277 research outputs found
On Entanglement Measures: Discrete Phase Space and Inverter-Chain Link Viewpoint
In contrast to abstract statistical analyses in the literature, we present a
concrete physical diagrammatic model of entanglement characterization and
measure with its underlying discrete phase-space physics. This paper serves as
a pedagogical treatment of this complex subject of entanglement measures. We
review the important inherent concurrence property of entangled qubits, as well
as underscore its emergent qubit behavior. From the discrete phase space point
of view, concurrence translates to translation symmetry of entangled binary
systems in some quantitative measure of entanglement. Although the focus is on
bipartite system, the notion is readily extendable to multi-partite system of
qubits, as can easily be deduced from the physical inverter-chain link model. A
diagrammatic analysis of the entanglement of formation for any multi-partite
qubit system is givenComment: 21 pages, 6 figure
Dynamics of Functional Phase Space Distribution in QFT: A Third Quantization and Dynamical Unification of QFT and CMP
We proposed a third quantization scheme to derive the quantum dynamics of the
functional phase space distribution in quantum field theory (QFT). The
derivation is straightforward and algorithmic. This readily yields the
ballistic quantum transport equation of QFT distribution in (p,q)- functional
phase space, not in ordinary position-momentum (p,q)-space. Our starting point
is the general mixed space representation in QFT. The end result serves as a
unification of the quantum superfield transport theory of condensed matter
physics (CMP) and QFT. This is summarized in a Table of correspondence. This
third quantization scheme may have significance in quantum fluctuation theory
of systems with many degrees of freedom. It may have relevance to cosmology:
gravity, multi-universes, and Yang-Mills theory.Comment: 24 pages, 0 figures. arXiv admin note: substantial text overlap with
arXiv:2204.0769
Multiple solutions to the likelihood equations in the Behrens-Fisher problem
The Behrens-Fisher problem concerns testing the equality of the means of two
normal populations with possibly different variances. The null hypothesis in
this problem induces a statistical model for which the likelihood function may
have more than one local maximum. We show that such multimodality contradicts
the null hypothesis in the sense that if this hypothesis is true then the
probability of multimodality converges to zero when both sample sizes tend to
infinity. Additional results include a finite-sample bound on the probability
of multimodality under the null and asymptotics for the probability of
multimodality under the alternative
Data-Discriminants of Likelihood Equations
Maximum likelihood estimation (MLE) is a fundamental computational problem in
statistics. The problem is to maximize the likelihood function with respect to
given data on a statistical model. An algebraic approach to this problem is to
solve a very structured parameterized polynomial system called likelihood
equations. For general choices of data, the number of complex solutions to the
likelihood equations is finite and called the ML-degree of the model. The only
solutions to the likelihood equations that are statistically meaningful are the
real/positive solutions. However, the number of real/positive solutions is not
characterized by the ML-degree. We use discriminants to classify data according
to the number of real/positive solutions of the likelihood equations. We call
these discriminants data-discriminants (DD). We develop a probabilistic
algorithm for computing DDs. Experimental results show that, for the benchmarks
we have tried, the probabilistic algorithm is more efficient than the standard
elimination algorithm. Based on the computational results, we discuss the real
root classification problem for the 3 by 3 symmetric matrix~model.Comment: 2 table
Swimming pool deck as environmental reservoir of Fusarium
While investigations on fungal contamination of swimming pools usually focus on dermatophytes, data on other potentially pathogenic molds are scarce. Here, we report the investigation of fungal colonization of the deck surrounding a hospital physical therapy swimming pool. Five series of samples from 8 sites were collected over one year from the pool surroundings. Concomitantly, 58 patients using the swimming pool were examined and samples obtained from those with suspected onychomycosis. All surface samples were positive for fungi, with Fusarium the most frequently recovered from 22 of 27 samples of sites surrounding the pool. Among the outpatients evaluated, two presented with a mixed onychomycosis from which Fusarium and Trichophyton rubrum were isolated. The questions of possible acquisition from the swimming pool area must be considered in both cases as the ungual lesions had developed within the previous three months. This warrants further studies to better understand the epidemiology of potentially pathogenic molds in areas surrounding pools in order to adopt appropriate measures to avoid contamination. This is of particular importance within medical institutions, considering the potential role of Fusarium onychomycosis as a starting point for disseminated infections in immunocompromised patient
Charging effects in the ac conductance of a double barrier resonant tunneling structure
There have been many studies of the linear response ac conductance of a
double barrier resonant tunneling structure (DBRTS). While these studies are
important, they fail to self-consistently include the effect of time dependent
charge density in the well. In this paper, we calculate the ac conductance by
including the effect of time dependent charge density in the well in a
self-consistent manner. The charge density in the well contributes to both the
flow of displacement currents and the time dependent potential in the well. We
find that including these effects can make a significant difference to the ac
conductance and the total ac current is not equal to the average of
non-selfconsitently calculated conduction currents in the two contacts, an
often made assumption. This is illustrated by comparing the results obtained
with and without the effect of the time dependent charge density included
properly
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