50,323 research outputs found
On integrability of the differential constraints arising from the singularity analysis
Integrability of the differential constraints arising from the singularity
analysis of two (1+1)-dimensional second-order evolution equations is studied.
Two nonlinear ordinary differential equations are obtained in this way, which
are integrable by quadratures in spite of very complicated branching of their
solutions.Comment: arxiv version is already offcia
Accurate nucleon electromagnetic form factors from dispersively improved chiral effective field theory
We present a theoretical parametrization of the nucleon electromagnetic form
factors (FFs) based on a combination of chiral effective field theory and
dispersion analysis. The isovector spectral functions on the two-pion cut are
computed using elastic unitarity, chiral pion-nucleon amplitudes, and timelike
pion FF data. Higher-mass isovector and isoscalar t-channel states are
described by effective poles, whose strength is fixed by sum rules (charges,
radii). Excellent agreement with the spacelike proton and neutron FF data is
achieved up to Q^2 \sim 1 GeV^2. Our parametrization provides proper
analyticity and theoretical uncertainty estimates and can be used for low-Q^2
FF studies and proton radius extraction.Comment: 5 pages, 3 figures, 2 table
Duality Relation for Quantum Ratchets
A duality relation between the long-time dynamics of a quantum Brownian
particle in a tilted ratchet potential and a driven dissipative tight-binding
model is reported. It relates a situation of weak dissipation in one model to
strong dissipation in the other one, and vice versa. We apply this duality
relation to investigate transport and rectification in ratchet potentials: From
the linear mobility we infer ground-state delocalization for weak dissipation.
We report reversals induced by adiabatic driving and temperature in the ratchet
current and its dependence on the potential shape.Comment: Modified content, corrected typo
Magnetic Miniband Structure and Quantum Oscillations in Lateral Semiconductor Superlattices
We present fully quantum-mechanical magnetotransport calculations for
short-period lateral superlattices with one-dimensional electrostatic
modulation. A non-perturbative treatment of both magnetic field and modulation
potential proves to be necessary to reproduce novel quantum oscillations in the
magnetoresistance found in recent experiments in the resistance component
parallel to the modulation potential. In addition, we predict oscillations of
opposite phase in the component perpendicular to the modulation not yet
observed experimentally. We show that the new oscillations originate from the
magnetic miniband structure in the regime of overlapping minibands.Comment: 6 pages with 4 figure
Crack initiation at notches in low cycle fatigue Final report, 1 Aug. 1968 - 15 Mar. 1969
Crack initiation at notches in low cycle fatigue determined by plastic strain distributio
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