Talk - Gabriele Ferrari: Spontaneous creation, dynamics and interaction of vortices in Bose-Einstein condensates
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Spontaneous creation, dynamics and interaction of vortices in Bose-Einstein condensates
INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy
When a system crosses a second-order phase transition on a finite timescale spontaneous symmetry breaking can cause the development of domains with independent order parameters, which then grow and approach each other creating boundary defects. This is known as Kibble-Zurek mechanism [1,2]. Originally introduced in cosmology, it applies both to classical and quantum phase transitions, in a wide variety of physical systems. We will discuss the conditions for the spontaneous creation of defects in Bose-Einstein condensates via the Kibble-Zurek mechanism and we will show that its typical signatures, such as the power-law scaling of the defects density on the quench time, can be recovered . These defects are identified as quantum vortices orthogonally oriented to the symmetry axis of the confining trap, as expected for solitonic vortices in a highly anisotropic condensate .
The real-time dynamics of vortices can be followed in the condensate using a weakly destructive stroboscopic technique, hence allowing for an accurate comparison between experimental data and theoretical models of dynamics of vortices in superfluids . In configurations with two vortex lines simultaneously present in the condensate signatures of interaction are observed in the form reconnections, rebounds and annihilation . This opens a new perspective to studies in the domain of quantum turbulence.
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