| February 11, 12:15
Dissipative eff ects in ultrathin superconducting wires coupled to a di ffusive metals
Ultrathin superconducting wires (UTSCW) fabricated recently by the means of novel experimental techniques have been the subject of intense experimental and theoretical research. When the diameter is smaller than the coherence length of the bulk superconductor, these systems are e ffectively one-dimensional (1D), since the order parameter can only vary along the parallel direction. Interestingly, the theory predicts the vanishing of long-range order (LRO) due to strong quantum critical fluctuations, a fact that allows the use of UTSCW to address fundamental questions in Quantum Critical Phenomena. In this work, we focus on UTSCW under the e ffect of environment-induced dissipation. Presumably, this is a realistic situation in many experimental setups. Remarkably, we show that a weak coupling to a di ffusive metallic fi lm can reinforce superconductivity in the wire through the quench of order-parameter fl uctuations. We obtain the critical points and phases of the system at T=0, and in particular, we predict a quantum phase transition towards a superconducting phase with LRO as a function of the wire's superconducting sti ffness and coupling parameter to the metal. We also discuss implications for experiments.
Alejandro Lobos, University of Geneva
Seminar Room THP
Contact: not specified