Superconductivity through Quantum Critical Fluctuations in the ...

current operators in the link (p, p + 1). Note that this isthe lattice equivalent of transforms as (r ⇥ p), where rand p are the position and momentum vectors along thelinks of the unit-cell.Quantum-Critical Fluctuations : Aji-cmv PRL(07); PR-B(09)OCuThe critical modes are the fluctuations among the fourconfigurations of observed order, i.e., among the fourorientations of the order parameter vector L.(a)(b)FIG. 1: a: The four domains of the circulating current phaseare shown. They may be specified by the four orientationsof a vector shown in red. b: Schematic representation of thecurrent due to the operator C(j i )In the fluctuations regime the vector L has the same criticalQuantum Ashkin-Teller model: In the quantum fluctuationregime, fluctuating flux and current patterns overany region of space and time are generated by the elementaryprocess of fluctuations between the four config-spectra as a model with a continuous rotations of L, i.e. thequantum- XY model.⇧ 0 maywhereof thecell.mate fr0.1µ B pCouppling ofa collecmatrix|⇥ i ± ⇤tering mtime-rethe conin detaas theonly useratorsthe operotatiorotatesator inP (1234