Volker Karle

I study driven and hybrid quantum matter at the interface of atomic, molecular and optical (AMO) physics and condensed matter. My goal is to understand how the non-equilibrium, topological, and entanglement structure of quantum systems can be turned into a resource for quantum sensing, tailored quantum materials, and quantum information applications.

I combine large-scale many-body numerics (exact diagonalization, Floquet engineering, and tensor-network / DMRG methods) with the design of minimal analytical models that expose the essential physics. A recurring theme is the role of nonlinear and periodically driven (Floquet) systems, from laser-kicked molecules and quantum rotors to cavity-coupled two-dimensional materials and driven-dissipative protocols. I also build and maintain open-source Julia packages for the symbolic and operator-algebra toolchain that underpins this work.

My current focus spans hybrid light-matter topology in chiral cavities, collective cat-state physics of molecules in microwave cavities, and multi-gap topology in periodically driven rotors. Earlier work covered area-law eigenstates and many-body scars, coupled superfluidity in 2D Bose mixtures, and cascading dynamics in climate tipping elements. A full list of publications is on Google Scholar and this site.

Feel free to reach me at vkarle[at]ist.ac.at or on Mastodon.

Positions & education

Oct 2026 – JSPS Postdoctoral Fellow, Oka group, University of Tokyo (ISSP)
2025 – 2026 Postdoctoral researcher, Lemeshko group, ISTA
2019 – 2025 PhD at ISTA (Lemeshko group)
2016 – 2018 M.Sc. Physics, University of Heidelberg
2011 – 2015 B.Sc. Physics, University of Freiburg

For a concise tour of current work, see the research overview, browse project pages, or explore the open-source software.

selected publications

arXiv

Collective rotational cat states of molecules in microwave cavities

Volker Karle^*, Florian Kluibenschedl, Mikhail Lemeshko, and 1 more author

arXiv preprint arXiv:2606.25815, 2026

Abs HTML Website

We show that an ensemble of polar molecules coupled to a microwave cavity supports hybrid rotational-photonic cat states: virtual multilevel transitions induce an effective Kerr nonlinearity that locks parity in the cavity sectors, extending light-matter cat-state physics to collective molecular rotations.
arXiv

Hybrid light-matter boundaries of graphene in a chiral cavity

Volker Karle^*, Oriana K. Diessel, Vasil Rokaj, and 1 more author

arXiv preprint arXiv:2510.13373, 2025

Abs HTML Website

We establish the bulk-boundary correspondence for graphene embedded in a circularly polarized cavity, showing that every light-matter interaction-induced gap hosts unidirectional chiral edge currents and that their dispersion, localization length and photon distribution obey a universal scaling set by the coupling.
arXiv

Anomalous multi-gap topological phases in periodically driven quantum rotors

Volker Karle^*, Mikhail Lemeshko, Adrien Bouhon, and 2 more authors

arXiv preprint arXiv:2408.16848, 2024

Abs HTML Website

We discovered novel multi-gap topological phases in periodically driven quantum systems, revealing unexpected connections between driving protocols and topological protection.
PRL

Topological charges of periodically kicked molecules

Volker Karle^*, Areg Ghazaryan, and Mikhail Lemeshko

Physical Review Letters, 2023

Abs DOI HTML Website

We introduced the concept of topological charges in molecular systems subject to periodic driving, opening new avenues for quantum control and topological protection in molecular physics.
PRL

Area-Law Entangled Eigenstates from Nullspaces of Local Hamiltonians

Volker Karle^*, Maksym Serbyn, and Alexios A. Michailidis

Physical Review Letters, 2021

Abs DOI HTML Website

We demonstrated a novel mechanism for generating area-law entangled states through nullspace engineering, providing new insights into quantum many-body scars and thermalization.