41,375 research outputs found
Six-dimensional D_N theory and four-dimensional SO-USp quivers
We realize four-dimensional N=2 superconformal quiver gauge theories with
alternating SO and USp gauge groups as compactifications of the six-dimensional
D_N theory with defects. The construction can be used to analyze infinitely
strongly-coupled limits and S-dualities of such gauge theories, resulting in a
new class of isolated four-dimensional N=2 superconformal field theories with
SO(2N)^3 flavor symmetry.Comment: 30 pages, 12 figures; v2: published versio
On the nature of the Mott transition in multiorbital systems
We analyze the nature of Mott metal-insulator transition in multiorbital
systems using dynamical mean-field theory (DMFT). The auxiliary multiorbital
quantum impurity problem is solved using continuous time quantum Monte Carlo
(CTQMC) and the rotationally invariant slave-boson (RISB) mean field
approximation. We focus our analysis on the Kanamori Hamiltonian and find that
there are two markedly different regimes determined by the nature of the lowest
energy excitations of the atomic Hamiltonian. The RISB results at
suggest the following rule of thumb for the order of the transition at zero
temperature: a second order transition is to be expected if the lowest lying
excitations of the atomic Hamiltonian are charge excitations, while the
transition tends to be first order if the lowest lying excitations are in the
same charge sector as the atomic ground state. At finite temperatures the
transition is first order and its strength, as measured e.g. by the jump in the
quasiparticle weight at the transition, is stronger in the parameter regime
where the RISB method predicts a first order transition at zero temperature.
Interestingly, these results seem to apply to a wide variety of models and
parameter regimes.Comment: Accepted for publication in Physical Review
The method of Gaussian weighted trajectories. V. On the 1GB procedure for polyatomic processes
In recent years, many chemical reactions have been studied by means of the
quasi-classical trajectory (QCT) method within the Gaussian binning (GB)
procedure. The latter consists in "quantizing" the final vibrational actions in
Bohr spirit by putting strong emphasis on the trajectories reaching the
products with vibrational actions close to integer values. A major drawback of
this procedure is that if N is the number of product vibrational modes, the
amount of trajectories necessary to converge the calculations is ~ 10^N larger
than with the standard QCT method. Applying it to polyatomic processes is thus
problematic. In a recent paper, however, Czako and Bowman propose to quantize
the total vibrational energy instead of the vibrational actions [G. Czako and
J. M. Bowman, J. Chem. Phys., 131, 244302 (2009)], a procedure called 1GB here.
The calculations are then only ~ 10 times more time-consuming than with the
standard QCT method, allowing thereby for considerable numerical saving. In
this paper, we propose some theoretical arguments supporting the 1GB procedure
and check its validity on model test cases as well as the prototype four-atom
reaction OH+D_2 -> HOD+D
Desalination effluents and the establishment of the non-indigenous skeleton shrimp Paracaprella pusilla Mayer, 1890 in the south-eastern Mediterranean
A decade long monitoring programme has revealed a flourishing population of the non-indigenous skeleton shrimp Paracaprella pusilla in the vicinity of outfalls of desalination plants off the Mediterranean coast of Israel. The first specimens were collected in 2010, thus predating all previously published records of this species in the Mediterranean Sea. A decade-long disturbance regime related to the construction and operation of the plants may have had a critical role in driving the population growth
On the Moyal deformation of Nahm Equations in seven dimensions
We show how the reduced (anti-)self-dual Yang-Mills equations in seven
dimensions described by the Nahm equations can be carried over to the
Weyl-Wigner-Moyal formalism. In the process some new solutions for the cases of
gauge groups SU(2) and SL(2,R) are explicitly obtained.Comment: 16+1 pages, LaTeX, no figure
Desalination effluents and the establishment of the non-indigenous skeleton shrimp Paracaprella pusilla Mayer, 1890 in the south-eastern Mediterranean
A decade long monitoring programme has revealed a flourishing population of the non-indigenous skeleton shrimp Paracaprella pusilla in the vicinity of outfalls of desalination plants off the Mediterranean coast of Israel. The first specimens were collected in 2010, thus predating all previously published records of this species in the Mediterranean Sea. A decade-long disturbance regime related to the construction and operation of the plants may have had a critical role in driving the population growth
Rapid Rotation of Low-Mass Red Giants Using APOKASC: A Measure of Interaction Rates on the Post-main-sequence
We investigate the occurrence rate of rapidly rotating (10 km
s), low-mass giant stars in the APOGEE-Kepler (APOKASC) fields with
asteroseismic mass and surface gravity measurements. Such stars are likely
merger products and their frequency places interesting constraints on stellar
population models. We also identify anomalous rotators, i.e. stars with 5 km
s10 km s that are rotating significantly faster
than both angular momentum evolution predictions and the measured rates of
similar stars. Our data set contains fewer rapid rotators than one would expect
given measurements of the Galactic field star population, which likely
indicates that asteroseismic detections are less common in rapidly rotating red
giants. The number of low-mass moderate (5-10 km s) rotators in our
sample gives a lower limit of 7% for the rate at which low-mass stars interact
on the upper red giant branch because single stars in this mass range are
expected to rotate slowly. Finally, we classify the likely origin of the rapid
or anomalous rotation where possible. KIC 10293335 is identified as a merger
product and KIC 6501237 is a possible binary system of two oscillating red
giants.Comment: 39 pages, 8 figures, 4 tables. Accepted for publication in the
Astrophysical Journal. For a brief video discussing key results from this
paper see http://youtu.be/ym_0nV7_YqI . The full table 1 is available at
http://www.astronomy.ohio-state.edu/~tayar/tab1_full.tx
Neutrino mean free paths in spin-polarized neutron Fermi liquids
Neutrino mean free paths in magnetized neutron matter are calculated using
the Hartree-Fock approximation with effective Skyrme and Gogny forces in the
framework of the Landau Fermi Liquid Theory. It is shown that describing
nuclear interaction with Skyrme forces and for magnetic field strengths
, the neutrino mean free paths stay almost unchanged
at intermediate densities but they largely increase at high densities when they
are compared to the field-free case results. However the description with Gogny
forces differs from the previous and mean free paths stay almonst unchanged or
decrease at densities . This different behaviour can be explained
due to the combination of common mild variation of the Landau parameters with
both types of forces and the values of the nucleon effective mass and induced
magnetization of matter under presence of a strong magnetic field as described
with the two parametrizations of the nuclear interaction.Comment: 9 pages, 3 figure
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