Past quantum state analysis of the photon number evolution in a cavity

Théo Rybarczyk (1) , Stefan Gerlich (1) , Bruno Peaudecerf (1) , Mariane Penasa (1) , Brian Julsgaard (2) , Klaus Moelmer (2) , Sébastien Gleyzes (1) , Michel Brune (1) , Jean-Michel Raimond (1) , Serge Haroche (1) , Igor Dotsenko (1)

1 LKB [Collège de France] - Laboratoire Kastler Brossel
2 Department of Physics and Astronomy [Aarhus]

A quantum system can be monitored through repeated interactions with meters, followed by their detection. The state of the system at time t is thus conditioned on the information obtained until that time. More insight in the state dynamics is provided, however, by the past quantum state (PQS) [S. Gammelmark et al. Phys. Rev. Lett. 111, 160401 (2013)]. It relies on all aspects of the system evolution which are recorded in the past and in the future of t. Using PQS analysis for the quantum non-demolition photon number counting in a cavity, we can reveal information hidden in the standard approach and resolve a wider range of number states. This experiment demonstrates the strong potential of PQS analysis.

Mots clés: CQED; QND; past quantum state; Ramsey interferometer; circular Rydberg states; Fock states

Domaines: Physique Quantique [quant-ph]

Théo Rybarczyk, Stefan Gerlich, Bruno Peaudecerf, Mariane Penasa, Brian Julsgaard, et al.. Past quantum state analysis of the photon number evolution in a cavity. 2014. ⟨hal-01053091⟩