Tuesday, April 21, 2015
4:00 pm
Cahill, Hameetman Auditorium – Cahill Center for Astronomy and Astrophysics

Gravitational-Wave Research Seminar

G4v - An Engineering Approach to Gravitation
Carver Mead, Caltech

View this seminar on YouTube at https://youtu.be/XdiG6ZPib3c.

This approach is based on the premise that the most fundamental and universal quantity characterizing any element of matter is the propagation four-vector of its wave function, from which its energy-momentum four-vector and its charge-current-density four-vector are derived.   The propagation four-vector of any element of matter contains, as an integral part, the propagation four-vectors of every other element of matter on its light-cone, through their electromagnetic and gravitational four-potentials.

When the first theories of mechanics, electromagnetism and gravitation were formulated, the elementary coupling of matter wave functions was not known. Force-law coupling was adopted, which is one full derivative away from the fundamental four-vector properties of matter. Not only does this second-order derivative characterization complicate the theory, but it pushes a great deal of the problem into boundary conditions that are often difficult to determine.

The present approach can be viewed as an attempt to develop clear and concise physical insights based on the large body of modern experimental observations.  Every attempt is made to keep the mathematics as simple as possible.  G4v is the gravitational equivalent of Collective Electrodynamics—the two interactions are of exactly the same form, but of opposite signs. Both couplings are based squarely on the elementary first-order four- vector coupling of matter wave functions. All calculations are carried out on elementary quantities (energy, momentum, current density, scalar and vector potentials). The concept of force, and its requirement for some force equation, although sometimes useful, is not required.

Results derived by G4v for Gravity-Probe B, gravitational redshift, precession of orbits, Shapiro delay, and deflection of light by massive bodies are the same as those of GR to first post-Newtonian order.  G4v predictions of gravitational-wave radiation patterns for binary systems, and antenna patterns for observatories like LIGO, differ markedly from those predicted by GR.  Total energy loss due to gravitational wave radiation from eccentric binary systems predicted by G4v may differ slightly from those of GR, and is still under study.

It should be possible to compare the predictions of G4v with those of GR within the next few years.

 

Contact Jonah Kanner jkanner@caltech.edu at 626-395-8437
For more information see CaJAGWR Home Page
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