21,104 research outputs found
Coherent imaging of a pure phase object with classical incoherent light
By using the ghost imaging technique, we experimentally demonstrate the
reconstruction of the diffraction pattern of a {\em pure phase} object by using
the classical correlation of incoherent thermal light split on a beam splitter.
The results once again underline that entanglement is not a necessary feature
of ghost imaging. The light we use is spatially highly incoherent with respect
to the object (m speckle size) and is produced by a
pseudo-thermal source relying on the principle of near-field scattering. We
show that in these conditions no information on the phase object can be
retrieved by only measuring the light that passed through it, neither in a
direct measurement nor in a Hanbury Brown-Twiss (HBT) scheme. In general, we
show a remarkable complementarity between ghost imaging and the HBT scheme when
dealing with a phase object.Comment: 13 pages, 11 figures. Published in Physical Review A. Replaced
version fixes some problems with Figs. 1, 4 and 1
Anisotropic multi-gap superfluid states in nuclear matter
It is shown that under changing density or temperature a nucleon Fermi
superfluid can undergo a phase transition to an anisotropic superfluid state,
characterized by nonvanishing gaps in pairing channels with singlet-singlet
(SS) and triplet-singlet (TS) pairing of nucleons (in spin and isospin spaces).
In the SS pairing channel nucleons are paired with nonzero orbital angular
momentum. Such two-gap states can arise as a result of branching from the
one-gap solution of the self-consistent equations, describing SS or TS pairing
of nucleons, that depends on the relationship between SS and TS coupling
constants at the branching point. The density/temperature dependence of the
order parameters and the critical temperature for transition to the anisotropic
two-gap state are determined in a model with the SkP effective interaction. It
is shown that the anisotropic SS-TS superfluid phase corresponds to a
metastable state in nuclear matter.Comment: Prepared with RevTeX4, 7p., 5 fi
Asymptotics of Quantum Relative Entropy From Representation Theoretical Viewpoint
In this paper it was proved that the quantum relative entropy can be asymptotically attained by Kullback Leibler divergences of
probabilities given by a certain sequence of POVMs. The sequence of POVMs
depends on , but is independent of the choice of .Comment: LaTeX2e. 8 pages. The title was changed from "Asymptotic Attainment
for Quantum Relative Entropy
Experimental evidence of high-resolution ghost imaging and ghost diffraction with classical thermal light
High-resolution ghost image and ghost diffraction experiments are performed
by using a single source of thermal-like speckle light divided by a beam
splitter. Passing from the image to the diffraction result solely relies on
changing the optical setup in the reference arm, while leaving untouched the
object arm. The product of spatial resolutions of the ghost image and ghost
diffraction experiments is shown to overcome a limit which was formerly thought
to be achievable only with entangled photons.Comment: 5 pages, 4 figure
Model-independent measurements of the sodium magneto-optical trap's excited-state population
We present model-independent measurements of the excited-state population of
atoms in a sodium (Na) magneto-optical trap (MOT) using a hybrid ion-neutral
trap composed of a MOT and a linear Paul trap (LPT). We photoionize excited Na
atoms trapped in the MOT and use two independent methods to measure the
resulting ions: directly by trapping them in our LPT, and indirectly by
monitoring changes in MOT fluorescence. By measuring the ionization rate via
these two independent methods, we have enough information to directly determine
the population of MOT atoms in the excited-state. The resulting measurement
reveals that there is a range of trapping-laser intensities where the
excited-state population of atoms in our MOT follows the standard two-level
model intensity-dependence. However, an experimentally determined effective
saturation intensity must be used instead of the theoretically predicted value
from the two-level model. We measured the effective saturation intensity to be
for the type-I Na MOT and
for the type-II Na MOT,
approximately 1.7 and 3.6 times the theoretical estimate, respectively. Lastly,
at large trapping-laser intensities, our experiment reveals a clear departure
from the two-level model at a critical intensity that we believe is due to a
state-mixing effect, whose critical intensity can be determined by a simple
power broadening model.Comment: 10 pages, 8 figure
The embedding structure and the shift operator of the U(1) lattice current algebra
The structure of block-spin embeddings of the U(1) lattice current algebra is
described. For an odd number of lattice sites, the inner realizations of the
shift automorphism areclassified. We present a particular inner shift operator
which admits a factorization involving quantum dilogarithms analogous to the
results of Faddeev and Volkov.Comment: 14 pages, Plain TeX; typos and a terminological mishap corrected;
version to appear in Lett.Math.Phy
The stationary phase point method for transitional scattering: diffractive radio scintillation for pulsar
The stationary phase point (SPP) method in one-dimensional case is introduced
to treat the diffractive scintillation. From weak scattering, where the SPP
number N=1, to strong scattering (N1), via transitional scattering regime
(N2,3), we find that the modulation index of intensity experiences the
monotonically increasing from 0 to 1 with the scattering strength,
characterized by the ratio of Fresnel scale \rf to diffractive scale
\rdiff.Comment: Hanas Meeting paper, appear in ChJAA, 2006, 6, Su
RankPL: A Qualitative Probabilistic Programming Language
In this paper we introduce RankPL, a modeling language that can be thought of
as a qualitative variant of a probabilistic programming language with a
semantics based on Spohn's ranking theory. Broadly speaking, RankPL can be used
to represent and reason about processes that exhibit uncertainty expressible by
distinguishing "normal" from" surprising" events. RankPL allows (iterated)
revision of rankings over alternative program states and supports various types
of reasoning, including abduction and causal inference. We present the
language, its denotational semantics, and a number of practical examples. We
also discuss an implementation of RankPL that is available for download
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