Dresden 2026 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 71: Ultrafast Phenomena

TT 71.3: Vortrag

Donnerstag, 12. März 2026, 10:00–10:15, HSZ/0103

Giant Dynamical Paramagnetism in the driven fluctuating superconductors — •Marios Michael¹, Duilio De Santis², Eugene Demler², and Patrick Lee³ — ¹Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38 01187 Dresden Germany — ²Institute for Theoretical Physics, ETH Zurich, 8093 Zurich, Switzerland — ³Department of Physics, MIT, 77 Massachusetts Avenue, 02139 Cambridge, MA, USA

In the past decade, photo-induced superconducting-like behaviors have been reported in a number of materials driven by intense pump fields. Of particular interest is the high-Tc cuprate Y Ba2 Cu2 O(6+x) (YBCO), where such effect has been reported up to the so-called pseudogap temperature T* ~ 300-400 K. In a recent tour-de-force experiment, a transient magnetic field which is proportional to and in the same direction of an applied field has been observed outside the sample, suggestive of flux exclusion due to the Meissner effect. In this talk I will present a different explanation of these experiments, based on the model of preformed Cooper pairs in the pseudogap phase. I will demonstrate that a combination of external magnetic field and strong terahertz drive used in experiments by Fava et al. Nature 2024, results in a novel Floquet instability in the model. This instability results in currents at the edges of the bilayer formed by defects or grain boundaries, with the current flowing in the opposite direction of the equilibrium screening current, producing a giant paramagnetic magnetization in the same direction as the applied field. We show how this scenario can fit most of the available data.

Keywords: Photo-induced superconductivity; Soliton dynamics; Ultra-fast magnetism; Pseudogap phase; High Tc cuprates