22,402 research outputs found
Compact QED under scrutiny: it's first order
We report new results from our finite size scaling analysis of 4d compact
pure U(1) gauge theory with Wilson action. Investigating several cumulants of
the plaquette energy within the Borgs-Kotecky finite size scaling scheme we
find strong evidence for a first-order phase transition and present a high
precision value for the critical coupling in the thermodynamic limit.Comment: Lattice2002(Spin
Comment on "c-axis Josephson tunneling in -wave superconductors''
This comment points out that the recent paper by Maki and Haas [Phys. Rev. B
{\bf 67}, 020510 (2003)] is completely wrong.Comment: 1 page, submittted to Phys. Rev.
Covariant derivative expansion of fermionic effective action at high temperatures
We derive the fermionic contribution to the 1-loop effective action for A_4
and A_i fields at high temperatures, assuming that gluon fields are slowly
varying but allowing for an arbitrary amplitude of A_4.Comment: RevTex 4, 11 pages, 3 figures. Version 2: Typos corrected; magnetic
fields restricted to parallel sector. Version accepted for publication in PR
A Time-Orbiting Potential Trap for Bose-Einstein Condensate Interferometry
We describe a novel atom trap for Bose-Einstein condensates of 87Rb to be
used in atom interferometry experiments. The trap is based on a time-orbiting
potential waveguide. It supports the atoms against gravity while providing weak
confinement to minimize interaction effects. We observe harmonic oscillation
frequencies omega_x, omega_y, omega_z as low as 2 pi times (6.0,1.2,3.3) Hz. Up
to 2 times 10^4 condensate atoms have been loaded into the trap, at estimated
temperatures as low as 850 pK. We anticipate that interferometer measurement
times of 1 s or more should be achievable in this device.Comment: 9 pages, 3 figure
Evolutionary dynamics on strongly correlated fitness landscapes
We study the evolutionary dynamics of a maladapted population of
self-replicating sequences on strongly correlated fitness landscapes. Each
sequence is assumed to be composed of blocks of equal length and its fitness is
given by a linear combination of four independent block fitnesses. A mutation
affects the fitness contribution of a single block leaving the other blocks
unchanged and hence inducing correlations between the parent and mutant
fitness. On such strongly correlated fitness landscapes, we calculate the
dynamical properties like the number of jumps in the most populated sequence
and the temporal distribution of the last jump which is shown to exhibit a
inverse square dependence as in evolution on uncorrelated fitness landscapes.
We also obtain exact results for the distribution of records and extremes for
correlated random variables
Covariant derivative expansion of Yang-Mills effective action at high temperatures
Integrating out fast varying quantum fluctuations about Yang--Mills fields
A_i and A_4, we arrive at the effective action for those fields at high
temperatures. Assuming that the fields A_i and A_4 are slowly varying but that
the amplitude of A_4 is arbitrary, we find a non-trivial effective gauge
invariant action both in the electric and magnetic sectors. Our results can be
used for studying correlation functions at high temperatures beyond the
dimensional reduction approximation, as well as for estimating quantum weights
of classical static configurations such as dyons.Comment: Minor changes. References added. Paper accepted for publication in
Phys.Rev.
Investigation of double beta decay with the NEMO-3 detector
The double beta decay experiment NEMO~3 has been taking data since February
2003. The aim of this experiment is to search for neutrinoless
() decay and investigate two neutrino double beta decay in
seven different isotopically enriched samples (Mo, Se,
Ca, Zr, Cd, Te and Nd). After analysis of
the data corresponding to 3.75 y, no evidence for decay in the
Mo and Se samples was found. The half-life limits at the 90%
C.L. are y and y, respectively.
Additionally for decay the following limits at the 90% C.L.
were obtained, y for Ca, y
for Zr and y for Nd. The
decay half-life values were precisely measured for all investigated isotopes.Comment: 12 pages, 4 figures, 5 tables; talk at conference on "Fundamental
Interactions Physics" (ITEP, Moscow, November 23-27, 2009
On viscous flow and azimuthal anisotropy of quark-gluon plasma in strong magnetic field
We calculate the viscous pressure tensor of the quark-gluon plasma in strong
magnetic field. It is azimuthally anisotropic and is characterized by five
shear viscosity coefficients, four of which vanish when the field strength eB
is much larger than the plasma temperature squared. We argue, that the
azimuthally anisotropic viscous pressure tensor generates the transverse flow
with asymmetry as large as 1/3, even not taking into account the collision
geometry. We conclude, that the magnitude of the shear viscosity extracted from
the experimental data ignoring the magnetic field must be underestimated.Comment: 10 page
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