Quantum critical responses via holographic models and conformal perturbation theory

          @misc{ pirsa_PIRSA:17060018,
            doi = {10.48660/17060018},
            url = {https://pirsa.org/17060018},
            author = {Sierens, Todd},
            keywords = {Other},
            language = {en},
            title = {Quantum critical responses via holographic models and conformal perturbation theory},
            publisher = {Perimeter Institute},
            year = {2017},
            month = {jun},
            note = {PIRSA:17060018 see, \url{https://pirsa.org}}
          }
          

Abstract

We investigate response functions near quantum critical points, allowing for finite temperature and a mild deformation by a relevant scalar. When the quantum critical point is described by a conformal field theory, we use conformal perturbation theory and holography to determine the two leading corrections to the scalar two-point function and to the conductivity. We build a bridge between the couplings fixed by conformal symmetry with the interaction couplings in the gravity theory. We construct a minimal holographic model that allows us to numerically obtain the response functions at all frequencies, independently confirming the corrections to the high-frequency response functions. In addition to probing the physics of the ultraviolet, the holographic model probes the physics of the infrared giving us qualitative insight into new physics scalings.