6,158 research outputs found
Rutherford scattering with radiation damping
We study the effect of radiation damping on the classical scattering of
charged particles. Using a perturbation method based on the Runge-Lenz vector,
we calculate radiative corrections to the Rutherford cross section, and the
corresponding energy and angular momentum losses.Comment: Latex, 11 pages, 4 eps figure
Initial value representation for the SU(n) semiclassical propagator
The semiclassical propagator in the representation of SU(n) coherent states
is characterized by isolated classical trajectories subjected to boundary
conditions in a doubled phase space. In this paper we recast this expression in
terms of an integral over a set of initial-valued trajectories. These
trajectories are monitored by a filter that collects only the appropriate
contributions to the semiclassical approximation. This framework is suitable
for the study of bosonic dynamics in n modes with fixed total number of
particles. We exemplify the method for a Bose-Einstein condensate trapped in a
triple-well potential, providing a detailed discussion on the accuracy and
efficiency of the procedure.Comment: 24 pages, 6 figure
Derived bracket construction and Manin products
We will extend the classical derived bracket construction to any algebra over
a binary quadratic operad. We will show that the derived product construction
is a functor given by the Manin white product with the operad of permutation
algebras. As an application, we will show that the operad of prePoisson
algebras is isomorphic to Manin black product of the Poisson operad with the
preLie operad. We will show that differential operators and Rota-Baxter
operators are, in a sense, Koszul dual to each other.Comment: This is the final versio
Quantum Key Distribution using Continuous-variable non-Gaussian States
In this work we present a quantum key distribution protocol using
continuous-variable non-Gaussian states, homodyne detection and post-selection.
The employed signal states are the Photon Added then Subtracted Coherent States
(PASCS) in which one photon is added and subsequently one photon is subtracted.
We analyze the performance of our protocol, compared to a coherent state based
protocol, for two different attacks that could be carried out by the
eavesdropper (Eve). We calculate the secret key rate transmission in a lossy
line for a superior channel (beam-splitter) attack, and we show that we may
increase the secret key generation rate by using the non-Gaussian PASCS rather
than coherent states. We also consider the simultaneous quadrature measurement
(intercept-resend) attack and we show that the efficiency of Eve's attack is
substantially reduced if PASCS are used as signal states.Comment: We have included an analysis of the simultaneous quadrature
measurement attack plus 2 figures; we have also clarified some point
State sum construction of two-dimensional open-closed Topological Quantum Field Theories
We present a state sum construction of two-dimensional extended Topological
Quantum Field Theories (TQFTs), so-called open-closed TQFTs, which generalizes
the state sum of Fukuma--Hosono--Kawai from triangulations of conventional
two-dimensional cobordisms to those of open-closed cobordisms, i.e. smooth
compact oriented 2-manifolds with corners that have a particular global
structure. This construction reveals the topological interpretation of the
associative algebra on which the state sum is based, as the vector space that
the TQFT assigns to the unit interval. Extending the notion of a
two-dimensional TQFT from cobordisms to suitable manifolds with corners
therefore makes the relationship between the global description of the TQFT in
terms of a functor into the category of vector spaces and the local description
in terms of a state sum fully transparent. We also illustrate the state sum
construction of an open-closed TQFT with a finite set of D-branes using the
example of the groupoid algebra of a finite groupoid.Comment: 33 pages; LaTeX2e with xypic and pstricks macros; v2: typos correcte
Distinct magnetic signatures of fractional vortex configurations in multiband superconductors
Vortices carrying fractions of a flux quantum are predicted to exist in
multiband superconductors, where vortex core can split between multiple
band-specific components of the superconducting condensate. Using the
two-component Ginzburg-Landau model, we examine such vortex configurations in a
two-band superconducting slab in parallel magnetic field. The fractional
vortices appear due to the band-selective vortex penetration caused by
different thresholds for vortex entry within each band-condensate, and
stabilize near the edges of the sample. We show that the resulting fractional
vortex configurations leave distinct fingerprints in the static measurements of
the magnetization, as well as in ac dynamic measurements of the magnetic
susceptibility, both of which can be readily used for the detection of these
fascinating vortex states in several existing multiband superconductors.Comment: 5 pages, 4 figure
Modeling electrodialysis and a photochemical process for their integration in saline wastewater treatment.
Oxidation processes can be used to treat industrial wastewater containing non-biodegradable organic compounds. However, the presence of dissolved salts may inhibit or retard the treatment process. In this study, wastewater desalination by electrodialysis (ED) associated with an advanced oxidation process (photo-Fenton) was applied to an aqueous NaCl solution containing phenol. The influence of process variables on the demineralization factor was investigated for ED in pilot scale and a correlation was obtained between the phenol, salt and water fluxes with the driving force. The oxidation process was investigated in a laboratory batch reactor and a model based on artificial neural networks was developed by fitting the experimental data describing the reaction rate as a function of the input variables. With the experimental parameters of both processes, a dynamic model was developed for ED and a continuous model, using a plug flow reactor approach, for the oxidation process. Finally, the hybrid model simulation could validate different scenarios of the integrated system and can be used for process optimization
Nail pitting and onycholysis
info:eu-repo/semantics/publishedVersio
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