43,143 research outputs found
Entanglement witnesses arising from Choi type positive linear maps
We construct optimal PPTES witnesses to detect PPT entangled
edge states of type constructed recently \cite{kye_osaka}. To do this,
we consider positive linear maps which are variants of the Choi type map
involving complex numbers, and examine several notions related to optimality
for those entanglement witnesses. Through the discussion, we suggest a method
to check the optimality of entanglement witnesses without the spanning
property.Comment: 18 pages, 4 figures, 1 tabl
Electron Addition Spectrum in the Supersymmetric t-J Model with Inverse-Square Interaction
The electron addition spectrum A^+(k,omega) is obtained analytically for the
one-dimensional (1D) supersymmetric t-J model with 1/r^2 interaction. The
result is obtained first for a small-sized system and its validity is checked
against the numerical calculation. Then the general expression is found which
is valid for arbitrary size of the system. The thermodynamic limit of
A^+(k,omega) has a simple analytic form with contributions from one spinon, one
holon and one antiholon all of which obey fractional statistics. The upper edge
of A^+(k,omega) in the (k,omega) plane includes a delta-function peak which
reduces to that of the single-electron band in the low-density limit.Comment: 5 pages, 1 figure, accepted for publication in Phys. Rev. Let
Particulate lubricants in cosmetic applications
Polymer powders are commonly added to cosmetic formulations to improve product performance and skin feel. This study investigates the effect of particle concentration and size on the lubricating properties of powder suspensions. Results are reported for various particle sizes and concentrations. When the tribological contact was fully immersed the addition of particles had no effect. However different behaviour was observed when the contact was only partially lubricated. In this case, a three-stage friction coefficient curve was observed. By varying the particle size and concentration it was shown that the duration and magnitude of each stage can be controlled
The measurement of reflective function in adolescents with and without borderline traits
Reflective function refers to the capacity to reflect on the mind of self and others in the context of the attachment relationship. Reflective function (and its conceptual neighbor, mentalizing) has been shown to be an important correlate of a variety of disorders, including borderline personality disorder (BPD). The current study examined the construct validity of the Reflective Function Questionnaire for Youths (RFQY) in an inpatient sample of adolescents. Adequate internal consistency was established for the RFQY. Significant positive associations with an interview-based measure of reflective function and an experimental-based assessment of mentalization were found for the RFQY. Strong negative relations with BPD features were found and adolescent patients who scored above clinical cut-off for BPD symptoms demonstrated significantly poorer reflective function compared to patients without the disorder. These findings provide preliminary support for the notion that reflective function can be validly and reliably assessed in adolescent populations
Stiff polymer in monomer ensemble
We make use of the previously developed formalism for a monomer ensemble and
include angular dependence of the segments of the polymer chains thus
described. In particular we show how to deal with stiffness when the polymer
chain is confined to certain regions. We investigate the stiffness from the
perspectives of a differential equation, integral equations, or recursive
relations for both continuum and lattice models. Exact analytical solutions are
presented for two cases, whereas numerical results are shown for a third case.Comment: 10 pages, including 6 figure
Neutrino reactions via neutral and charged current by Quasi-particle Random Phase Approximation(QRPA)
We developed the quasi-particle random phase approximation (QRPA) for the
neutrino scattering off even-even nuclei via neutral current (NC) and charged
cur- rent (CC). The QRPA has been successfully applied for the \beta and
\beta\beta decay of relevant nuclei. To describe neutrino scattering, general
multipole transitions by weak interactions with a finite momentum transfer are
calculated for NC and CC reaction with detailed formalism. Since we consider
neutron-proton (np) pairing as well as neutron-neutron (nn) and proton-proton
(pp) pairing correlations, the nn + pp QRPA and np QRPA are combined in a
framework, which enables to describe both NC and CC reactions in a consistent
way. Numerical results for \nu-^{12}C, -^{56}Fe and -^{56}Ni reactions are
shown to comply with other theoretical calculations and reproduce well
available experimental data
Combinatorial interpretation of Haldane-Wu fractional exclusion statistics
Assuming that the maximal allowed number of identical particles in state is
an integer parameter, q, we derive the statistical weight and analyze the
associated equation which defines the statistical distribution. The derived
distribution covers Fermi-Dirac and Bose-Einstein ones in the particular cases
q = 1 and q -> infinity (n_i/q -> 1), respectively. We show that the derived
statistical weight provides a natural combinatorial interpretation of
Haldane-Wu fractional exclusion statistics, and present exact solutions of the
distribution equation.Comment: 8 pages, 2 eps-figure
Large magnetoresistance using hybrid spin filter devices
A magnetic "spin filter" tunnel barrier, sandwiched between a non-magnetic
metal and a magnetic metal, is used to create a new magnetoresistive tunnel
device, somewhat analogous to an optical polarizer-analyzer configuration. The
resistance of these trilayer structures depends on the relative magnetization
orientation of the spin filter and the ferromagnetic electrode. The spin
filtering in this configuration yields a previously unobserved
magnetoresistance effect, exceeding 100%.Comment: 3.5 pages, 3 figures, submitted to Appl. Phys. Let
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