Much of our understanding of vibrational excitations and elasticity is based upon analysis of
frames consisting of sites connected by bonds occupied by central-force springs, the stability …

The presence of optical polarization anisotropies, such as Faraday or Kerr effects, linear
birefringence, and magnetoelectric birefringence are evidence for broken symmetry states of …

The anomalous transport and thermodynamic properties in the quantum-critical region, in
the cuprates, and in the quasi-two dimensional Fe-based superconductors and heavy …

Optical spectroscopies are most often used to probe dynamical correlations in materials, but
they are also a probe of symmetry. Polarization anisotropies are of course sensitive to …

There is evidence that the pseudogap phase in the cuprates breaks time-reversal symmetry.
Here we show that pair density wave (PDW) states give rise to a translational invariant …

High resolution polar Kerr effect measurements were performed on La 1.875 Ba 0.125 CuO
4 single crystals revealing that a finite Kerr signal is measured below an onset temperature …

We review the recent developments in the field of cuprate superconductors with special
focus on the recently observed charge order in the underdoped compounds. We introduce …

This paper exposes in a detailed manner the recent findings about the SU (2) scenario for
the underdoped phase of the cuprate superconductors. The SU (2) symmetry is formulated …

The paper briefly surveys theoretical models for the polar Kerr effect (PKE) and time-reversal
symmetry breaking in the pseudogap phase of cuprate superconductors. By elimination, the …

We propose a novel chiral order parameter to explain the unusual polar Kerr effect in
underdoped cuprates. It is based on the loop-current model by Varma, which is …