Minganti Fabrizio, Bartolo Nicola, Lolli Jared, Casteels Wim, Ciuti Cristiano
Université Paris Diderot, Sorbonne Paris Cité, Laboratoire Matériaux et Phénomènes Quantiques, CNRS-UMR7162, 75013 Paris, France.
Sci Rep. 2016 May 31;6:26987. doi: 10.1038/srep26987.
In quantum optics, photonic Schrödinger cats are superpositions of two coherent states with opposite phases and with a significant number of photons. Recently, these states have been observed in the transient dynamics of driven-dissipative resonators subject to engineered two-photon processes. Here we present an exact analytical solution of the steady-state density matrix for this class of systems, including one-photon losses, which are considered detrimental for the achievement of cat states. We demonstrate that the unique steady state is a statistical mixture of two cat-like states with opposite parity, in spite of significant one-photon losses. The transient dynamics to the steady state depends dramatically on the initial state and can pass through a metastable regime lasting orders of magnitudes longer than the photon lifetime. By considering individual quantum trajectories in photon-counting configuration, we find that the system intermittently jumps between two cats. Finally, we propose and study a feedback protocol based on this behaviour to generate a pure cat-like steady state.
在量子光学中，光子薛定谔猫态是具有相反相位且包含大量光子的两个相干态的叠加。最近，在受工程化双光子过程驱动的耗散谐振器的瞬态动力学中观测到了这些态。在此，我们给出了这类系统稳态密度矩阵的精确解析解，其中包括单光子损耗，而单光子损耗被认为不利于实现猫态。我们证明，尽管存在显著的单光子损耗，唯一的稳态是两个具有相反宇称的类猫态的统计混合。到稳态的瞬态动力学极大地依赖于初始状态，并且可以经过一个比光子寿命长几个数量级的亚稳区域。通过考虑光子计数配置中的单个量子轨迹，我们发现系统会在两个类猫态之间间歇性跳跃。最后，我们基于这种行为提出并研究了一种反馈协议，以生成一个纯类猫态的稳态。
