In this paper we provide a microscopic derivation of the master equation for Jaynes-Cummings model with cavity losses. We single out both differences phenomenological used in literature and approximations under which correctly describes dynamics atom-cavity system. Some examples wherein equations give rise to different predictions are discussed detail.

A two-interacting-qubit quantum Rabi-like model with vanishing transverse fields on the qubit-pair is studied. Independently of coupling regime, this can be exactly and unitarily reduced to two independent single-spin Rabi models, where spin-spin plays role field. This transformation analytical treatment provide key prove integrability our model. The existence different first-order phase transitions, characterized by discontinuous two-spin magnetization, mean photon number concurrence, brought light.

This manuscript aims to illustrate a quantum-classical dissipative theory (suited be converted effective algorithms for numerical simulations) within the long-term project of studying molecular processes in brain. Other approaches, briefly sketched text, have advocated need deal with both quantum and classical dynamic variables when At variance these other frameworks, manuscript’s formalism allows us explicitly treat dynamical variables. The must not because formal requirements but brain...

The dynamics of a typical open quantum system, namely Brownian particle in harmonic potential, is studied focussing on its non-Markovian regime. Both an analytic approach and stochastic wave function are used to describe the exact time evolution system. border between two very different dynamical regimes, Lindblad non-Lindblad identified relevant physical variables governing passage from one regime other singled out. short detail by looking at mean energy, squeezing, Mandel parameter Wigner

A simple systematic way of obtaining analytically solvable Hamiltonians for quantum two-level systems is presented. In this method, a time-dependent Hamiltonian and the resulting unitary evolution operator are connected through an arbitrary function time, furnishing us with new cases. The method surprisingly simple, direct, transparent applicable to wide class no involved constraint on input function. few examples illustrate how leads dynamics.

We apply the time-convolutionless (TCL) projection operator technique to model of a central spin, which is coupled spin bath via nonuniform Heisenberg interaction. The second-order results TCL method for coherences and populations are determined analytically compared numerical simulations full von Neumann equation total system. approach found yield an excellent approximation in strong field regime description both short-time dynamics long time behavior.

Employing the stochastic wave function method, we study quantum features of entropy production in nonequilibrium processes open systems. It is demonstrated that continuous measurements on environment introduce an additional, nonthermal contribution to flux, which shown be a direct consequence fluctuations. These lead definition single trajectory contributions, accounts for difference between classical and trajectories results correction standard form integral fluctuation theorem.

Two coupled two-level systems placed under external time-dependent magnetic fields are modeled by a general Hamiltonian endowed with symmetry that enables us to reduce the total dynamics into two independent two-dimensional subdynamics. Each of subdynamics is shown be brought an exactly solvable form appropriately engineering and thus we obtain exact time evolution compound system. Several physically relevant interesting quantities evaluated disclose intriguing phenomena in such

A spin-boson-like model with two interacting qubits is analysed. The turns out to be exactly solvable since it characterized by the exchange symmetry between spins. explicit expressions of eigenstates and eigenenergies make possible analytically unveil occurrence first-order quantum phase transitions. latter are physically relevant they abrupt changes in two-spin subsystem concurrence, net spin magnetization mean photon number.

Two-level quantum systems are fundamental physical models that continue to attract growing interest due their crucial role as a building block of technologies. The exact analytical solution the dynamics these is central control theory and its applications, such computing. In this study, we reconsider two-state charge transfer problem by extending using methodology developed study (pseudo)spin in electrodynamics contexts. This approach allows us build time evolution operator for system show...

An original method to exactly solve the non-Markovian master equation describing interaction of a single harmonic oscillator with quantum environment in weak-coupling limit is reported. By using superoperatorial approach, we succeed deriving operatorial solution for density matrix system. Our independent physical properties environment. We show usefulness our explicit expressions dissipative time evolution some observables interest system, such as, example, its mean energy.

We analyze the non-relativistic problem of a quantum particle that bounces back and forth between two moving walls. recast this into equivalent one in fixed box whose dynamics is governed by an appropriate time-dependent Schroedinger operator.

The conceptual analysis of quantum mechanics brings to light that a theory inherently consistent with observations should be able describe both and classical systems, i.e., quantum-classical hybrids. For example, the orthodox interpretation measurements requires transient creation Despite its limitations in defining limit, Ehrenfest's theorem makes simplest contact between mechanics. Here, we generalized Ehrenfest bipartite systems. To study hybrids, employed formalism based on...

The dynamics of two two-level dipole-dipole interacting atoms coupled to a common electro-magnetic bath and closely located inside lossy cavity, is reported. Initially injecting only one excitation in the two-atom cavity system, loss mechanisms asymptotically drive matter sample toward stationary maximally entangled state. role played by closeness atoms, with respect such cooperative behavior, carefully discussed. Stationary radiation trapping effects are found transparently interpreted.

We show how the Majorana representation can be used to express pure states of an N-qubit system as points on Bloch sphere. compare this geometrical with alternative one, proposed recently by present authors.

A master equation approach to the study of environmental effects in adiabatic population transfer three-state systems is presented. systematic comparison with non-Hermitian Hamiltonian [Vitanov and Stenholm, Phys. Rev. 56, 1463 (1997)] shows that, weak-coupling limit, two treatments lead essentially same results. In contrast, strong-damping limit predictions are quite different: particular, counterintuitive sequences STIRAP scheme turn out be much more efficient than expected before. This...

The exact quantum dynamics of a single spin-1/2 in generic time-dependent classical magnetic field is investigated and compared with the motion studied by Rabi Schwinger. possibility regarding scenario this paper as generalization that considered Schwinger discussed notion resonance condition introduced carefully legitimated analysed. Several examples help to disclose analogies departures induced generalized system respect exhibited precessing around $z$-axis. We find that, under condition,...

In contrast to classical systems, actual implementation of non-Hermitian Hamiltonian dynamics for quantum systems is a challenge because the processes energy gain and dissipation are based on underlying Hermitian system-environment that trace preserving. Recently, scheme engineering Hamiltonians as result repetitive measurements an anicillary qubit has been proposed. The induced conditional main system described by effective arisng from procedure. this paper we demonstrate effectiveness such...

We study the open system dynamics of a harmonic oscillator coupled with an artificially engineered reservoir. single out reservoir and variables governing passage between Lindblad type non-Lindblad reduced system's oscillator. demonstrate existence conditions under which virtual exchanges energy take place. propose to use trapped ion reservoirs in order simulate quantum Brownian motion.

We introduce the $N$-photon quantum superposition of two orthogonal generalized binomial states electromagnetic field. then propose, using resonant atom-cavity interactions, non-conditional schemes to generate and reveal such a for two-photon case in single-mode high-$Q$ cavity. finally discuss implementation proposed schemes.

A microscopic derivation of the master equation for Jaynes-Cummings model with cavity losses is given, taking into account terms in dissipator which vary frequencies order vacuum Rabi frequency. Our approach allows to single out physical contexts wherein usual phenomenological turns be fully justified and constitutes an extension our previous analysis [Scala M. {\em et al.} 2007 Phys. Rev. {\bf 75}, 013811], where a was given framework Rotating Wave Approximation.

We derive the master equation of a system two coupled qubits by taking into account their interaction with independent bosonic baths.Important features dynamics are brought to light, such as structure stationary state at general temperatures and behaviour entanglement zero temperature, showing phenomena sudden death birth well presence for long times.The model here presented is quite versatile can be interest in study both Josephson junction architectures cavity-QED.

In population trapping the occupation of a decaying quantum level keeps constant nonzero value. We show that an atom-cavity system interacting with environment characterized by nonflat spectrum, in non-Markovian limit, exhibits such behavior, effectively realizing preservation nonclassical states against dissipation. Our results allow us to understand role cavity losses hybrid solid state systems and pave way proper description leakage recently developed electrodynamic systems.