Speaker: Hugo Terças (Departamento de Física, IST).

Abstract: Dark solitons, the depressions formed in quantum fluids resulting from the competition between dispersion and nonlinearity, are extremely stable objects. In this talk, we discuss how to make use of dark solitons in quasi-one-dimensional Bose-Einstein condensates to produce two-level systems (qubits). We calculate the soliton spectrum and the conditions for a qubit to exist. We also compute the coupling between phonons (quantum excitations) and solitons and investigate the emission rate of the qubit in that case. Remarkably, the qubit lifetime is estimated to be of the order of hundreds of milliseconds, being only limited by the dark-soliton “death” through quantum evaporation. We also present a protocol for the spontaneous generation of phononic entanglement in such solitary qubits.

Short bio: Hugo Terças is an expert in quantum matter, with emphasis in quantum fluids and plasmas. His current research focuses on Bose-Einstein condensates and quantum (graphene) plasmas, with applications ranging from fundamental physics to quantum information. Hugo has an international scientific career, having been hired in competitive projects (Marie Curie ITN and ERC synergy grants) in top-ranked institutes in Europe. After being awarded the competitive IF-FCT grant, he is now a co-leader of the quantum plasma team at IPFN, where he supervises numerous students and executes the important european project (PhoQus), in consortium with many renowned colleagues abroad. He is the author of 2 books, 40 peer-reviewed publications in top-ranked journals, while being an active referee of the APS journals. Hugo is also delivering courses at both graduate and undergraduate levels, in the quality of Invited Assistant Professor in the physics department of Instituto Superior Técnico.