Search results for "Computer Science Application"
showing 10 items of 3998 documents
Real-time switching between multiple steady-states in quantum transport
2010
Creative Commons Attribution License 3.0.
Time-dependent Landauer-Büttiker formula for transient dynamics
2013
We solve analyti ally the Kadano Baym equations for a nonintera ting jun tion onne ted to an arbitrary number of nonintera ting wide-band terminals. The initial equilibrium state is properly des ribed by the addition of an imaginary tra k to the time ontour. From the solution we obtain the time-dependent ele tron densities and urrents within the jun tion. The nal results are analyti expressions as a fun tion of time, and therefore no time propagation is needed either in transient or in steady-state regimes. We further present and dis uss some appli ations of the obtained formulae. peerReviewed
Emission and null coordinates: geometrical properties and physical construction
2011
A Relativistic Positioning System is defined by four clocks (emitters) broadcasting their proper time. Then, every event reached by the signals is naturally labeled by these four times which are the emission coordinates of this event. The coordinate hypersurfaces of the emission coordinates are the future light cones based on the emitter trajectories. For this reason the emission coordinates have been also named null coordinates or light coordinates. Nevertheless, other coordinate systems used in different relativistic contexts have the own right to be named null or light coordinates. Here we analyze when one can say that a coordinate is a null coordinate and when one can say that a coordin…
Kadanoff-Baym approach to time-dependent quantum transport in AC and DC fields
2010
We have developed a method based on the embedded Kadanoff-Baym equations to study the time evolution of open and inhomogeneous systems. The equation of motion for the Green's function on the Keldysh contour is solved using different conserving many-body approximations for the self-energy. Our formulation incorporates basic conservation laws, such as particle conservation, and includes both initial correlations and initial embedding effects, without restrictions on the time-dependence of the external driving field. We present results for the time-dependent density, current and dipole moment for a correlated tight binding chain connected to one-dimensional non-interacting leads exposed to DC …
An introduction to relativistic hydrodynamics
2007
We review formulations of the equations of (inviscid) general relativistic hydrodynamics and (ideal) magnetohydrodynamics, along with methods for their numerical solution. Both systems can be cast as first-order, hyperbolic systems of conservation laws, following the explicit choice of an Eulerian observer and suitable fluid and magnetic field variables. During the last fifteen years, the so-called (upwind) high-resolution shock-capturing schemes based on Riemann solvers have been successfully extended from classical to relativistic fluid dynamics, both special and general. Nowadays, general relativistic hydrodynamical simulations in relativistic astrophysics are routinely performed, partic…
Description of giant resonances with Skyrme forces
2011
Some representative cases of the description and analysis of giant resonances within the self-consistent separable random-phase-approximation model (SRPA) based on the Skyrme functional are discussed. It is shown that SRPA with SLy6 force well describes the dipole giant resonance in rare-earth and actinide regions. The sensitivity of the E1 strength near the particle thresholds to nuclear deformation is scrutinized. Finally, the open problems of description of spin-flip M1 resonance are discussed.
From Halo Effective Field Theory to the study of breakup and transfer reactions: reliably probing the halo structure of 11 Be and 15 C
2020
Abstract In this work we study one-neutron halo nuclei, and in particular 11Be and 15C, which can be seen as an inert core of 10Be or 14C plus a loosely bound neutron. During the last decades several transfer and breakup reactions involving these systems have been measured on different targets and energies. We study these processes using one single structure model for each nucleus applying the halo effective field theory (Halo EFT) at next-to-leading order NLO. The main parameters of this EFT are adjusted on nuclear-structure data and/or ab initio predictions. We model the transfer reaction within the Adiabatic Distorted Wave Approximation (ADWA) and the breakup process applying an eikonal …
Anomalous properties of hot dense nonequilibrium plasmas
2005
A concise overview of a number of anomalous properties of hot dense nonequilibrium plasmas is given. The possibility of quasistationary megagauss magnetic field generation due to Weibel instability is discussed for plasmas created in atom tunnel ionization. The collisionless absorption and reflection of a test electromagnetic wave normally impinging on the plasma with two-temperature bi-maxwellian electron velocity distribution function are studied. Due to the wave magnetic field influence on the electron kinetics in the skin layer the wave absorption and reflection significantly depend on the degree of the electron temperature anisotropy. The linearly polarized impinging wave during reflec…
Stellar physics with the ALHAMBRA photometric system
2011
GREAT-ESF Workshop: Stellar Atmospheres in the Gaia Era 23–24 June 2011, Vrije Universiteit Brussels, Belgium.
Black hole entropy in loop quantum gravity
2012
4 pags., 2 figs. -- Loops 11: Non-Perturbative / Background Independent Quantum Gravity 23–28 May 2011, Madrid, Spain