1. Quantum phase transitions with parity-symmetry breaking and hysteresis
- Author
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Trenkwalder, A., Spagnolli, G., Semeghini, Giulia, Coop, S., Landini, M., Castilho, P., Pezzè, L., Modugno, Giovanni, Inguscio, Massimo, Smerzi, M. Fattori, A. Smerzi, and Fattori, M.
- Subjects
Transizioni di fase quantistiche ,Condensed Matter::Quantum Gases ,Quantum phase transition ,Physics ,Condensed matter physics ,Condensed Matter::Other ,Cavity quantum electrodynamics ,General Physics and Astronomy ,Quantum simulator ,Parity (physics) ,Quantum phases ,Condensed Matter::Mesoscopic Systems and Quantum Hall Effect ,01 natural sciences ,Article ,010305 fluids & plasmas ,FÍSICA ATÔMICA ,Quantum mechanics ,Quantum critical point ,0103 physical sciences ,Principal quantum number ,Bose-Einstein condensate ,double-well ,gas ,Physics::Atomic Physics ,Symmetry breaking ,010306 general physics - Abstract
Symmetry-breaking quantum phase transitions play a key role in several condensed matter, cosmology and nuclear physics theoretical models(1-3). Its observation in real systems is often hampered by finite temperatures and limited control of the system parameters. In this work we report, for the first time, the experimental observation of the full quantum phase diagram across a transition where the spatial parity symmetry is broken. Our system consists of an ultracold gas with tunable attractive interactions trapped in a spatially symmetric double-well potential. At a critical value of the interaction strength, we observe a continuous quantum phase transition where the gas spontaneously localizes in one well or the other, thus breaking the underlying symmetry of the system. Furthermore, we show the robustness of the asymmetric state against controlled energy mismatch between the two wells. This is the result of hysteresis associated with an additional discontinuous quantum phase transition that we fully characterize. Our results pave the way to the study of quantum critical phenomena at finite temperature(4), the investigation of macroscopic quantum tunnelling of the order parameter in the hysteretic regime and the production of strongly quantum entangled states at critical points(5). more...
- Published
- 2016
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