2008/10/31 by Yasunari Kurita, Michikazu Kobayashi, Takao Morinari +2 · 1 citation
Physics and Astronomy · #cond-mat.other #gr-qc
paper · pdf · doi:10.1103/physreva.79.043616
published as Phys.Rev.A79:043616,2009 · 8 pages, 6 figures
arxiv created 2009/03/18 · arxiv updated 2010/11/02
We construct quantum field theory in an analogue curved spacetime in Bose-Einstein condensates based on the Bogoliubov-de Gennes equations, by exactly relating quantum particles in curved spacetime with Bogoliubov quasiparticle excitations in Bose-Einstein condensates. Here, we derive a simple formula relating the two, which can be used to calculate the particle creation spectrum by solving the time-dependent Bogoliubov-de Gennes equations. Using our formulation, we numerically investigate particle creation in an analogue expanding Universe which can be expressed as Bogoliubov quasiparticles in an expanding Bose-Einstein condensate. We obtain its spectrum, which follows the thermal Maxwell-Boltzmann distribution, the temperature of which is experimentally attainable. Our derivation of the analogy is useful for general Bose-Einstein condensates and not limited to homogeneous ones, and our simulation is the first example of particle creations by solving the Bogoliubov-de Gennes equation in an inhomogeneous condensate.