4,228 research outputs found
New classical properties of quantum coherent states
A noncommutative version of the Cramer theorem is used to show that if two quantum systems are prepared independently, and if their center of mass is found to be in a coherent state, then each of the component systems is also in a coherent state, centered around the position in phase space predicted by the classical theory. Thermal coherent states are also shown to possess properties similar to classical ones
Searching for dominant rescattering sources in B to two pseudoscalar decays
Various rescattering sources are analyzed in the context of the SU(3) flavor
symmetry. In particular, the possibility to account for intermediate charm at
the hadronic level in B to PP is thoroughly investigated. Then, the
rescattering sources are compared in light of recent B to two charmless
pseudoscalar decay measurements, with emphasis on the size of strong phases and
on patterns of direct CP-asymmetries.Comment: LaTeX, 24 pages, 5 figure
Wigner Measure Propagation and Conical Singularity for General Initial Data
We study the evolution of Wigner measures of a family of solutions of a
Schr\"odinger equation with a scalar potential displaying a conical
singularity. Under a genericity assumption, classical trajectories exist and
are unique, thus the question of the propagation of Wigner measures along these
trajectories becomes relevant. We prove the propagation for general initial
data.Comment: 24 pages, 1 figur
Phase Space Models for Stochastic Nonlinear Parabolic Waves: Wave Spread and Singularity
We derive several kinetic equations to model the large scale, low Fresnel
number behavior of the nonlinear Schrodinger (NLS) equation with a rapidly
fluctuating random potential. There are three types of kinetic equations the
longitudinal, the transverse and the longitudinal with friction. For these
nonlinear kinetic equations we address two problems: the rate of dispersion and
the singularity formation.
For the problem of dispersion, we show that the kinetic equations of the
longitudinal type produce the cubic-in-time law, that the transverse type
produce the quadratic-in-time law and that the one with friction produces the
linear-in-time law for the variance prior to any singularity.
For the problem of singularity, we show that the singularity and blow-up
conditions in the transverse case remain the same as those for the homogeneous
NLS equation with critical or supercritical self-focusing nonlinearity, but
they have changed in the longitudinal case and in the frictional case due to
the evolution of the Hamiltonian
Controlling the dynamics of a coupled atom-cavity system by pure dephasing : basics and potential applications in nanophotonics
The influence of pure dephasing on the dynamics of the coupling between a
two-level atom and a cavity mode is systematically addressed. We have derived
an effective atom-cavity coupling rate that is shown to be a key parameter in
the physics of the problem, allowing to generalize the known expression for the
Purcell factor to the case of broad emitters, and to define strategies to
optimize the performances of broad emitters-based single photon sources.
Moreover, pure dephasing is shown to be able to restore lasing in presence of
detuning, a further demonstration that decoherence can be seen as a fundamental
resource in solid-state cavity quantum electrodynamics, offering appealing
perspectives in the context of advanced nano-photonic devices.Comment: 10 pages, 7 figure
Phantom Black Holes in Einstein-Maxwell-Dilaton Theory
We obtain the general static, spherically symmetric solution for the
Einstein-Maxwell-dilaton system in four dimensions with a phantom coupling for
the dilaton and/or the Maxwell field. This leads to new classes of black hole
solutions, with single or multiple horizons. Using the geodesic equations, we
analyse the corresponding Penrose diagrams revealing, in some cases, new causal
structures.Comment: Latex file, 32 pages, 15 figures in eps format. Typo corrected in Eq.
(3.18
Spectral and scattering theory for some abstract QFT Hamiltonians
We introduce an abstract class of bosonic QFT Hamiltonians and study their
spectral and scattering theories. These Hamiltonians are of the form
H=\d\G(\omega)+ V acting on the bosonic Fock space \G(\ch), where
is a massive one-particle Hamiltonian acting on and is a Wick
polynomial \Wick(w) for a kernel satisfying some decay properties at
infinity. We describe the essential spectrum of , prove a Mourre estimate
outside a set of thresholds and prove the existence of asymptotic fields. Our
main result is the {\em asymptotic completeness} of the scattering theory,
which means that the CCR representations given by the asymptotic fields are of
Fock type, with the asymptotic vacua equal to the bound states of . As a
consequence is unitarily equivalent to a collection of second quantized
Hamiltonians
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