7 citations · 23 across the 5 of their papers we have counts for
5 papers
Are Quasiparticles and Phonons Identical in Bose--Einstein Condensates?
Kazumasa Tsutsui, Yusuke Kato, Takafumi Kita
We study an interacting spinless Bose-Einstein condensate to clarify theoretically whether the spectra of its quasiparticles (one-particle excitations) and collective modes (two-pa…
Quantum Correlations of Ideal Bose and Fermi Gases in the Canonical Ensemble
Kazumasa Tsutsui, Takafumi Kita
We derive an expression for the reduced density matrices of ideal Bose and Fermi gases in the canonical ensemble, which corresponds to the Bloch--De Dominicis (or Wick's) theorem i…
Lifetime of Single-Particle Excitations in a Dilute Bose-Einstein Condensate at Zero Temperature
Kazumasa Tsutsui, Takafumi Kita
We study the lifetime of single-particle excitations in a dilute homogeneous Bose-Einstein condensate at zero temperature based on a self-consistent perturbation expansion of satis…
Ground-State Energy and Condensate Density of a Dilute Bose Gas Revisited
Kazumasa Tsutsui, Takafumi Kita
The ground-state energy per particle and condensate density of a dilute Bose gas are studied with a self-consistent perturbation expansion satisfying the Hugenholtz-Pin…
Studying Superfluid Transition of a Dilute Bose Gas by Conserving Approximations
K. Tsutsui, T. Kita
We consider the Bose-Einstein transition of homogeneous weakly interacting spin-0 particles based on the normal-state Phi-derivable approximation. Self-consistent calculations of G…