24,847 research outputs found
Universal joint-measurement uncertainty relation for error bars
We formulate and prove a new, universally valid uncertainty relation for the necessary error bar widths in any approximate joint measurement of position and momentum
Equilibrium states and invariant measures for random dynamical systems
Random dynamical systems with countably many maps which admit countable
Markov partitions on complete metric spaces such that the resulting Markov
systems are uniformly continuous and contractive are considered. A
non-degeneracy and a consistency conditions for such systems, which admit some
proper Markov partitions of connected spaces, are introduced, and further
sufficient conditions for them are provided. It is shown that every uniformly
continuous Markov system associated with a continuous random dynamical system
is consistent if it has a dominating Markov chain. A necessary and sufficient
condition for the existence of an invariant Borel probability measure for such
a non-degenerate system with a dominating Markov chain and a finite (16) is
given. The condition is also sufficient if the non-degeneracy is weakened with
the consistency condition. A further sufficient condition for the existence of
an invariant measure for such a consistent system which involves only the
properties of the dominating Markov chain is provided. In particular, it
implies that every such a consistent system with a finite Markov partition and
a finite (16) has an invariant Borel probability measure. A bijective map
between these measures and equilibrium states associated with such a system is
established in the non-degenerate case. Some properties of the map and the
measures are given.Comment: The article is published in DCDS-A, but without the 3rd paragraph on
page 4 (the complete removal of the paragraph became the condition for the
publication in the DCDS-A after the reviewer ran out of the citation
suggestions collected in the paragraph
Interference in presence of Dissipation
We study a particle on a ring in presence of various dissipative
environments. We develop and solve a variational scheme assuming low frequency
dominance. We analyze our solution within a renormalization group (RG) scheme
to all orders which reproduces a 2 loop RG for the Caldeira-Legget environment.
In the latter case the Aharonov-Bohm (AB) oscillation amplitude is exponential
in -R^2 where R is the ring's radius. For either a charge or an electric dipole
coupled to a dirty metal we find that the metal induces dissipation, however
the AB amplitude is ~ R^{-2} for large R, as for free particles. Cold atoms
with a large electric dipole may show a crossover between these two behaviors.Comment: 5 pages, added motivations and reference
Spin-orbit and tensor mean-field effects on spin-orbit splitting including self-consistent core polarizations
A new strategy of fitting the coupling constants of the nuclear energy
density functional is proposed, which shifts attention from ground-state bulk
to single-particle properties. The latter are analyzed in terms of the bare
single-particle energies and mass, shape, and spin core-polarization effects.
Fit of the isoscalar spin-orbit and both isoscalar and isovector tensor
coupling constants directly to the f5/2-f7/2 spin-orbit splittings in 40Ca,
56Ni, and 48Ca is proposed as a practical realization of this new programme. It
is shown that this fit requires drastic changes in the isoscalar spin-orbit
strength and the tensor coupling constants as compared to the commonly accepted
values but it considerably and systematically improves basic single-particle
properties including spin-orbit splittings and magic-gap energies. Impact of
these changes on nuclear binding energies is also discussed.Comment: 15 pages, 7 figures, submitted to Physical Review
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