Spontaneous PT symmetry breaking of a ferromagnetic superfluid in a gradient field

Thomas Vanderbruggen (1) , Silvana Palacios (1) , Simon Coop (1) , Natali Martinez de Escobar (1) , Morgan Mitchell (2, 1)

1 ICFO - Institut de Ciencies Fotoniques [Castelldefels]
2 ICREA - Institució Catalana de Recerca i Estudis Avançats = Catalan Institution for Research and Advanced Studies

We consider the interaction of a ferromagnetic spinor Bose-Einstein condensate with a magnetic field gradient. The magnetic field gradient realizes a spin-position coupling that explicitly breaks time-reversal symmetry T and space parity P, but preserves the combined PT symmetry. We observe using numerical simulations, a first-order phase transition spontaneously breaking this re-maining symmetry. The transition to a low-gradient phase, in which gradient effects are frozen out by the ferromagnetic interaction, suggests the possibility of high-coherence magnetic sensors unaffected by gradient dephasing.

Domaines: Gaz Quantiques [cond-mat.quant-gas]; Physique Quantique [quant-ph]; Physique Atomique [physics.atom-ph]; Optique / photonique

Thomas Vanderbruggen, Silvana Palacios, Simon Coop, Natali Martinez de Escobar, Morgan Mitchell. Spontaneous PT symmetry breaking of a ferromagnetic superfluid in a gradient field. 2015. ⟨hal-01110100v2⟩