42,704 research outputs found
Nodal Structure of Superconductors with Time-Reversal Invariance and Z2 Topological Number
A topological argument is presented for nodal structures of superconducting
states with time-reversal invariance. A generic Hamiltonian which describes a
quasiparticle in superconducting states with time-reversal invariance is
derived, and it is shown that only line nodes are topologically stable in
single-band descriptions of superconductivity. Using the time-reversal
symmetry, we introduce a real structure and define topological numbers of line
nodes. Stability of line nodes is ensured by conservation of the topological
numbers. Line nodes in high-Tc materials, the polar state in p-wave paring and
mixed singlet-triplet superconducting states are examined in detail.Comment: 11 pages, 8 figure
Towards unravelling the structural distribution of ultra-high-energy cosmic ray sources
We investigate the possibility that near future observations of
ultra-high-energy cosmic rays (UHECRs) can unveil their local source
distribution, which reflects the observed local structures if their origins are
astrophysical objects. In order to discuss this possibility, we calculate the
arrival distribution of UHE protons taking into account their propagation
process in intergalactic space i.e. energy losses and deflections by
extragalactic magnetic field (EGMF). For a realistic simulation, we construct
and adopt a model of a structured EGMF and UHECR source distribution, which
reproduce the local structures actually observed around the Milky Way. The
arrival distribution is compared statistically to their source distribution
using correlation coefficient. We specially find that UHECRs above
eV are best indicators to decipher their source distribution within
100 Mpc, and detection of about 500 events on all the sky allows us to unveil
the local structure of UHE universe for plausible EGMF strength and the source
number density. This number of events can be detected by five years observation
by Pierre Auger Observatory.Comment: 7pages, 4 figures, submitted to Ap
Bounds on Cubic Lorentz-Violating Terms in the Fermionic Dispersion Relation
We study the recently proposed Lorentz-violating dispersion relation for
fermions and show that it leads to two distinct cubic operators in the
momentum. We compute the leading order terms that modify the non-relativistic
equations of motion and use experimental results for the hyperfine transition
in the ground state of the ion to bound the values of the
Lorentz-violating parameters and for neutrons. The resulting
bounds depend on the value of the Lorenz-violating background four-vector in
the laboratory frame.Comment: Revtex 4, four pages. Version to match the one to appear in Physical
Review
Point interactions in one dimension and holonomic quantum fields
We introduce and study a family of quantum fields, associated to
delta-interactions in one dimension. These fields are analogous to holonomic
quantum fields of M. Sato, T. Miwa and M. Jimbo. Corresponding field operators
belong to an infinite-dimensional representation of the group SL(2,\Rb) in
the Fock space of ordinary harmonic oscillator. We compute form factors of such
fields and their correlation functions, which are related to the determinants
of Schroedinger operators with a finite number of point interactions. It is
also shown that these determinants coincide with tau functions, obtained
through the trivialization of the -bundle over a Grassmannian
associated to a family of Schroedinger operators.Comment: 17 page
Solitons and Almost-Intertwining Matrices
We define the set of almost-intertwining matrices to be all triples(X,Y,Z) of
n x n matrices for which XZ=YX+T for some rank one matrix T. A surprisingly
simple formula is given for tau-functions of the KP hierarchy in terms of such
triples. The tau-functions produced in this way include the soliton and
vanishing rational solutions. The induced dynamics of the eigenvalues of the
matrix X are considered, leading in special cases to the Ruijsenaars-Schneider
particle system
R-parity violating supersymmetric contributions to the neutron beta decay
We investigate the contribution to the angular correlation coefficients of
the neutron beta decay within the R-parity violating (RPV) minimal
supersymmetric standard model (MSSM). The RPV effects contribute to the scalar
interaction at the tree level. The effective scalar interaction of the neutron
beta decay is constructed by making use of the relation between isospin
asymmetries and the proton-neutron mass difference. On the basis of the recent
update of the analyses of the superallowed Fermi transitions and the recent
measurement of transverse polarization of the emitted electrons at PSI, we
deduce new upper limits on the RPV couplings. We also point out the existence
of new types of angular correlations which are sensitive to the RPV
interactions.Comment: 11 pages, 2 figures, minor errors corrected, references adde
On correlation functions of integrable models associated to the six-vertex R-matrix
We derive an analog of the master equation obtained recently for correlation
functions of the XXZ chain for a wide class of quantum integrable systems
described by the R-matrix of the six-vertex model, including in particular
continuum models. This generalized master equation allows us to obtain multiple
integral representations for the correlation functions of these models. We
apply this method to derive the density-density correlation functions of the
quantum non-linear Schrodinger model.Comment: 21 page
Microwave Heating of Water, Ice and Saline Solution: Molecular Dynamics Study
In order to study the heating process of water by the microwaves of 2.5-20GHz
frequencies, we have performed molecular dynamics simulations by adopting a
non-polarized water model that have fixed point charges on rigid-body
molecules. All runs are started from the equilibrated states derived from the
I ice with given density and temperature. In the presence of microwaves,
the molecules of liquid water exhibit rotational motion whose average phase is
delayed from the microwave electric field. Microwave energy is transferred to
the kinetic and inter-molecular energies of water, where one third of the
absorbed microwave energy is stored as the latter energy. The water in ice
phase is scarcely heated by microwaves because of the tight hydrogen-bonded
network of water molecules. Addition of small amount of salt to pure water
substantially increases the heating rate because of the weakening by defects in
the water network due to sloshing large-size negative ions.Comment: 21 pages, 13 figure
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