15,615 research outputs found
Universal properties of hard-core bosons confined on one-dimensional lattices
Based on an exact treatment of hard-core bosons confined on one-dimensional
lattices, we obtain the large distance behavior of the one-particle density
matrix, and show how it determines the occupation of the lowest natural orbital
in the thermodynamic limit. We also study the occupation of
the natural orbitals for large- at low densities. Both quantities show
universal behavior independently of the confining potential. Finite-size
corrections and the momentum distribution function for finite systems are also
analyzed.Comment: Revtex file, 5 pages, 5 figures. Content and references added.
Published versio
Channel Coding and Lossy Source Coding Using a Constrained Random Number Generator
Stochastic encoders for channel coding and lossy source coding are introduced
with a rate close to the fundamental limits, where the only restriction is that
the channel input alphabet and the reproduction alphabet of the lossy source
code are finite. Random numbers, which satisfy a condition specified by a
function and its value, are used to construct stochastic encoders. The proof of
the theorems is based on the hash property of an ensemble of functions, where
the results are extended to general channels/sources and alternative formulas
are introduced for channel capacity and the rate-distortion region. Since an
ensemble of sparse matrices has a hash property, we can construct a code by
using sparse matrices, where the sum-product algorithm can be used for encoding
and decoding by assuming that channels/sources are memoryless.Comment: submitted to IEEE Transactions on Information Theory, 42 page
Quantum disordered phase in a doped antiferromagnet
A quantitative description of the transition to a quantum disordered phase in
a doped antiferromagnet is obtained with a U(1) gauge-theory, where the gap in
the spin-wave spectrum determines the strength of the gauge-fields. They
mediate an attractive long-range interaction whose possible bound-states
correspond to charge-spin separation and pairing.Comment: 11 pages, LaTex, chris-preprint-1994-
Flavor changing nucleon decay
Recent discovery of neutrino large mixings implies the large mixings in the
diagonalizing matrices of fields in grand unified theory
(GUT), while the diagonalizing matrices of fields of are
expected to have small mixings like Cabibbo-Kobayashi-Maskawa matrix. We
calculate the predictions of flavor changing nucleon decays (FCND) in ,
, and GUT models which have the above features for mixings. We
found that FCND can be the main decay mode especially for GUT with higher rank
unification group. Recent report for process implies
or GUT if the signal is from the nucleon decay.Comment: 5 pages, 4 figures v2:references are added v3:references, figures and
texts are improved v4:final version to be published in PL
Construction of Slepian-Wolf Source Code and Broadcast Channel Code Based on Hash Property
The aim of this paper is to prove theorems for the Slepian-Wolf source coding
and the broadcast channel coding (independent messages and no common message)
based on the the notion of a stronger version of the hash property for an
ensemble of functions. Since an ensemble of sparse matrices has a strong hash
property, codes using sparse matrices can realize the achievable rate region.
Furthermore, extensions to the multiple source coding and multiple output
broadcast channel coding are investigated.Comment: The proofs of Lemmas 4 and 9 are revised. Some proofs are simplified.
Some typos are fixed. A part of this paper has been published in Proceedings
of 2010 IEEE International Symposium on Information Theory (ISIT2010) and
Proceedings of 7th Asia-Europe Workshop "CONCEPTS in INFORMATION THEORY"
(AEW7), 2011, 39 page
Construction of Multiple Access Channel Codes Based on Hash Property
The aim of this paper is to introduce the construction of codes for a general
discrete stationary memoryless multiple access channel based on the the notion
of the hash property. Since an ensemble of sparse matrices has a hash property,
we can use sparse matrices for code construction. Our approach has a potential
advantage compared to the conventional random coding because it is expected
that we can use some approximation algorithms by using the sparse structure of
codes.Comment: This paper has been presented in part at Proc. 2011 IEEE Internal
Symposium on Information Theory and submitted to IEEE Transactions on
Information Theory. 39 page
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