Light shifts and multiple quantum transitions

J.A. Hermann, S. Swain

M. S. Shahriar, G. S. Pati, K. Salit

Recently, we have shown that for conditions under which the so-called light-shift imbalance induced blockade occurs, the collective excitation of an ensemble of a multilevel atom can be treated as a closed two-level system. In this paper, we describe how such a system can be used as a quantum bit (qubit) for quantum communication and quantum computing. Specifically, we show how to realize a controlled-NOT gate using the collective qubit and an easily accessible ring cavity, via an extension of the so-called Pellizzari scheme. We also describe how multiple, small-scale quantum computers realized using these qubits can be linked effectively for implementing a quantum internet. We describe the details of the energy levels and transitions in an $^{87}\mathrm{Rb}$ atom that could be used for implementing these schemes.

Masahiro Fukuoka, Akira Hanatani, Shigeyoshi Goka

SummaryA simple light-shift measurement method using multiple photodetectors (PDs) suitable for chip-scale atomic clocks (CSACs) and miniature atomic clocks (MACs) was proposed. This method can be used with at least two photodetectors in real-time operations. To increase the long-term frequency stabilities of CSACs and MACs, the proposed method can be used as a zero light shift detector for active light shift stabilization[1].

P. Jung

Leonti N Labzowsky, Dmitry A. Solovyev, G. Plunien +2 more

The process of nonresonant photon scattering on a hydrogen atom is considered as a microscopic model for a quantum-mechanical description of the reflection of light on a mirror. Multiple reflections of this kind then can serve as a model for light storage within a system of mirrors. In combination with modern high-precision measurements of atomic transition frequencies, such a storage of light could allow for new information on the time variation of fundamental constants, such as the fine-structure constant. The intensity distribution shift arising due to the inherent asymmetry of the natural line profile sets an ultimate limit for the preservation of the photon light frequency during storage. In the case of a ‘hydrogen mirror’ this shift appears to be much larger than the relative accuracy of about 10 −15 required in measurements of a time dependence of the fine-structure constant. Possibilities of achieving the required accuracy are discussed.