Entanglement production in Quantized Chaotic Systems

Quantum chaos is a subject whose major goal is to identify and to investigate different quantum signatures of classical chaos. Here we study entanglement production in coupled chaotic systems as a possible quantum indicator of classical chaos. We use coupled kicked tops as a model for our extensive numerical studies. We find that, in general, presence of chaos in the system produces more entanglement. However, coupling strength between two subsystems is also very important parameter for the entanglement production. Here we show how chaos can lead to large entanglement which is universal and describable by random matrix theory (RMT). We also explain entanglement production in coupled strongly chaotic systems by deriving a formula based on RMT. This formula is valid for arbitrary coupling strengths, as well as for sufficiently long time. Here we investigate also the effect of chaos on the entanglement production for the mixed initial state. We find that many properties of the mixed state entanglement production are qualitatively similar to the pure state entanglement production. We however still lack an analytical understanding of the mixed state entanglement production in chaotic systems.Comment: 16 pages, 5 figures. To appear in Pramana:Journal of Physic

Modeling Complex Nuclear Spectra - Regularity versus Chaos

A statistical analysis of the spectrum of two particle - two hole doorway states in a finite nucleus is performed. On the unperturbed mean-field level sizable attractive correlations are present in such a spectrum. Including particle-hole rescattering effects via the residual interaction introduces repulsive dynamical correlations which generate the fluctuation properties characteristic of the Gaussian Orthogonal Ensemble. This signals that the underlying dynamics becomes chaotic. This feature turns out to be independent of the detailed form of the residual interaction and hence reflects the generic nature of the fluctuations studied.Comment: 8 pages of text (LATEX), figures (not included, available from the authors), Feb 9

NUCLEAR SPIN-LATTICE RELAXATION IN A LITHIUM-SILICATE GLASS

La vitesse de relaxation spin-réseau T1-1 du 8Li dans le verre de silicate (SiO2)0,67(Li2O)0,33 a été mesurée dans l'intervalle de température 6K ≤ T ≤ 340K et pour un intervalle de champ magnétique 14 mT ≤ B ≤ 830 mT utilisant la décroissance β assymétrique des noyaux 8Li polarisés. La polarisation a montré une décroissance non-exponentielle . On a trouvé que T1-1 dépend approximativement linéairement de B-1 et T pour T < 170K . Les résultats peuvent être expliqués à l'aide d'un modèle phénoménologique.The spin-lattice relaxation rate T1-1 of 8Li in the silicate glass (SiO2)0.67(Li2O)0.33 has been measured over the temperature range 6K ≤ T ≤ 340K and the magnetic field range 14 mT ≤ B ≤ 830 mT using the asymmetric β-decay radiation of polarized 8Li nuclei. The polarization showed non-exponential decay. T1-1 was found to depend approximately linearly on B-1 and T for T < 170K. The results can be explained within the frame of a phenomenological model

Parametric S-matrix fluctuations in quantum theory of chaotic scattering

We study the effects of an arbitrary external perturbation in the statistical properties of the S-matrix of quantum chaotic scattering systems in the limit of isolated resonances. We derive, using supersymmetry, an exact non-perturbative expression for the parameter dependent autocorrelator of two S-matrix elements. Universality is obtained by appropriate rescaling of the physical parameters. We propose this universal function as a new signature of quantum chaos in open systems.Comment: 4 pages, 1 figure appended, written in REVTeX, Preprint OUTP-94-13S (University of Oxford