Birth, death, and revival of spontaneous emission in a three-atom system
Simon Mährlein, Lukas Götzendörfer, Kevin Günthner, Jörg Evers, Joachim von Zanthier
2020
Physical Review Research
Three identical two-level atoms in free space prepared in particular entangled single-photon excited states display a "birth," "death," and a nonperiodic "revival" of spontaneous emission in selected directions. Instead of recording the spontaneously emitted photon with a maximum probability at t = 0 as for a single atom, a "birth" manifests itself in an initially zero photon detection probability, increasing thereafter in particular directions. Alternatively, the photon detection probability
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... creases in particular directions from an initially maximal value to completely disappear ("death") and to reappear again ("revival"). We show how these phenomena can be induced in the fully excited system, by projecting the atomic ensemble into the required entangled single-photon excited state via detection of the first two spontaneously emitted photons. To observe death and revival of spontaneous emission it is necessary to provide both spatial and temporal interference for which a minimum of three atoms is required. Hereby, the third atom, located at a large distance with respect to the other two atoms, can be used to tune the time and direction of the death of the photon. From this manipulation of spontaneous decay at a distance, we anticipate multiple applications, in fundamental science as well as in quantum technologies. Collapse and revival occur for many phenomena in quantum physics appearing in different aspects and forms [1-7]. Typically, an observable of a system falls off in time to vanish at a given moment only to reappear again, in some cases even to its original value, sometimes in a periodic manner. A prominent example from atomic physics is a two-level atom interacting with a single mode of a cavity, as described by the Jaynes-Cummings model [1] . Here, in the absence of losses, the atomic inversion [2] as well as the atomic dipole moment [3] display periodic collapses and revivals, what has been observed also experimentally [4, 5] . Another well-known example are spin echos [6] , where the spins of an inhomogenously broadened atomic ensemble precess at a different pace in an external magnetic field, producing after some time a zero total magnetization; yet, a suitable inversion pulse can effectively reverse the dephasing process leading after some time to a revival of the initial magnetization. A common feature of collapse and revival is that it typically occurs in closed systems, e.g., subject to particular boundary conditions. Here, lossy channels, as the infinite amount of vacuum modes in spontaneous decay, are typically not involved. Indeed, losses tend to prohibit rephasing and revivals in a
doi:10.1103/physrevresearch.2.013278
fatcat:64nkxqt4lbfihad44gizr2spmi