Search results for " Dissipation"
showing 10 items of 80 documents
Fast Control of Quantum States in Quantum Dots: Limits due to Decoherence
2005
We study the kinetics of confined carrier-phonon system in a quantum dot under fast optical driving and discuss the resulting limitations to fast coherent control over the quantum state in such systems.
Quantum control theory for decoherence suppression in quantum gates
2007
We show how quantum optimal control theory can help achieve high-fidelity quantum gates in real experimental settings. We discuss several optimization methods (from iterative algorithms to optimization by interference and to impulsive control) and different physical scenarios (from optical lattices to atom chips and to Rydberg atoms).
Space-Time Symmetries in Quantum Physics
2013
The transformations in space and in time which belong to the Galilei group play an important role in quantum theory. In some respect and for some aspects, their role is new as compared to classical mechanics.
Quantum capacitance: a microscopic derivation
2010
We start from microscopic approach to many body physics and show the analytical steps and approximations required to arrive at the concept of quantum capacitance. These approximations are valid only in the semi-classical limit and the quantum capacitance in that case is determined by Lindhard function. The effective capacitance is the geometrical capacitance and the quantum capacitance in series, and this too is established starting from a microscopic theory.
Dissipative dynamics in a quantum bistable system: Crossover from weak to strong damping
2015
The dissipative dynamics of a quantum bistable system coupled to a Ohmic heat bath is investigated beyond the spin-boson approximation. Within the path-integral approach to quantum dissipation, we propose an approximation scheme which exploits the separation of time scales between intra- and interwell (tunneling) dynamics. The resulting generalized master equation for the populations in a space localized basis enables us to investigate a wide range of temperatures and system-environment coupling strengths. A phase diagram in the coupling-temperature space is provided to give a comprehensive account of the different dynamical regimes.
Vibrating soliton pairs in a mode-locked laser cavity
2006
International audience; We show numerically the existence of vibrating soliton pairs that are consistent with observations performed with a passively mode-locked fiber laser. These vibrating pairs are new types of multisoliton complexes that exist in the vicinity of the phase-locked soliton pairs discovered a few years ago [Opt. Lett. 27, 966 (2002)]. The pairs are found numerically with a laser propagation model that includes nonlinear dissipation and cavity periodicity, and they can appear following a Hopf-type bifurcation when a cavity parameter is tuned.
Light bullets and dynamic pattern formation in nonlinear dissipative systems
2005
In the search for suitable new media for the propagation of (3+1) D optical light bullets, we show that nonlinear dissipation provides interesting possibilities. Using the complex cubic-quintic Ginzburg-Landau equation model with localized initial conditions, we are able to observe stable light bullet propagation or higher-order transverse pattern formation. The type of evolution depends on the model parameters. ©2005 Optical Society of America.
How Do Schr\"odinger's Cats Die?
2008
Recent experiments with superconducting qubits are motivated by the goal of fabricating a quantum computer, but at the same time they illuminate the more fundamental aspects of quantum mechanics. In this paper we analyze the physics of switching current measurements from the point of view of macroscopic quantum mechanics.
Soliton Statistical Mechanics: Statistical Mechanics of the Quantum and Classical Integrable Models
1988
It is shown how the Bethe Ansatz (BA) analysis for the quantum statistical mechanics of the Nonlinear Schrodinger Model generalises to the other quantum integrable models and to the classical statistical mechanics of the classical integrable models. The bose-fermi equivalence of these models plays a fundamental role even at classical level. Two methods for calculating the quantum or classical free energies are developed: one generalises the BA method the other uses functional integral methods. The familiar classical action-angle variables of the integrable models developed for the real line R are used throughout, but the crucial importance of periodic boundary conditions is recognized and t…