Long-lived Macroscopic Schrödinger Cat States in Atomic Ensembles*

How to create and stabilize large-size Schrödinger cat states remains challenging. This is mainly attributed to dissipation (and in particular, single-particle loss) induced by the environment. In Ref. [1], we proposed a method to obtain large-size and long-lived Schrödinger cat states in atomic ensembles. Specifically, we show that a fully quantum parametric amplifier can simultaneously lead to two-atomic-excitation loss and driving, and then robust atomic-cat states against spin dephasing. As a result, our approach enables an extremely long cat-state lifetime, which, under realistic parameters, is up to four orders of magnitude longer than that of common intracavity optical cat states, and reaches tens of milliseconds. Therefore, our work opens up a new way towards the long-standing goal of engineering large-size and long-lived cat states, with immediate interests both in fundamental studies of quantum mechanics and noise-immune quantum information processing.

[1] Wei Qin, Adam Miranowicz, Hui Jing, and Franco Nori,
Long-lived Macroscopic Schrödinger Cat States in Atomic Ensembles,
available online at: shorturl.at/gmvE0