3,395 research outputs found
Monte Carlo simulation of the classical two-dimensional one component plasma
Monte Carlo simulation, lattice dynamics in the harmonic approximation, and solution of the hypernetted chain equation were used to study the classical two-dimensional one component plasma. The system consists of a single species of charged particles immersed in a uniform neutralizing background. The particles interact via a l/r potential, where r is the two dimensional separation. Equations of state were calculated for both the liquid and solid phases. Results of calculation of the thermodynamic functions and one and two particle correlation functions are presented
Short-coherence length superconductivity in the Attractive Hubbard Model in three dimensions
We study the normal state and the superconducting transition in the
Attractive Hubbard Model in three dimensions, using self-consistent
diagrammatics. Our results for the self-consistent -matrix approximation are
consistent with 3D-XY power-law critical scaling and finite-size scaling. This
is in contrast to the exponential 2D-XY scaling the method was able to capture
in our previous 2D calculation. We find the 3D transition temperature at
quarter-filling and to be . The 3D critical regime is much
narrower than in 2D and the ratio of the mean-field transition to is
about 5 times smaller than in 2D. We also find that, for the parameters we
consider, the pseudogap regime in 3D (as in 2D) coincides with the critical
scaling regime.Comment: 4 pages, 5 figure
Classification of the line-soliton solutions of KPII
In the previous papers (notably, Y. Kodama, J. Phys. A 37, 11169-11190
(2004), and G. Biondini and S. Chakravarty, J. Math. Phys. 47 033514 (2006)),
we found a large variety of line-soliton solutions of the
Kadomtsev-Petviashvili II (KPII) equation. The line-soliton solutions are
solitary waves which decay exponentially in -plane except along certain
rays. In this paper, we show that those solutions are classified by asymptotic
information of the solution as . Our study then unravels some
interesting relations between the line-soliton classification scheme and
classical results in the theory of permutations.Comment: 30 page
Interchain Coupling Effects and Solitons in CuGeO_3
The effects of interchain coupling on solitons and soliton lattice structures
in CuGeO3 are explored. It is shown that interchain coupling substantially
increases the soliton width and changes the soliton lattice structures in the
incommensurate phase. It is proposed that the experimentally observed large
soliton width in CuGeO3 is mainly due to interchain coupling effects.Comment: 4 pages, LaTex, one eps figure included. No essential changes except
forma
Dynamical simulation of current fluctuations in a dissipative two-state system
Current fluctuations in a dissipative two-state system have been studied
using a novel quantum dynamics simulation method. After a transformation of the
path integrals, the tunneling dynamics is computed by deterministic integration
over the real-time paths under the influence of colored noise. The nature of
the transition from coherent to incoherent dynamics at low temperatures is
re-examined.Comment: 4 pages, 4 figures; to appear in Phys. Rev. Letter
Modulation of the local density of states within the -density wave theory in the underdoped cuprates
The low temperature scanning tunneling microscopy spectra in the underdoped
regime is analyzed from the perspective of coexisting -density wave and
d-wave superconducting states. The calculations are carried out in the presence
of a low concentration of unitary impurities and within the framework of the
fully self-consistent Bogoliubov-de Gennes theory, which allows local
modulations of the magnitude of the order parameters in response to the
impurities. Our theory captures the essential aspects of the experiments in the
underdoped BSCCO at very low temperatures.Comment: 4 pages, 4 eps figures, RevTex4. New added material as well as
reference
Correlation Lengths in Quantum Spin Ladders
Analytic expressions for the correlation length temperature dependences are
given for antiferromagnetic spin-1/2 Heisenberg ladders using a finite-size
non-linear sigma-model approach. These calculations rely on identifying three
successive crossover regimes as a function of temperature. In each of these
regimes, precise and controlled approximations are formulated. The analytical
results are found to be in excellent agreement with Monte Carlo simulations for
the Heisenberg Hamiltonian.Comment: 5 pages LaTeX using RevTeX, 3 encapsulated postscript figure
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