1,523 research outputs found
Semiclassical Green Function in Mixed Spaces
A explicit formula on semiclassical Green functions in mixed position and
momentum spaces is given, which is based on Maslov's multi-dimensional
semiclassical theory. The general formula includes both coordinate and momentum
representations of Green functions as two special cases of the form.Comment: 8 pages, typeset by Scientific Wor
Exact trace formulae for a class of one-dimensional ray-splitting systems
Based on quantum graph theory we establish that the ray-splitting trace
formula proposed by Couchman {\it et al.} (Phys. Rev. A {\bf 46}, 6193 (1992))
is exact for a class of one-dimensional ray-splitting systems. Important
applications in combinatorics are suggested.Comment: 14 pages, 3 figure
Comment on "Gravity Waves, Chaos, and Spinning Compact Binaries"
In this comment, I argue that chaotic effects in binary black hole inspiral
will not strongly impact the detection of gravitational waves from such
systems.Comment: 1 page, comment on gr-qc/991004
Spectral Statistics: From Disordered to Chaotic Systems
The relation between disordered and chaotic systems is investigated. It is
obtained by identifying the diffusion operator of the disordered systems with
the Perron-Frobenius operator in the general case. This association enables us
to extend results obtained in the diffusive regime to general chaotic systems.
In particular, the two--point level density correlator and the structure factor
for general chaotic systems are calculated and characterized. The behavior of
the structure factor around the Heisenberg time is quantitatively described in
terms of short periodic orbits.Comment: uuencoded file with 1 eps figure, 4 page
Factors associated with appropriate inhaler use in patients with COPD - lessons from the REAL survey
The authors thank Clarice Field (PhD) and Paul McKiernan (PhD) of Novartis for providing medical writing support, which was funded by Novartis AG, Basel, Switzerland, in accordance with Good Publication Practice (GPP3) guidelines (http://www.ismpp.org/gpp3). Pankaj Goyal and Joao Mendes, Novartis Pharma AG, Basel, contributed to the design and conceptualization of study. The survey was designed by PDD, London, United Kingdom, and GfK Switzerland AG, Basel, Switzerland. The survey was conducted by GfK Switzerland AG, Basel, Switzerland, and sponsored by Novartis Pharma AG, Basel, Switzerland.Peer reviewedPublisher PD
Echolocation by Quasiparticles
It is shown that the local density of states (LDOS), measured in an Scanning
Tunneling Microscopy (STM) experiment, at a single tip position contains
oscillations as a function of Energy, due to quasiparticle interference, which
is related to the positions of nearby scatterers. We propose a method of STM
data analysis based on this idea, which can be used to locate the scatterers.
In the case of a superconductor, the method can potentially distinguish the
nature of the scattering by a particular impurity.Comment: 4+ page
Universality in chaotic quantum transport: The concordance between random matrix and semiclassical theories
Electronic transport through chaotic quantum dots exhibits universal, system
independent, properties, consistent with random matrix theory. The quantum
transport can also be rooted, via the semiclassical approximation, in sums over
the classical scattering trajectories. Correlations between such trajectories
can be organized diagrammatically and have been shown to yield universal
answers for some observables. Here, we develop the general combinatorial
treatment of the semiclassical diagrams, through a connection to factorizations
of permutations. We show agreement between the semiclassical and random matrix
approaches to the moments of the transmission eigenvalues. The result is valid
for all moments to all orders of the expansion in inverse channel number for
all three main symmetry classes (with and without time reversal symmetry and
spin-orbit interaction) and extends to nonlinear statistics. This finally
explains the applicability of random matrix theory to chaotic quantum transport
in terms of the underlying dynamics as well as providing semiclassical access
to the probability density of the transmission eigenvalues.Comment: Refereed version. 5 pages, 4 figure
A new vibrational level of the H molecular ion
A new state of the H molecular ion with binding energy of
1.09 a.u. below the first dissociation limit is predicted, using
highly accurate numerical nonrelativistic quantum calculations. It is the first
L=0 excited state, antisymmetric with respect to the exchange of the two
protons. It manifests itself as a huge p-H scattering length of
Bohr radii.Comment: 6 pages + 3 figure
Application of the Feshbach-resonance management to a tightly confined Bose-Einstein condensate
We study suppression of the collapse and stabilization of matter-wave
solitons by means of time-periodic modulation of the effective nonlinearity,
using the nonpolynomial Schroedinger equation (NPSE) for BEC trapped in a tight
cigar-shaped potential. By means of systematic simulations, a stability region
is identified in the plane of the modulation amplitude and frequency. In the
low-frequency regime, solitons feature chaotic evolution, although they remain
robust objects.Comment: Physical Review A, in pres
Coherent control of population transfer between communicating defects
Population transfer between two identical, communicating defects in a
one-dimensional tight-binding lattice can be systematically controlled by
external time-periodic forcing. Employing a force with slowly changing
amplitude, the time it takes to transfer a particle from one defect to the
other can be altered over several orders of magnitude. An analytical expression
is derived which shows how the forcing effectively changes the energy splitting
between the defect states, and numerical model calculations illustrate the
possibility of coherent control of the transfer.Comment: 7 pages, 6 figures, to appear in Phys. Rev.
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