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The loop-current state discovered in under-doped cuprates is characterized by a vector ${bf Omega}$ which has four possible orientations which correspond to different domains of order in a perfect sample. Since translational symmetry remains unchanged in the pure limit, no gap occurs at the chemical potential. On the other hand Scanning tunneling microscopy (STM) has revealed that the magnitude of the pseudo-gap in under-doped cuprates varies spatially and is correlated with disorder. For disorder coupling also to the direction of ${bf Omega}$, there can only be a finite temperature dependent static correlation length for the loop-current state below the ordering temperature of the pure problem. It is shown that, in this situation, singular forward scattering of fermions for large correlation lengths induces an angle dependent pseudo-gap in the single-particle spectral function near the chemical potential. The peaks in the spectral function at the fermi-vectors are away from the chemical potential proportionally to the square of the average loop order parameter measurable by polarized neutron scattering. This result is tested. Due to the finite correlation length there always exist low frequency excitations at long wavelength at all temperatures in the ordered phase. Such fluctuations motionally average over the shifts in frequencies of local probes such as NMR and muon resonance expected for a truly static order.
Within the microscopic theory of the normal-state pseudogap state, the doping and temperature dependence of the charge dynamics in doped cuprates is studied in the whole doping range from the underdoped to heavily overdoped. The conductivity spectrum
The proposed loop-current order in cuprates cannot give the observed pseudogap and the Fermi-arcs because it preserves translation symmetry. A modification to a periodic arrangement of the four possible orientations of the order parameter with a larg
We show that a one-dimensional quantum wire with as few as 2 channels of interacting fermions can host metallic states of matter that are stable against all perturbations up to $q^text{th}$-order in fermion creation/annihilation operators for any fix
We study the quantum transition from an antiferromagnet to a superconductor in a model for electron- and hole-doped cuprates by means of a variational cluster perturbation theory approach. In both cases, our results suggest a tendency towards phase s
The conjecture made recently by the group at Sherbrooke, that their observed anomalous thermal Hall effect in the pseudo-gap phase in the cuprates is due to phonons, is supported on the basis of an earlier result that the observed loop-current order