Nonlinear transport through a dynamic impurity in a strongly interacting one-dimensional electron gas

We analyze the transport properties of a Luttinger liquid with an imbedded impurity of explicitly time-dependent strength. We employ a radiative boundary condition formalism to describe the coupling to the voltage sources. Assuming the impurity time dependence to be oscillatory we present a full analytic perturbative result in impurity strength for arbitrary interaction parameter calculated with help of Coulomb gas expansion (CGE). Moreover, a full analytic solution beyond the above restriction is possible for a special non-trivial interaction strength which has been achieved independently by full resummation of CGE series as well as via refermionization technique. The resulting nonlinear current-voltage characteristic turns out to be very rich due to the presence of the additional energy scale associated with the impurity oscillation frequency. In accordance with the previous studies we also find an enhancement of the linear conductance of the wire to values above the unitary limit G0 = 2e2/h.Comment: 8 pages, 3 figures, submitted to PR

Automatic design of optical systems by digital computer

Computer program uses geometrical optical techniques and a least squares optimization method employing computing equipment for the automatic design of optical systems. It evaluates changes in various optical parameters, provides comprehensive ray-tracing, and generally determines the acceptability of the optical system characteristics

Full counting statistics of spin transfer through ultrasmall quantum dots

We analyze the spin-resolved full counting statistics of electron transfer through an ultrasmall quantum dot coupled to metallic electrodes. Modelling the setup by the Anderson Hamiltonian, we explicitly take into account the onsite Coulomb repulsion $U$. We calculate the cumulant generating function for the probability to transfer a certain number of electrons with a preselected spin orientation during a fixed time interval. With the cumulant generating function at hand we are then able to calculate the spin current correlations which are of outmost importance in the emerging field of spintronics. We confirm the existing results for the charge statistics and report the discovery of the new type of correlation between the spin-up and -down polarized electrons flows, which has a potential to become a powerful new instrument for the investigation of the Kondo effect in nanostructures.Comment: 5 pages, 1 figur

Charge transfer statistics of a molecular quantum dot with strong electron-phonon interaction

We analyze the nonequilibrium transport properties of a quantum dot with a harmonic degree of freedom (Holstein phonon) coupled to metallic leads, and derive its full counting statistics (FCS). Using the Lang-Firsov (polaron) transformation, we construct a diagrammatic scheme to calculate the cumulant generating function. The electron-phonon interaction is taken into account exactly, and the employed approximation represents a summation of a diagram subset with respect to the tunneling amplitude. By comparison to Monte Carlo data the formalism is shown to capture the basic properties of the strong coupling regime

FORTRAN optical lens design program

Computer program uses the principles of geometrical optics to design optical systems containing up to 100 planes, conic or polynomial aspheric surfaces, 7 object points, 6 colors, and 200 rays. This program can be used for the automatic design of optical systems or for the evaluation of existing optical systems

A Rigorous Finite-Element Domain Decomposition Method for Electromagnetic Near Field Simulations

Rigorous computer simulations of propagating electromagnetic fields have become an important tool for optical metrology and design of nanostructured optical components. A vectorial finite element method (FEM) is a good choice for an accurate modeling of complicated geometrical features. However, from a numerical point of view solving the arising system of linear equations is very demanding even for medium sized 3D domains. In numerics, a domain decomposition method is a commonly used strategy to overcome this problem. Within this approach the overall computational domain is split up into smaller domains and interface conditions are used to assure continuity of the electromagnetic field. Unfortunately, standard implementations of the domain decomposition method as developed for electrostatic problems are not appropriate for wave propagation problems. In an earlier paper we therefore proposed a domain decomposition method adapted to electromagnetic field wave propagation problems. In this paper we apply this method to 3D mask simulation.Comment: 9 pages, 7 figures, SPIE conference Advanced Lithography / Optical Microlithography XXI (2008