Generation of Squeezed States: Rydberg Atoms in a High Q Cavity

Bryan J. Dalton

Jiteng Sheng, Yuanxi Chao, Santosh Kumar +3 more

We present an experimental study of cavity-assisted Rydberg-atom electromagnetically induced transparency (EIT) using a high-finesse optical cavity ($F\ensuremath{\sim}28\phantom{\rule{0.16em}{0ex}}000$). Rydberg atoms are excited via a two-photon transition in a ladder-type EIT configuration. A three-peak structure of the cavity transmission spectrum is observed when Rydberg EIT is generated inside the cavity. The two symmetrically spaced side peaks are caused by bright-state polaritons, while the central peak corresponds to a dark-state polariton. Anticrossing phenomena and the effects of mirror adsorbate electric fields are studied under different experimental conditions. We determine a lower bound on the coherence time for the system of $7.26\ifmmode\pm\else\textpm\fi{}0.06\phantom{\rule{1em}{0ex}}\ensuremath{\mu}\mathrm{s}$, most likely limited by laser dephasing. The cavity-Rydberg EIT system can be useful for single-photon generation using the Rydberg blockade effect, studying many-body physics, and generating novel quantum states among many other applications.

Aditi Ray, Ravinder Rupchand Puri

Mohamed Ridza Wahiddin, B. M. Garraway, R. Bullough

It is shown that some 17 Rydberg Na atoms initially placed into a coherent atomic state and super-radiating into a low-Q microwave cavity at temperatures T ≲ 0·4 K will show modest squeezing in the fluorescence field, the squeezing arising from terms oscillating at twice the cavity frequency. It is also shown that similar numbers of Rydberg atoms undergoing resonance fluorescence in a coherent single-mode microwave driving field and without any cavity will show more substantial squeezing in the fluorescence field.

Mohamed Ridza Wahiddin, Saad S. M. Hassan, JUSSI TIMONEN +1 more

J. M. C. Malbouisson, B. Baseia

Higher-generation Schrödinger cat states of the quantized electromagnetic field can be produced in a high-Q cavity, starting from a coherent state, through the passage of prepared Rydberg atoms interacting dispersively across it. These states are natural generalizations of the even and odd coherent states, the N th-generations corresponding to specific superpositions of 2 N states on a circle in phase space with well defined parity, and present very peculiar properties. Their photon statistics interchange between super- and sub-Poissonian behaviours and the nature of the photon bunching oscillates as the field intensity in the cavity is varied. For higher-generation even states, the minimum value of the Mandel factor almost reaches −1.0 and the state represents the Fock state |2 N ). Squeezing properties and the Wigner function of these higher-generation Schrödinger cat states are also considered.