3,258 research outputs found
Growth and formation of the foreleg skeleton inbred mice and rats under conditions of hypo-, normo- and hyperdynamia
Inbred 1 month old males of C57B 1/6, CBA, CC57Br/Mw interlinear hybrid mice of the first generation and rats of the August and Wistar lines were subjected to conditions of hypo-, normo- and hyperdynamia for 2 months. The statistically reliable dependence is shown between mechanical underloadings and overloadings and macro microscopic changes in the hind limb skeleton of animals. Genetic determination of growth and formation of the forelimb skeleton is established. Hereditary susceptibility and the phenomenon of heterosis are preserved under all motor conditions
Refining the Proof of Planar Equivalence
We outline a full non-perturbative proof of planar (large-N) equivalence
between bosonic correlators in a theory with Majorana fermions in the adjoint
representation and one with Dirac fermions in the two-index (anti)symmetric
representation. In a particular case (one flavor), this reduces to our previous
result - planar equivalence between super-Yang--Mills theory and a
non-supersymmetric ``orientifold field theory.'' The latter theory becomes
one-flavor massless QCD at N=3.Comment: 15 pages, Latex. 6 figures. v2: Comments and refs. added. v3: ref.[9]
corrected. To appear in Phys.Rev.
Analytic solution for kinetic equilibrium of beta-processes in nucleonic plasma with relativistic pairs
The analytic solution is obtained describing kinetic equilibrium of the
-processes in the nucleonic plasma with relativistic pairs. The nucleons
are supposed to be non-relativistic and non-degenerate, while the
electrons and positrons are ultra-relativistic due to high temperature
K), or high density g/cm), or both, where
is a number of nucleons per one electron. The consideration is simplified
because of the analytic connection of the density with the electron chemical
potential in the ultra-relativistic plasma, and Gauss representation of Fermi
functions. Electron chemical potential and number of nucleons per one initial
electron are calculated as functions of and .Comment: 16 pages, 6 figure
Thermal Duality and Hagedorn Transition from p-adic Strings
We develop the finite temperature theory of p-adic string models. We find
that the thermal properties of these non-local field theories can be
interpreted either as contributions of standard thermal modes with energies
proportional to the temperature, or inverse thermal modes with energies
proportional to the inverse of the temperature, leading to a "thermal duality"
at leading order (genus one) analogous to the well known T-duality of string
theory. The p-adic strings also recover the asymptotic limits (high and low
temperature) for arbitrary genus that purely stringy calculations have yielded.
We also discuss our findings surrounding the nature of the Hagedorn transition.Comment: 4 pages and 4 figure
On Quantum Nature of Black-Hole Spacetime: A Possible New Source of Intense Radiation
Atoms and the planets acquire their stability from the quantum mechanical
incompatibility of the position and momentum measurements. This incompatibility
is expressed by the fundamental commutator [x, p_x]=i hbar, or equivalently,
via the Heisenberg's uncertainty principle Delta x Delta p_x sim hbar. A
further stability-related phenomenon where the quantum realm plays a dramatic
role is the collapse of certain stars into white dwarfs and neutron stars.
Here, an intervention of the Pauli exclusion principle, via the fermionic
degenerate pressure, stops the gravitational collapse. However, by the
neutron-star stage the standard quantum realm runs dry. One is left with the
problematic collapse of a black hole. This essay is devoted to a concrete
argument on why the black-hole spacetime itself should exhibit a quantum
nature. The proposed quantum aspect of spacetime is shown to prevent the
general-relativistic dictated problematic collapse. The quantum nature of
black-hole spacetime is deciphered from a recent result on the universal
equal-area spacing [=lambda_P^2 4 ln(3)] for black holes. In one interpretation
of the emergent picture, an astrophysical black hole can fluctuate to
sqrt{pi/ln(3)} approx 1.7 times its classical size, and thus allow radiation
and matter to escape to the outside observers. These fluctuations I conjecture
provide a new source, perhaps beyond Hawking radiation, of intense radiation
from astrophysical black holes and may be the primary source of observed
radiation from those galactic cores what carry black hole(s). The presented
interpretation may be used as a criterion to choose black holes from black hole
candidates.Comment: This essay received an "honorable mention" in the 1999 Essay
Competition of the Gravity Research Foundation - Ed. Int. J. Mod. Phys. D
(1999, in press). For Joseph Knech
Looping on the Bloch sphere: Oscillatory effects in dephasing of qubits subject to broad-spectrum noise
For many implementations of quantum computing, 1/f and other types of
broad-spectrum noise are an important source of decoherence. An important step
forward would be the ability to back out the characteristics of this noise from
qubit measurements and to see if it leads to new physical effects. For certain
types of qubits, the working point of the qubit can be varied. Using a new
mathematical method that is suited to treat all working points, we present
theoretical results that show how this degree of freedom can be used to extract
noise parameters and to predict a new effect: noise-induced looping on the
Bloch sphere. We analyze data on superconducting qubits to show that they are
very near the parameter regime where this looping should be observed.Comment: 4 pages, 3 figure
Temperature square dependence of the low frequency 1/f charge noise in the Josephson junction qubits
To verify the hypothesis about the common origin of the low frequency 1/f
noise and the quantum f noise recently measured in the Josephson charge qubits,
we study temperature dependence of the 1/f noise and decay of coherent
oscillations. T^2 dependence of the 1/f noise is experimentally demonstrated,
which supports the hypothesis. We also show that dephasing in the Josephson
charge qubits off the electrostatic energy degeneracy point is consistently
explained by the same low frequency 1/f noise that is observed in the transport
measurements.Comment: 4 pages, 2 figure
The Hopf Skyrmion in QCD with Adjoint Quarks
We consider a modification of QCD in which conventional fundamental quarks
are replaced by Weyl fermions in the adjoint representation of the color SU(N).
In the case of two flavors the low-energy chiral Lagrangian is that of the
Skyrme-Faddeev model. The latter supports topologically stable solitons with
mass scaling as N^2. Topological stability is due to the existence of a
nontrivial Hopf invariant in the Skyrme-Faddeev model. Our task is to identify,
at the level of the fundamental theory, adjoint QCD, an underlying reason
responsible for the stability of the corresponding hadrons. We argue that all
"normal" mesons and baryons, with mass O(N^0), are characterized by (-1)^Q
(-1)^F =1, where Q is a conserved charge corresponding to the unbroken U(1)
surviving in the process of the chiral symmetry breaking (SU(2) \to U(1) for
two adjoint flavors). Moreover, F is the fermion number (defined mod 2 in the
case at hand). We argue that there exist exotic hadrons with mass O(N^2) and
(-1)^Q (-1)^F = -1. They are in one-to-one correspondence with the Hopf
Skyrmions. The transition from nonexotic to exotic hadrons is due to a shift in
F, namely F \to F - {\cal H} where {\cal H} is the Hopf invariant. To detect
this phenomenon we have to extend the Skyrme-Faddeev model by introducing
fermions.Comment: 18 pages, 3 figures; v.2: a reference and a comment added; v.3: two
comments added, figures improve
Nature of 45 degree vortex lattice reorientation in tetragonal superconductors
The transformation of the vortex lattice in a tetragonal superconductor which
consists of its 45 degree reorientation relative to the crystal axes is studied
using the nonlocal London model. It is shown that the reorientation occurs as
two successive second order (continuous) phase transitions. The transition
magnetic fields are calculated for a range of parameters relevant for
borocarbide superconductors in which the reorientation has been observed
The puzzle of 90 degree reorientation in the vortex lattice of borocarbide superconductors
We explain 90 degree reorientation in the vortex lattice of borocarbide
superconductors on the basis of a phenomenological extension of the nonlocal
London model that takes full account of the symmetry of the system. We propose
microscopic mechanisms that could generate the correction terms and point out
the important role of the superconducting gap anisotropy.Comment: 4 pages, 2 eps figure
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