2,715 research outputs found
Stationary states of an electron in periodic structures in a constant uniform electrical field
On the basis of the transfer matrix technique an analytical method to
investigate the stationary states, for an electron in one-dimensional periodic
structures in an external electrical field, displaying the symmetry of the
problem is developed. These solutions are shown to be current-carrying. It is
also shown that the electron spectrum for infinite structures is continuous,
and the corresponding wave functions do not satisfy the symmetry condition of
the problem.Comment: 10 pages (Latex), no figures, in the revised variant some mistakes in
the English text are corrected and also the first two paragraphs in the
Conclusion are refined (Siberian physical-technical institute at the Tomsk
state university, Tomsk, Russia
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Effects of Process Variables and Size Scale on Solidification Microstructure in Laser-Based Solid Freeform Fabrication of Ti-6Al-4V
Mechanical Engineerin
Photon Shot Noise Dephasing in the Strong-Dispersive Limit of Circuit QED
We study the photon shot noise dephasing of a superconducting transmon qubit
in the strong-dispersive limit, due to the coupling of the qubit to its readout
cavity. As each random arrival or departure of a photon is expected to
completely dephase the qubit, we can control the rate at which the qubit
experiences dephasing events by varying \textit{in situ} the cavity mode
population and decay rate. This allows us to verify a pure dephasing mechanism
that matches theoretical predictions, and in fact explains the increased
dephasing seen in recent transmon experiments as a function of cryostat
temperature. We investigate photon dynamics in this limit and observe large
increases in coherence times as the cavity is decoupled from the environment.
Our experiments suggest that the intrinsic coherence of small Josephson
junctions, when corrected with a single Hahn echo, is greater than several
hundred microseconds.Comment: 5 pages, 4 figures; includes Supporting Online Material of 6 pages
with 5 figure
On the upper bound of the electronic kinetic energy in terms of density functionals
We propose a simple density functional expression for the upper bound of the
kinetic energy for electronic systems. Such a functional is valid in the limit
of slowly varying density, its validity outside this regime is discussed by
making a comparison with upper bounds obtained in previous work. The advantages
of the functional proposed for applications to realistic systems is briefly
discussed.Comment: 10 pages, no figure
Fluctuating magnetic moments in liquid metals
We re-analyze literature data on neutron scattering by liquid metals to show
that non-magnetic liquid metals possess a magnetic moment that fluctuates on a
picosecond time scale. This time scale follows the motion of the cage-diffusion
process in which an ion rattles around in the cage formed by its neighbors. We
find that these fluctuating magnetic moments are present in liquid Hg, Al, Ga
and Pb, and possibly also in the alkali metals.Comment: 17 pages, 5 figures, submitted to PR
Testing the Principle of Equivalence by Solar Neutrinos
We discuss the possibility of testing the principle of equivalence with solar
neutrinos. If there exists a violation of the equivalence principle quarks and
leptons with different flavors may not universally couple with gravity. The
method we discuss employs a quantum mechanical phenomenon of neutrino
oscillation to probe into the non-universality of the gravitational couplings
of neutrinos. We develop an appropriate formalism to deal with neutrino
propagation under the weak gravitational fields of the sun in the presence of
the flavor mixing. We point out that solar neutrino observation by the next
generation water Cherenkov detectors can improve the existing bound on
violation of the equivalence principle by 3-4 orders of magnitude if the
nonadiabatic Mikheyev-Smirnov-Wolfenstein mechanism is the solution to the
solar neutrino problem.Comment: Latex, 17 pages + 6 uuencoded postscript figures, KEK-TH-396,
TMUP-HEL-9402 (unnecessary one reference was removed
Quasi Harmonic Lattice Dynamics and Molecular Dynamics calculations for the Lennard-Jones solids
We present Molecular Dynamics (MD), Quasi Harmonic Lattice Dynamics (QHLD)
and Energy Minimization (EM) calculations for the crystal structure of Ne, Ar,
Kr and Xe as a function of pressure and temperature. New Lennard-Jones (LJ)
parameters are obtained for Ne, Kr and Xe to reproduce the experimental
pressure dependence of the density. We employ a simple method which combines
results of QHLD and MD calculations to achieve densities in good agreement with
experiment from 0 K to melting. Melting is discussed in connection with
intrinsic instability of the solid as given by the QHLD approximation. (See
http://www.fci.unibo.it/~valle for related papers)Comment: 7 pages, 5 figures, REVte
Constraints on new interactions from neutron scattering experiments
Constraints for the constants of hypothetical Yukawa-type corrections to the
Newtonian gravitational potential are obtained from analysis of neutron
scattering experiments. Restrictions are obtained for the interaction range
between 10^{-12} and 10^{-7} cm, where Casimir force experiments and atomic
force microscopy are not sensitive. Experimental limits are obtained also for
non-electromagnetic inverse power law neutron-nucleus potential. Some
possibilities are discussed to strengthen these constraints.Comment: 18 pages, 3 figure
Political ideology and American intergroup discrimination: A patriotism perspective
In this research we take the theoretical approach advocated by Greenwald and Pettigrew (2014) and demonstrate the powerful role of ingroup favoritism, rather than hostility, in American intergroup biases. Specifically, we take a novel perspective to understanding the relationship between political ideology and discrimination against ethnic-minority Americans by focusing on the role of patriotism. Across three studies, we show that political ideology is a strong predictor of resource allocation biases and this effect is mediated by American patriotism and not by prejudice or nationalism. Conservatives report greater levels of patriotism than liberals, and patriotism is associated with donating more to American, as opposed to ethnic-minority American, organizations. We further show that the link between patriotism and partiality to the national group is mediated by stronger ‘American=White’ associations. These findings have important implications for intergroup relations and diversity-related policy issues in the United States
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