Transport Properties of Strong-Coupled Superconductors.

Marcin Mierzejewski, J. Zieliński, P. Entel

Andrea Amoretti, Martina Meinero, Daniel K. Brattan +7 more

High-temperature superconductors are strongly coupled systems which present a complicated phase diagram with many coexisting phases. This makes it difficult to understand the mechanism which generates their singular transport properties. Hydrodynamics, which mostly relies on the symmetries of the system without referring to any specific microscopic mechanism, constitutes a promising framework to analyze these materials. In this paper we show that, in the strange metal phase of the cuprates, a whole set of transport coefficients are described by a universal hydrodynamic framework once one accounts for the effects of quantum critical charge-density waves. We corroborate our theoretical prediction by measuring the DC transport properties of Bi-2201 close to optimal doping, proving the validity of our approach. Our argument can be used as a consistency check to understand the universality class governing the behavior of high-temperature cuprate superconductors.

Kevin Michael Ryan

A. Komnik

We investigate the transport properties of different realizations of one-dimensional quantum wires coupled to a number of external electrodes in terms of the full counting statistics. Focusing on the setups in which edge states of Majorana type are realizable, we analyze the effects of the exchange of charge carriers with the environment. We find a very strong suppression of the nonlocal current correlations, which decay exponentially with the coupling strength and the wire length. Local properties such as transport currents and current correlations measured at individual contacts between the wire and external electrodes turn out to develop an asymmetry when they are energy resolved. We provide a number of exact analytical solutions and discuss experimental implications of our findings.

Brian D. Josephson

Qijin Chen, Ioan Kosztin, Kathryn Levin

In this paper we present predictions for thermodynamic and transport properties of a BCS to Bose-Einstein crossover theory, below T(c), which satisfies the reasonable constraints that it yields (i) the Leggett ground state and (ii) BCS theory at weak coupling and all temperatures T. The nature of the strong coupling limit is inferred, along with the behavior of the Knight shift, superfluid density, and specific heat. Comparisons with existing data on short coherence length superconductors, such as organic and high T(c) systems, are presented, which provide some support for the present picture.