4,291 research outputs found
Observable NMR signal from circulating current order in YBCO
Assuming, as suggested by recent neutron scattering experiments, that a
broken symmetry state with orbital current order occurs in the pseudo-gap phase
of the cuprate superconductors, we show that there must be associated
equilibrium magnetic fields at various atomic sites in the unit cell, which
should be detectable by NMR experiments
An advanced Jones calculus for the classification of periodic metamaterials
By relying on an advanced Jones calculus we analyze the polarization
properties of light upon propagation through metamaterial slabs in a
comprehensive manner. Based on symmetry considerations, we show that all
periodic metamaterials may be divided into five different classes only. It is
shown that each class differently affects the polarization of the transmitted
light and sustains different eigenmodes. We show how to deduce these five
classes from symmetry considerations and provide a simple algorithm that can be
applied to decide by measuring transmitted intensities to which class a given
metamaterial is belonging to only
Bloch cavity solitons in nonlinear resonators with intracavity photonic crystals
We predict a novel type of cavity solitons, Bloch cavity solitons, existing in nonlinear resonators with
the refractive index modulated in both longitudinal and transverse directions and for both focusing (at
normal diffraction) and defocusing (at anomalous diffraction) nonlinearities. We develop a modified
mean-field theory and analyze the properties of these novel cavity solitons demonstrating, in particular,
their substantial narrowing in the zero-diffraction regime
Superconductivity and non-Fermi liquid behavior near a nematic quantum critical point
Using determinantal quantum Monte Carlo, we compute the properties of a
lattice model with spin itinerant electrons tuned through a quantum
phase transition to an Ising nematic phase. The nematic fluctuations induce
superconductivity with a broad dome in the superconducting enclosing the
nematic quantum critical point. For temperatures above , we see strikingly
non-Fermi liquid behavior, including a "nodal - anti nodal dichotomy"
reminiscent of that seen in several transition metal oxides. In addition, the
critical fluctuations have a strong effect on the low frequency optical
conductivity, resulting in behavior consistent with "bad metal" phenomenology
Spontaneous parity breaking of graphene in the quantum Hall regime
We propose that the inversion symmetry of the graphene honeycomb lattice is
spontaneously broken via a magnetic field dependent Peierls distortion. This
leads to valley splitting of the Landau level but not of the other Landau
levels. Compared to quantum Hall valley ferromagnetism recently discussed in
the literature, lattice distortion provides an alternative explanation to all
the currently observed quantum Hall plateaus in graphene.Comment: 4 pages, to appear in Phys. Rev. Let
Magneto-Roton Modes of the Ultra Quantum Crystal: Numerical Study
The Field Induced Spin Density Wave phases observed in quasi-one-dimensional
conductors of the Bechgaard salts family under magnetic field exhibit both Spin
Density Wave order and a Quantized Hall Effect, which may exhibit sign
reversals. The original nature of the condensed phases is evidenced by the
collective mode spectrum. Besides the Goldstone modes, a quasi periodic
structure of Magneto-Roton modes, predicted to exist for a monotonic sequence
of Hall Quantum numbers, is confirmed, and a second mode is shown to exist
within the single particle gap. We present numerical estimates of the
Magneto-Roton mode energies in a generic case of the monotonic sequence. The
mass anisotropy of the collective mode is calculated. We show how differently
the MR spectrum evolves with magnetic field at low and high fields. The
collective mode spectrum should have specific features, in the sign reversed
"Ribault Phase", as compared to modes of the majority sign phases. We
investigate numerically the collective mode in the Ribault Phase.Comment: this paper incorporates material contained in a previous cond-mat
preprint cond-mat/9709210, but cannot be described as a replaced version,
because it contains a significant amount of new material dealing with the
instability line and with the topic of Ribault Phases. It contains 13 figures
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