7,755 research outputs found
Field-induced spin-density-wave phases in TMTSF organic conductors: quantization versus non-quantization
We study the magnetic-field-induced spin-density-wave (FISDW) phases in TMTSF
organic conductors in the framework of the quantized nesting model. In
agreement with recent suggestions, we find that the SDW wave-vector
deviates from its quantized value near the transition temperature for all
phases with quantum numbers . Deviations from quantization are more
pronounced at low pressure and higher and may lead to a suppression of the
first-order transitions for . Below a critical pressure, we
find that the N=0 phase invades the entire phase diagram in accordance with
earlier experiments. We also show that at T=0, the quantization of
and hence the Hall conductance is always exact. Our results suggest a novel
phase transition/crossover at intermediate temperatures between phases with
quantized and non-quantized .Comment: 4 pages, 4 figures, Revte
Effective action and collective modes in quasi-one-dimensional spin-density-wave systems
We derive the effective action describing the long-wavelength low-energy
collective modes of quasi-one-dimensional spin-density-wave (SDW) systems,
starting from the Hubbard model within weak coupling approximation. The
effective action for the spin-wave mode corresponds to an anisotropic
non-linear sigma model together with a Berry phase term. We compute the spin
stiffness and the spin-wave velocity. We also obtain the effective action for
the sliding mode (phason) taking into account the density fluctuations from the
outset and in presence of a weak external electromagnetic field. This leads to
coupled equations for the phase of the SDW condensate and the charge density
fluctuations. We also calculate the conductivity and the density-density
correlation function.Comment: 16 pages, Resubmitted to Physical Review B with minor suggested
change
The Gaussian Radon Transform in Classical Wiener Space
We study the Gaussian Radon transform in the classical Wiener space of
Brownian motion. We determine explicit formulas for transforms of Brownian
functionals specified by stochastic integrals. A Fock space decomposition is
also established for Gaussian measure conditioned to closed affine subspaces in
Hilbert spaces
A Gaussian Radon Transform for Banach Spaces
We develop a Radon transform on Banach spaces using Gaussian measure and
prove that if a bounded continuous function on a separable Banach space has
zero Gaussian integral over all hyperplanes outside a closed bounded convex set
in the Hilbert space corresponding to the Gaussian measure then the function is
zero outside this set
Quantum Free Yang-Mills on the Plane
We construct a free-probability quantum Yang-Mills theory on the two
dimensional plane, determine the Wilson loop expectation values, and show that
this theory is the limit of U(N) quantum Yang-Mills theory on the
plane.Comment: 24 pages, tikz figure
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