Prof. Dr. Johann Kroha
3.017
Nußallee 12
53115 Bonn
Welcome to the webpage of the research group of Prof. Dr. Johann Kroha. I am a Professor of Condensed Matter and Many-Body Theoretical Physics at the Physikalisches Institut of the Rheinische Friedrich-Wilhelms-Universtät Bonn and a member of the Bethe Center for Theoretical Physics (BCTP).
Current Research Interests:
- Nonequilibrium dynamics in interacting quantum systems
- Strongly correlated electron systems
- Topology and interactions in quantum systems
- Ultracold Bose gases
- Open quantum systems
ORCID ID: 0000-0002-3340-9166
News
Many substances change their properties when they are cooled below a certain critical temperature. Such a phase transition occurs, for example, when water freezes. However, in certain metals there are phase transitions that do not exist in the macrocosm. They arise because of the special laws of quantum mechanics that apply in the realm of nature’s smallest building blocks. It is thought that the concept of electrons as carriers of quantized electric charge no longer applies near these exotic phase transitions. Researchers at the University of Bonn and ETH Zurich have now found a way to prove this directly. Their findings allow new insights into the exotic world of quantum physics. The publication has now been released in the journal Nature Physics.
Student researchers are always a welcome addition to our group!
This includes Bachelor's, Master's and PhD students. There are always open questions and projects on various levels of depth and difficulty. Our main research topics are listed at the top of the page. If you are interested, please don't hesitate to contact us to see if we have open positions.
General requirements:
- Curiosity and interest in learning.
We value students who possess a genuine curiosity and eagerness to learn about new physics concepts and methodologies. - Enjoyment of theoretical considerations.
Whether it's grappling with theoretical frameworks or engaging in numerical calculations, an appreciation for theoretical thinking is essential. - A solid mathematical background.
Mathematics is an essential part of theoretical physics, not only in the mathematical description of reality, but also in computer-assisted simulations.
- Non-Markovian Dynamics of Open Quantum Systems via Auxiliary Particles with Exact Operator Constraint
Tim Bode, Michael Kajan, Francisco Meirinhos, Johann Kroha,
Phys. Rev. Research 6, 013220 (2024). - Temporal bistability in the dissipative Dicke-Bose-Hubbard system
Tianyi Wu, Sayak Ray, Johann Kroha,
Annalen der Physik, 2300505 (2024). - Critical slowing down near a magnetic quantum phase transition with fermionic breakdown
Chia-Jung Yang, Kristin Kliemt, Cornelius Krellner, Johann Kroha, Manfred Fiebig, Shovon Pal,
Nature Physics 19, 1605-1610 (2023). - Quantum spin liquid in an RKKY-coupled two-impurity Kondo system
Krzysztof P. Wójcik and Johann Kroha,
Phys. Rev. B 107, L121111 (2023). - Real- and Fourier space observation of the anomalous pi mode in Floquet engineered plasmonic waveguide arrays
Anna Sidorenko, Zlata Fedorova (Cherpakova), Johann Kroha, Stefan Linden,
Phys. Rev. Research 4, 033184 (2022). - Observation of a non-Hermitian phase transition in an optical quantum gas
Fahri Emre Öztürk, Tim Lappe, Göran Hellmann, Julian Schmitt, Jan Klaers, Frank Vewinger, Johann Kroha, Martin Weitz,
Science 372 (6537), 88-91 (2021). - Expansion dynamics in two-dimensional Bose-Hubbard lattices: BEC and thermal cloud
Mauricio Trujillo-Martinez, Anna Posazhennikova, and Johann Kroha,
Phys. Rev. A 103, 033311(2021). - Teraherz Conductivity of Heavy-fermion Systems from Time-resolved Spectroscopy
Chia-Jung Yang, Shovon Pal, Farzaneh Zamani, Kristin Kliemt, Cornelius Krellner, Oliver Stockert, Hilbert v. Löhneysen, Johann Kroha, and Manfred Fiebig,
Phys. Rev. Research 2, 033296 (2020). - Observation of topological transport quantization by dissipation in fast Thouless pumps
Z. Fedorova, H. Qiu, S. Linden, J. Kroha,
Nature Communications 11, 3758 (2020).
- DFG-Sonderforschungsbereich SFB 608 "Komplexe Übergangsmetallverbindungen mit Spin- und Ladungsfreiheitsgraden und Unordnung"
- DFG Forschergruppe 557 "Light Confinement and Control with Structured Dielectrics and Metals"
- DFG Schwerpunktprogramm 1113 "Photonic Crystals"
- DFG Schwerpunktprogramm 1153 "Cluster in Kontakt mit Oberflächen: Elektronenstruktur und Magnetismus"
- DFG Project "Transport durch normal- und supraleitende Quanten-Punktkontakte mit komplexer elektronischer Struktur"
- DFG Project "Theory of Random Lasing and Light Localization in Strongly Disordered Media"
- Anschubfinanzierung durch Universität Bonn für DFG Forschergruppe (2003-2004) "Light Confinement and Control with Structured Dielectrics and Metals"
- DFG-Schwerpunktprogramm 1031 (1997-2003) "Quasikristalle: Struktur und physikalische Eigenschaften"
Prof. Dr. Johann Kroha
3.017
Nußallee 12
53115 Bonn
