Kolloquium der Theoretischen Physik
Sommersemester 2013
jeden zweiten Dienstag jeweils von 16-18h im Hörsaal F
um zahlreiches Erscheinen wird gebeten
23.04.2013
Matthias Schmidt (Uni Bayreuth)
Recent developments in dynamical density functional theory
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The dynamics of complex soft matter systems is a topic of considerable current interest, both from an experimental and theoretical perspective. Among the various theories aiming to provide a microscopic description of complex transport and pattern formation phenomena the dynamical density functional theory (DDFT) has emerged as a prime candidate. We discuss its current status and possible extensions.
07.05.2013
Michael Hartmann (TU München)
Nanomechanical Qubits
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We introduce an approach to quantum information processing where the information is stored in the motional degrees of freedom of nanomechanical resonators. In our optomechanical approach, nanomechanical oscillators couple to laser driven resonances of an optical cavity. By lowering the resonance frequency of the oscillators via inhomogeneous electrostatic fields, we significantly enhance their intrinsic geometric nonlinearity per phonon. This causes the motional sidebands to split into separate spectral lines for each eigenstate of the mechanical motion and transitions between such eigenstates can be selectively addressed. This can be used to generate stationary phonon Fock states. Moreover the two lowest mechanical energy levels can be employed as qubits where single qubit rotations are conducted by radio frequency voltage pulses that are applied to individual resonators. Two qubit entangling gates in turn are implemented via a coupling of two qubits to a common optical resonance of the cavity.
04.06.2013
Gabriel Bester (MPI für Festkörperforschung, Stuttgart)
Next Frontiers in the ab-initio modeling of nanostructures: at the crossroads of solid state physics and quantum optics.
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18.06.2013
Renate Loll (Nijmegen)
Causal Dynamical Triangulations: Creating Quantum Spacetime Dynamically
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The search for "quantum spacetime" - the putative quantum description of spacetime at Planckian scales - can be approached in many ways, from semiheuristic mathematical modelling to fully-fledged nonperturbative systems of "quantum gravity". My colloquium talk will introduce Causal Dynamical Triangulations (CDT), a nonperturbative path integral method for constructing a fundamental theory of quantum gravity, including its motivation, ingredients and computational implementation. I will then give an overview of old and new results obtained in CDT quantum gravity, including the statistical model's phase structure, the emergence of semiclassical geometry and counterintuitive properties found on short length scales, and what they may tell us about the nature of quantum spacetime and nonperturbative formulations of quantum gravity in general.
16.07.2013
Patrick Rinke (Fritz-Haber-Institut Berlin)
Towards a unified description of ground and excited states with view to hybrid organic/inorganic systems
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