1. Scuola Internazionale Superiore di Studi Avanzati (SISSA), Via Bonomea 265, I-34136 Trieste, Italy.
2. Pitaevskii BEC Center, Department of Physics, University of Trento, Via Sommarive 14, I-38123 Povo, Trento, Italy.
3. INFN-TIFPA, Via Sommarive 14, I-38123 Povo, Trento, Italy.
4. Department of Physics and BiQuTe Center, University of Milano-Bicocca, Piazza della Scienza 3, I-20126 Milan, Italy.
5. Department of Physics, University of Trento, Via Sommarive 14, I-38123 Povo, Trento, Italy.