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P.W. Anderson said "More is different". It says the macroscopic quantum phenomena such as superfluids, superconductors, quantum anti-ferromagnetism, fractional quantum Hall states, etc. emerge as the number of interacting particles gets more and more. However, he left the question how these emergent quantum or topological phenomena change under different inertial frames. In this colloquium, we address this outstanding problem. We propose there is an emergent space-time corresponding to any emergent quantum phenomenon, especially near a quantum/topological phase transition (QPT). We demonstrate this new emergent space-time structure by studying one of the simplest QPTs: Superfluid (SF)-Mott transitions of interacting bosons in a square lattice observed in a frame moving with a constant velocity v relative to the underlaying lattice. By both constructing effective actions and performing microscopic calculations on a lattice, we find that the new emergent space-time leads to several new effects in the moving frame such as the change of the ground state ( the Mott phase near the QPT may turn into a SF phase, but not the other way around ), the emergence of new class of QPTs, the rising of the Kosterlize-Thouless (KT) transition temperature, the change of the condensation momentum, the sign reverse of the Doppler shift in the excitation spectrum relative to the bare velocity v, etc. Contrast to the Doppler shifts and Temperature shifts in a relativistic quantum field theory, the Unruh effects in an accelerating observer, the emergent curved space-time from the Sachdev-Ye-Kitaev model are made. Finally, we show that despite these effects are hard to observe in real materials, but could be detected in cold atoms loaded in an optical lattice.
Refs: arXiv:2207.10475, arXiv:cond-mat/0512480 ( substantially revised version).
Prof. Ye received his Ph.D. from Yale University. Now he is a Professor at Mississippi State University, also a visitor at the (still building) Great Bay University. He is a condensed matter theorist working on the interdisciplinary field of condensed matter, quantum optics, cold atoms, non-relativistic quantum field theory, Turbulence and conformal field theory. Recently, he has been particularly interested to explore possible deep connections among quantum/topological phases, supersymmetry breaking, Sachdev-Ye-Kitaev models, curved space-time, quantum black holes from material's point of views.
Tencent Meeting link: https://meeting.tencent.com/dm/I0GG8sIqjmsU Meeting ID: 665 714 579