Analog quantum simulation on surfaces

We study interacting many-body quantum systems using standard spectroscopic detection schemes and by constructing controllable quantum systems of single atoms and molecules on surfaces as a platform for the analog simulation of the many-body systems.

In an analog quantum simulation, experimentally controllable quantum systems are measured to understand the properties of another quantum system. The most advanced analog quantum simulators are based on ultracold atoms in optical lattices and have been used, for example, to study quantum magnetism or to detect topological quantum matter. Atoms and molecules on surfaces, combined with the manipulation capabilities of scanning probe microscopes (SPMs), are an interesting alternative for analog quantum simulations of strongly correlated systems. The quantum system to be simulated can be fabricated with atomic precision from individual atoms or molecules, and the interaction strength between the atoms/molecules can be tuned by adjusting the distance between them using the SPM.

Our research focuses on the study of quantum magnetism at the atomic scale. This includes the study of quantum phase transitions in nanostructures [1] as well as the design of artificial quantum magnets on surfaces. This provides atomic-scale access to the properties of exotic quantum many-body states, such as a finite-size realization of a resonating valence-bond state [2]. We characterize the resulting (collective) magnetic properties using standard spectroscopic, i.e. non-resonant, detection schemes [1][3][4][5] and electron spin resonance (ESR) [2]. In the future, we will also use our atomic-scale quantum sensors as control and read-out devices for the analog quantum simulators.

References

[1] T. Esat, B. Lechtenberg, T. Deilmann, C. Wagner, P. Krüger, R. Temirov, M. Rohlfing, F. B. Anders, F. S. Tautz, A chemically driven quantum phase transition in a two-molecule Kondo system. Nature Phys. 12, 867–873 (2016)

[2] K. Yang, S.-H. Phark, Y. Bae, T. Esat, P. Willke, A. Ardavan, A. J. Heinrich, C. P. Lutz, Probing resonating valence bond states in artificial quantum magnets. Nat Commun. 12, 993 (2021)

[3] T. Esat, T. Deilmann, B. Lechtenberg, C. Wagner, P. Krüger, R. Temirov, F.B. Anders, M. Rohlfing, F. S. Tautz. Transfering spin into an extended π orbital of a large molecule. Phys. Rev. B. 91, 144415 (2015)

[4] F. Eickhoff, E. Kolodzeiski, T. Esat, N. Fournier, C. Wagner, T. Deilmann, R. Temirov, M. Rohlfing, F.S. Tautz, F.B. Anders. Inelastic electron tunneling spectroscopy for probing strongly correlated many-body systems by scanning tunneling microscopy. Physical Review B 101, 125405 (2020)

[5] T. Esat, M. Ternes, R. Temirov, F. S. Tautz, Electron spin secluded inside a bottom-up assembled standing metal-molecule nanostructure. Phys. Rev. Research 5, 033200 (2023)