Talks

coffee, tea, cookies at 16:15 in the main hall
Monday 16:30-17:30
Seminar room 1+2
- monthly seminars -
Seminar room 4
- weekly seminars -
Monday 11:00-12:00
Room 1D1
Wednesday 16:30 - 17:30
Seminar room 1D1
Thursday 14:00-15:00
Seminar room 4

 

 

 

Talks in chronological order

21 Mar 2019
11:00 AM

Models of motion of substance in channels of a network

Nikolay Vitanov (Bulgarian Academy of Science, Sofia)

Seminarroom 4
21 Mar 2019
02:00 PM

Simulation of the 2D Hubbard model and finite correlation length scaling with iPEPS

Philippe Corboz (University of Amsterdam)

tba

Seminarroom 4
22 Mar 2019
02:00 PM

Magnetic impurity, disorder and interaction effects in 2D topological insulators

Jun-Hui Zheng (Goethe Universität Frankfurt)

In this first part, I would like to discuss the effects of strong magnetic impurities on the edge transport of a quantum spin Hall insulator. The location of the impurity strongly influences its effects. When it is near to the edge of the system, antiresonance of the transmission for the edge states happens. The interaction effects will be also discussed based on the renormalization theory. In the second part, I will discuss transport properties and topological phase transition in 2D interacting disordered Chern insulator within the dynamical mean-field theory. The band inversion induced by the disorder and interaction and the delocalization effects induced by interaction are discussed. We found that the repulsive onsite interaction is really friendly to the topological phase in the disordered Chern insulator

Room 1D1 iCal Event
02 Apr 2019
03:00 PM

Careers Talk

Orestis Georgiou (Ultrahaptics)

Seminarroom 4 iCal Event
03 Apr 2019
11:00 AM

Dynamics of a single polymer chain in an active bath

Rajarshi Chakrabarti (Indian Institute of Technology Bombay)

A prime example of non-equilibrium or active environment is a biological cell. In order to understand in-vivo functioning of biomolecules such as proteins, chromatins, a description beyond equilibrium is absolutely necessary. In this context, biomolecules have been modeled as Rouse chains in Gaussian active bath [1, 2]. However, these non-equilibrium fluctuations in biological cells are non-Gaussian [3]. This motivates us to take a Rouse chain subjected to a series of pulses of force with finite duration, mimicking run and tumble motion of a class of micro-organisms [4]. Thus by construction, this active force is non-Gaussian. Our analytical calculations show that the mean square displacement (MSD) of chain center of mass grows faster, but chain reconfiguration is slower for short chains. The reconfiguration time of a chain with N monomers scales as N σ , where the exponent σ ≃ 1.6 − 2. The MSD of the tagged monomer in this active bath also shows superdiffusion at an intermediate time unlike a monomer of a Rouse chain. In addition, the chain swells. We compare this activity-induced swelling with that of a Rouse chain in a Gaussian active bath [1]. [1] N. Samanta and R. Chakrabarti, J. Phys. A 49, 195601 (2016). [2] D. Osmanovi ́c and Y. Rabin, Soft Matter 13, 963 (2017). [3] O. Pohl, M. Hintsche, Z. Alirezaeizanjani, M. Seyrich, C. Beta, and H. Stark, PLoS Comp. Biol. 13, 1005329 (2017). [4] S. Chaki and R. Chakrabarti, J. Chem. Phys. 150, 094902 (2019).

Room 1D1 iCal Event
08 Apr 2019
04:30 PM

Colloquium: tba.

Prof. Alexander Balatsky (NORDITA, Stockholm, Schweden)

Seminarroom 1+2 iCal Event
25 Apr 2019
02:00 PM

tba

Christof Weitenberg (Universität Hamburg))

Seminarroom 4 iCal Event
29 Apr 2019
04:30 PM

Colloquium: tba.

Prof. Frederick C. MacKintosh (Rice University, USA)

Seminarroom 1+2 iCal Event
06 May 2019
04:30 PM

Colloquium: Interplay between superconductivity and non-Fermi liquid above a quantum critical point in a metal

Prof. Andrey Chubukov (University of Minnesota, USA)

I discuss the interplay between non-Fermi liquid behavior and superconductivity near a quantum-critical point (QCP) in a metal. It is widely thought that the tendency towards superconductivity and towards non-Fermi liquid behavior compete with each other, and if the pairing interaction is reduced below a certain threshold, the system displays a naked non-Fermi liquid QC behavior. I show that the situation is more complex. First, there is a difference between spin-triple and spin-singlet superconductivity. For spin-triplet pairing, thermal fluctuations are crucial and make superconducting transition first order. For spin-singlet pairing, they are essentially irrelevant, and the transition is second order. Second, I show that for spin-singlet pairing, there are multiple solutions with the same gap symmetry. For all solutions, except one, Tc vanishes when the pairing interaction drops below the threshold. For the one special solution, Tc remains finite even when the pairing interaction is arbitrary small, despite that there is no Cooper logarithm. I argue that superconductivity between this Tc and a lower T, when other solutions appear, is special, as it is entirely induced by fermions with the first Matsubara frequency. I show that this has specific implications for the observable quantities, such as the density of states and the spectral function.

Seminarroom 1+2 iCal Event
08 May 2019
04:30 PM

Quantum Dynamics Seminar

Robert Binder (Universität Frankfurt)

Room 1D1 iCal Event
13 May 2019
04:30 PM

Colloquium: tba.

Prof. Dr. Atac Imamoglu (ETH Zürich, Inst. für Quantenelektronik)

Seminarroom 1+2 iCal Event
20 May 2019
04:30 PM

Colloquium: tba.

Seminarroom 1+2 iCal Event
27 May 2019
04:30 PM

Colloquium: tba.

Prof. Dr. Georgi Dvali (LMU München / New York Univ.)

Seminarroom 1+2 iCal Event
03 Jun 2019
04:30 PM

Colloquium: tba

Prof. Lakshminarayanan Mahadevan (Harvard University, USA)

Seminarroom 1+2 iCal Event
17 Jun 2019
04:30 PM

Colloquium: tba.

Seminarroom 1+2 iCal Event
24 Jun 2019
04:30 PM

Colloquium: tba.

Seminarroom 1+2 iCal Event