### Abstract

The formulation for zero mode of a Bose–Einstein condensate beyond the Bogoliubov approximation at zero temperature [Y. Nakamura et al., Phys. Rev. A 89 (2014) 013613] is extended to finite temperature. Both thermal and quantum fluctuations are considered in a manner consistent with a concept of spontaneous symmetry breakdown for a finite-size system. Therefore, we need a proper treatment of the zero mode operators, which invoke non-trivial enhancements in depletion condensate and thermodynamical quantities such as the specific heat. The enhancements are visible in the weak interaction case. Our approach reproduces the results of a homogeneous system in the Bogoliubov approximation in a large particle number limit.

Original language | English |
---|---|

Pages (from-to) | 484-498 |

Number of pages | 15 |

Journal | Annals of Physics |

Volume | 376 |

DOIs | |

Publication status | Published - 2017 Jan 1 |

### Fingerprint

### Keywords

- Bose–Einstein condensation
- Cold atom
- Finite temperature
- Quantum field theory
- Spontaneous symmetry breaking
- Zero mode

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*Annals of Physics*,

*376*, 484-498. https://doi.org/10.1016/j.aop.2016.12.020

**Thermal and quantum fluctuations of confined Bose–Einstein condensate beyond the Bogoliubov approximation.** / Nakamura, Y.; Kawaguchi, T.; Torii, Y.; Yamanaka, Yoshiya.

Research output: Contribution to journal › Article

*Annals of Physics*, vol. 376, pp. 484-498. https://doi.org/10.1016/j.aop.2016.12.020

}

TY - JOUR

T1 - Thermal and quantum fluctuations of confined Bose–Einstein condensate beyond the Bogoliubov approximation

AU - Nakamura, Y.

AU - Kawaguchi, T.

AU - Torii, Y.

AU - Yamanaka, Yoshiya

PY - 2017/1/1

Y1 - 2017/1/1

N2 - The formulation for zero mode of a Bose–Einstein condensate beyond the Bogoliubov approximation at zero temperature [Y. Nakamura et al., Phys. Rev. A 89 (2014) 013613] is extended to finite temperature. Both thermal and quantum fluctuations are considered in a manner consistent with a concept of spontaneous symmetry breakdown for a finite-size system. Therefore, we need a proper treatment of the zero mode operators, which invoke non-trivial enhancements in depletion condensate and thermodynamical quantities such as the specific heat. The enhancements are visible in the weak interaction case. Our approach reproduces the results of a homogeneous system in the Bogoliubov approximation in a large particle number limit.

AB - The formulation for zero mode of a Bose–Einstein condensate beyond the Bogoliubov approximation at zero temperature [Y. Nakamura et al., Phys. Rev. A 89 (2014) 013613] is extended to finite temperature. Both thermal and quantum fluctuations are considered in a manner consistent with a concept of spontaneous symmetry breakdown for a finite-size system. Therefore, we need a proper treatment of the zero mode operators, which invoke non-trivial enhancements in depletion condensate and thermodynamical quantities such as the specific heat. The enhancements are visible in the weak interaction case. Our approach reproduces the results of a homogeneous system in the Bogoliubov approximation in a large particle number limit.

KW - Bose–Einstein condensation

KW - Cold atom

KW - Finite temperature

KW - Quantum field theory

KW - Spontaneous symmetry breaking

KW - Zero mode

UR - http://www.scopus.com/inward/record.url?scp=85009494360&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85009494360&partnerID=8YFLogxK

U2 - 10.1016/j.aop.2016.12.020

DO - 10.1016/j.aop.2016.12.020

M3 - Article

AN - SCOPUS:85009494360

VL - 376

SP - 484

EP - 498

JO - Annals of Physics

JF - Annals of Physics

SN - 0003-4916

ER -