Atoms in a Classical Light Field

Zhang Ying-Jie, Yun‐Jie Xia, Ren Ting-Qi +3 more

A two-level atom drvien by a strong classical field interacts with a single-mode light field, and the interaction between the atom and the light field can turn into an effective anti-Jaynes-Cummings model under the conditions of strong driving and large detuning. In this paper, we mainly study the two-mode entangled coherent light field in this model, in which one mode of the entangled coherent light field interacts with a two-level atom driven by a strong classical field. During the evolution of the total system, we make a selective measurement on the atom. Through tuning the evolution time and the parameter of the coherent field, we can easily control the quantum statistical properties of the other mode of the entangled light fields and generate the expected non-classical light field in a longer interaction time and a wider region of coherent parameter.

Zhongjie Wang

The quantum properties of the light field in the system of thermal radiation field interacting with two identical entangled atoms are studied by means of time evolution operator and numerical calculations.The results show that the entanglement degree of the initial two identical two-level entangled atoms and the intensity of the thermal radiation field have influence on the quantum properties of light field.For the initial light field with appropriate intensity,the non-classical properties of the light field will appear.The non-classical properties are increased by the growth of the intensity of the initial thermal radiation field,but the influence of the entanglement degree on the non-classical properties is complex.

Katharina Soukup, Fabio Di Pumpo, Tobias Asano +2 more

The far-field patterns of atoms diffracted from a classical light field or from a quantum one in a photon-number state are identical. On the other hand, diffraction from a field in a coherent state, which shares many properties with classical light, displays a completely different behavior. We show that in contrast to the diffraction patterns, the interference signal of an atom interferometer with light-pulse beam splitters and mirrors in intense coherent states does approach the limit of classical fields. However, low photon numbers reveal the granular structure of light, leading to a reduced visibility since welcher-Weg (which-way) information is encoded into the field. We discuss this effect for a single photon-number state as well as a superposition of two such states.