Maximum entropy of fields with given degrees of higher order coherence

B. A. Sotskii, Столяров Александр Дмитриевич

Zhi-Xiang Jin, Long-Mei Yang, Shao-Ming Fei +4 more

Tang-Kun Liu

The field entropy can be regarded as a measurement of the degree of entanglement between the light field and the atoms of a system which is composed of two-level atoms initially in an entangled state interacting with the Schrödinger cat state. The influences of the strength of light field and the phase angle between the two coherent states on the field entropy are discussed by using numerical calculations. The result shows that when the strength of light field is large enough the field entropy is not zero and the degrees of entanglement between the atoms and the three different states of the light fields are equal. When the strength of the light field is small, the degree of entanglement is maximum in a system of the two entangled atoms interacting with an odd coherent state; it is intermediate for a system of the two entangled atoms interacting with the Yurke–Stoler coherent state and it is minimum in a system of the two entangled atoms interacting with an even coherent state.

Cai Zhang

The field entropy evolution of a system which is composed of two moving entangled atoms interacting with the Schrdinger cat state is studied by means of the full quantum theory.The influences of the strength of light field,the phase angle between the two coherent states,the atomic motion and the field-model structure parameter on the field entropy are discussed.The result shows that the atomic motion leads to the periodic evolution of the field entropy.When the strength of light field is small,the degree of entanglement is maximum in a system of the moving atoms interacting with an odd coherent state;it is intermediate for a system of the the moving atoms interacting with Yurke-Stoler coherent state,and it is minimum in a system of the moving atoms interacting with an even coherent state.When the strength of light field is large enough,the degrees of entanglement between the moving atoms and the three different states of the light fields become equal,and the properties of field entropy evolvement are also same.With increasing atomic speed or field-model structure parameter,the evolution period of the field entropy is shortter,the degree of entanglement between field and moving atoms is weaker.

Wu Shu

The field entropy evolution in a system of the Schrodinger cat state light field interacting with a two-level atom was studied by solving Milburn equation.The influence of intrinsic decoherence,the strength of light field and the phase angle between the two coherence states on the field entropy evolution was discussed.The results show that the field entropy vibration will be weak gradually because of the intrinsic decoherence,and the degree of entanglement in the field-atom system approaches to a certain value with time evolution.Furthermore,the degree of entanglement in the field-atom system only depends on the strength of light field and the phase angle between the two coherence states,and have nothing to do with intrinsic decoherence.When the strength of light field is relatively small,the degree of entanglement is maximum in a system of a two-level atom interacting with an odd coherence state light field,and it is minimum in a system of a two-level atom interacting with an even coherence state light field;it is intermediate for a system of a two-level atom interacting with Yurke-Stoler coherence state light field.When the intrinsic decoherence is fixed and the strength of light field is relatively large,the degree of entanglement in the field-atom system existing in the Yurke-stoler,the even coherence state and odd coherence state tends to the same.

Timothy C. Wallstrom