Majorana single-charge transistor

We study transport through a Coulomb blockaded topologically nontrivial superconducting wire (with Majorana end states) contacted by metallic leads. An exact formula for the current through this interacting Majorana single-charge transistor is derived in terms of wire spectral functions. A comprehensive picture follows from three different approaches. We find Coulomb oscillations with universal halving of the finite-temperature peak conductance under strong blockade conditions, where the valley conductance mainly comes from elastic cotunneling. The nonlinear conductance exhibits finite-voltage sidebands due to anomalous tunneling involving Cooper pair splittingThis work was supported by the DFG (Grant No. EG-96/ 9-1 and SFB TR 12), by the EU network SE2ND, and by the Spanish MICINN under Contract FIS2008-0420

Iterative summation of path integrals for nonequilibrium molecular quantum transport

We formulate and apply a nonperturbative numerical approach to the nonequilibrium current, $I(V)$, through a voltage-biased molecular conductor. We focus on a single electronic level coupled to an unequilibrated vibration mode (Anderson-Holstein model), which can be mapped to an effective three-state problem. Performing an iterative summation of real-time path integral (ISPI) expressions, we accurately reproduce known analytical results in three different limits. We then study the crossover regime between those limits and show that the Franck-Condon blockade persists in the quantum-coherent low-temperature limit, with a nonequilibrium smearing of step features in the $IV$ curve.Comment: 4 pages, 4 figure

Nonclassical energy transfer in photosynthetic FMO complex

Excitation energy transfer in a photosynthetic FMO complex has been simulated using the stochastic Schrödinger equation. Fluctuating chromophore transition energies are simulated from the quantum correlation function which allows to properly include the finite temperature. The resulting excitation dynamics shows fast thermalization of chromophore occupations into proper thermal equilibrium. The relaxation process is characterized by entropy dynamics, which shows nonclassical behavior

Polarization REsearch for Fusion Experiments and Reactors - The PREFER Collaboration: Purposes and Present Status

The PREFER (Polarization REsearch for Fusion Experiments and Reactors) collaboration aims to address the know–hows in different fields and techniques to the challenging bet on fusion with polarized fuel. The efforts on a variety of duties and goals are shared between different research groups, indicated here by underlining in the authors’ list the scientific responsibles. Starting from still open questions of fusion reaction physics, as for example the study of D+D spin–dependent cross–sections (Vasilyev) to the acceleration of polarized ions from laser-induced plasmas (Büscher), there are many connections between the involved research groups. The collaboration is also tackling the production of nuclear polarized molecules, recombined from a polarized atomic beam (Engels), and its cryogenic condensation and transport (Ciullo). Other options for the production of polarized fuel are investigated in parallel, like spin separation of molecules in polarized molecular beam sources (Toporkov), or via photodissociation of molecules into polarized hydrogen/deuterium atoms (Rakitzis). The status of the different fields under investigation and the connections between these topics and the different research groups will be provided