Topological effects in dissipative quantum systems (Marcel Wagner)
- Datum: 26.04.2018
- Uhrzeit: 11:00 - 12:00
- Vortragende(r): Marcel Wagner
- Institut für theoretische Physik, Universität Stuttgart
- Raum: B 0.42 (small room in the livrary)
- Gastgeber: MPQ, Theory Division
By
contrast, an extension of topologically protected phases to the dissipative
scenario remains an open question that is addressed in resent
research.
In the talk two different ways of introducing effects of dissipation to a
quantum system are used. Both allow for a generalization of the notion of
topological phases to open quantum systems. Within an effective description,
which uses complex potentials, it is shown that a non-Hermitian analog of
the Berry phase features a strict quantization and hence suits as a topological
invariant of the dissipative system. This concept is transferred to the
more general framework of Lindblad master equations treated within the
scope of superoperators. Both descriptions are exemplified by a system showing
topologically nontrivial phases in absence of dissipation, viz. the
Su-Schrieffer-Heeger model coupled to different types of reservoirs.