Connecting Dissipation and Phase Slips in a Josephson Junction between Fermionic Superfluids

Year: 2018

Authors: Burchianti A., Scazza F., Amico A., Valtolina G., Seman J.A, Fort C., Zaccanti M., Inguscio M., Roati G.

Autors Affiliation: CNR, INO, I-50019 Sesto Fiorentino, Italy; Univ Florence, LENS, I-50019 Sesto Fiorentino, Italy; Univ Florence, Dipartimento Fis & Astron, I-50019 Sesto Fiorentino, Italy; Univ Nacl Autonoma Mexico, Inst Fis, Mexico City 01000, DF, Mexico; Univ Colorado, JILA, Boulder, CO 80309 USA.

Abstract: We study the emergence of dissipation in an atomic Josephson junction between weakly coupled superfluid Fermi gases. We find that vortex-induced phase slippage is the dominant microscopic source of dissipation across the Bose-Einstein condensate-Bardeen-Cooper-Schrieffer crossover. We explore different dynamical regimes by tuning the bias chemical potential between the two superfluid reservoirs. For small excitations, we observe dissipation and phase coherence to coexist, with a resistive current followed by well-defined Josephson oscillations. We link the junction transport properties to the phase-slippage mechanism, finding that vortex nucleation is primarily responsible for the observed trends of conductance and critical current. For large excitations, we observe the irreversible loss of coherence between the two superfluids, and transport cannot be described only within an uncorrelated phase-slip picture. Our findings open new directions for investigating the interplay between dissipative and superfluid transport in strongly correlated Fermi systems, and general concepts in out-of-equilibrium quantum systems.

Journal/Review: PHYSICAL REVIEW LETTERS

Volume: 120 (2)      Pages from: 025302-1  to: 025302-6

More Information: We acknowledge inspiring discussions with F. Dalfovo, T. Giamarchi, F. Piazza, N. Proukakis, A. Smerzi, A. Trombettoni, and K. Xhani. We especially acknowledge the LENS Quantum Gases group. This work was supported by the ERC through Grant No. 307032 QuFerm2D and by the Marie Sklodowska-Curie programme (Grant No. 705269 to F.S.). J.A.S. acknowledges supporting grants from Universidad Nacional Autonoma de Mexico-Direccion General de Asuntos del Personal Academico/Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica IA101716 and Consejo Nacional de Ciencia y Tecnologia (CONACyT) LN-271322.
KeyWords: Bose-Einstein condensation; Electron gas; Josephson junction devices; Quantum chemistry; Quantum optics; Statistical mechanics; Superconducting films; Vortex flow, Bardeen-Cooper-Schrieffer; Bose-Einstein condensates; Fermionic superfluid; Josephson oscillations; Josephson-junction; Out of equilibrium; Resistive currents; Superfluid Fermi gas, Fermions
DOI: 10.1103/PhysRevLett.120.025302

Citations: 69
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