KEK Theory Seminar/Dr. Da-Shin Lee
We explore possible analogies between quantum phenomena in curved spacetime and cold laboratory condensates whose speed of sound can be tuned by means of an external field. In the first instance, the creation of causal horizons when a system undergoes rapid changes can lead to the creation of defects e.g. cosmic strings and monopoles. We see to what extent this can be mimicked in condensates by the spontaneous creation of vortices in a field ramp. Secondly, by examining the phonon geodesics in the acoustic metric we can look for spontaneous phonon creation that mimics spontaneous particle creation in curved space-time. Also, the fluctuating nature of the phonon background suggests analogies with quantum gravity.
 D.-S. Lee, C. Y. Lin, and R. J. Rivers: "Derivation of Hydrodynamics for the Gapless Mode in the BEC-BCS Crossover from the Exact One-Loop Effective Action," Phys. Rev. Lett. 98, 020603 (2007).
 C.-Y. Lin, D.-S. Lee, and R. J. Rivers, "The role of Causality in Tunable Fermi Gas Condensates," J. Phys. Cond. Matter 25, 04211 (2013).
 J.-T. Hsiang, C.-Y. Lin, D.-S. Lee, and R. J. Rivers, "Quantum Stochastic Behavior in Cold Fermi Gases: Phonon Propagation," Phys. Rev. A 91, 051603(R) (2015).