Theory of the Quantum Critical Fluctuations in Cuprates

TL;DR

This paper develops a quantum Ashkin-Teller model to describe critical fluctuations in cuprates, linking symmetry-breaking order parameters to marginal Fermi-liquid behavior and providing a framework applicable to other quantum phase transitions.

Contribution

It introduces a quantum generalization of the Ashkin-Teller model with kinetic energy and dissipation, elucidating the nature of quantum critical fluctuations in cuprates.

Findings

Quantum critical fluctuations match the form proposed in 1989.

Correlations are governed by two sets of charges with distinct temporal and spatial interactions.

The model and methods are applicable to various quantum phase transitions.

Abstract

The statistical mechanics of the time-reversal and inversion symmetry breaking order parameter, possibly observed in the pseudogap region of the phase diagram of the Cuprates, can be represented by the Ashkin-Teller model. We add kinetic energy and dissipation to the model for a quantum generalization and show that the correlations are determined by two sets of charges, one interacting locally in time and logarithmically in space and the other locally in space and logarithmically in time. The quantum critical fluctuations are derived and shown to be of the form postulated in 1989 to give the marginal fermi-liquid properties. The model solved and the methods devised are likely to be of interest also to other quantum phase transitions.