Dynamical response near quantum critical points

Understand

We study high frequency response functions, notably the optical conductivity, in the vicinity of quantum critical points (QCPs) by allowing for both detuning from the critical coupling and finite temperature.

• We consider general dimensions and dynamical exponents.
• This leads to a unified understanding of sum rules.
• In systems with emergent Lorentz invariance, powerful methods from conformal field theory allow us to fix the high frequency response in terms of universal coefficients.