Scientific Results

Discrete breathers and negative-temperature states

Year: 2013

Authors: Iubini S., Franzosi R., Livi R., Oppo G.-L., Politi A.

Autors Affiliation: Dipartimento di Fisica e Astronomia—CSDC, Università di Firenze and INFN Sezione di Firenze, Via Sansone 1, I-50019 Sesto Fiorentino, Italy; CNR—Istituto dei Sistemi Complessi, Via Madonna del Piano 10, I-50019 Sesto Fiorentino, Italy; ICS, SUPA and Department of Physics, University of Strathclyde,107 Rottenrow, Glasgow G4 ONG, UK; ICSMB, SUPA and Department of Physics, University of Aberdeen, Aberdeen AB24 3UE, UK; QSTAR, Largo Enrico Fermi 2, I-50125 Firenze, Italy

Abstract: We explore the statistical behaviour of the discrete nonlinear Schrodinger equation as a test bed for the observation of negative-temperature (i.e. above infinite temperature) states in Bose-Einstein condensates in optical lattices and arrays of optical waveguides. By monitoring the microcanonical temperature, we show that there exists a parameter region where the system evolves towards a state characterized by a finite density of discrete breathers and a negative temperature. Such a state persists over very long (astronomical) times since the convergence to equilibrium becomes increasingly slower as a consequence of a coarsening process. We also discuss two possible mechanisms for the generation of negative-temperature states in experimental setups, namely, the introduction of boundary dissipations and the free expansion of wavepackets initially in equilibrium at a positive temperature.


Volume: 15      Pages from: 023032  to: 023032

More Information: RL acknowledges financial support from the Italian MIUR-PRIN project no. 20083C8XFZ and G-LO from the EU Commission FET Open Grant HIDEAS. We acknowledge financial support from EPSRC grant EP/I006826/1. SI and AP thank T Carletti for useful discussions on the implementation of symplectic integrators.
KeyWords: Bose-Einstein condensates; Boundary dissipations; Coarsening process; Convergence to equilibrium; Dinger equation; Discrete breather; Finite density; Microcanonical temperature; Negative temperatures; Parameter regions; Possible mechanisms, Bose-Einstein condensation; Equipment testing, Nonlinear equations
DOI: 10.1088/1367-2630/15/2/023032

Citations: 36
data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2022-01-16
References taken from IsiWeb of Knowledge: (subscribers only)
Connecting to view paper tab on IsiWeb: Click here
Connecting to view citations from IsiWeb: Click here

This site uses cookies. If you decide to continue browsing we consider that you accept their use. For more information about cookies and how to delete them please read our Info Policy on cookies use.
Read more