Stochastic resonance (SR) induced by the signal modulation is investigated, by introducing the signal-modulated gain into a single-mode laser system. Using the linear approximation method, we detailedly calculate the signal-to-noise ratio (SNR) of a gain-noise model of the single-mode laser,...

In previous papers we have studied stationary [Physica A 197 (1993) 364] and transient [Physica A 268 (1999) 121] solutions of a quantized LC-circuit showing squeezing effect generated by a time-dependent parameter. Here we extend this issue studying the transfer of this effect in coupled...

Vacuum fluctuations of the electromagnetic field induce current fluctuations in resistively shunted Josephson junctions that are measurable in terms of a physically relevant power spectrum. In this paper we investigate under which conditions vacuum fluctuations can be gravitationally active,...

We analyze in detail the discrete-time quantum walk on the line by separating the quantum evolution equation into Markovian and interference terms. As a result of this separation, it is possible to show analytically that the quadratic increase in the variance of the quantum walker's position...

Given an arbitrary probability distribution and a nondegenerate energy spectrum, so that a mean energy U can be computed, we derive the partition function Z and the entropic functional S that satisfy the basic relation dU=TdS. The procedure is illustrated by considering examples of typical...

We consider a new model of quantum walk on a one-dimensional momentum space that includes both discrete jumps and continuous drift. Its time evolution has two stages; a Markov diffusion followed by localized dynamics. As in the well known quantum kicked rotor, this model can be mapped into a...

A new Bell-type inequality is derived through the use of the Tsallis entropy to quantify the dependence between the classical outcomes of measurements performed on a bipartite quantum system, as typical of an EPR experiment. This new inequality is confronted with standard correlation-based Bell...

We give a detailed account of the derivation of a master equation for two-coupled cavities in the presence of dissipation. The analytical solution is presented and physical limits of interest are discussed. Firstly, we show that the decay rate of initial coherent states can be significantly...

We consider the effect of different unitary noise mechanisms on the evolution of a quantum walk (QW) on a linear chain with a generic coin operation: (i) bit-flip channel noise, restricted to the coin subspace of the QW and (ii) topological noise caused by randomly broken links in the linear...

Several dynamical equations for quantum information density (QID) in an open quantum electrodynamic system are studied. We discuss extending the kinetic equation of QID to the domain of quantum fields. To do this, we start from the Schwinger–Tomonaga equation and related kinetic equations for...