Manipulating a Bose-Einstein condensate with a single photon

Heping Zeng, Fucheng Lin, Weiping Zhang

Cuilu Zhai, Wangjun Lu, Ya‐Feng Jiao +1 more

Abstract A proposal is made on how to manipulate photon blockades (PBs) and photon‐induced tunneling (PIT) in an optomechanical cavity with a Bose‐Einstein Condensate. It is shown that the single‐photon blockade (1PB) can emerge with appropriate scattering strength between atoms. Further, by tuning interatomic scattering strength, the switch between 1PB and PIT at the fixed optical detuning can be realized in interatomic repulsion or attraction conditions. The enhancement of 1PB can also be achieved. The scattering control of PBs can be understood from the perspective of the anharmonicity of the energy levels modulated by the interatomic collision. Such a system can be equivalent to a conventional optomechanical system plus an interatomic scattering term. It is found that although there are no PBs in the conventional optomechanical system, in the BEC optomechanical system (BECOMS), PBs can occur at the fixed optical detuning. Moreover, the BECOMS can exhibit stronger 1PB under the same optomechanical coupling intensity. Due to the advantages of intrinsic strong optomechanical nonlinearity and the negligible thermal noise of the mechanical environment, BECOMS is promising for experimental realization of PBs. The results open new possibilities for manipulating few‐photon states in quantum regime in cavity optomechanics with a Bose‐Einstein Condensate.

JIA Shaopeng, ZHANG Rui, Bo Li +4 more

本文通过单原子掺杂调控腔玻色–爱因斯坦凝聚体（Bose-Einstein condensate，BEC）系统中的量子导引性质。结果表明，单原子掺杂的腔BEC系统可等效为一个广义Dicke模型，其正常相和超辐射相均展现出丰富的量子导引特性。在有杂质原子的情况下，正常相中腔场与凝聚原子之间仅存在单向量子导引，超辐射相中则同时存在单向和双向量子导引；在无杂质原子的情况下，正常相和超辐射相中腔场与凝聚原子之间均同时存在单向和双向量子导引。研究发现，单个杂质原子可作为调控量子导引的“单原子开关”：通过开启或关闭杂质与BEC之间的相互作用，不仅能够灵活控制单向量子导引的方向，还能实现单向与双向量子导引之间的相互转换。此外，量子导引参数在量子相变临界点处发生突变，可作为判定量子相变发生的有效标志。这些结果为利用单原子调控腔场-BEC系统中的量子导引，以及探测广义Dicke模型中正常相与超辐射相之间的量子相变提供了新途径。

Allard P. Mosk

Ben Kassenberg, Mario Vretenar, Jan Andre Klärs

Simon L. Cornish, Donatella Cassettari

When the atoms in a gas are cooled to extremely low temperatures, their quantum-mechanical nature starts to dominate the properties of the whole gas. Under the appropriate conditions, the atoms will 'condense' into a single quantum state of the system-a phenomenon known as Bose-Einstein condensation (BEC). The resulting 'condensate' behaves as a single, observable quantum-mechanical object. During the last decade, this new state of matter has displayed many remarkable properties. In this paper, we review some of the most recent experimental developments in the BEC field, highlighting the role of atomic interactions and the high degree of control with which condensates may be manipulated.