SKM 2021 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 5: Poster Session: Superconductivity
TT 5.32: Poster
Monday, September 27, 2021, 13:30–16:00, P
Collisionless drag for a one-dimensional two-component Bose-Hubbard model — •Daniele Contessi1,4, Donato Romito2,3, Matteo Rizzi4,5, and Alessio Recati1,2 — 1Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy — 2INO-CNR BEC Center, 38123 Povo, Italy — 3Mathematical Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, United Kingdom — 4Forschungszentrum Jülich, Institute of Quantum Control (PGI-8), 52425 Jülich, Germany — 5Institute for Theoretical Physics, University of Cologne, D-50937 Köln, Germany
We theoretically investigate the elusive Andreev-Bashkin collisionless drag for a two-component one-dimensional Bose-Hubbard model on a ring. By means of Tensor Network algorithms, we calculate superfluid stiffness matrix as a function of the interactions and of the lattice filling. We focus on the region close to the so-called pair-superfluid phase, where we observe that the drag can become comparable with the total superfluid density. We elucidate the importance of the drag in determining the long-range behavior of the correlation functions and the spin speed of sound. In this way we are able to provide an expression for the spin Luttinger parameter KS in terms of drag and the spin susceptibility. Our results are promising in view of implementing the system by using ultra-cold Bose mixtures trapped in deep optical lattices. Importantly the mesoscopicity of the system appears to favour a large drag, avoiding the Berezinskii-Kosterlitz-Thouless jump at the transition to the pair superfluid phase which would reduce the region where a large drag can be observed.