Collapse of Metastability by the Quantum Fluctuation

Hiroto Kobayashi, Naomichi Hatano, Akira Terai +1 more

Marco Zoli

Sergei V. Iordanskii, A. M. Finkel'Shteǐn

Sergei V. Iordanskii, A. M. Finkel'Shteǐn

Josselin C. Garnier, F. Kh. Abdullaev, Bakhtiyor B. Baizakov

The dynamics of a metastable attractive Bose-Einstein condensate trapped by a system of laser beams is analyzed in the presence of small fluctuations of the laser intensity. It is shown that the condensate will eventually collapse. The expected collapse time is inversely proportional to the integrated covariance of the time autocorrelation function of the laser intensity and it decays logarithmically with the number of atoms. Numerical simulations of the stochastic three-dimensional Gross-Pitaevskii equation confirm analytical predictions for small and moderate values of mean-field interaction.

Nguyen Thanh Phuc, Yuki Kawaguchi, Masahito Ueda

Spinor Bose-Einstein condensates provide a unique example in which the Bogoliubov theory fails to describe the metastability associated with first-order quantum phase transitions. This problem is resolved by developing the spinor Beliaev theory which takes account of quantum fluctuations of the condensate. It is these fluctuations that generate terms of higher than the fourth order in the order-parameter field which are needed for the first-order phase transitions. Besides the conventional first-order phase transitions which are accompanied by metastable states, we find a class of first-order phase transitions which are not accompanied by metastable states. The absence of metastability in these phase transitions holds to all orders of approximation since the metastability is prohibited by the symmetry of the Hamiltonian at the phase boundary. Finally, the possibility of macroscopic quantum tunneling from a metastable state to the ground state is discussed.