November 2014  
Fr 
07.11.2014
SR 4, Institut für Theoretische Physik, A03.101
SFB 937

14:00 
Seminar
Roland Netz FU Berlin
DNA dynamics, protein force spectroscopy and viscoelastic properties of polymeric networks Kontakt:
Glormann

Di 
18.11.2014
SR 3, Institut für Theoretische Physik, A03.101
SFB 937

17:15 
Seminar
Frieder Mugele University of Twente (NL)
TBA Kontakt:
Glormann

Do 
20.11.2014
Seminarraum A 03.101
Theoretische Physik

12:00 
Statistische Mechanik komplexer Systeme (Forschungsseminar M.Phy.410)
Guojie Zhang MPI Mainz
Hierarchical Modeling of Highly Entangled Polymer Melts: Kontakt:
Marcus Müller

Di 
25.11.2014
Seminarraum A3.101
Theoretische Physik

14:15 
Theoretischphysikalisches Seminar
Herbert Spohn TU München
Equilibrium time correlations for anharmonic chains Since the 1970ies it has been recognized that onedimensional systems generically have anomalous transport. One manifestation is to consider the superdiffusive spreading of sound and heat peak for the time correlations of the conserved quantities in equilibrium. Recently I proposed a nonlinear extension of fluctuating hydrodynamics to capture the large scale behavior of the correlations. In my talk I will explain the basic theoretical construction and compare with molecular dynamics simulations. The theory amounts to a multicomponent extension of the onedimensional KPZ equation. Kontakt:
J. Oberreuter

Dezember 2014  
Di 
02.12.2014
SR 3, Institut für Theoretische Physik, A03.101
SFB 937

17:15 
Seminar
Yael Roichman Tel Aviv University
TBA Kontakt:
Glormann

Di 
16.12.2014
Seminarraum A3.101
Theoretische Physik

14:15 
Theoretischphysikalisches Seminar
Markus Heyl Universität Innsbruck
Manybody localization and quantum ergodicity in disordered longrange Ising model Ergodicity in quantum manybody systems is —despite its fundamental importance — still an open problem. Manybody localization provides a general framework for quantum ergodicity, and may therefore offer important insights. In this talk, it will be shown using both numerical and analytical methods that longrange interacting Ising models with transversefield disorder enter a manybody localized phase at infinite temperature, irrespective of the disorder strength. As a consequence, these systems are nonergodic. To characterize and quantify quantum ergodicity, a measure for distances in Hilbert space will be introduced. It will be shown that in spin1/2 systems it is equivalent to a simple local observable in real space, which can be measured in current experiments of superconducting qubits, polar molecules, Rydberg atoms, and trapped ions. Kontakt:
S. Kehrein

Januar 2015  
Di 
20.01.2015
Seminarraum A3.101
Theoretische Physik

14:15 
Theoretischphysikalisches Seminar
Robin Steinigeweg Technical University of Braunschweig
Realtime relaxation of currents in spin1/2 chains: Progress by quantum typicality We use the concept of typicality to study the realtime dynamics of spin and energy currents in spin1/2 models in one dimension and at nonzero temperatures [1,2]. These chains are the integrable XXZ chain and a nonintegrable modification due to the presence of a staggered magnetic field oriented in z direction. In the framework of linear response theory, we numerically calculate autocorrelation functions by propagating a single pure state, drawn at random as a typical representative of the full statistical ensemble. By comparing to smallsystem data from exact diagonalization (ED) and existing shorttime data from timedependent density matrix renormalization group (tDMRG), we show that typicality is satisfied in finite systems over a wide range of temperature and is fulfilled in both, integrable and nonintegrable systems. For the integrable case [1], we calculate the longtime dynamics of the spin current and extract the spin Drude weight for large systems outside the range of ED. We particularly provide strong evidence that the hightemperature Drude weight vanishes at the isotropic point. For the nonintegrable case [2], we obtain the full relaxation curve of the energy current and determine the heat conductivity as a function of magnetic field, exchange anisotropy, and temperature. 