3,470 research outputs found
Predictions for the unitarity triangle angles in a new parametrization
A new approach to the parametrization of the CKM matrix, , is considered
in which is written as a linear combination of the unit matrix and a
non-diagonal matrix which causes intergenerational-mixing, that is
. Such a depends on 3 real parameters
including the parameter . It is interesting that a value of
is required to fit the available data on the CKM-matrix
including CP-violation. Predictions of this fit for the angles ,
and for the unitarity triangle corresponding to
, are given. For
=, we obtain , and
. These values are just about in agreement, within errors,
with the present data. It is very interesting that the unitarity triangle is
expected to be approximately a right-angled, isosceles triangle. Our prediction
is in excellent agreement with the value reported by the Belle collaboration at the Lepton-Photon 2001 meeting.Comment: 11 pages, latex, no figure
Spectra of phase point operators in odd prime dimensions and the extended Clifford group
We analyse the role of the Extended Clifford group in classifying the spectra
of phase point operators within the framework laid out by Gibbons et al for
setting up Wigner distributions on discrete phase spaces based on finite
fields. To do so we regard the set of all the discrete phase spaces as a
symplectic vector space over the finite field. Auxiliary results include a
derivation of the conjugacy classes of .Comment: Latex, 19page
Hudson's Theorem for finite-dimensional quantum systems
We show that, on a Hilbert space of odd dimension, the only pure states to
possess a non-negative Wigner function are stabilizer states. The Clifford
group is identified as the set of unitary operations which preserve positivity.
The result can be seen as a discrete version of Hudson's Theorem. Hudson
established that for continuous variable systems, the Wigner function of a pure
state has no negative values if and only if the state is Gaussian. Turning to
mixed states, it might be surmised that only convex combinations of stabilizer
states give rise to non-negative Wigner distributions. We refute this
conjecture by means of a counter-example. Further, we give an axiomatic
characterization which completely fixes the definition of the Wigner function
and compare two approaches to stabilizer states for Hilbert spaces of
prime-power dimensions. In the course of the discussion, we derive explicit
formulas for the number of stabilizer codes defined on such systems.Comment: 17 pages, 3 figures; References updated. Title changed to match
published version. See also quant-ph/070200
The Schwinger SU(3) construction - I: Multiplicity problem and relation to induced representations
The Schwinger oscillator operator representation of SU(3) is analysed with
particular reference to the problem of multiplicity of irreducible
representations. It is shown that with the use of an unitary
representation commuting with the SU(3) representation, the infinity of
occurrences of each SU(3) irreducible representation can be handled in complete
detail. A natural `generating representation' for SU(3), containing each
irreducible representation exactly once, is identified within a subspace of the
Schwinger construction; and this is shown to be equivalent to an induced
representation of SU(3).Comment: Latex, 25 page
Particle alignments and shape change in Ge and Ge
The structure of the nuclei Ge and Ge is studied
by the shell model on a spherical basis. The calculations with an extended
Hamiltonian in the configuration space
(, , , ) succeed in reproducing
experimental energy levels, moments of inertia and moments in Ge isotopes.
Using the reliable wave functions, this paper investigates particle alignments
and nuclear shapes in Ge and Ge.
It is shown that structural changes in the four sequences of the positive-
and negative-parity yrast states with even and odd are caused by
various types of particle alignments in the orbit.
The nuclear shape is investigated by calculating spectroscopic moments of
the first and second states, and moreover the triaxiality is examined by
the constrained Hatree-Fock method.
The changes of the first band crossing and the nuclear deformation depending
on the neutron number are discussed.Comment: 18 pages, 21 figures; submitted to Phys. Rev.
Quantum phase space distributions in thermofield dynamics
It is shown that the the quantum phase space distributions corresponding to a
density operator can be expressed, in thermofield dynamics, as overlaps
between the state and "thermal" coherent states. The usefulness
of this approach is brought out in the context of a master equation describing
a nonlinear oscillator for which exact expressions for the quantum phase
distributions for an arbitrary initial condition are derived.Comment: 17 pages, revtex, no figures. number of pages were incorrectly stated
as 3 instead of 17. No other correction
Linear amplification and quantum cloning for non-Gaussian continuous variables
We investigate phase-insensitive linear amplification at the quantum limit
for single- and two-mode states and show that there exists a broad class of
non-Gaussian states whose nonclassicality survives even at an arbitrarily large
gain. We identify the corresponding observable nonclassical effects and find
that they include, remarkably, two-mode entanglement. The implications of our
results for quantum cloning outside the Gaussian regime are also addressed.Comment: published version with reference updat
TOLERANCE SHOWN BY Rattus rattus TO AN ANTICOAGULANT RODENTICIDE
Apart from using 0.005% concentration, the recommended field dose of 0.025% of the anticoagulant is used along with an alternate food for individual rats for a varying number of days. Those that had survived were taken as tolerant, provided they showed an mg/kg intake beyond the tolerance limit, survived a six days of feeding, exhibited bait-shyness and did not exhibit hemorrhage after death. In determining the criteria for tolerance to an anticoagulant by a rat, one should take into account four composite factors. These are, six days of even 0.025% feeding, bait-shyness when alternate food is given, higher mg/kg intake than the tolerance level and a loss of intensive hemorrhage after death
First-principles quantum dynamics in interacting Bose gases I: The positive P representation
The performance of the positive P phase-space representation for exact
many-body quantum dynamics is investigated. Gases of interacting bosons are
considered, where the full quantum equations to simulate are of a
Gross-Pitaevskii form with added Gaussian noise. This method gives tractable
simulations of many-body systems because the number of variables scales
linearly with the spatial lattice size. An expression for the useful simulation
time is obtained, and checked in numerical simulations. The dynamics of first-,
second- and third-order spatial correlations are calculated for a uniform
interacting 1D Bose gas subjected to a change in scattering length. Propagation
of correlations is seen. A comparison is made to other recent methods. The
positive P method is particularly well suited to open systems as no
conservation laws are hard-wired into the calculation. It also differs from
most other recent approaches in that there is no truncation of any kind.Comment: 21 pages, 7 figures, 2 tables, IOP styl
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