Atomic States

Hiroki Saito, Masahito Ueda

This paper develops an idea of manipulating the squeezed atom state to generate a few-photon state whose phase or photon-number fluctuations are prescribed at our disposal. The squeezed atom state is a collective atomic state whose quantum fluctuations in population difference or collective dipole are smaller than those of the coherent atom state. It is shown that the squeezed atom state can be generated by the interaction of atoms with a coherent state of the electromagnetic field, and that it can be used as a tunable source of squeezed radiation. A variety of squeezed states including the photonnumber squeezed state and the phase squeezed state can be produced by manipulating the atomic state. This is owing to the fact that quantumstatistical information of the atomic state is faithfully transferred to that of the photon state. Possible experimental situations to implement our theory are discussed.

Ilexa Yardley

Hiroki Saito, Masahito Ueda

This paper develops a method of manipulating the squeezed atom state to generate a few-photon state whose phase or photon-number fluctuations are prescribed at our disposal. The squeezed-atom state is a collective atomic state whose quantum fluctuations in population difference or collective dipole are smaller than those of the coherent atom state. It is shown that the squeezed-atom state can be generated by the interaction of atoms with a coherent state of the electromagnetic field, and that it can be used as a tunable source of squeezed radiation. A variety of squeezed states, including the photon-number squeezed state and the phase squeezed state, can be produced by manipulating the atomic state. This is owing to the fact that quantum-statistical information of the atomic state is faithfully transferred to that of the photon state. Possible experimental situations to implement our theory are discussed.

Maximilian Schlosshauer

Xue-Ping Zang, Ming Yang, Wang Xian-cai +2 more

In this paper, we study how to fuse two W states into a larger W state in a cavity quantum electrodynamic system. Two atoms are collided within a detuned vacuum cavity mode. One atom is from the first N-atom W state system, and the other is from the second M-atom W state system. The two atoms will be detected after flying out of the cavity mode. If only one excitation is detected between the two atoms, an (N + M − 2)-atom W state can be generated with some probability. If no excitation is detected between the two atoms, the remaining (N − 1)-atom W state and (M − 1)-atom W state can be re-fused using the same procedure, continuing until two excitations are detected between the two atoms. Using this procedure, the chance of entanglement of the two W states is as large as possible. A feasibility analysis indicates that this scheme can be implemented using existing experimental technologies.

Lev Deych