title: Velocity-dependent quantum phase slips in 1D atomic superfluids.
abstract: Quantum phase slips are the primary excitations in one-dimensional superfluids and superconductors at low temperatures but their existence in ultracold quantum gases has not been demonstrated yet. We now study experimentally the nucleation rate of phase slips in one-dimensional superfluids realized with ultracold quantum gases, flowing along a periodic potential. We observe a crossover between a regime of temperature-dependent dissipation at small velocity and interaction and a second regime of velocity-dependent dissipation at larger velocity and interaction. This behavior is consistent with the predicted crossover from thermally-assisted quantum phase slips to purely quantum phase slips.
authors.affiliation: LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Tanzi
authors.affiliation: LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy.
authors.forename: Simona
authors.initials: S
authors.lastname: Scaffidi Abbate
authors.affiliation: LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Cataldini
authors.affiliation: LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Gori
authors.affiliation: LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Lucioni
authors.affiliation: LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy.|Istituto Nazionale di Ottica, CNR, 50019 Sesto Fiorentino, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Inguscio
authors.affiliation: LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy.|Istituto Nazionale di Ottica, CNR, 50019 Sesto Fiorentino, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Modugno
authors.affiliation: LENS and Dipartimento di Fisica e Astronomia, Università di Firenze, 50019 Sesto Fiorentino, Italy.|Istituto Nazionale di Ottica, CNR, 50019 Sesto Fiorentino, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: D'Errico