51,522 research outputs found
The Philosophical Works: Concerning Human Understanding, A Dissertation on the Passions, Concerning the Principles of Morals, The Natural History of Religion; Essays withdrawn or unpublished
General features of Bianchi-I cosmological models in Lovelock gravity
We derived equations of motion corresponding to Bianchi-I cosmological models
in the Lovelock gravity. Equations derived in the general case, without any
specific ansatz for any number of spatial dimensions and any order of the
Lovelock correction. We also analyzed the equations of motion solely taking
into account the highest-order correction and described the drastic difference
between the cases with odd and even numbers of spatial dimensions. For
power-law ansatz we derived conditions for Kasner and generalized Milne regimes
for the model considered. Finally, we discuss the possible influence of matter
in the form of perfect fluid on the solutions obtained.Comment: extended version of published Brief Repor
Combining in-domain and out-of-domain speech data for automatic recognition of disordered speech
A New Symmetric Expression of Weyl Ordering
For the creation operator \adag and the annihilation operator of a
harmonic oscillator, we consider Weyl ordering expression of (\adag a)^n and
obtain a new symmetric expression of Weyl ordering w.r.t. \adag a \equiv N
and a\adag =N+1 where is the number operator. Moreover, we interpret
intertwining formulas of various orderings in view of the difference theory.
Then we find that the noncommutative parameter corresponds to the increment of
the difference operator w.r.t. variable . Therefore, quantum
(noncommutative) calculations of harmonic oscillators are done by classical
(commutative) ones of the number operator by using the difference theory. As a
by-product, nontrivial relations including the Stirling number of the first
kind are also obtained.Comment: 15 pages, Latex2e, the title before replacement is "Orderings of
Operators in Quantum Physics", new proofs by using a difference operator
added, some references added, to appear in Modern Physics Letters
D-instanton partition functions
Duality arguments are used to determine D-instanton contributions to certain
effective interaction terms of type II supergravity theories in various
dimensions. This leads to exact expressions for the partition functions of the
finite N D-instanton matrix model in d=4 and 6 dimensions that generalize our
previous expression for the case d=10. These results are consistent with the
fact that the Witten index of the T-dual D-particle process should only be
non-vanishing for d=10.Comment: 20 pages, harvmac, typos corrected, reference adde
Cooperative Chiral Order in Copolymers of Chiral and Achiral Units
Polyisocyanates can be synthesized with chiral and achiral pendant groups
distributed randomly along the chains. The overall chiral order, measured by
optical activity, is strongly cooperative and depends sensitively on the
concentration of chiral pendant groups. To explain this cooperative chiral
order theoretically, we map the random copolymer onto the one-dimensional
random-field Ising model. We show that the optical activity as a function of
composition is well-described by the predictions of this theory.Comment: 13 pages, including 3 postscript figures, uses REVTeX 3.0 and
epsf.st
Measuring Active-Sterile Neutrino Oscillations with a Stopped Pion Neutrino Source
The question of the existence of light sterile neutrinos is of great interest
in many areas of particle physics, astrophysics, and cosmology. Furthermore,
should the MiniBooNE experiment at Fermilab confirm the LSND oscillation
signal, then new measurements are required to identify the mechanism
responsible for these oscillations. Possibilities include sterile neutrinos, CP
or CPT violation, variable mass neutrinos, Lorentz violation, and extra
dimensions. In this paper, we consider an experiment at a stopped pion neutrino
source to determine if active-sterile neutrino oscillations with delta-m
greater than 0.1 eV2 can account for the signal. By exploiting stopped pi+
decay to produce a monoenergetic nu_mu source, and measuring the rate of the
neutral current reaction nu_x + 12C -> nu_x +12C* as a function of distance
from the source, we show that a convincing test for active-sterile neutrino
oscillations can be performed.Comment: 10 pages, 9 figure
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