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IQI Weekly Seminar

Tuesday, May 31, 2016
3:00pm to 4:00pm
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Annenberg 107
Size-Driven Quantum Phase Transitions
Johannes Bausch, University of Cambridge,

Can the properties of the thermodynamic limit of a many-body quantum system be extrapolated by analyzing a sequence of finite-size cases? We present models with relatively low local Hilbert space dimensions for which such an approach gives completely misleading results: a translationally invariant local Hamiltonian on a square lattice with constant spectral gap and classical product ground state for system sizes smaller than a threshold, and a ground state with topological degeneracy for larger system sizes. The resulting effect may be viewed as a new type of quantum phase transition that is driven by the size of the system rather than by a local field or coupling.

(joint work with Toby S. Cubitt, Angelo Lucia, David Perez-Garcia, Michael M. Wolf; http://arxiv.org/abs/1512.05687)

For more information, please contact Jackie O'Sullivan by phone at 626.395.4964 or by email at [email protected].