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Inflationary Quasiparticle Creation and Thermalization Dynamics in Coupled Bose-Einstein Condensates
Anna Posazhennikova1, Mauricio Trujillo-Martinez2, Johann Kroha2,3
1Department of Physics, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom.
Physical Review Letters
|June 18, 2016
Summary
We studied a Bose gas in a double-well potential, observing avalanche-like quasiparticle creation and thermalization. This system acts as a reservoir, mimicking early universe particle creation dynamics.
Area of Science:
- Quantum physics
- Many-body systems
- Non-equilibrium dynamics
Background:
- Bose-Einstein condensates (BECs) in double-well potentials serve as models for isolated, non-equilibrium systems.
- Josephson oscillations in BECs are a key feature of such systems.
Purpose of the Study:
- Investigate quasiparticle (QP) creation and thermalization dynamics in a driven BEC.
- Understand the mechanisms behind QP generation and system relaxation.
- Explore analogies with early universe cosmology.
Main Methods:
- Solving time-dependent Keldysh-Bogoliubov equations.
- Analyzing the dynamics of BEC and QP oscillations.
- Characterizing the thermalization process.
Main Results:
- Observed avalanche-like quasiparticle creation driven by parametric resonance between BEC and QP oscillations.
- Identified slow, exponential relaxation to a thermal state at an elevated temperature.
- Found that thermalization is governed by the initial excitation energy of the BEC.
- Discovered a crossover regime due to effective decoupling of QP and BEC oscillations.
Conclusions:
- The BEC acts as a grand canonical reservoir, enabling thermalization of the quasiparticle system.
- The observed dynamics are analogous to elementary particle creation in early universe models.
- The system provides a controllable platform for studying non-equilibrium quantum dynamics.
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