A generalized microscopic model of quantum jump superoperators

Alexandre V. Dodonov, V. V. Dodonov, Salomon Sylvain Mizrahi

Salomon Sylvain Mizrahi, Alexandre V. Dodonov, V. V. Dodonov

Teppo Häyrynen, Joel Oksanen, Jukka Tulkki

Alexandre V. Dodonov, Salomon Sylvain Mizrahi, V. V. Dodonov

We examine some aspects of the continuous photodetection model for photocounting processes in cavities. First, we work out a microscopic model that describes the field-detector interaction and deduce a general expression for the Quantum Jump Superoperator (QJS), that shapes the detector's post-action on the field upon a detection. We show that in particular cases our model recovers the QJSs previously proposed ad hoc in the literature and point out that by adjusting the detector parameters one can engineer QJSs. Then we set up schemes for experimental verification of the model. By taking into account the ubiquitous non-idealities, we show that by measuring the lower photocounts moments and the mean waiting time one can check which QJS better describes the photocounting phenomenon.

Alexandre V. Dodonov, Salomon Sylvain Mizrahi, V. V. Dodonov

We discuss the quantum-jump operation in an open system and show that jump superoperators related to a system under measurement can be derived from the interaction of that system with a quantum measurement apparatus. We give two examples for the interaction of a monochromatic electromagnetic field in a cavity (the system) with two-level atoms and with a harmonic oscillator (representing two different kinds of detectors). We show that the derived quantum-jump superoperators have a ``nonlinear'' form $J\ensuremath{\rho}=\ensuremath{\gamma}\phantom{\rule{0.2em}{0ex}}\mathrm{diag}[F(\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{n})a\ensuremath{\rho}{a}^{\ifmmode\dagger\else\textdagger\fi{}}F(\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{n})]$, where the concrete form of the function $F(\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{n})$ depends on assumptions made about the interaction between the system and detector. Under certain conditions the asymptotical power-law dependence $F(\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{n})={(\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{n}+1)}^{\ensuremath{-}\ensuremath{\beta}}$ is obtained. A continuous transition to the standard Srinivas-Davies form of the quantum-jump superoperator (corresponding to $\ensuremath{\beta}=0$) is shown.

Dominique Spehner, Jean Bellissard