means of converting mechanical energy to electrical energy in quantum applications.</p><p data-block-key="e94aa">"These materials, however, tend to cause energy loss for electrical and sound waves, and loss is a big killer in the quantum world," Mirhosseini says. In contrast, the new method developed by Mirhosseini and his team is independent on the properties of specific materials, making it compatible with established quantum devices, which are based on microwaves.</p><p data-block-key="fu2ja">Creating effective storage devices with small footprints has been another practical challenge for researchers working on quantum applications, says Alkim Bozkurt, a graduate student in Mirhosseini's group and the lead author of the paper.</p><p data-block-key="cq1ch">"However, our method enables the storage of quantum information from electrical circuits for durations two orders of magnitude longer than other compact mechanical devices," he adds.</p><p data-block-key="f6dbc">The paper describing the work, titled, "<a href="https://www.nature.com/articles/s41567-023-02080-w">A quantum electromechanical interface for long-lived phonons</a>," appears in the June 22 issue of <i>Nature Physics.</i> Co-authors include Chaitali Joshi and Han Zhao, both postdoctoral scholars in electrical engineering and applied physics; and Peter Day and Henry LeDuc, who are scientists at the Jet Propulsion Laboratory, which Caltech manages for NASA. The research was funded in part by the <a href="http://kni.caltech.edu/programs/kni_wheatley_scholars">KNI-Wheatley Scholars</a> program.</p>Unlocking Photonic Computing Power with Artificial 'Life'2023-06-06T21:27:00+00:002023-06-07T22:08:08.933828+00:00Emily Velascoevelasco@caltech.eduhttps://www.caltech.edu/about/news/unlocking-photonic-computing-power-with-artificial-life<p data-block-key="xl2tb">The never-ending quest for faster, smaller computers that can do more has led manufacturers to design ever tinier transistors that are now packed into computer chips by the tens of billions.</p><p data-block-key="agh9j">And so far, this tactic has worked. Computers have never been more powerful than they are now. But there are limits: Traditional silicon transistors can only get so small because of difficulties in manufacturing devices that are, in some cases, only a few dozen atoms wide. In response, researchers have begun developing computing technologies, like quantum computers, that do not rely on silicon transistors.</p><p data-block-key="a9vm7">Another avenue of research is photonic computing, which uses light in place of electricity, similar to how fiber optic cables have replaced copper wires in computer networks. New research by Caltech's Alireza Marandi, assistant professor of electrical engineering and applied physics, uses optical hardware to realize cellular automata, a type of computer model consisting of a "world" (a gridded area) containing "cells" (each square of the grid) that can live, die, reproduce, and evolve into multicellular creatures with their own unique behaviors. These automata have been used to perform computing tasks and, according to Marandi, they are ideally suited to photonic technologies.</p><p data-block-key="88k8h">"If you compare an optical fiber with a copper cable, you can transfer information much faster with an optical fiber," Marandi says. "The big question is can we utilize that information capacity of light for computing as opposed to just communication? To address this question, we are particularly interested in thinking about unconventional computing hardware architectures that are a better fit for photonics than digital electronics."</p><h3 data-block-key="cc0eq">Cellular automata</h3><p data-block-key="43ssd">To fully grasp the hardware Marandi's group designed, it is important to understand what cellular automata are and how they work. Technically speaking, they are computational models, but that term does little to help most people understand them. It is more helpful to think of them as simulated cells that follow a very basic set of rules (each type of automata has its own set of rules). From these simple rules can emerge incredibly complex behaviors. One of the best-known cellular automata, called <i>The Game of Life</i> or<i> Conway's Game of Life,</i> was developed by English mathematician John Conway in 1970. It has just four rules that are applied to a grid of "cells" that can either be alive or dead. Those rules are:</p><ol><li data-block-key="8hre2">Any live cell with fewer than two live neighbors dies, as if by underpopulation.</li><li data-block-key="610op">Any live cell with more than three live neighbors dies, as if by overcrowding.</li><li data-block-key="h89n">Any live cell with two or three live neighbors lives to the next generation.</li><li data-block-key="7q6t">Any dead cell with exactly three live neighbors will come to life, as if by reproduction.</li></ol><p data-block-key="2678t">A computer running the Game of Life repeatedly applies these rules to the world in which the cells live at a regular interval, with each interval being considered a generation. Within a few generations, those simple rules lead to the cells organizing themselves into complex forms with evocative names like loaf, beehive, toad, and heavyweight spaceship.</p><p data-block-key="ek4pp"></p><embed alt="A small grid shows a D-shaped structure on an angle, made of pixels." embedtype="image" format="LeftAlignSmall" id="9771"/><p data-block-key="jn1f"></p><embed alt="A small grid shows a oval-shaped structure, made of pixels." embedtype="image" format="RightAlignSmall" id="9772"/><p data-block-key="77go"></p><p data-block-key="6anpi"></p><embed alt="A small grid shows a small structure that oscillates between two forms." embedtype="image" format="LeftAlignSmall" id="9773"/><p data-block-key="3k15o"></p><p data-block-key="2q55t"></p><embed alt="A pixelated structure slowly travels along a grid as it oscillates between forms." embedtype="image" format="RightAlignSmall" id="9774"/><p data-block-key="bfuhq"></p><p data-block-key="de9o5"></p><p data-block-key="2rl0p">Basic, or "elementary," cellular automata like The Game of Life appeal to researchers working in mathematics and computer science theory, but they can have practical applications too. Some of the elementary cellular automata can be used for random number generation, physics simulations, and cryptography. Others are computationally as powerful as conventional computing architectures—at least in principle. In a sense, these task-oriented cellular automata are akin to an ant colony in which the simple actions of individual ants combine to perform larger collective actions, such as <a href="https://www.admissions.caltech.edu/explore-more/news/the-science-of-underground-kingdoms">digging tunnels</a>, or collecting food and taking it back to the nest. More "advanced" cellular automata, which have more complicated rules (although still based on neighboring cells), can be used for practical computing tasks such as identifying objects in an image.</p><p data-block-key="dgvvh">Marandi explains: "While we are fascinated by the type of complex behaviors that we can simulate with a relatively simple photonic hardware, we are really excited about the potential of more advanced photonic cellular automata for practical computing applications."</p><h3 data-block-key="iqvl">Ideal for Photonic Computing</h3><p data-block-key="b69at">Marandi says cellular automata are well suited to photonic computing for a couple of reasons. Since information processing is happening at an extremely local level (remember in cellular automata, cells interact only with their immediate neighbors), they eliminate the need for much of the hardware that makes photonic computing difficult: the various gates, switches, and devices that are otherwise required for moving and storing light-based information. And the high-bandwidth nature of photonic computing means cellular automata can run incredibly fast. In traditional computing, cellular automata might be designed in a computer language, which is built upon another layer of "machine" language below that, which itself sits atop the binary zeroes and ones that make up digital information.</p><p data-block-key="7khfo">In contrast, in Marandi's photonic computing device, the cellular automaton's cells are just ultrashort pulses of light, which can allow operation up to three orders of magnitude quicker than the fastest digital computers. As those pulses of light interact with each other in a hardware grid, they can process information on the go without being slowed down by all the layers that underlie traditional computing. In essence, traditional computers run digital simulations of cellular automata, but Marandi's device runs actual cellular automata.</p><p data-block-key="jdif">"The ultrafast nature of photonic operations, and the possibility of on-chip realization of photonic cellular automata could lead to next-generation computers that can perform important tasks much more efficiently than digital electronic computers," Marandi says.</p><p data-block-key="eljf7">The paper describing the work, titled, "<a href="https://www.nature.com/articles/s41377-023-01180-9">Photonic Elementary Cellular Automata for Simulation of Complex Phenomena</a>," appears in the May 30 issue of the journal <i>Light: Science & Applications.</i> The lead author is Gordon H.Y. Li (MS '22), graduate student in applied physics; with co-authors Christian R. Leefmans, graduate student in applied physics; and James Williams, graduate student in electrical engineering.</p><p data-block-key="3qtfd">Funding for the research was provided by U.S. Army's Army Research Office, the Air Force Office of Scientific Research, and the National Science Foundation.</p>Two Faculty Awarded 2023 Guggenheim Fellowships2023-04-17T22:10:00+00:002023-04-18T13:20:12.780115+00:00Caltech Media Relationsmr@caltech.eduhttps://www.caltech.edu/about/news/guggenheim-fellows-anandkumar-ooguri<p data-block-key="bbnsr"><a href="http://tensorlab.cms.caltech.edu/users/anima/index.html">Anima Anandkumar</a>, Caltech's Bren Professor of Computing and Mathematical Sciences, and <a href="https://ooguri.caltech.edu/">Hirosi Ooguri</a>, Caltech's Fred Kavli Professor of Theoretical Physics and Mathematics and director of the <a href="https://burkeinstitute.caltech.edu/">Walter Burke Institute for Theoretical Physics</a>, have been named 2023 Guggenheim Fellows.</p><p data-block-key="2gol">They were among 171 scientists, writers, scholars, and artists honored by the John Simon Guggenheim Memorial Foundation, which, since 1925, has sought to "further the development of scholars and artists by assisting them to engage in research in any field of knowledge and creation in any of the arts, under the freest possible conditions," according to <a href="https://www.gf.org/news/foundation-news/announcing-the-2023-guggenheim-fellows/">the foundation's press release</a>. The fellowships were awarded based on peer reviews of nearly 2,500 applications.</p><p data-block-key="884j0">Anandkumar is a computer scientist and leader in artificial intelligence (AI) research. She develops novel and efficient AI methods that enable and accelerate progress in interdisciplinary scientific domains, including weather forecasting, <a href="/about/news/rapid-adaptation-of-deep-learning-teaches-drones-to-survive-any-weather">autonomous drone flight</a>, scientific simulations, <a href="/about/news/researchers-tackle-covid-19-with-ai">disease modeling</a>, <a href="/about/news/machine-learning-speeds-quantum-chemistry-calculations">chemistry</a>, and the <a href="https://scienceexchange.caltech.edu/topics/artificial-intelligence-research/artificial-intelligence-experts/ai-science-alvarez-anandkumar?utm_source=caltechnews&utm_medium=web&utm_campaign=cseai">social sciences</a>.</p><p data-block-key="c3qp2">"I saw the potential for AI to transform vast scientific domains, and Caltech is the perfect place to pursue this," Anandkumar says. "Its emphasis on interdisciplinary collaborations provides a fertile ground to pursue a broad range of problems while also helping to develop unifying theoretical frameworks for machine learning algorithms."</p><p data-block-key="7o54f">In addition to her appointment in the <a href="https://www.cms.caltech.edu/">Department of Computing and Mathematical Sciences</a>, she is an affiliated faculty member with the <a href="https://cast.caltech.edu/">Center for Autonomous Systems and Technologies</a>.</p><p data-block-key="blet6">Anandkumar is a fellow of IEEE and the <a href="https://www.eas.caltech.edu/news/anima-anandkumar-named-an-acm-fellow">Association for Computing Machinery (ACM)</a>, and she has received several awards including the Alfred P. Sloan Fellowship and the NSF Career Award. Previously, she taught at UC Irvine and was principal scientist at Amazon Web Services. Anandkumar holds degrees from the Indian Institute of Technology Madras and Cornell University, and conducted postdoctoral research at MIT.</p><p data-block-key="1k8ij">Ooguri is well known for his contributions to string theory. He received the Guggenheim grant to apply his research to one of the biggest mysteries in physics today: <a href="https://magazine.caltech.edu/post/quantum-gravity?utm_medium=web&utm_campaign=magazine-fall21&utm_source=caltechnews&utm_content=&utm_term=">quantum gravity</a>. Quantum gravity refers to a set of theories attempting to unify the microscopic world of quantum physics with the macroscopic world of gravity and space itself. "It is not well appreciated how hard it is to build a consistent theoretical framework to unify general relativity and quantum mechanics," Ooguri says.</p><p data-block-key="cvjk1">While on sabbatical from Caltech in the 2023–24 academic year, he plans to use the fellowship to make connections with other researchers, start new collaborations, and ultimately seek answers to these fundamental questions about the universe.</p><p data-block-key="bp9cv">Ooguri, who grew up in rural Japan, has <a href="/about/news/superstring-theorist-honored-science-writing-prize-43479">authored</a> eight popular science books, and <a href="/about/news/science-communication-conversation-hirosi-ooguri-51749">produced a science movie</a>. "I became a scientist because of the books I read in the bookstore in my childhood neighborhood, and I feel it is my responsibility to inspire the public and the next generation of scientists by communicating the excitement of science," he says.</p><p data-block-key="95fjn">Ooguri received his bachelor's degree from Kyoto University in 1984 and his PhD from the University of Tokyo in 1989. Before becoming a Caltech professor in 2000, he was a professor at the University of Tokyo, the University of Chicago, Kyoto University, and UC Berkeley. He is a <a href="/about/news/american-academy-arts-and-sciences-elects-two-caltech-50547">fellow of the American Academy of Arts and Sciences</a> and the <a href="/about/news/caltech-faculty-named-ams-fellows-37310">American Mathematical Society</a>, and he is the recipient of the <a href="/about/news/physicist-hirosi-ooguri-awarded-novel-research-black-holes-1371">Leonard Eisenbud Prize for Mathematics and Physics</a> from the American Mathematical Society, the Humboldt Research Award, the <a href="/about/news/ooguri-receives-chunichi-award-50716">Chunichi Cultural Award</a>, the Nishina Memorial Prize, a <a href="/about/news/caltech-physicists-are-awarded-new-funding-simons-foundation-23620">Simons Investigator Award</a>, and the <a href="/about/news/string-theorist-wins-hamburg-prize-82362">Hamburg Prize</a> for Theoretical Physics. In 2019, he was honored by the emperor of Japan with a <a href="/about/news/emperor-japan-bestow-medal-honor-hirosi-ooguri">Medal of Honor</a>.</p><p data-block-key="5ba9v"><i>More information about the Guggenheim Fellowship is available</i> <a href="https://www.gf.org/"><i>on the foundation's website</i></a><i>.</i></p>Caltech Outreach Captivates Crowds at City of STEM and Los Angeles Maker Faire2023-04-14T19:00:00+00:002023-04-18T16:16:34.278587+00:00https://www.caltech.edu/about/news/city-of-stem-outreach<p data-block-key="bbnsr">As a throng of children and adults crowded close for a better view, Caltech graduate student <a href="https://magazine.caltech.edu/post/socaltech-arian-jadbabaie">Arian Jadbabaie</a> doused a ceramic puck in liquid nitrogen and released it above a flexible strip of magnets—where it began to levitate.</p><p data-block-key="862hm">Then, with a showman's flair, he lifted the magnet strip and flipped it upside down, while the puck, now a freezing cold superconductor with white vapor cascading from its surface, continued floating a centimeter <i>below</i> the magnets, pinned in place by the magnetic field.</p><p data-block-key="dojvh"></p><embed alt="Arian Jadbabaie presents a superconductor demonstration to a large audience" embedtype="image" format="LeftAlignLarge" id="9604"/><p data-block-key="a77bm"></p><p data-block-key="ab9f8"></p><p data-block-key="5bca3">This <a href="https://www.youtube.com/watch?v=T46hxSHiOoE">scientific wizardry</a> was part of the City of STEM and Los Angeles Maker Faire, held on Saturday, April 1, at Los Angeles State Historic Park. The fair, which combined two previously separate events for the first time, drew an estimated 22,000 attendees to engage with science, technology, engineering, art, and math (STEAM) demonstrations, exhibits, and activities. Caltech's Center for Teaching, Learning, and Outreach (CTLO) coordinated a booth at the event where Jadbabaie and several other Caltech students gave science demonstrations to the public.</p><p data-block-key="5bpjb">Alex Johnson, a bioengineering graduate student in Victoria Orphan's research group, shared videos and equipment from the group's research on microorganisms living in unique environments like methane seeps on the ocean floor.</p><p data-block-key="d3na3">"It's been so valuable to do this outreach because it forces me to think about how my work resonates with the public and how to explain it to people," says Johnson. "When we're researching, we get focused in on these problems so intensely, but people are really interested in the broader implications and how the research impacts them."</p><p data-block-key="6sddv">What's his strategy for good science communication? "I start by talking with people and figuring out what they're interested in, and then I try to connect my research back to that."</p><p data-block-key="cao2c">"These kinds of outreach opportunities are really important for students' professional development," says Kitty Cahalan, CTLO's assistant director for educational outreach. "Not to mention it makes you feel good! Students who do outreach are getting out in the community, recognizing the value they can provide others, and reevaluating their own knowledge. It reminds you why you're doing science in the first place."</p><p data-block-key="76ulr">Caltech's booth, one among hundreds at the event, maintained a steady flow of guests throughout the day, thanks in no small part to Jadbabaie's sensational demonstration.</p><p data-block-key="8o7is">"The levitating superconductor demo is focused on providing a clear visual manifestation of quantum physics," says Jadbabaie, a physics student in Nick Hutzler's lab. "I use a material called YBCO, which is an insulating ceramic when warm and does not conduct electricity nor interact with magnetic fields. However, as I cool it down with liquid nitrogen, it transforms into a superconductor, which is a quantum phase of matter unique from solid, liquid, and gas."</p><p data-block-key="28b9b">Families engaged with Jadbabaie's demonstration, and he responded to their questions with ease. His passion and enthusiasm were on display as he repeated the demo—pouring the nitrogen, levitating the puck, and explaining the science—to large groups of spectators for several hours without breaks.</p><p data-block-key="5nvjh">"I've been involved in science outreach since my undergrad at Washington University in St. Louis," says Jadbabaie. "When I came to Caltech in 2016, I knew I wanted to get involved here, so I reached out to the CTLO, and they helped me get started. I applied for funding through Caltech's Moore-Hufstedler Fund to purchase the equipment for this demo.</p><p data-block-key="9a4r1">"I do this because I want to genuinely share my passion and awe for the universe with everyone. I want to create a moment with the audience where we both are experiencing the wonder of the universe; we can understand and connect to parts of nature, but we are also in awe of how nature is always more incredible than what we can imagine and conceptualize. Seeing that feeling in the faces of the audience, old and young, is really meaningful to me."</p><p data-block-key="7hk0l">"The work we do at CTLO is about making Caltech porous," says Cahalan. "We want people in the community to feel like they belong on campus. And we want our people at Caltech to feel like they're part of the broader Los Angeles and Pasadena communities. It's all connected."</p><p data-block-key="5tu4o"></p><p data-block-key="9ioc1"></p><p data-block-key="6lsvn">The CTLO provides educational outreach opportunities throughout the year. To get involved, contact Kitty Cahalan or <a href="https://ctlo.caltech.edu/">visit the CTLO website</a> to learn more.</p>Randomness in Quantum Machines Helps Verify Their Accuracy2023-01-24T17:25:00+00:002023-01-24T22:51:53.598260+00:00Whitney Clavinwclavin@caltech.eduhttps://www.caltech.edu/about/news/randomness-in-quantum-machines-helps-verify-their-accuracy<p data-block-key="kydhj">In quantum computers and other experimental quantum systems, information spreads around the devices and quickly becomes scrambled like dice in a game of Boggle. This scrambling process happens as the basic units of the system, called qubits (like computer bits only quantum) become entangled with one another; <a href="https://scienceexchange.caltech.edu/topics/quantum-science-explained/entanglement">entanglement</a> is a phenomenon in quantum physics where particles link up with each other and remain connected even though they are not in direct contact.</p><p data-block-key="e9l61">These quantum devices mimic what happens in nature and allow scientists to develop new, exotic materials that are potentially useful in medicine, computer electronics, and other fields. While full-scale quantum computers are still years away, researchers are already performing experiments on so-called quantum simulators—quantum devices tailored to solve specific problems, such as efficiently simulating high-temperature superconductors and other quantum materials. The machines could also solve complex optimization problems, such as planning routes for autonomous vehicles to ensure they don't collide.</p><p data-block-key="efp30">One challenge in using these quantum machines is that they are very prone to errors, much more so than classical computers. It is also much harder to identify errors in these newer systems. "For the most part, quantum computers make a lot of mistakes," says Adam Shaw, a Caltech graduate student in physics and one of two lead authors of a study in the journal <i>Nature</i> about a new method to verify the accuracy of quantum devices. "You cannot open the machine and look inside, and there is a huge amount of information being stored—too much for a classical computer to account for and verify."</p><p data-block-key="qsbh">In the <i>Nature</i> study, Shaw and co-lead author Joonhee Choi, a former postdoctoral scholar at Caltech who is now a professor at Stanford University, demonstrate a novel way to measure a quantum device's accuracy, also known as fidelity. Both researchers work in the laboratory of <a href="https://pma.caltech.edu/people/manuel-a-endres">Manuel Endres</a>, a professor of physics at Caltech and a Rosenberg scholar. The key to their new strategy is randomness. The scientists have discovered and characterized a newfound type of randomness pertaining to the way information is scrambled in the quantum systems. But even though the quantum behavior is random, universal statistical patterns can be identified in the noise.</p><p data-block-key="70vn2">"We are interested in better understanding what happens when the information is scrambled," Choi says. "And by analyzing this behavior with statistics, we can look for deviations in the patterns that indicate errors have been made."</p><p data-block-key="4mvc3">"We don't want just a result from our quantum machines; we want a verified result," Endres says. "Because of quantum chaos, a single microscopic error leads to a completely different macroscopic outcome, quite similar to the butterfly effect. This enables us to detect the error efficiently."</p><p data-block-key="2jvad">The researchers demonstrated their protocol on a quantum simulator with as many as 25 qubits. To find whether errors have occurred, they measured the behavior of the system down to the single qubit level thousands of times. By looking at how qubits evolved over time, the researchers could identify patterns in the seemingly random behavior and then look for deviations from what they expected. Ultimately, by finding errors, researchers will know how and when to fix them.</p><p data-block-key="6d5vi">"We can trace how information moves across a system with single qubit resolution," Choi says. "The reason we can do this is that we also discovered that this randomness, which just happens naturally, is represented at the level of just one qubit. You can see the universal random pattern in the subparts of the system."</p><p data-block-key="c5b4t">Shaw compares their work to measuring the choppiness of waves on a lake. "If a wind comes, you'll get peaks and troughs on the lake, and while it may look random, one could identify a pattern to the randomness and track how the wind affects the water. We would be able to tell if the wind changes by analyzing how the pattern changes. Our new method similarly allows us to look for changes in the quantum system that would indicate errors."</p><p data-block-key="1jmil">The <i>Nature</i> study titled "<a href="https://arxiv.org/abs/2103.03535">Probing</a> random states and benchmarking with many-body quantum chaos," is funded by the National Science Foundation via the Institute for Quantum Information and Matter, or IQIM; the Defense Advanced Research Projects Agency (DARPA); the Army Research Office, the Eddleman Quantum Institute graduate fellowship; the Troesh postdoctoral fellowship; the Gordon and Betty Moore Foundation; the J. Yang & Family Foundation; the Harvard Quantum Initiative (HQI) graduate fellowship; the Junior Fellowship from the Harvard Society of Fellows; the Department of Energy; and the Miller Institute for Basic Research in Science at UC Berkeley. Other authors include Ran Finkelstein, Hsin-Yuan Huang, and <a href="https://pma.caltech.edu/people/fernando-brandao">Fernando Brandão</a> of Caltech; Ivaylo Madjarov, Xin Xie, and Jacob Covey, who performed the research while previously at Caltech; Jordan Cotler and Anant Kale of Harvard University; Daniel Mark and Soonwon Choi of MIT; and Hannes Pichler of University of Innsbruck in Austria.</p>2022 Year in Review2022-12-19T19:49:00+00:002022-12-23T16:16:02.688609+00:00Caltech Media Relationsmr@caltech.eduhttps://www.caltech.edu/about/news/2022-year-in-review<p data-block-key="makzi">As the end of 2022 quickly approaches, Caltech News looks back at our coverage of the research, discoveries, events, and experiences that shaped the Institute. Here are some highlights.</p><h2 data-block-key="7pr79">Revealing the Secrets of the Red Planet</h2><p data-block-key="bb3av">Caltech researchers used data gathered both in space by the Mars Reconnaissance Orbiter (MRO) and on the ground by the Mars Perseverance Rover to continue to probe the Red Planet's past and any potential signs it was previously hospitable to life. In January, MRO survey data revealed that liquid water was on Mars about one billion years earlier than suspected. Meanwhile, Perseverance made a beeline across the floor of Jezero Crater during spring 2022, <a href="/about/news/as-mars-perseverance-rover-rolls-along-the-delta-scientists-at-caltech-roll-up-their-sleeves">arriving at an ancient river delta</a> in April. The delta is thought to be one of the best possible places to search for past signs of life; there, Perseveranc<i>e</i> found <a href="/about/news/rock-samples-from-the-floor-of-jezero-crater-show-significant-contact-with-water-together-with-possible-organic-compounds">signs of past water along with evidence of possible organic compounds</a> in the igneous rocks on the crater floor. After a few months at the delta, Perseverance project scientist <a href="https://www.gps.caltech.edu/people/kenneth-a-farley">Ken Farley</a> announced in September the discovery of a class of <a href="https://www.nasa.gov/press-release/nasa-s-perseverance-rover-investigates-geologically-rich-mars-terrain">organic molecules in two samples of mudstone rock</a> collected from a feature called Wildcat Ridge. While these organic molecules can be produced through nonliving chemical processes, some of the molecules themselves are among the building blocks of life.</p><h2 data-block-key="a57fq">Surveying the Cosmos and Our Interaction with It</h2><p data-block-key="9afbb">Not all eyes aimed toward space are set on Mars, however. New instruments and surveys provided insights related to other celestial bodies in our Milky Way galaxy, such as asteroids, and helped discover an abundance of planets outside of our solar system.</p><p data-block-key="b66m5">In March, the <a href="https://exoplanetarchive.ipac.caltech.edu/">NASA Exoplanet Archive</a>, an official catalog for exoplanets—planets that circle other stars beyond our sun—housed at Caltech's IPAC astronomy center, officially <a href="/about/news/exoplanet-count-tops-5000">hit a new milestone</a>: 5,000 exoplanets.</p><p data-block-key="a6013">Looking even farther out into the universe from planet Earth, Caltech researchers made several discoveries, including a tight-knit pair of supermassive black holes locked in an <a href="/about/news/colossal-black-holes-locked-in-dance-at-heart-of-galaxy">epic waltz</a>, and a new "<a href="/about/news/black-widow-star-devours-its-rapidly-circling-companion">black widow</a>" star system, spotted by the Zwicky Transient Facility (ZTF), in which a rapidly spinning dead star called a pulsar is slowly evaporating its companion.</p><p data-block-key="6rk5i">Caltech's ZTF sky survey instrument, based at Palomar Observatory, had <a href="/about/news/first-asteroid-found-inside-orbit-venus">previously discovered the first known asteroid to circle entirely within the orbit of Venus</a>. To honor the Pauma band of Indigenous peoples whose ancestral lands include Palomar Mountain, the ZTF team asked the band to <a href="/about/news/native-americans-name-asteroid-ayl%C3%B3chaxnim-or-venus-girl">name the asteroid</a>. They chose <a href="https://caltech.box.com/s/21v4d2vw0qcmw9g1eqdjmlmwgii42637">'Ayló'chaxnim</a>, which means "Venus girl" in their native language of Luiseño.</p><p data-block-key="8gbm2">And far closer to home, new faculty member and historian <a href="https://www.hss.caltech.edu/people/lisa-ruth-rand">Lisa Ruth Rand</a> set her sights on the debris we have left in Earth's orbit (and beyond), and what it can tell us about humanity and our evolving relationship with space.</p><h2 data-block-key="9rjgo">Building Better Ways to See the Universe</h2><p data-block-key="bagcn">Caltech astronomers continue to lead the way in the development of ever more powerful instruments for answering fundamental questions about our place in the universe. The <a href="/about/news/keck-observatorys-newest-planet-hunter-puts-its-eye-on-the-sky">new Keck Planet Finder</a>, led by astronomer <a href="/about/news/keck-observatorys-newest-planet-hunter-puts-its-eye-on-the-sky">Andrew Howard</a>, will take advantage of the W. M. Keck Observatory's giant telescopes to search for and characterize hundreds, and ultimately, thousands of exoplanets, including Earth-size planets that may harbor conditions suitable for life.</p><p data-block-key="1tge2">NASA has also <a href="/about/news/nasa-selects-uvex-mission-proposal-for-further-study">selected the UltraViolet EXplorer (UVEX)</a> proposal, led by astronomer <a href="https://pma.caltech.edu/people/fiona-a-harrison">Fiona Harrison</a>, for further study. If selected to become a mission, UVEX would conduct a deep survey of the whole sky in ultraviolet light to provide new insights into galaxy evolution and the life cycle of stars. Harrison's current NASA mission, NuSTAR (Nuclear Spectroscopic Telescope Array), an X-ray telescope that hunts black holes, <a href="/about/news/nustar-celebrates-10-years-in-space">celebrated 10 years in space</a>. Meanwhile, the development of NASA's SPHEREx (Spectro-Photometer for the History of the Universe, Epoch of Reionization and Ices Explorer), led by astronomer <a href="https://pma.caltech.edu/people/james-j-jamie-bock">Jamie Bock</a>, is forging ahead with a customized test chamber <a href="/about/news/a-test-chamber-for-nasas-new-cosmic-mapmaker-makes-a-dramatic-entrance">delivered this year to Caltech</a>.</p><p data-block-key="9niks">As new telescopes continue to come together, a venerable Caltech telescope is being taken apart atop Maunakea in Hawai‘i. The Caltech Submillimeter Observatory (CSO) <a href="/about/news/caltech-submillimeter-observatory-decommissioning-receives-final-permits-and-selects-contractors">received the final permits</a> to begin its decommissioning process. Scientists plan to ultimately repurpose the telescope and put it back together in Chile.</p><h2 data-block-key="69uv1">Improving Human Health</h2><p data-block-key="5ge0n">Caltech's fundamental quest for understanding life and our origins also inspires many research efforts and innovations with the potential to improve human health and well-being.</p><p data-block-key="78dfs">Continuing work that began with the COVID-19 pandemic, Pamela Björkman and colleagues developed a <a href="/about/news/sars-coronavirus-variant-vaccine-bjorkman">new type of vaccine</a> that protects against the virus that causes COVID-19 and closely related viruses, while Sarkis Mazmanian has shown how an imbalance of gut microbes <a href="/about/news/gut-microbes-influence-binge-eating-of-sweet-treats-in-mice">can cause binge eating</a>. Meanwhile, other researchers made real what would have seemed like science fiction only a few years ago: Caltech medical engineer Wei Gao created an <a href="/about/news/artificial-skin-gives-robots-sense-of-touch-and-beyond">artificial skin for robots</a> that interfaces with human skin and allows a human operator to "feel" what the robot is sensing; chemical engineer Mikhail Shapiro engineered a strain of <a href="/about/news/fighting-cancer-with-sound-controlled-bacteria">remote-controlled bacteria</a> that seek out tumors inside the human body to deliver targeted drugs on command; and neuroscientist Richard Andersen and colleagues developed a brain–machine interface that can <a href="/about/news/brain-machine-interface-device-predicts-internal-speech">read a person's brain activity</a> and translate it into the words the person was thinking— technology that may one day allow people with full-body paralysis to speak. Additionally, Caltech researchers created a <a href="/about/news/synthetic-mouse-embryo-with-brain-and-beating-heart-grown-from-stem-cells">"synthetic" mouse embryo</a>, complete with brain and beating heart; completed a 20-year quest to decode one of <a href="/about/news/decoding-a-key-part-of-the-cell-atom-by-atom">the most complex and important pieces of machinery in our cells</a>; and discovered how fruit flies' <a href="/about/news/how-fruit-flies-sniff-out-their-environments">extremely sensitive noses help them find food</a>.</p><h2 data-block-key="ae3i">Advancing Sustainability Solutions</h2><p data-block-key="l8li">In 2022, Caltech paid tribute to its long history of advances in sustainability and then looked forward to pioneering new initiatives and technologies that will reduce humanity's footprint on Earth's fragile environment. Through the <a href="https://magazine.caltech.edu/post/caltech-heritage-projects-oral-history">newly launched Caltech Heritage Project</a>, a series of oral histories published this year captured the pivotal role Caltech alumni played in <a href="/about/news/todays-electric-vehicles-owe-debt-to-caltech-alumni">the electric car revolution</a>. Meanwhile, in April, <a href="/about/news/caltech-energy-10-ce10-aims-to-develop-the-roadmap-toward-a-50-percent-reduction-in-us-global-warming-gas-emissions-by-2032">Caltech hosted the Caltech Energy 10 (CE10) conference</a>, bringing thought leaders to campus to chart a path toward achieving the Biden administration's stated goal to cut U.S. global warming gas emissions by 50 percent within the next 10 years.</p><p data-block-key="5hh40">Caltech researchers continue to contribute to research to generate cleaner energy, ranging from work in the laboratory of John Dabiri (MS '03, PhD '05) to <a href="/about/news/tweaking-turbine-angles-squeezes-more-power-out-of-wind-farms">optimize wind farms</a> to efforts to create and commercialize technology for capturing carbon already released into the atmosphere (which earned <a href="/about/news/startup-from-caltech-nabs-xprize-award">a Caltech-based startup an XPrize Award</a>).</p><p data-block-key="cd9kn">On campus, Caltech began construction of the <a href="https://magazine.caltech.edu/post/caltechs-green-gateway-the-resnick-sustainability-center">Resnick Sustainability Center</a>, scheduled to open in 2024, which will bring together talent from across campus to tackle issues related to climate change and other human impacts on the natural environment. And as the year wraps up, the Space-based Solar Power Project is <a href="/about/news/space-solar-power-atwater-hajimiri-pellegrino">preparing to launch a demonstration</a> into space to test three key elements of its ambitious plan to harvest solar energy in space—where there are no cloudy days—and beam it wirelessly down to Earth.</p><h2 data-block-key="919l0">Harnessing the Power of Data to Advance Science</h2><p data-block-key="3r4bo">As the <a href="https://www.ai4science.caltech.edu/">AI4Science Initiative</a> continually demonstrates and the <a href="https://scienceexchange.caltech.edu/topics/artificial-intelligence-research?utm_source=caltechnews&utm_medium=web&utm_campaign=cseai">Caltech Science Exchange recently highlighted</a>, artificial intelligence (AI) and machine learning (ML) have applications that reach every corner of campus. In 2022, AI was used to generate <a href="/about/news/caltech-researchers-help-generate-first-image-of-black-hole-at-the-center-of-our-galaxy">the first-ever picture of the black hole at the center of our own galaxy</a> (only the second image of a black hole ever created), to pave the way to <a href="/about/news/improving-aircraft-design-with-machine-learning-and-a-more-efficient-model-of-turbulent-airflows">improve aircraft design</a>, to <a href="/about/news/rapid-adaptation-of-deep-learning-teaches-drones-to-survive-any-weather">help drones fly autonomously</a> in real-weather conditions, and to <a href="/about/news/researchers-tackle-covid-19-with-ai">fight COVID-19</a>. This election year, researchers from Caltech discussed how machine learning can both <a href="https://scienceexchange.caltech.edu/topics/artificial-intelligence-research/artificial-intelligence-experts/ai-science-alvarez-anandkumar?utm_source=caltechnews&utm_medium=web&utm_campaign=cseai">combat misinformation</a> and fight online bullying.</p><h2 data-block-key="e1lla">Forging Quantum Frontiers</h2><p data-block-key="futes">Caltech continues its role as a major hub of quantum research. The newly announced <a href="/about/news/ginsburgs-give-to-create-new-quantum-center-and-building-at-caltech">Dr. Allen and Charlotte Ginsburg Center for Quantum Precision Measurement</a> will unite a diverse community of theorists and experimentalists devoted to understanding quantum systems and their potential uses (see a <a href="https://youtu.be/zqRezABOAdY">video about the new center</a>). The 25th annual <a href="https://qipconference.org/">Conference on Quantum Information Processing</a>, or QIP, the world's largest gathering of researchers in the field of quantum information, a discipline that unites quantum physics and computer science, <a href="/about/news/caltech-hosts-largest-quantum-information-conference">was held in Pasadena</a> for the first time and represented the first major collaboration between Caltech and the new <a href="/about/news/caltech-and-amazon-partner-to-create-new-hub-of-quantum-computing">AWS Center for Quantum Computing</a> on campus.</p><p data-block-key="51e4a">Fundamental research in the quantum sciences charged ahead, with findings that included a quantum computer-based experiment to <a href="/about/news/physicists-observe-wormhole-dynamics-using-a-quantum-computer">test theoretical wormholes</a> and new demonstrations showing how graphene can be used in <a href="/about/news/graphene-boosts-flexible-and-wearable-electronics">flexible and wearable electronics</a>.</p><h2 data-block-key="17b89">Pioneering People</h2><p data-block-key="daf2">This year, members of the Caltech community received recognition for expanding the boundaries of scientific knowledge, but also for humanitarian endeavors and for blazing new educational and occupational paths for others to follow.</p><p data-block-key="d0309">In March, Roman Korol, a Caltech graduate student, <a href="/about/news/organizing-aid-to-his-native-ukraine">launched a project</a> to collect and distribute humanitarian aid for families affected by the war in Ukraine.</p><p data-block-key="88vng">In April, Jessica Watkins, who worked on the Mars Curiosity rover mission while a postdoc at Caltech, made history as the <a href="/about/news/former-caltech-postdoc-launches-into-space">first Black woman on the International Space Station</a>. From space, she <a href="/about/news/nasa-astronaut-jessica-watkins-holds-a-qa-from-space">hosted a live Q&A</a> for Caltech students and faculty in Ramo Auditorium and <a href="/about/news/wind-drives-geology-on-mars-these-days">reviewed a paper</a> describing how geology on Mars works in dramatically different ways than on Earth.</p><p data-block-key="27l2o">In May, alumna Laurie Leshin (MS '89, PhD '95) <a href="/about/news/caltech-names-laurie-leshin-ms-89-phd-95-director-of-jpl">assumed leadership of JPL</a>, becoming its first female director.</p><p data-block-key="83gle">In June, Carver Mead (BS '56, MS '57, PhD '60), one of the fathers of modern computing, <a href="/about/news/carver-mead-awarded-kyoto-prize-by-inamori-foundation">received the 2022 Kyoto Prize</a> for leading contributions to the establishment of the guiding principles for very large-scale integration systems design, which enables the basis for integrated computer circuits.</p><p data-block-key="99gae">In October, Caltech alumnus John Clauser (BS '64) <a href="/about/news/caltech-alum-wins-nobel-prize-in-physics">shared the 2022 Nobel Prize in Physics</a> "for experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science." The same month, <a href="https://www.jpl.nasa.gov/news/edward-stone-retires-after-50-years-as-nasa-voyagers-project-scientist">Edward Stone retired</a> as the project scientist for NASA's Voyager mission a half-century after taking on the role. Under his guidance, the Voyager probes explored the solar system's four gas-giant planets and became the first human-made objects to reach interstellar space, the region between stars containing material generated by the death of nearby stars. Also, Tracy Dennison <a href="/about/news/tracy-dennison-begins-tenure-as-chair-of-the-division-of-the-humanities-and-social-sciences">began her term</a> as the new Ronald and Maxine Linde Leadership Chair of the Division of the Humanities and Social Sciences.</p><p data-block-key="1i42u">In November, 50 years after they entered Caltech as the Institute's <a href="https://magazine.caltech.edu/post/reflections-on-72">first Black female students</a>, Karen Maples, MD (BS '76); Deanna Hunt (BS '76); and Lauretta Carroll (BS '77) reflected on the challenges and successes they experienced then and in the years that followed.</p><h2 data-block-key="f2mn6">Institute News</h2><p data-block-key="88d5a">Throughout the year, the Institute took steps to implement new programs and bolster existing ones that underscore Caltech's guiding values, such as supporting students and postdoctoral scholars, creating a more inclusive environment, and celebrating and accounting for its history.</p><p data-block-key="5jsko">To create more opportunities for students and increase interdisciplinary research, Caltech <a href="/about/news/new-graduate-track-to-combine-study-of-medical-and-electrical-engineering">created a new graduate education track</a> that combines medical engineering and electrical engineering. To further boost interdisciplinary research and expand Caltech's prominence as a hub for mathematics, the Institute became the <a href="/about/news/american-institute-of-mathematics-moves-to-caltech">new home of the American Institute of Mathematics</a>, an independent nonprofit organization funded in part by the National Science Foundation.</p><p data-block-key="9fosq">The Institute, which this year kicked off a partnership with the Carnegie Institution for Science, also <a href="/about/news/caltech-joins-sea-change-as-charter-member">became a charter member of SEA Change</a>, an initiative of the American Association for the Advancement of Science that supports educational institutions as they systemically transform to improve diversity, equity, accessibility, and inclusion in science, technology, engineering, mathematics, and medicine.</p><p data-block-key="9en86">The Institute expanded its <a href="/about/news/presidential-postdoctoral-fellows">Presidential Postdoctoral Fellowship</a>, which supports efforts to diversify academia by recruiting and supporting promising postdoctoral scholars from underrepresented communities.</p><p data-block-key="1bi6e">On campus, Caltech marked the <a href="/about/news/grant-d-venerable-house-dedication">dedication of the Grant D. Venerable House</a>, honoring its namesake alumnus, who was the first Black undergraduate student to graduate from Caltech and an active student leader and athlete during his time on campus. It also celebrated the <a href="/about/news/caltech-celebrates-dedication-of-the-lee-f-browne-dining-hall">dedication of the Lee F. Browne Dining Hall</a>, honoring the late Lee Franke Browne, a former Caltech employee and lecturer who dedicated his life and career to efforts that expanded students' access to STEM and who advanced human rights.</p><h2 data-block-key="e33ik">In the Community</h2><p data-block-key="8itgo">With the return of in-person events, the Institute was able to reestablish and strengthen ties to the local community through educational programs for area students, and through cultural events and lectures whose online components often reached even broader audiences across the world.</p><p data-block-key="1t506">This year, the Institute celebrated the <a href="/about/news/caltechs-seismo-lab-celebrates-100-years-at-the-forefront-of-earthquake-science">centennial of the Caltech Seismological Laboratory</a>, marking an unparalleled century at the forefront of earthquake science and geophysics.</p><p data-block-key="4si1b">Caltech also celebrated the <a href="https://magazine.caltech.edu/post/watson-lectures-100-years">100th anniversary of the Watson Lectures</a>, which launched in 1922 as a way to benefit the public through education and outreach. Continuing that tradition, Caltech partnered with local schools to bring high school students to campus to see the lectures and engaged young students through other educational outreach programs, including the new <a href="/about/news/caltech-earthquake-fellows">Caltech Earthquake Fellows program</a> and the <a href="/about/news/outreach-program-engages-public-high-school-students-in-the-discovery-of-exoplanets">Caltech Planet Finder Academy</a>, both of which launched this year. Other programs designed to bolster science education for young students included <a href="/about/news/high-school-students-research-at-caltech">Summer Research Connection</a>, a program that invites high school students and teachers from Pasadena Unified School District and other nearby schools into Caltech laboratories, and the <a href="/about/news/caltech-virtual-host-national-science-olympiad-2022">National Science Olympiad Tournament</a>, which Caltech hosted this year for the first time and whose students played the main role in conducting the event.</p><p data-block-key="5fcm8">For the campus community, <a href="/about/news/techfest-2022-start-fall-term">TechFest</a> returned to campus for the first time since the start of the COVID-19 pandemic, welcoming students with an in-person block party on Beckman Mall complete with games and fireworks.</p><p data-block-key="2s02g"><a href="https://events.caltech.edu/">Caltech's Public Programming</a> was able to re-engage with the community through in-person events, including <a href="https://events.caltech.edu/series/caltechlive-performing-arts">CaltechLive!</a> events such as the performance of Nobuntu, a female a cappella quintet from Zimbabwe; and lectures from the <a href="https://events.caltech.edu/series/science-journeys"><i>Science Journeys</i></a>, <a href="https://events.caltech.edu/series/movies-that-matter"><i>Movies that Matter</i></a> and <a href="https://events.caltech.edu/series/behind_the_book"><i>Behind the Book</i></a> series that showcased such varied topics as a journey to the center of Jupiter, a discussion of the science of cooking, and how climate migration will reshape the world.</p>Physicists observe wormhole dynamics using a quantum computer2022-11-30T16:00:00+00:002022-12-01T17:15:19.811468+00:00Whitney Clavinwclavin@caltech.eduhttps://www.caltech.edu/about/news/physicists-observe-wormhole-dynamics-using-a-quantum-computer<p data-block-key="7cpt9">Scientists have, for the first time, developed a quantum experiment that allows them to study the dynamics, or behavior, of a special kind of theoretical wormhole. The experiment has not created an actual wormhole (a rupture in space and time), rather it allows researchers to probe connections between theoretical wormholes and quantum physics, a prediction of so-called quantum gravity. Quantum gravity refers to a set of theories that seek to connect gravity with quantum physics, two fundamental and well-studied descriptions of nature that appear inherently incompatible with each other.</p><p data-block-key="9fl1g">"We found a quantum system that exhibits key properties of a gravitational wormhole yet is sufficiently small to implement on today's quantum hardware," says <a href="https://www.pma.caltech.edu/people/maria-spiropulu">Maria Spiropulu</a>, the principal investigator of the U.S. Department of Energy Office of Science research program Quantum Communication Channels for Fundamental Physics (QCCFP) and the Shang-Yi Ch'en Professor of Physics at Caltech. "This work constitutes a step toward a larger program of testing quantum gravity physics using a quantum computer. It does not substitute for direct probes of quantum gravity in the same way as other planned experiments that might probe quantum gravity effects in the future using quantum sensing, but it does offer a powerful testbed to exercise ideas of quantum gravity."</p><p data-block-key="80qre">The research will be published December 1 in the journal <i>Nature</i>. The study's first authors are Daniel Jafferis of Harvard University and Alexander Zlokapa (BS '21), a former undergraduate student at Caltech who started on this project for his bachelor's thesis with Spiropulu and has since moved on to graduate school at MIT.</p><p data-block-key="62t3a">Wormholes are bridges between two remote regions in spacetime. They have not been observed experimentally, but scientists have theorized about their existence and properties for close to 100 years. In 1935, Albert Einstein and Nathan Rosen described wormholes as tunnels through the fabric of spacetime in accordance with Einstein's general theory of relativity, which describes gravity as a curvature of spacetime. Researchers call wormholes Einstein–Rosen bridges after the two physicists who invoked them, while the term "wormhole" itself was coined by physicist John Wheeler in the 1950s.</p><p data-block-key="7q8g2">The notion that wormholes and quantum physics, specifically entanglement (a phenomenon in which two particles can remain connected across vast distances), may have a connection was first proposed in theoretical research by Juan Maldacena and Leonard Susskind in 2013. The physicists speculated that wormholes (or "ER") were equivalent to entanglement (also known as "EPR" after Albert Einstein, Boris Podolsky [PhD '28], and Nathan Rosen, who first proposed the concept). In essence, this work established a new kind of theoretical link between the worlds of gravity and quantum physics. "It was a very daring and poetic idea," says Spiropulu of the ER = EPR work.</p><p data-block-key="ftqdr">Later, in 2017, Jafferis, along with his colleagues Ping Gao and Aron Wall, extended the ER = EPR idea to not just wormholes but traversable wormholes. The scientists concocted a scenario in which negative repulsive energy holds a wormhole open long enough for something to pass through from one end to the other. The researchers showed that this gravitational description of a traversable wormhole is equivalent to a process known as quantum teleportation. In quantum teleportation, a protocol that has been <a href="/about/news/quantum-internet-tested-caltech-and-fermilab">experimentally demonstrated</a> over long distances via optical fiber and over the air, information is transported across space using the principles of quantum entanglement.</p><p data-block-key="bc36g">The present work explores the equivalence of wormholes with quantum teleportation. The Caltech-led team performed the first experiments that probe the idea that information traveling from one point in space to another can be described in either the language of gravity (the wormholes) or the language of quantum physics (quantum entanglement).</p><p data-block-key="1vnso">A key finding that inspired possible experiments occurred in 2015, when Caltech's <a href="https://pma.caltech.edu/people/alexei-kitaev">Alexei Kitaev</a>, the Ronald and Maxine Linde Professor of Theoretical Physics and Mathematics, showed that a simple quantum system could exhibit the same duality later described by Gao, Jafferis, and Wall, such that the model's quantum dynamics are equivalent to quantum gravity effects. This Sachdev–Ye–Kitaev, or SYK model (named after Kitaev, and Subir Sachdev and Jinwu Ye, two other researchers who worked on its development previously) led researchers to suggest that some theoretical wormhole ideas could be studied more deeply by doing experiments on quantum processors.</p><p data-block-key="7j3d9">Furthering these ideas, in 2019, Jafferis and Gao showed that by entangling two SYK models, researchers should be able to perform wormhole teleportation and thus produce and measure the dynamical properties expected of traversable wormholes.</p><p data-block-key="au6k4">In the new study, the team of physicists performed this type of experiment for the first time. They used a "baby" SYK-like model prepared to preserve gravitational properties, and they observed the wormhole dynamics on a quantum device at Google, namely the Sycamore quantum processor. To accomplish this, the team had to first reduce the SYK model to a simplified form, a feat they achieved using machine learning tools on conventional computers.</p><p data-block-key="d6vsp">"We employed learning techniques to find and prepare a simple SYK-like quantum system that could be encoded in the current quantum architectures and that would preserve the gravitational properties," says Spiropulu. "In other words, we simplified the microscopic description of the SYK quantum system and studied the resulting effective model that we found on the quantum processor. It is curious and surprising how the optimization on one characteristic of the model preserved the other metrics! We have plans for more tests to get better insights on the model itself."</p><p data-block-key="as7pq">In the experiment, the researchers inserted a qubit—the quantum equivalent of a bit in conventional silicon-based computers—into one of their SYK-like systems and observed the information emerge from the other system. The information traveled from one quantum system to the other via quantum teleportation—or, speaking in the complementary language of gravity, the quantum information passed through the traversable wormhole.</p><p data-block-key="c4l5r">"We performed a kind of quantum teleportation equivalent to a traversable wormhole in the gravity picture. To do this, we had to simplify the quantum system to the smallest example that preserves gravitational characteristics so we could implement it on the Sycamore quantum processor at Google," says Zlokapa.</p><p data-block-key="3dtbh">Co-author Samantha Davis, a graduate student at Caltech, adds, "It took a really long time to arrive at the results, and we surprised ourselves with the outcome."</p><p data-block-key="131br">"The near-term significance of this type of experiment is that the gravitational perspective provides a simple way to understand an otherwise mysterious many-particle quantum phenomenon," says <a href="https://pma.caltech.edu/people/john-p-preskill">John Preskill</a>, the Richard P. Feynman Professor of Theoretical Physics at Caltech and director of the Institute for Quantum Information and Matter (IQIM). "What I found interesting about this new Google experiment is that, via machine learning, they were able to make the system simple enough to simulate on an existing quantum machine while retaining a reasonable caricature of what the gravitation picture predicts."</p><p data-block-key="cquap">In the study, the physicists report wormhole behavior expected both from the perspectives of gravity and from quantum physics. For example, while quantum information can be transmitted across the device, or teleported, in a variety of ways, the experimental process was shown to be equivalent, at least in some ways, to what might happen if information traveled through a wormhole. To do this, the team attempted to "prop open the wormhole" using pulses of either negative repulsive energy pulse or the opposite, positive energy. They observed key signatures of a traversable wormhole only when the equivalent of negative energy was applied, which is consistent with how wormholes are expected to behave.</p><p data-block-key="fmd1k">"The high fidelity of the quantum processor we used was essential," says Spiropulu. "If the error rates were higher by 50 percent, the signal would have been entirely obscured. If they were half we would have 10 times the signal!"</p><p data-block-key="6s6f6">In the future, the researchers hope to extend this work to more complex quantum circuits. Though bona fide quantum computers may still be years away, the team plans to continue to perform experiments of this nature on existing quantum computing platforms.</p><p data-block-key="9g3eg">"The relationship between quantum entanglement, spacetime, and quantum gravity is one of the most important questions in fundamental physics and an active area of theoretical research," says Spiropulu. "We are excited to take this small step toward testing these ideas on quantum hardware and will keep going."</p><p data-block-key="drii4">The study titled "<a href="https://www.nature.com/articles/s41586-022-05424-3">Traversable wormhole dynamics on a quantum processer</a>" was funded by the U.S. Department of Energy Office of Science via the QCCFP research program. Other authors include: Joseph Lykken of Fermilab; David Kolchmeyer, formerly at Harvard and now a postdoc at MIT; Nikolai Lauk, formerly a postdoc at Caltech; and Hartmut Neven of Google.</p><p data-block-key="93rvh">More information can be found at the Alliance for Quantum Technologies website: <a href="https://inqnet.caltech.edu/wormhole2022">https://inqnet.caltech.edu/wormhole2022</a>.</p>New Theory of Electron Spin to Aid Quantum Devices2022-11-09T19:55:00+00:002022-11-11T16:52:39.027497+00:00Emily Velascoevelasco@caltech.eduhttps://www.caltech.edu/about/news/new-theory-of-electron-spin-to-aid-quantum-devices<p data-block-key="uq3xs">Electrons—those little subatomic particles that help make up the atoms in our bodies and the electricity flowing through your phone or computer right now—have some properties like mass and charge that will be familiar to anyone who has taken a high school physics class. But electrons also have a more abstract property known as spin, which describes how they interact with magnetic fields.</p><p data-block-key="ct8qr">Electron spin is of particular importance to a field of research called spintronics, which aims to develop quantum electronic devices that use spin in memory storage and information processing. Spin is also central to qubits—the basic unit of information used in quantum computing.</p><p data-block-key="6922g">The problem with using spin in these quantum devices is that its quantum states can be easily disrupted. To be used in a device, the electron spins need to preserve their quantum state for as long as possible to avoid loss of information. This is known as spin coherence, and it is so delicate that even the tiny vibrations of the atoms that make up the device can wipe out the spin state irreversibly.</p><p data-block-key="569kv"></p><embed alt="A portrait of Marco Bernardi. He stands in front of a blue chalkboard covered in writing with his arms crossed." embedtype="image" format="RightAlignSmall" id="8084"/><p data-block-key="f4eu1"></p><p data-block-key="dmt52">In a new paper published in the journal <i>Physical Review Letters</i>, <a href="https://eas.caltech.edu/people/bmarco">Marco Bernardi</a>, professor of applied physics, physics and materials science; and Jinsoo Park (MS '20, PhD '22), postdoctoral scholar research associate in applied physics and materials science, have developed a new theory and numerical calculations to predict spin decoherence in materials with high accuracy. Bernardi explains:</p><indent data-block-key="tqis"><i>"Existing theories of spin relaxation and decoherence focus on simple models and qualitative understanding. After years of systematic efforts, my group has developed computational tools to study quantitatively how electrons interact and move in materials.<br/></i></indent><indent data-block-key="67qea"><i>This new paper has taken our work a few steps further: we have adapted a theory of electrical transport to study spin, and discovered that this method can capture two main mechanisms governing spin decoherence in materials—spin scattering off atomic vibrations, and spin precession modified by atomic vibrations. This unified treatment allows us to study the behavior of the electron spin in a wide range of materials and devices essential for future quantum technologies. It is almost startling that in some cases we can predict spin decoherence times with an accuracy of a few percent of the measured values—down to a billionth of a second—and access microscopic details of spin motion beyond the reach of experiments. Ironically, our research tools—computers and quantum mechanics—can now be used to develop new computers that use quantum mechanics."</i></indent><p data-block-key="bgve7"></p><embed alt="A portrait of Jinsoo Park" embedtype="image" format="LeftAlignSmall" id="9288"/><p data-block-key="ep03v"></p><p data-block-key="beeat">The paper describing the research, titled, <a href="https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.129.197201">Predicting Phonon-Induced Spin Decoherence from First Principles: Colossal Spin Renormalization in Condensed Matter</a>," appears in the November 2 issue of <i>Physical Review Letters.</i> Its companion paper describing the theory in detail, titled "<a href="https://journals.aps.org/prb/abstract/10.1103/PhysRevB.106.174404">Many-body theory of phonon-induced spin relaxation and decoherence</a>," appears in issue 17 of <i>Physical Review B</i> as an Editor's Suggestion. The lead author is Park. Co-authors are Bernardi and Yao Luo, a graduate student in applied physics; and Jin-Jian Zhou, a former Caltech postdoc now at the Beijing Institute of Technology.</p><p data-block-key="8bf81">Funding for the research was provided by the National Science Foundation.</p>