96,600 research outputs found
On the Triality Theory for a Quartic Polynomial Optimization Problem
This paper presents a detailed proof of the triality theorem for a class of
fourth-order polynomial optimization problems. The method is based on linear
algebra but it solves an open problem on the double-min duality left in 2003.
Results show that the triality theory holds strongly in a tri-duality form if
the primal problem and its canonical dual have the same dimension; otherwise,
both the canonical min-max duality and the double-max duality still hold
strongly, but the double-min duality holds weakly in a symmetrical form. Four
numerical examples are presented to illustrate that this theory can be used to
identify not only the global minimum, but also the largest local minimum and
local maximum.Comment: 16 pages, 1 figure; J. Industrial and Management Optimization, 2011.
arXiv admin note: substantial text overlap with arXiv:1104.297
Optimal Controlled Teleportation
We give the analytic expressions of maximal probabilities of successfully
controlled teleportating an unknown qubit via every kind of tripartite states.
Besides, another kind of localizable entanglement is also determined.
Furthermore, we give the sufficient and necessary condition that a three-qubit
state can be collapsed to an EPR pair by a measurement on one qubit, and
characterize the three-qubit states that can be used as quantum channel for
controlled teleporting a qubit of unknown information with unit probability and
with unit fidelity.Comment: 4 page
Effective potentials for atom-atom interaction at low temperatures
We discuss the concept and design of effective atom-atom potentials that
accurately describe any physical processes involving only states around the
threshold. The existence of such potentials gives hope to a quantitative, and
systematic, understanding of quantum few-atom and quantum many-atom systems at
relatively low temperatures.Comment: 4 pages, 4 figure
First law of black hole mechanics in Einstein-Maxwell and Einstein-Yang-Mills theories
The first law of black hole mechanics is derived from the Einstein-Maxwell
(EM) Lagrangian by comparing two infinitesimally nearby stationary black holes.
With similar arguments, the first law of black hole mechanics in
Einstein-Yang-Mills (EYM) theory is also derived.Comment: Modified version, major changes made in the introduction. 14 pages,
no figur
A Simultaneous Quantum Secure Direct Communication Scheme between the Central Party and Other M Parties
We propose a simultaneous quantum secure direct communication scheme between
one party and other three parties via four-particle GHZ states and swapping
quantum entanglement. In the scheme, three spatially separated senders, Alice,
Bob and Charlie, transmit their secret messages to a remote receiver Diana by
performing a series local operations on their respective particles according to
the quadripartite stipulation. From Alice, Bob, Charlie and Diana's Bell
measurement results, Diana can infer the secret messages. If a perfect quantum
channel is used, the secret messages are faithfully transmitted from Alice, Bob
and Charlie to Diana via initially shared pairs of four-particle GHZ states
without revealing any information to a potential eavesdropper. As there is no
transmission of the qubits carrying the secret message in the public channel,
it is completely secure for the direct secret communication. This scheme can be
considered as a network of communication parties where each party wants to
communicate secretly with a central party or server.Comment: 4 pages, no figur
Photoinduced Electron Pairing in a Driven Cavity
We demonstrate how virtual scattering of laser photons inside a cavity via two-photon processes can induce controllable long-range electron interactions in two-dimensional materials. We show that laser light that is red (blue) detuned from the cavity yields attractive (repulsive) interactions whose strength is proportional to the laser intensity. Furthermore, we find that the interactions are not screened effectively except at very low frequencies. For realistic cavity parameters, laser-induced heating of the electrons by inelastic photon scattering is suppressed and coherent electron interactions dominate. When the interactions are attractive, they cause an instability in the Cooper channel at a temperature proportional to the square root of the driving intensity. Our results provide a novel route for engineering electron interactions in a wide range of two-dimensional materials including AB-stacked bilayer graphene and the conducting interface between LaAlO3 and SrTiO3
Polarized Deep Inelastic Scattering Off the "Neutron" From Gauge/String Duality
We investigate deep inelastic scattering off the polarized "neutron" using
gauge/string duality. The "neutron" corresponds to a supergravity mode of the
neutral dilatino. Through introducing the Pauli interaction term into the
action in space, we calculate the polarized deep inelastic
structure functions of the "neutron" in supergravity approximation at large t'
Hooft coupling and finite with . In
comparison with the charged dilatino "proton," which has been obtained in the
previous work by Gao and Xiao, we find the structure functions of the "neutron"
are power suppressed at the same order as the ones of the "proton." Especially,
we find the Burkhardt-Cottingham-like sum rule, which is satisfied in the work
by Gao and Xiao, is broken due to the Pauli interaction term. We also
illustrate how such a Pauli interaction term can arise naturally from higher
dimensional fermion-graviton coupling through the usual Kaluza-Klein reduction.Comment: 21pages,5figures, published versio
Peltier effect in normal metal-insulator-heavy fermion metal junctions
A theoretical study has been undertaken of the Peltier effect in normal metal
- insulator - heavy fermion metal junctions. The results indicate that, at
temperatures below the Kondo temperature, such junctions can be used as
electronic microrefrigerators to cool the normal metal electrode and are
several times more efficient in cooling than the normal metal - heavy fermion
metal junctions.Comment: 3 pages in REVTeX, 2 figures, to be published in Appl. Phys. Lett.,
April 7, 200
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