926 research outputs found
Method for Assessing Potential in Distribution Logistics
In addition to the production, which is already frequently optimized, improving the distribution logistics also opens up tremendous potential for increasing an enterprise’s competitiveness. Here too though, numerous interactions need to be taken into account, enterprises thus need to be able to identify and weigh between different potentials for economically efficient optimizations. In order to be able to assess potentials, enterprises require a suitable method. This paper first briefly presents the need for this research before introducing the procedure that will be used to develop an appropriate method that not only considers interactions but is also quickly and easily implemented
Time-resolved observation of spin-charge deconfinement in fermionic Hubbard chains
Elementary particles such as the electron carry several quantum numbers, for
example, charge and spin. However, in an ensemble of strongly interacting
particles, the emerging degrees of freedom can fundamentally differ from those
of the individual constituents. Paradigmatic examples of this phenomenon are
one-dimensional systems described by independent quasiparticles carrying either
spin (spinon) or charge (holon). Here we report on the dynamical deconfinement
of spin and charge excitations in real space following the removal of a
particle in Fermi-Hubbard chains of ultracold atoms. Using space- and
time-resolved quantum gas microscopy, we track the evolution of the excitations
through their signatures in spin and charge correlations. By evaluating
multi-point correlators, we quantify the spatial separation of the excitations
in the context of fractionalization into single spinons and holons at finite
temperatures
Antiferro-quadrupole state of orbital-degenerate Kondo lattice model with f^2 configuration
To clarify a key role of orbitals in the emergence of
antiferro-quadrupole structure in PrPb, we investigate the ground-state
property of an orbital-degenerate Kondo lattice model by numerical
diagonalization techniques. In PrPb, Pr has a
configuration and the crystalline-electric-field ground state is a non-Kramers
doublet . In a - coupling scheme, the state is
described by two local singlets, each of which consists of two electrons
with one in and another in orbitals. Since in a cubic
structure, has localized nature, while orbitals are
rather itinerant, we propose the orbital-degenerate Kondo lattice model for an
effective Hamiltonian of PrPb. We show that an antiferro-orbital state is
favored by the so-called double-exchange mechanism which is characteristic of
multi-orbital systems.Comment: 3 pages, 3 figures, Proceedings of Skutterudite2007 (September 26-30,
2007, Kobe
Spatially dependent Rabi oscillations: an approach to sub-diffraction-limited CARS microscopy
We present a theoretical investigation of coherent anti-Stokes Raman
scattering (CARS) that is modulated by periodically depleting the ground state
population through Rabi oscillations driven by an additional control laser. We
find that such a process generates optical sidebands in the CARS spectrum and
that the frequency of the sidebands depends on the intensity of the control
laser light field. We show that analyzing the sideband frequency upon scanning
the beams across the sample allows one to spatially resolve emitter positions
where a spatial resolution of 65 nm, which is well below the diffraction-limit,
can be obtained
On Secure Implementation of an IHE XUA-Based Protocol for Authenticating Healthcare Professionals
The importance of the Electronic Health Record (EHR) has been addressed in recent years by governments and institutions.Many large scale projects have been funded with the aim to allow healthcare professionals to consult patients data. Properties such as confidentiality, authentication and authorization are the key for the success for these projects. The Integrating the Healthcare Enterprise (IHE) initiative promotes the coordinated use of established standards for authenticated and secure EHR exchanges among clinics and hospitals. In particular, the IHE integration profile named XUA permits to attest user identities by relying on SAML assertions, i.e. XML documents containing authentication statements. In this paper, we provide a formal model for the secure issuance of such an assertion. We first specify the scenario using the process calculus COWS and then analyse it using the model checker CMC. Our analysis reveals a potential flaw in the XUA profile when using a SAML assertion in an unprotected network. We then suggest a solution for this flaw, and model check and implement this solution to show that it is secure and feasible
Self-consistent Coulomb picture of an electron-electron bilayer system
In this work we implement the self-consistent Thomas-Fermi approach and a
local conductivity model to an electron-electron bilayer system. The presence
of an incompressible strip, originating from screening calculations at the top
(or bottom) layer is considered as a source of an external potential
fluctuation to the bottom (or top) layer. This essentially yields modifications
to both screening properties and the magneto-transport quantities. The effect
of the temperature, inter-layer distance and density mismatch on the density
and the potential fluctuations are investigated. It is observed that the
existence of the incompressible strips plays an important role simply due to
their poor screening properties on both screening and the magneto-resistance
(MR) properties. Here we also report and interpret the observed MR Hysteresis
within our model.Comment: 12 pages, 12 figures, submitted to PR
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