41,883 research outputs found
Quantum and Fisher Information from the Husimi and Related Distributions
The two principal/immediate influences -- which we seek to interrelate here
-- upon the undertaking of this study are papers of Zyczkowski and
Slomczy\'nski (J. Phys. A 34, 6689 [2001]) and of Petz and Sudar (J. Math.
Phys. 37, 2262 [1996]). In the former work, a metric (the Monge one,
specifically) over generalized Husimi distributions was employed to define a
distance between two arbitrary density matrices. In the Petz-Sudar work
(completing a program of Chentsov), the quantum analogue of the (classically
unique) Fisher information (montone) metric of a probability simplex was
extended to define an uncountable infinitude of Riemannian (also monotone)
metrics on the set of positive definite density matrices. We pose here the
questions of what is the specific/unique Fisher information metric for the
(classically-defined) Husimi distributions and how does it relate to the
infinitude of (quantum) metrics over the density matrices of Petz and Sudar? We
find a highly proximate (small relative entropy) relationship between the
probability distribution (the quantum Jeffreys' prior) that yields quantum
universal data compression, and that which (following Clarke and Barron) gives
its classical counterpart. We also investigate the Fisher information metrics
corresponding to the escort Husimi, positive-P and certain Gaussian probability
distributions, as well as, in some sense, the discrete Wigner
pseudoprobability. The comparative noninformativity of prior probability
distributions -- recently studied by Srednicki (Phys. Rev. A 71, 052107 [2005])
-- formed by normalizing the volume elements of the various information
metrics, is also discussed in our context.Comment: 27 pages, 10 figures, slight revisions, to appear in J. Math. Phy
Reply to Comment on "Quantum phase transition in the four-spin exchange antiferromagnet"
We argue that our analysis of the J-Q model, presented in Phys. Rev. B 80,
174403 (2009), and based on a field-theory description of coupled dimers,
captures properly the strong quantum fluctuations tendencies, and the
objections outlined by L. Isaev, G. Ortiz, and J. Dukelsky, arXiv:1003.5205,
are misplaced
Lower levels of damaged protein biomarkers in the plasma of overweight type 2 diabetic men following supplementation with a standardised bilberry extract
Peer reviewedPublisher PD
Development of phosphorylated adhesives
The synthesis of epoxy prepolymers containing phosphorus was carried out in such a manner as to provide adhesives containing at least 5 percent of this element. The purpose of this was to impart fire retardant properties to the adhesive. The two epoxy derivatives, bis(4-glycidyl-oxyphenyl)phenylphosphine oxide and bis(4-glycidyl-2-methoxyphenyl)phenylphosphonate, and a curing agent, bis(3-aminophenyl)methylphosphine oxide, were used in conjunction with one another and along with conventional epoxy resins and curing agents to bond Tedlar and Polyphenylethersulfone films to Kerimid-glass syntactic foam-filled honeycomb structures. Elevated temperatures are required to cure the epoxy resins with the phosphorus-contaning diamine; however, when Tedlar is being bonded, lower curing temperatures must be used to avoid shrinkage and the concomitant formation of surface defects. Thus, the phosphorus-containing aromatic amine curing agent cannot be used alone, although it is possible to use it in conjunction with an aliphatic amine which would allow lower cure temperatures to be used. The experimental epoxy resins have not provided adhesive bonds quite as strong as those provided by Epon 828 when compared in peel tests, but the differences are not very significant. It should be noted, if optimum properties are to be realized. In any case the fire retardant characteristics of the neat resin systems obtained are quite pronounced, since in most cases the self-extinguishing properties are evident almost instantly when specimens are removed from a flame
Pseudoparticle Description of the 1D Hubbard Model Electronic Transport Properties
We extend the pseudoparticle transport description of the Hubbard chain to
all energy scales. In particular we compute the mean value of the electric
current transported by any Bethe-ansatz state and the transport masses of the
charge carriers. We present numerical results for the optical conductivity of
the model at half-filling for values of U/t=3 and 4. We show that these are in
good agreement with the pseudoparticle description of the finite-energy
transitions involving new pseudoparticle energy bands.Comment: 4 pages, RevTex, one figure (can be obtained upon request from
[email protected]). To apper in the Proceedings of the Euroconference on
"Correlations in Unconventional Quantum Liquids" in Zeitschrift f\"ur Physik
B- Condensed Matter (Dedicated to the memory of Sir Rudolph Peierls
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