Fluctuation damping of isolated, oscillating Bose-Einstein condensates

Lappe, Tim; Posazhennikova, Anna; Kroha, Johann

doi:10.1103/physreva.98.023626

Cited by 9 publications

(8 citation statements)

References 22 publications

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“…Consequently, it is sensitive to details of the experimental setup, which can be realized in very dissimilar ways. [34,36,52] In Figure 8 we have chosen a different value of the BEC-QP coupling k, which results in a drastic suppression of QPs and therefore their negligible effect on the junction dynamics. In this case the Bose Josephson junction is well described within the semiclassical two-mode approximation, [33] although a small density of incoherent excitations may be excited intermediately.…”

Section: Results Within Bogoliubov-hartree-fock Approximationmentioning

confidence: 99%

Thermalization of Isolated Bose‐Einstein Condensates by Dynamical Heat Bath Generation

2017

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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 initial 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).

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Section: Results Within Bogoliubov-hartree-fock Approximationmentioning

confidence: 99%

Thermalization of Isolated Bose‐Einstein Condensates by Dynamical Heat Bath Generation

2017

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“…( 22). Consequently, it is sensitive to details of the experimental setup, which can be realized in very dissimilar ways [34,36,52]. In Fig.…”

Section: Quasiparticle Creation and Thermalization Dynamics A Results...mentioning

confidence: 99%

Thermalization of isolated Bose-Einstein condensates by dynamical heat bath generation

Posazhennikova,

Trujillo-Martinez,

Kroha

2017

Preprint

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If and how an isolated quantum system thermalizes despite its unitary time evolution is a longstanding, 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 initial 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).

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“…A damping can also be attributable to phase noise and particle dissipation [29][30][31]. An energy loss through excitations to higher energy transverse modes is discussed in [23] and very recently in [32,33].…”

Section: Introductionmentioning

confidence: 99%

Analytical pendulum model for a bosonic Josephson junction

Pigneur

Schmiedmayer

2018

Phys. Rev. A

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We present an analytical description of the tunneling dynamics between two coupled Bose-Einstein condensates in the Josephson regime. The model relies on the classical analogy with a rigid pendulum and focuses on two dynamical modes of this system: Josephson oscillations and Macroscopic Quantum Self-Trapping. The analogy is extended to include an energy difference between the two superfluids caused by an asymmetry in the trapping potential. The model is compatible with the mean-field predictions of the two-mode Bose-Hubbard model. It gives new insights on the mean-field model by involving experimentally measurable parameters with reduced correlations. For agreement with recent experimental observations, we establish heuristic formulas including a dissipation. We conclude with a convincing application of the model to several sets of experimental results.

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Fluctuation damping of isolated, oscillating Bose-Einstein condensates

Cited by 9 publications

References 22 publications

Thermalization of Isolated Bose‐Einstein Condensates by Dynamical Heat Bath Generation

Thermalization of Isolated Bose‐Einstein Condensates by Dynamical Heat Bath Generation

Thermalization of isolated Bose-Einstein condensates by dynamical heat bath generation

Analytical pendulum model for a bosonic Josephson junction

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