Freiburg 2024 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 16: Bosonic Quantum Gases III (joint session Q/A)
Q 16.1: Talk
Tuesday, March 12, 2024, 11:00–11:15, Aula
Sub-unity superfluid fraction of a supersolid from self-induced Josephson effect — •Nicolò Antolini1,2, Giulio Biagioni2,3, Beatrice Donelli1,2,4,5, Luca Pezzè1,2,4, Augusto Smerzi1,2,4, Marco Fattori1,2,3, Andrea Fioretti2, Carlo Gabbanini2, Massimo Inguscio1,6, Luca Tanzi1,2, and Giovanni Modugno1,2,3 — 1LENS, University of Florence — 2CNR-INO — 3Department of Physics and Astronomy, University of Florence — 4QSTAR — 5Università degli Studi di Napoli — 6Università Campus Bio-Medico di Roma
Many quantum materials in various systems feature a spatially modulated macroscopic wavefunction resulting from spontaneous breaking of gauge and translational symmetries. Their connection with supersolids has only been traced in a few cases since a universal property able to quantify the differences between supersolids, superfluids/superconductors, and crystals has not been established. A key property is the superfluid fraction, measuring the reduction in superfluid stiffness due to spatial modulations, leading to the non-standard superfluid dynamics of supersolids. We employ the Josephson effect to locally measure the superfluid fraction in a supersolid. Even without a physical barrier, the Josephson effect arises spontaneously in a supersolid, and single lattice cells act as self-induced Josephson junctions. We studied a cold-atom dipolar supersolid, revealing a significant sub-unity superfluid fraction. Our results point to new research directions, like the study of partially quantized vortices and supercurrents, and have an impact on the understanding of other supersolid-like systems.
Keywords: Supersolid; Superfluidity; Dipolar Quantum Gases; Josephson Effect; Novel State of Matter