[Category and Topological Order Seminar] Emergent space-time meets emergent quantum phenomena


Speaker:Jinwu Ye

Date: 2022/09/20

Time: 13:30 -15:00

Venue: BIMSA 1131



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 talk, we try to 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 explore the emergent space-time in  one of the simplest QPTs: Superfluid (SF)-Mott transitions of interacting bosons in a square lattice. By constructing effective actions and performing microscopic calculations on a lattice, we find an counter-intuitive effect:  a Mott phase near the QPT may tune into a SF phase, but not the other way around. We also demonstrate several other novel effects of observing emergent quantum phenomena in a different inertial frame. Contrast to the Doppler shifts in a relativistic quantum field theory and Unruh effects in an accelerating  observer are made. Doing various light or neutron scattering measurements in a moving sample may become an effective way not only  measure various intrinsic properties of the materials, tune various quantum and topological phases through novel phase transitions, but also probe the new emergent space-time structure near any QPT.