Passarelli Gianluca, Turkeshi Xhek, Russomanno Angelo, Lucignano Procolo, Schirò Marco, Fazio Rosario
CNR-SPIN, c/o Complesso di Monte S. Angelo, via Cinthia-80126-Napoli, Italy.
JEIP, UAR 3573 CNRS, Collège de France, PSL Research University, 75321 Paris Cedex 05, France.
Phys Rev Lett. 2024 Apr 19;132(16):163401. doi: 10.1103/PhysRevLett.132.163401.
We study the properties of a monitored ensemble of atoms driven by a laser field and in the presence of collective decay. The properties of the quantum trajectories describing the atomic cloud drastically depend on the monitoring protocol and are distinct from those of the average density matrix. By varying the strength of the external drive, a measurement-induced phase transition occurs separating two phases with entanglement entropy scaling subextensively with the system size. Incidentally, the critical point coincides with the superradiance transition of the trajectory-averaged dynamics. Our setup is implementable in current light-matter interaction devices, and most notably, the monitored dynamics is free from the postselection measurement problem, even in the case of imperfect monitoring.
我们研究了由激光场驱动且存在集体衰变的受监测原子系综的性质。描述原子云的量子轨迹的性质极大地取决于监测协议，并且与平均密度矩阵的性质不同。通过改变外部驱动的强度，会发生测量诱导的相变，将两个相分开，其中纠缠熵随系统大小以次广延方式缩放。顺便提一下，临界点与轨迹平均动力学的超辐射相变相重合。我们的设置在当前的光与物质相互作用装置中是可实现的，最值得注意的是，即使在监测不完善的情况下，受监测的动力学也不存在后选择测量问题。
