48 research outputs found
Superconductors with Topological Order and their Realization in Josephson Junction Arrays
We will describe a new superconductivity mechanism, proposed by the authors
in [1], which is based on a topologically ordered ground state rather than on
the usual Landau mechanism of spontaneous symmetry breaking. Contrary to anyon
superconductivity it works in any dimension and it preserves P-and
T-invariance. In particular we will discuss the low-energy effective field
theory, what would be the Landau-Ginzburg formulation for conventional
superconductors.Comment: invited review, to appear in "Superconductivity Research Advances",
Nova Publishers, 32 page
Symmetry Aspects and Finite-Size Scaling of Quantum Hall Fluids
The exactness and universality observed in the quantum Hall effect suggests
the existence of a symmetry principle underlying Laughlin's theory. We review
the role played by the infinite and conformal algebras as
dynamical symmetries of incompressible quantum fluids and show how they predict
universal finite-size effects in the excitation spectrum.Comment: 15 pages, CERN-TH-6784/93, LateX fil
Gauge Topological Nature of the Superconductor-Insulator Transition
It has long been believed that, at absolute zero, electrons can form only one
quantum coherent state, a superconductor. Yet, several two dimensional
superconducting systems were found to harbor the superinsulating state with
infinite resistance, a mirror image of superconductivity, and a metallic state
often referred to as Bose metal, characterized by finite longitudinal and
vanishing Hall resistances. The nature of these novel and mysterious quantum
coherent states is the subject of intense study.Here, we propose a topological
gauge description of the superconductor-insulator transition (SIT) that enables
us to identify the underlying mechanism of superinsulation as Polyakov's linear
confinement of Cooper pairs via instantons. We find a criterion defining
conditions for either a direct SIT or for the SIT via the intermediate Bose
metal and demonstrate that this Bose metal phase is a Mott topological
insulator in which the Cooper pair-vortex liquid is frozen by Aharonov-Bohm
interactions