arXiv subjects

Claude Leroy

Publications and source records attributed to Claude Leroy.

22 records · Page 2Linked to original sources

arXiv2015

Chaotic spin-spin entanglement on a recursive lattice

We propose an exactly solvable multisite interaction spin-1/2 Ising-Heisenberg model on a triangulated Husimi lattice for the rigorous studies of chaotic entanglement. By making use of the generalized star-triangle transformation, we map the initial model onto an effective Ising one on a Husimi lattice, which we solve then exactly by applying the recursive method. Expressing the entanglement of the Heisenberg spins, that we quantify by means of the concurrence, in terms of the magnetic quantities of the system, we demonstrate its bifurcation and chaotic behavior. Furthermore, we show that the underlying chaos may slightly enhance the amount of the entanglement, and present on the phase diagram the transition lines from the uniform to periodic and from the periodic to chaotic regimes.

cond-mat.stat-mech↗

arXiv2014

Generation of entanglement in systems of intercoupled qubits

We consider systems of two and three qubits, mutually coupled by Heisenberg-type exchange interaction and interacting with external laser fields. We show that these systems allow one to create maximally entangled Bell states, as well as three qubit Greenberger-Horne-Zeilinger and W states. In particular, we point out that some of the target states are the eigenstates of the initial bare system. Due to this, one can create entangled states by means of pulse area and adiabatic techniques, when starting from a separable (non-entangled) ground state. On the other hand, for target states, not present initially in the eigensystem of the model, we apply the robust stimulated Raman adiabatic passage and $π$ pulse techniques, that create desired coherent superpositions of non-entangled eigenstates.

quant-ph↗

arXiv2011

High contrast D$_{1}$ line electromagnetically induced transparency in nanometric-thin rubidium vapor cell

Electromagnetically induced transparency (EIT) on atomic D$_{1}$ line of rubidium is studied using a nanometric-thin cell with atomic vapor column length in the range of L= 400 - 800 nm. It is shown that the reduction of the cell thickness by 4 orders as compared with an ordinary cm-size cell still allows to form an EIT resonance for $L= λ$ ($λ=794$ nm) with the contrast of up to 40%. Remarkable distinctions of EIT formation in nanometric-thin and ordinary cells are demonstrated. Despite the Dicke effect of strong spectral narrowing and increase of the absorption for $L=$ $λ/2$, EIT resonance is observed both in the absorption and the fluorescence spectra for relatively low intensity of the coupling laser. Well resolved splitting of the EIT resonance in moderate magnetic field for $L=$ $λ$ can be used for magnetometry with nanometric spatial resolution. The presented theoretical model well describes the observed results.

physics.atom-ph↗

arXiv2005

Leptoquark Single and Pair production at LHC with CalcHEP/CompHEP in the complete model

We study combined leptoquark (LQ) single and pair production at LHC at the level of detector simulation. A set of kinematical cuts has been worked out to maximize significance for combined signal events. It was shown that combination of signatures from LQ single and pair production not only significantly increases the LHC reach, but also allows us to give the correct signal interpretation. In particular, it was found that the LHC has potential to discover LQ with a mass up to 1.2 TeV and 1.5 TeV for the case of scalar and vector LQ, respectively, and LQ single production contributes 30-50% to the total signal rate for LQ-l-q coupling, taken equal to the electromagnetic coupling. This work is based on implementation of the most general form of scalar and vector LQ interactions with quarks and gluons into CalcHEP/CompHEP packages. This implementation, which authors made publicly available, was one the most important aspects of the study.

hep-ph↗