Nonlinear dynamics of the cold atom analog false vacuum
Abstract
We investigate the nonlinear dynamics of cold atom systems that can in princi- ple serve as quantum simulators of false vacuum decay. The analog false vacuum manifests as a metastable vacuum state for the relative phase in a two-species Bose-Einstein con- densate (BEC), induced by a driven periodic coupling between the two species. In the appropriate low energy limit, the evolution of the relative phase is approximately governed by a relativistic wave equation exhibiting true and false vacuum configurations. In previous work, a linear stability analysis identified exponentially growing short-wavelength modes driven by the time-dependent coupling. These modes threaten to destabilize the analog false vacuum. Here, we employ numerical simulations of the coupled Gross-Pitaevski equa- tions (GPEs) to determine the non-linear evolution of these linearly unstable modes. We find that unless a physical mechanism modifies the GPE on short length scales, the analog false vacuum is indeed destabilized. We briefly discuss various physically expected correc- tions to the GPEs that may act to remove the exponentially unstable modes. To investigate the resulting dynamics in cases where such a removal mechanism exists, we implement a hard UV cutoff that excludes the unstable modes as a simple model for these corrections. We use this to study the range of phenomena arising from such a system. In particular, we show that by modulating the strength of the time-dependent coupling, it is possible to observe the crossover between a second and first order phase transition out of the false vacuum.
- Publication:
-
Journal of High Energy Physics
- Pub Date:
- October 2019
- DOI:
- 10.1007/JHEP10(2019)174
- arXiv:
- arXiv:1904.07873
- Bibcode:
- 2019JHEP...10..174B
- Keywords:
-
- Lattice Quantum Field Theory;
- Nonperturbative Effects;
- Solitons Monopoles and Instantons;
- High Energy Physics - Theory;
- Astrophysics - Cosmology and Nongalactic Astrophysics;
- Condensed Matter - Quantum Gases;
- General Relativity and Quantum Cosmology
- E-Print:
- v2: Version accepted to JHEP. Explanatory material added. Results unchanged. v1: 21 pages+appendices, 15 figures