Thermalization of isolated Bose-Einstein condensates by dynamical heat bath generation
| Autor: | Anna Posazhennikova, Mauricio Trujillo-Martinez, Johann Kroha |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
Population
FOS: Physical sciences General Physics and Astronomy 01 natural sciences 010305 fluids & plasmas law.invention symbols.namesake law Quantum mechanics 0103 physical sciences Quantum system 010306 general physics education Eigenstate thermalization hypothesis Condensed Matter - Statistical Mechanics Physics Condensed Matter::Quantum Gases education.field_of_study Quantum Physics Statistical Mechanics (cond-mat.stat-mech) Thermal reservoir Time evolution Quantum Gases (cond-mat.quant-gas) symbols Quasiparticle Quantum Physics (quant-ph) Hamiltonian (quantum mechanics) Condensed Matter - Quantum Gases Bose–Einstein condensate |
| Popis: | If and how an isolated quantum system thermalizes despite its unitary time evolution is a long-standing, open problem of many-body physics. The eigenstate thermalization hypothesis (ETH) postulates that thermalization happens at the level of individual eigenstates of a system's Hamiltonian. However, the ETH requires stringent conditions to be validated, and it does not address how the thermal state is reached dynamically from an inital non-equilibrium state. We consider a Bose-Einstein condensate (BEC) trapped in a double-well potential with an initial population imbalance. We find that the system thermalizes although the initial conditions violate the ETH requirements. We identify three dynamical regimes. After an initial regime of undamped Josephson oscillations, the subsystem of incoherent excitations or quasiparticles (QP) becomes strongly coupled to the BEC subsystem by means of a dynamically generated, parametric resonance. When the energy stored in the QP system reaches its maximum, the number of QPs becomes effectively constant, and the system enters a quasi-hydrodynamic regime where the two subsystems are weakly coupled. In this final regime the BEC acts as a grand-canonical heat reservoir for the QP system (and vice versa), resulting in thermalization. We term this mechanism dynamical bath generation (DBG). Published version, 20 pages, 19 figures, minor grammar and typos corrected |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|