Martin Luther University Halle-Wittenberg

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Seminar schedule

The Seminars & literature chats of our group take place every working Monday, 11:15, Karl-Freiherr-von-Fritsch Str. 3, in Room

October 12th
Time: 16:00
Dr. Michael Sekaniaguest speaker
October 19thLevan Chotorlishviliseminar or chat
October 26thConrad Schusterseminar or chat
November 2ndSeyyed Ruhollah Etesamiseminar or chat
November 9thBahman Roostaeiguest speaker
November 16thYaroslav Pavlyukhseminar or chat
November 23thJamal Berakdarseminar or chat
November 30thMichael Schülerseminar or chat
December 7thTBAguest speaker
December 14thAlexander Sukhovseminar or chat
January 11thMaryam Azimiseminar or chat
January 18thStefan Stagraczyńskiseminar or chat
January 25thJonas Wätzelseminar or chat

Dr. Michael Sekania

Institut für Physik

Universität Augsburg

Revealing "string states" in the Hubbard chain using quench dynamics

Recently, spin-imbalanced fermions in one dimension have attracted considerable attention both theoretically and experimentally. This system was successfully simulated using ultracold atoms in optical lattices. The phase diagram was measured and found to be in agreement with exact analytical calculations. It has been also theoretically predicted that the spin-charge separation, an important property of Luttinger liquids, is absent in spin imbalanced fermion systems.

Based on our numerical (time-dependent Density-Matrix Renormalization Group method) and analytical calculations (Bethe Ansatz) for the Hubbard model, we propose quench experiments which not only reveal the breakdown of spin-charge separation, but also make it possible to study the so called ”string” bound states in this system.

Bahman Roostaei

Dynamics of Domain Walls in Helical Magnetic Systems

Observation of helical domains in certain metallic magnetic systems  introduces a new class of domain walls rarely studied in the past. There  are at least two general types of domain walls separating helical  domains: vortex walls and Hubert walls, both behaving fundamentally  different compared to conventional domain walls such as Bloch walls. One  of the many interesting features of such structures is their  topological nature. We study the elasticity, pinning and also  interaction of these walls with spin polarized current.