The interplay between universal quantum correlations and specific mechanisms, involving short-lived magnetic clusters, in HTSC's

Abstract

Recently the theory of dilation analyticity (or the Complex Scaling Method, CSM) was applied, for the first time, to the domain of quantum statistics far from equilibrium. As a result a novel kind of universal coherence has been revealed from first principles. The corresponding irreducible structures, called coherent-dissipative structures, represent a short-lived and spatially restricted cooperative phenomenon. The crucial points of the theory are stressed and similarities as well as differences with (1) the BCS-states of superconductivity and (2) the dissipative structures of the Brussels school are pointed out. Here the general theory is applied to quantum correlations in high-Tc superconductors and the large energy gap compared to standard BCS results, as well as the recently found universal linear relation between Tc and the carrier density/effective mass, will be discussed. The conditions for these correlations to occur in the Cu-O based HSTC's are discussed in terms of a specific model for the superconductivity mechanism, involving the motion of charge carriers surrounded by a cluster of frustrated spins (created by the introduction of O-associated holes in an otherwise antiferromagnetic ground state). The motion and lifetime of these magnetic clusters are limited by the "magnetic wall" conditions (including exchange and anisotropy terms). An effective mass as well as a thermal deBroglie wavelength can be estimated for these objects. By referring back to the general theory it is possible to check the consistency of the description and discuss the conditions for short and long range coherence in the motion of the carriers.