5,392 research outputs found
Medical Monitoring in Missouri After Meyer ex rel. Coplin v. Fluor Corp.: Sound Policy Should Be Restored to a Vague and Unsound Directive
Developments in Rare Kaon Decay Physics
We review the current status of the field of rare kaon decays. The study of
rare kaon decays has played a key role in the development of the standard
model, and the field continues to have significant impact. The two areas of
greatest import are the search for physics beyond the standard model and the
determination of fundamental standard-model parameters. Due to the exquisite
sensitivity of rare kaon decay experiments, searches for new physics can probe
very high mass scales. Studies of the k->pnn modes in particular, where the
first event has recently been seen, will permit tests of the standard-model
picture of quark mixing and CP violation.Comment: One major revision to the text is the branching ratio of KL->ppg,
based on a new result from KTeV. Several references were updated, with minor
modifications to the text. A total of 48 pages, with 28 figures, in LaTeX; to
be published in the Annual Review of Nuclear and Particle Science, Vol. 50,
December 200
Raman Adiabatic Transfer of Optical States
We analyze electromagnetically induced transparency and light storage in an
ensemble of atoms with multiple excited levels (multi-Lambda configuration)
which are coupled to one of the ground states by quantized signal fields and to
the other one via classical control fields. We present a basis transformation
of atomic and optical states which reduces the analysis of the system to that
of EIT in a regular 3-level configuration. We demonstrate the existence of dark
state polaritons and propose a protocol to transfer quantum information from
one optical mode to another by an adiabatic control of the control fields
Energy transfer in porphyrin-functionalized graphene
We present a theoretical study on the molecule–substrate interaction within the porphyrin-functionalized graphene. Recent experiments on porphyrin-functionalized carbon nanotubes have revealed an extremely efficient energy transfer from the adsorbed molecules to the carbon substrate. To investigate the energy transfer mechanism, we have characterized the hybrid structure within the density functional theory including the calculation of the molecular transition dipole moment, which allows us to determine the Förster coupling rate. We find a strongly pronounced Förster-induced energy transfer in the range of fs−1 inline image confirming the experimental observations
Photoemission spectroscopy and sum rules in dilute electron-phonon systems
A family of exact sum rules for the one-polaron spectral function in the
low-density limit is derived. An algorithm to calculate energy moments of
arbitrary order of the spectral function is presented. Explicit expressions are
given for the first two moments of a model with general electron-phonon
interaction, and for the first four moments of the Holstein polaron. The sum
rules are linked to experiments on momentum-resolved photoemission
spectroscopy. The bare electronic dispersion and the electron-phonon coupling
constant can be extracted from the first and second moments of spectrum. The
sum rules could serve as constraints in analytical and numerical studies of
electron-phonon models.Comment: 4 page
Ab-initio angle and energy resolved photoelectron spectroscopy with time-dependent density-functional theory
We present a time-dependent density-functional method able to describe the
photoelectron spectrum of atoms and molecules when excited by laser pulses.
This computationally feasible scheme is based on a geometrical partitioning
that efficiently gives access to photoelectron spectroscopy in time-dependent
density-functional calculations. By using a geometrical approach, we provide a
simple description of momentum-resolved photoe- mission including multi-photon
effects. The approach is validated by comparison with results in the literature
and exact calculations. Furthermore, we present numerical photoelectron angular
distributions for randomly oriented nitrogen molecules in a short near infrared
intense laser pulse and helium-(I) angular spectra for aligned carbon monoxide
and benzene.Comment: Accepted for publication on Phys. Rev.
Quantum coherence and carriers mobility in organic semiconductors
We present a model of charge transport in organic molecular semiconductors
based on the effects of lattice fluctuations on the quantum coherence of the
electronic state of the charge carrier. Thermal intermolecular phonons and
librations tend to localize pure coherent states and to assist the motion of
less coherent ones. Decoherence is thus the primary mechanism by which
conduction occurs. It is driven by the coupling of the carrier to the molecular
lattice through polarization and transfer integral fluctuations as described by
the hamiltonian of Gosar and Choi. Localization effects in the quantum coherent
regime are modeled via the Anderson hamiltonian with correlated diagonal and
non-diagonal disorder leading to the determination of the carrier localization
length. This length defines the coherent extension of the ground state and
determines, in turn, the diffusion range in the incoherent regime and thus the
mobility. The transfer integral disorder of Troisi and Orlandi can also be
incorporated. This model, based on the idea of decoherence, allowed us to
predict the value and temperature dependence of the carrier mobility in
prototypical organic semiconductors that are in qualitative accord with
experiments
Complete Characterization of Quantum-Optical Processes
The technologies of quantum information and quantum control are rapidly
improving, but full exploitation of their capabilities requires complete
characterization and assessment of processes that occur within quantum devices.
We present a method for characterizing, with arbitrarily high accuracy, any
quantum optical process. Our protocol recovers complete knowledge of the
process by studying, via homodyne tomography, its effect on a set of coherent
states, i.e. classical fields produced by common laser sources. We demonstrate
the capability of our protocol by evaluating and experimentally verifying the
effect of a test process on squeezed vacuum.Comment: 5 pages, 4 figure
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