Dissipation and fluctuations in elongated bosonic Josephson junctions

Year: 2021

Authors: Binanti F., Furutani K., Salasnich L.

Autors Affiliation: Dipartimento di Fisica e Astronomia, Galileo Galilei, Universita di Padova, Via Marzolo 8, Padova, 35131, Italy; INFN, Sezione di Padova, Via Marzolo 8, Padova, 35131, Italy; Padua Quantum Technologies Research Center, Universita di Padova, Via Gradenigo 6/b, Padova, 35131, Italy; CNR, INO, Via Nello Carrara 1, Sesto Fiorentino, 50019, Italy

Abstract: We investigate the dynamics of bosonic atoms in elongated Josephson junctions. We find that these systems are characterized by an intrinsic coupling between the Josephson mode of macroscopic quantum tunneling and the sound modes. This coupling of Josephson and sound modes gives rise to a damped and stochastic Langevin dynamics for the Josephson degree of freedom. From a microscopic Lagrangian, we deduce and investigate the damping coefficient and the stochastic noise, which includes thermal and quantum fluctuations. Finally, we study the time evolution of relative-phase and population-imbalance fluctuations of the Josephson mode and their oscillating thermalization to equilibrium.


Volume: 103 (6)      Pages from: 063309-1  to: 063309-8

More Information: The authors acknowledge Anna Minguzzi and Juan Polo for useful clarifications. L.S. thanks Andrea Tononi and Flavio Toigo for enlightening discussions. K.F. was supported by a Ph.D. fellowship from the Fondazione Cariparo.
KeyWords: quantum-noise
DOI: 10.1103/PhysRevA.103.063309