Bosonic Coherent States

E. Celeghini, Mario Rasetti

Akira Shimizu, Takayuki Miyadera

We study spatial correlation functions of local operators of interacting many bosons confined in a box of a large, but volume V, for various `ground states' whose energy densities are almost degenerate. The ground states include the coherent state of interacting bosons (CSIB), the number state of interacting bosons (NSIB), and the number-phase squeezed state of interacting bosons, which interpolates between the CSIB and NSIB. It was shown previously that only the CSIB is robust (i.e., does not decohere for a macroscopically long time) against the leakage of bosons into an environment. We show that for the CSIB the spatial correlation of any local operators A(r) and B(r') (which are localized around r and r', respectively) vanishes as |r - r' | \sim V^{1/3} \to \infty, i.e., the CSIB has the `cluster property.' In contrast, the other ground states do not possess the cluster property. Therefore, we have successfully shown that the robust state has the cluster property. This ensures the consistency of the field theory of bosons with macroscopic theories.

Alastair Brodlie

A. Kuriyama, C. Providencia, J. d. Providencia +2 more

The treatment of the multiboson coherent state is extended for the completeness of the formulation. The basic idea of the extension is presented in terms of expanding the boson space. The MYT boson mapping plays a central role. The resultant multiboson coherent state includes the state obtained in our previous treatment and the form suggests that various multiboson coherent states are possible in the deformed boson scheme.

A. Kuriyama, Constança Providência, João da Providência +2 more

An idea for a deformed boson scheme developed by the present authors is applied to the case of boson-pair coherent state. In this state, the even and odd boson number difference is stressed and various concrete examples of boson-pair coherent states are given. Concerning some of them, mutual relations are investigated in connection to the su(1,1)-algebra. A formulation in terms of the MYT boson mapping is also presented.

Luca Salasnich