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[Fizinfo] next Monday 14:15: Simon Körber on topological frequency conversion

Chronological Thread 
  • From: Andras Palyi <palyi AT>
  • Subject: [Fizinfo] next Monday 14:15: Simon Körber on topological frequency conversion
  • Date: Fri, 12 Feb 2021 12:34:39 +0100

Dear Colleagues,

Next Monday the BME Exotic Quantum Phases seminar series continues with this

Speaker: Simon Körber (Würzburg)
Title: Interacting topological frequency converter
Abstract: see below

Time: Feb 15, 14:15 Budapest time
Location: online in Teams

About the speaker: Simon is theoretical physicist with an expertise in
correlated electron systems, Shiba states in superconductors, and topological
features of non-equilibrium quantum systems. Currently he is a 3rd-year PhD
student in Würzburg, in the group of Björn Trauzettel.

Link to join the meeting in Teams:


Best regards,
Andras Palyi

= = =


Non-equilibrium quantum systems host a plethora of topological phenomena. A
topological property of quantum dynamics can be related to the effective
dimensional extension of the system by time-periodic drives. Following this
line of reasoning, it has been shown that a two-level system coupled to two
circularly polarized drives can mediate a frequency conversion between the
two fields that happens at a topologically quantized rate [1]. In this talk,
we will address two types of questions that naturally arise for this kind of
quantum system.

The first is whether interaction can change the topological features in the
dynamically-induced synthetic dimension. We positively answer this question
by adding spin-spin interactions to the prototypical model of the topological
frequency converter [2]. We demonstrate that the interplay of interaction and
synthetic dimension gives rise to striking topological phenomena that have no
counterpart in the non-interacting regime. Remarkably, these features already
appear for the minimal case of two interacting spins, and can result into an
enhancement of frequency conversion as a direct manifestation of the
correlated topological response.

Given a realization of the topological frequency converter by an externally
driven spin qubit, the second question that arises is how environmental
effects may affect the dynamical topological response. By studying a
quasiperiodically driven central spin model, we demonstrate that the coupling
to the surrounding (nuclear) spin bath can lead to an amplification of the
frequency conversion that is proportional to the number of (nuclear) spins of
the host material.

[1] I. Martin, G. Refael, and B. Halperin, Phys. Rev. X 7, 041008 (2017).

[2] S. Körber, L. Privitera, J. C. Budich, and B. Trauzettel, Phys. Rev.
Research 2, 022023(R) (2020).

  • [Fizinfo] next Monday 14:15: Simon Körber on topological frequency conversion, Andras Palyi, 02/12/2021

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