184,198 research outputs found
Tropical cyclone intensities from satellite microwave data
Radial profiles of mean 1000 mb to 250 mb temperature from the Nimbus 6 scanning microwave spectrometer (SCAMS) were constructed around eight intensifying tropical storms in the western Pacific. Seven storms showed distinct inward temperature gradients required for intensification; the eighth displayed no inward gradient and was decaying 24 hours later. The possibility that satellite data might be used to forecast tropical cyclone turning motion was investigated using estimates obtained from Nimbus 6 SCAMS data tapes of the mean 1000 mb to 250 mb temperature field around eleven tropical storms in 1975. Analysis of these data show that for turning storms, in all but one case, the turn was signaled 24 hours in advance by a significant temperature gradient perpendicular to the storm's path, at a distance of 9 deg to 13 deg in front of the storm. A thresholding technique was applied to the North Central U.S. during the summer to estimate precipitation frequency. excep
Massive Complex Scalar Field in a Kerr-Sen Black Hole Background: Exact Solution of Wave Equation and Hawking Radiation
The separated radial part of a massive complex scalar wave equation in the
Kerr-Sen geometry is shown to satisfy the generalized spheroidal wave equation
which is, in fact, a confluent Heun equation up to a multiplier. The Hawking
evaporation of scalar particles in the Kerr-Sen black hole background is
investigated by the Damour-Ruffini-Sannan's method. It is shown that quantum
thermal effect of the Kerr-Sen black hole has the same characteras that of the
Kerr-Newman black hole.Comment: Revtex, 5 pages, no figure, submitted to Phys. Rev.
A General Effective Theory for Dense Quark Matter
A general effective action for quark matter at nonzero temperature and/or
nonzero density is derived. Irrelevant quark modes are distinguished from
relevant quark modes, and hard from soft gluon modes, by introducing two
separate cut-offs in momentum space, one for quarks, , and one for
gluons, . Irrelevant quark modes and hard gluon modes are then
exactly integrated out in the functional integral representation of the QCD
partition function. Depending on the specific choice for and
, the resulting effective action contains well-known effective
actions for hot and/or dense quark matter, for instance the ``Hard Thermal
Loop'' (HTL) or the ``Hard Dense Loop'' (HDL) action, as well as the
high-density effective theory proposed by Hong and others.Comment: 10 pages, 6 figures, contribution to proceedings of SEWM 200
Comment on "Time-Dependent Density-Matrix Renormalization Group: A Systematic Method for the Study of Quantum Many-Body Out-of- Equilibrium Systems"
In a recent Letter [Phys. Rev. Lett. 88, 256403(2002), cond-mat/0109158]
Cazalilla and Marston proposed a time-dependent density- matrix renormalization
group (TdDMRG) algorithm for the accurate evaluation of out-of-equilibrium
properties of quantum many-body systems. For a point contact junction between
two Luttinger liquids, a current oscillation develops after initial transient
in the insulating regime. Here we would like to point out that (a) the observed
oscillation is an artifact of the method; (b) the TdDMRG can be significantly
improved by incorporating the non-equilibrium evolution of the goundstate into
the density matrix.Comment: 1 page, 2 figure
Geometric entanglement from matrix product state representations
An efficient scheme to compute the geometric entanglement per lattice site
for quantum many-body systems on a periodic finite-size chain is proposed in
the context of a tensor network algorithm based on the matrix product state
representations. It is systematically tested for three prototypical critical
quantum spin chains, which belong to the same Ising universality class. The
simulation results lend strong support to the previous claim [Q.-Q. Shi, R.
Or\'{u}s, J. O. Fj{\ae}restad, and H.-Q. Zhou, New J. Phys \textbf{12}, 025008
(2010); J.-M. St\'{e}phan, G. Misguich, and F. Alet, Phys. Rev. B \textbf{82},
180406R (2010)] that the leading finite-size correction to the geometric
entanglement per lattice site is universal, with its remarkable connection to
the celebrated Affleck-Ludwig boundary entropy corresponding to a conformally
invariant boundary condition.Comment: 4+ pages, 3 figure
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