Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:1912.04434 · Physical Review A

Generating a nonequilibrium stationary state from a ground-state condensate through an almost adiabatic cycle

Atushi Tanaka, Takaaki Nakamura, Taksu Cheon

Published Jul 10, 2020• 2 citations
arXivHTMLPDF

Abstract

It is shown, through a mean-field description, that the ground state of weakly interacting Bose particles in a quasi-one-dimensional box trap can be converted into an excited stationary state by an almost adiabatic cyclic operation that involves a quench: A sharp impurity potential is applied, and its strength is varied during the cycle, which induces a nonequilibrium stationary state exhibiting the inversion of population. This process is robust in the sense that the resultant stationary state is almost independent of the details of the cycle, such as the position of the impurity, as long as the cycle is far enough from critical regions. The case of the failure of the population inversion due to the strong interparticle interactions is also examined.

DOI
10.1103/physreva.102.013308

Related papers

Complete population inversion of Bose particles by an adiabatic cycle

Atushi Tanaka, Taksu Cheon

We show that an adiabatic cycle excites Bose particles confined in a one-dimensional box. During the adiabatic cycle, a wall described by a δ -shaped potential is applied and its strength and position are slowly varied. When the system is initially prepared in the ground state, namely, in the zero-temperature equilibrium state, the adiabatic cycle brings all Bosons into the first excited one-particle state, leaving the system in a nonequilibrium state. The absorbed energy during the cycle is proportional to the number of Bosons.

arXiv:1512.07946•New Journal of Physics•Apr 27, 2016•3 citations

Adiabatic cycles in quantum systems with contact interactions

Atushi Tanaka, Taksu Cheon

An adiabatic cycle involving the δ-function potential is shown to excite Bose particles confined in a one-dimensional box.We consider a cycle, during which a wall described by a δ potential is applied and its strength and position are slowly varied.When the system is initially prepared in the equilibrium ground state, the adiabatic cycle brings all bosons into the first excited one-particle state, leaving the system in a nonequilibrium state.The absorbed energy during the cycle is proportional to the number of bosons.

Nanosystems Physics Chemistry Mathematics•Feb 20, 2017•0 citations

Stationary states in the many-particle description of Bose-Einstein condensates with balanced gain and loss

Dennis Dast, Daniel Haag, Holger Cartarius +2 more

Bose-Einstein condensates with balanced gain and loss can support stationary states despite the exchange of particles with the environment. In the mean-field approximation this is described by the $\mathcal{PT}$-symmetric Gross-Pitaevskii equation with real eigenvalues. In this work we study the role of stationary states in the appropriate many-particle description. It is shown that without particle interaction there exist two nonoscillating trajectories which can be interpreted as the many-particle equivalent of the stationary $\mathcal{PT}$-symmetric mean-field states. Furthermore, the system has a nonequilibrium steady state which acts as an attractor in the oscillating regime. This steady state is a pure condensate for strong gain and loss contributions if the interaction between the particles is sufficiently weak.

arXiv:1705.10497•Physical Review A•Aug 28, 2017•11 citations

Interaction-induced localization of an impurity in a trapped Bose-Einstein condensate

Ryan M. Kalas, D. Blume

We study the ground-state properties of a trapped Bose-Einstein condensate with a neutral impurity. By varying the strength of the attractive atom-impurity interactions, the degree of localization of the impurity at the trap center can be controlled. As the impurity becomes more strongly localized, the peak condensate density, which can be monitored experimentally, grows markedly. For strong enough attraction, the impurity can make the condensate unstable by strongly deforming the atom density in the neighborhood of the impurity. This 'collapse' can possibly be investigated in bosenova-type experiments.

Bulletin of the American Physical Society•May 18, 2006•0 citations

Nonequilibrium states of a quenched Bose gas

Ben Kain, Hong Yuan Ling

Yin and Radzihovsky [X. Yin and L. Radzihovsky, Phys. Rev. A 88, 063611 (2013)] recently developed a self-consistent extension of a Bogoliubov theory, in which the condensate number density ${n}_{c}$ is treated as a mean field that changes with time, in order to analyze a JILA experiment by Makotyn et al. [P. Makotyn et al., Nat. Phys. 10, 116 (2014)] on a $^{85}\mathrm{Rb}$ Bose gas following a deep quench to a large scattering length. We apply this theory to construct a closed set of equations that highlight the role of ${\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{n}}_{c}$, which is to induce an effective interaction between quasiparticles. We show analytically that such a system supports a steady state characterized by a constant condensate density and a steady but periodically changing momentum distribution, whose time average is described exactly by the generalized Gibbs ensemble. We discuss how the ${\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{n}}_{c}$-induced effective interaction, which cannot be ignored on the grounds of the adiabatic approximation for modes near the gapless Goldstone mode, can significantly affect condensate populations and Tan's contact for a Bose gas that has undergone a deep quench.

arXiv:1401.2390•Physical Review A•Dec 17, 2014•30 citations

Interaction-induced single-impurity tunneling in a binary mixture of trapped ultracold bosons

Kevin Keiler, Peter Schmelcher

We investigate the tunneling dynamics of an ultracold bosonic impurity species which interacts repulsively with a second, larger Bose gas. Both species are held in a finite-sized quasi-one-dimensional box potential. In addition, the impurity bosons experience a periodic potential generated by an optical lattice. We initially prepare our binary mixture in its ground state, such that the impurities and Bose gas are phase separated and the impurities localize pairwise in adjacent sites of the periodic potential, by tuning the interaction strengths and the lattice depth correspondingly. The dynamics is initiated by suddenly lowering the repulsive interspecies interaction strength, thereby entering a different regime in the crossover diagram. For specific postquench interspecies interaction strengths we find that a single impurity tunnels first to the neighboring empty site and depending on the quench strength can further tunnel to the next-neighboring site. Interestingly, this effect is highly sensitive to the presence of the Bose gas and does not occur when the Bose gas does not interact with the impurity species throughout the dynamics. Moreover, we find that the tunneling process is accompanied by strong entanglement between the Bose gas and the impurity species as well as correlations among the impurities.

arXiv:1907.07956•Physical Review A•Oct 29, 2019•12 citations
It is shown, through a mean-field description, that the ground state of weakly interacting Bose particles in a quasi-one-dimensional box trap can be converted into an excited stationary state by an almost adiabatic cyclic operation that involves a quench: A sharp impurity potential is applied, and its strength is varied during the cycle, which induces a nonequilibrium stationary state exhibiting the inversion of population. This process is robust in the sense that the resultant stationary state is almost independent of the details of the cycle, such as the position of the impurity, as long as the cycle is far enough from critical regions. The case of the failure of the population inversion due to the strong interparticle interactions is also examined.
We show that an adiabatic cycle excites Bose particles confined in a one-dimensional box. During the adiabatic cycle, a wall described by a δ -shaped potential is applied and its strength and position are slowly varied. When the system is initially prepared in the ground state, namely, in the zero-temperature equilibrium state, the adiabatic cycle brings all Bosons into the first excited one-particle state, leaving the system in a nonequilibrium state. The absorbed energy during the cycle is proportional to the number of Bosons.
An adiabatic cycle involving the δ-function potential is shown to excite Bose particles confined in a one-dimensional box.We consider a cycle, during which a wall described by a δ potential is applied and its strength and position are slowly varied.When the system is initially prepared in the equilibrium ground state, the adiabatic cycle brings all bosons into the first excited one-particle state, leaving the system in a nonequilibrium state.The absorbed energy during the cycle is proportional to the number of bosons.
Bose-Einstein condensates with balanced gain and loss can support stationary states despite the exchange of particles with the environment. In the mean-field approximation this is described by the PT\mathcal{PT}PT-symmetric Gross-Pitaevskii equation with real eigenvalues. In this work we study the role of stationary states in the appropriate many-particle description. It is shown that without particle interaction there exist two nonoscillating trajectories which can be interpreted as the many-particle equivalent of the stationary PT\mathcal{PT}PT-symmetric mean-field states. Furthermore, the system has a nonequilibrium steady state which acts as an attractor in the oscillating regime. This steady state is a pure condensate for strong gain and loss contributions if the interaction between the particles is sufficiently weak.
We study the ground-state properties of a trapped Bose-Einstein condensate with a neutral impurity. By varying the strength of the attractive atom-impurity interactions, the degree of localization of the impurity at the trap center can be controlled. As the impurity becomes more strongly localized, the peak condensate density, which can be monitored experimentally, grows markedly. For strong enough attraction, the impurity can make the condensate unstable by strongly deforming the atom density in the neighborhood of the impurity. This 'collapse' can possibly be investigated in bosenova-type experiments.
Yin and Radzihovsky [X. Yin and L. Radzihovsky, Phys. Rev. A 88, 063611 (2013)] recently developed a self-consistent extension of a Bogoliubov theory, in which the condensate number density nc{n}_{c}nc​ is treated as a mean field that changes with time, in order to analyze a JILA experiment by Makotyn et al. [P. Makotyn et al., Nat. Phys. 10, 116 (2014)] on a 85Rb^{85}\mathrm{Rb}85Rb Bose gas following a deep quench to a large scattering length. We apply this theory to construct a closed set of equations that highlight the role of ${\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{n}}_{c}$, which is to induce an effective interaction between quasiparticles. We show analytically that such a system supports a steady state characterized by a constant condensate density and a steady but periodically changing momentum distribution, whose time average is described exactly by the generalized Gibbs ensemble. We discuss how the ${\stackrel{\ifmmode \dot{}\else \.{}\fi{}}{n}}_{c}$-induced effective interaction, which cannot be ignored on the grounds of the adiabatic approximation for modes near the gapless Goldstone mode, can significantly affect condensate populations and Tan's contact for a Bose gas that has undergone a deep quench.
We investigate the tunneling dynamics of an ultracold bosonic impurity species which interacts repulsively with a second, larger Bose gas. Both species are held in a finite-sized quasi-one-dimensional box potential. In addition, the impurity bosons experience a periodic potential generated by an optical lattice. We initially prepare our binary mixture in its ground state, such that the impurities and Bose gas are phase separated and the impurities localize pairwise in adjacent sites of the periodic potential, by tuning the interaction strengths and the lattice depth correspondingly. The dynamics is initiated by suddenly lowering the repulsive interspecies interaction strength, thereby entering a different regime in the crossover diagram. For specific postquench interspecies interaction strengths we find that a single impurity tunnels first to the neighboring empty site and depending on the quench strength can further tunnel to the next-neighboring site. Interestingly, this effect is highly sensitive to the presence of the Bose gas and does not occur when the Bose gas does not interact with the impurity species throughout the dynamics. Moreover, we find that the tunneling process is accompanied by strong entanglement between the Bose gas and the impurity species as well as correlations among the impurities.