Search results for "quantum [statistics]"
showing 10 items of 4295 documents
Entanglement dynamics in superconducting qubits affected by local bistable impurities
2012
We study the entanglement dynamics for two independent superconducting qubits each affected by a bistable impurity generating random telegraph noise (RTN) at pure dephasing. The relevant parameter is the ratio $g$ between qubit-RTN coupling strength and RTN switching rate, that captures the physics of the crossover between Markovian and non-Markovian features of the dynamics. For identical qubit-RTN subsystems, a threshold value $g_\mathrm{th}$ of the crossover parameter separates exponential decay and onset of revivals; different qualitative behaviors also show up by changing the initial conditions of the RTN. We moreover show that, for different qubit-RTN subsystems, when both qubits are …
Black Holes in Extended Gravity Theories in Palatini Formalism
2013
We consider several physical scenarios where black holes within classical gravity theories including R 2 and Ricci-squared corrections and formulated a la Palatini can be analytically studied.
Non-supersymmetric Extremal Black Holes: First-Order Flows and Stabilisation Equations
2013
We review the results of [1, 2] on reducing the second-order equations of motion for stationary extremal black holes in four-dimensional \({\textit{N}}\,=\,2\) supergravity to first-order flow equations and further to non-differential stabilisation equations.
Excision technique in constrained formulations of Einstein equations: collapse scenario
2015
We present a new excision technique used in constrained formulations of Einstein equations to deal with black hole in numerical simulations. We show the applicability of this scheme in several scenarios. In particular, we present the dynamical evolution of the collapse of a neutron star to a black hole, using the CoCoNuT code and this excision technique.
Numerical Simulations of Relativistic Wind Accretion onto Black Holes Using Godunov-Type Methods
2001
We have studied numerically the so-called Bondi-Hoyle (wind) accretion onto a rotating black hole in general relativity. We have used the Kerr-Schild form of the Kerr metric, free of coordinate singularities at the black hole horizon. The ‘test-fluid’ approximation has been adopted, assuming no dynamical evolution of the gravitational field. We have used a formulation of the relativistic hydrodynamic equations which casts them into a first-order hyperbolic system of conservation laws. Our studies were performed using a Godunov-type scheme based on Marquina’s flux-formula.
NONSINGULAR BLACK HOLES IN PALATINI EXTENSIONS OF GENERAL RELATIVITY
2015
An introduction to extended theories of gravity formulated in metric-affine (or Palatini) spaces is presented. Focusing on spherically symmetric configurations with electric fields, we will see that in these theories the central singularity present in General Relativity is generically replaced by a wormhole structure. The resulting space-time becomes geodesically complete and, therefore, can be regarded as non-singular. We illustrate these properties considering two different models, namely, a quadratic f(R) theory and a Born-Infeld like gravity theory.
Research of Complex Forms in Cellular Automata by Evolutionary Algorithms
2004
This paper presents an evolutionary approach for the search for new complex cellular automata. Two evolutionary algorithms are used: the first one discovers rules supporting gliders and periodic patterns, and the second one discovers glider guns in cellular automata. An automaton allowing us to simulate AND and NOT gates is discovered. The results are a step toward the general simulation of Boolean circuits by this automaton and show that the evolutionary approach is a promising technic for searching for cellular automata that support universal computation.
Unveiling the role of upper excited electronic states in the photochemistry and laser performance of: anti -B18H22
2020
13 pags., 7 figs., -- This article is part of the themed collection: Journal of Materials Chemistry C HOT Papers
Dipole Moment Surface of the van der Waals Complex CH4–N2
2010
The interaction-induced dipole moment surface of the van der Waals CH(4)-N(2) complex has been calculated for a broad range of intermolecular separations R and configurations in the approximation of the rigid interacting molecules at the MP2 and CCSD(T) levels of theory using the correlation-consistent aug-cc-pVTZ basis set with the basis set superposition error correction. The simple model to account for the exchange effects in the range of small overlap of the electron shells of interacting molecules and the induction and dispersion interactions for large R has been suggested. This model allows describing the dipole moment of van der Waals complexes in analytical form both for large R, wh…
An ab initio study of the tautomeric equilibria of the N-oxides of hydroxypyridines in the vapour phase
1993
Abstract An ab initio self-consistent field molecular orbital study of the N-oxides of hydroxypyridines has been carried out. The optimized structures have been obtained at the 6-31G ∗ level, and the energy values have been computed at the 6-31G ∗ and MP2-6-31G ∗ //6-31G ∗ levels. The tautomerization energies for the three couples of systems in the vapour phase have been evaluated.