1,210 research outputs found
Neutral kaons in random media
The generalized dynamics describing the propagation of neutral kaons in
randomly fluctuating media is derived and analyzed. It takes into account
possible matter-induced effects leading to loss of phase coherence and
dissipation. The study of selected neutral kaon observables indicates that
these non-standard effects are amenable to a direct experimental analysis.Comment: 21 pages, plain-TeX, corrected typ
Damped harmonic oscillators in the holomorphic representation
Quantum dynamical semigroups are applied to the study of the time evolution
of harmonic oscillators, both bosonic and fermionic. Explicit expressions for
the density matrices describing the states of these systems are derived using
the holomorphic representation. Bosonic and fermionic degrees of freedom are
then put together to form a supersymmetric oscillator; the conditions that
assure supersymmetry invariance of the corresponding dynamical equations are
explicitly derived.Comment: 19 pages, plain-TeX, no figure
Dissipative effects in semileptonic B decays
We study the time evolution and decay of the neutral B-meson system using
quantum dynamical semigroups. New, nonstandard terms appear in the expression
of relevant observables; they can be parametrized in terms of six
phenomenological constants. Although very small, these parameters may be
detected in the new generation of dedicated B-meson experiments.Comment: 14 pages, plain-Te
Open Quantum Dynamics: Complete Positivity and Entanglement
We review the standard treatment of open quantum systems in relation to
quantum entanglement, analyzing, in particular, the behaviour of bipartite
systems immersed in a same environment. We first focus upon the notion of
complete positivity, a physically motivated algebraic constraint on the quantum
dynamics, in relation to quantum entanglement, i.e. the existence of
statistical correlations which can not be accounted for by classical
probability. We then study the entanglement power of heat baths versus their
decohering properties, a topic of increasing importance in the framework of the
fast developing fields of quantum information, communication and computation.
The presentation is self contained and, through several examples, it offers a
detailed survey of the physics and of the most relevant and used techniques
relative to both quantum open system dynamics and quantum entanglement.Comment: LaTex, 77 page
Complete positivity and correlated neutral kaons
In relation with experiments on correlated kaons at phi-factories, it is
shown that the request of complete positivity is necessary in any physically
consistent description of neutral kaons as open quantum systems.Comment: LaTeX, 9 page
Tests of Complete Positivity in Fiber Optics
We consider the propagation of polarized photons in optical fibers under the
action of randomly generated noise. In such situation, the change in time of
the photon polarization can be described by a quantum dynamical semigroup. We
show that the hierarchy among the decay constants of the polarization density
matrix elements as prescribed by complete positivity can be experimentally
probed using standard laboratory set-ups.Comment: 10 pages, LaTe
Complete positivity and neutron interferometry
We analyze the dynamics of neutron beams in interferometry experiments using
quantum dynamical semigroups. We show that these experiments could provide
stringent limits on the non-standard, dissipative terms appearing in the
extended evolution equations.Comment: 12 pages, plain Te
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