Mesure du Bs0B_{s}^{0} de plus court temps de vie dans le cadre de l'expérience LHCb

L'expérience LHCb est une expérience de seconde génération dédiée à l'étude de la violation de la symétrie CP dans les systèmes des hadrons beaux. La symétrie CP est la combinaison de la symétrie de conjugaison de charge (C) qui échange particule et anti-particule et de la symétrie de parité (P) qui inverse les directions d'espace. L'ensemble des hadrons beaux est produit. Son détecteur sera l'un des quatre devant être installé sur le grand collisionneur de protons (LHC). Dans l'objectif de tester la validité du modèle standard dans ce domaine, il sera nécessaire d'effectuer une série de mesures de précision concernant les paramètres qui définissent la violation de CP et les grandeurs physiques caractérisant le mélange et la désintégration des hadrons beaux. Ce document décrit la probabilité de mesure de la différence relative de largeur de désintégration dans le système du méson $B_{s}^{0}$ ($\frac{\Delta{\Gamma_s}}{\Gamma_s}$) à travers l'étude du canal $B_{s}^{0}\rightarrow\,D_{s}^{+}\,D_{s}^{-}

I Have Chicken Fat in My Urine! a Case of Candida Tropicalis Induced Emphysematous Pyelitis

A patient with uncontrolled diabetes mellitus presented with fever and flank pain. A computed tomography scan showed free air within both collecting systems. A diagnosis of emphysematous pyelitis was made after other alternative diagnoses were ruled out. Urine culture grew Candida tropicalis. The emphysematous pyelitis resolved with conservative management using antifungal therapy

The Mariner 5 flight path and its determination from tracking data

Mariner 5 flight path and its determination from tracking dat

Fundamental Limits on the Speed of Evolution of Quantum States

This paper reports on some new inequalities of Margolus-Levitin-Mandelstam-Tamm-type involving the speed of quantum evolution between two orthogonal pure states. The clear determinant of the qualitative behavior of this time scale is the statistics of the energy spectrum. An often-overlooked correspondence between the real-time behavior of a quantum system and the statistical mechanics of a transformed (imaginary-time) thermodynamic system appears promising as a source of qualitative insights into the quantum dynamics.Comment: 6 pages, 1 eps figur

Efficient generation of random multipartite entangled states using time optimal unitary operations

We review the generation of random pure states using a protocol of repeated two qubit gates. We study the dependence of the convergence to states with Haar multipartite entanglement distribution. We investigate the optimal generation of such states in terms of the physical (real) time needed to apply the protocol, instead of the gate complexity point of view used in other works. This physical time can be obtained, for a given Hamiltonian, within the theoretical framework offered by the quantum brachistochrone formalism. Using an anisotropic Heisenberg Hamiltonian as an example, we find that different optimal quantum gates arise according to the optimality point of view used in each case. We also study how the convergence to random entangled states depends on different entanglement measures.Comment: 5 pages, 2 figures. New title, improved explanation of the algorithm. To appear in Phys. Rev.

Multi-Qubit Systems: Highly Entangled States and Entanglement Distribution

A comparison is made of various searching procedures, based upon different entanglement measures or entanglement indicators, for highly entangled multi-qubits states. In particular, our present results are compared with those recently reported by Brown et al. [J. Phys. A: Math. Gen. 38 (2005) 1119]. The statistical distribution of entanglement values for the aforementioned multi-qubit systems is also explored.Comment: 24 pages, 3 figure

A genuine maximally seven-qubit entangled state

Contrary to A.Borras et al.'s [1] conjecture, a genuine maximally seven-qubit entangled state is presented. We find a seven-qubit state whose marginal density matrices for subsystems of 1,2- qubits are all completely mixed and for subsystems of 3-qubits is almost completely mixed

Time-optimal CNOT between indirectly coupled qubits in a linear Ising chain

We give analytical solutions for the time-optimal synthesis of entangling gates between indirectly coupled qubits 1 and 3 in a linear spin chain of three qubits subject to an Ising Hamiltonian interaction with equal coupling $J$ plus a local magnetic field acting on the intermediate qubit. The energy available is fixed, but we relax the standard assumption of instantaneous unitary operations acting on single qubits. The time required for performing an entangling gate which is equivalent, modulo local unitary operations, to the $\mathrm{CNOT}(1, 3)$ between the indirectly coupled qubits 1 and 3 is $T=\sqrt{3/2} J^{-1}$, i.e. faster than a previous estimate based on a similar Hamiltonian and the assumption of local unitaries with zero time cost. Furthermore, performing a simple Walsh-Hadamard rotation in the Hlibert space of qubit 3 shows that the time-optimal synthesis of the $\mathrm{CNOT}^{\pm}(1, 3)$ (which acts as the identity when the control qubit 1 is in the state $\ket{0}$, while if the control qubit is in the state $\ket{1}$ the target qubit 3 is flipped as $\ket{\pm}\rightarrow \ket{\mp}$) also requires the same time $T$.Comment: 9 pages; minor modification