Time-dependent entropies associated with single mode radiation in a cavity

David A. Branning

X. X. Yi

The emission spectrum of a two-level atom with moving mass centre interacting with a single-mode radiation field in a ring cavity and the field entropy evolution has been studied. As a result, the theoretical curves of the emission spectrum have been given; the features of the emission spectrum depend not only on the photon statistical distribution of the initial field, such as the coherent field and the Fock state, but also on the bandpass width γ of the filter detector and distribution of mass-centre momentum. The properties of field entropy evolution show a damping function of time; it is different from that when the atom is at rest.

弘樹 斎藤, Hiroki Saito

Bryan J. Dalton, P. L. Knight

Specific forms of the travelling and trapped vector mode functions for a three-dimensional Fabry-Perot cavity are developed from the general results of the preceding paper, with parameters describing the output cavity mirror chosen for a typical high Q cavity case. Cavity and external quasi-mode functions associated with the quasi-mode theory of macroscopic canonical quantization are then obtained via an idealized choice of output mirror parameters. The coupling constants describing photon exchange processes between the single cavity quasi-mode associated with each Fabry-Perot resonance and various external quasi-modes are calculated, and their slow dependence on the external quasi-mode frequency shows that the conditions for irreversible Markovian damping of the cavity quasi-mode are satisfied. For radiative atoms placed in the cavity the coupling constants for energy exchange processes with sideways travelling external quasi-modes also vary slowely, so that Markovian spontaneous emission damping occurs for the radiative atoms. However, their coupling with the isolated cavity quasi-modes is associated with reversible photon exchanges as represented via one photon Rabi frequencies. The standard model in cavity quantum electrodynamics, in which the basic processes are described by a cavity damping rate, a radiative atom spontaneous decay rate and an atom-cavity mode coupling constant has now been justified in terms of the quasi-mode theory of macroscopic canonical quantization.

C.T. Lee

M. A. Cirone, Kazimierz Rza̧żewski

The quantum radiation field inside a double cavity is examined. The double cavity consists of a cavity containing a reflecting mirror. Two independent radiation fields are present inside the cavity. It is then assumed that the mirror becomes suddenly transparent. The double cavity transforms thus into a single cavity. The relationship between the radiation fields before and after the change is investigated. It is shown that the sudden change excites the radiation modes of the single cavity. Only modes having a node at the position of the mirror are not excited. The sudden change of the mirror's reflectivity can thus generate photons from the vacuum. It is also shown that the sudden change produces squeezing. These features of the double cavity are then employed in a gedankenexperiment for the generation of entanglement between noninteracting atoms with the quantum eraser technique.