Decoherence in regular systems
نویسندگان
چکیده
We consider unitary evolution of finite bipartite quantum systems and study time dependence of purity for initial cat states – coherent superpositions of Gaussian wave-packets. We derive explicit formula for purity in systems with nonzero time averaged coupling, a typical situation for systems where an uncoupled part of the Hamiltonian is Liouville integrable. Previous analytical studies have been limited to harmonic oscillator systems but with our theory we are able to derive analytical results for general integrable systems. Two regimes are clearly identified, at short times purity decays due to decoherence whereas at longer times it decays because of relaxation. PACS numbers: 03.65.Yz, 03.65.Sq, 03.65.Ud Decoherence in regular systems 2
منابع مشابه
Study of decoherence of entangled states made up of two basic states in a linear chain of three qubits
Using Lindblad approach to study decoherence of quantum systems, we study the decoherence and decay of entangled states, formed by two basic states of a chain of thee qubits. We look on these states for a possible regular dependence on their decay as a function of their energy separation between the basic states under different types of environments. We didn’t find regular or significant depend...
متن کاملDecoherence, relaxation, and chaos in a kicked-spin ensemble.
We study the dynamics of a quantum spin ensemble controlled by trains of ultrashort pulses. To model disturbances of the kicks, we consider that the spins are submitted to different kick trains which follow regular, random, stochastic, or chaotic dynamical processes. These are described by dynamical systems on a torus. We study the quantum decoherence and the population relaxation of the spin e...
متن کاملDecoherence effects on quantum Fisher information of multi-qubit W states
Quantum fisher information of a parameter characterizing the sensitivity of a state with respect to parameter changes. In this paper, we study the quantum fisher information of the W state for four, five, six and seven particles in decoherence channels, such as amplitude damping, phase damping and depolarizing channel. Using Krauss operators for decoherence channels components, we investigate t...
متن کاملIndirect decoherence in optical lattices and cold gases
Abstract The interaction of two–level atoms with a common heat bath leads to an effective interaction between the atoms, such that with time the internal degrees of the atoms become correlated or even entangled. If part of the atoms remain unobserved this creates additional indirect decoherence for the selected atoms, on top of the direct decoherence due to the interaction with the heat bath. I...
متن کاملStability of Quantum Dynamics
The stability of quantum systems to perturbations of the Hamiltonian is studied. This stability is quantified by the fidelity, an overlap of an ideal state obtained by the unperturbed evolution, and a perturbed state obtained by the perturbed evolution, both starting from the same initial state. Dependence of fidelity on the initial state as well as on the dynamical properties of the system is ...
متن کامل