The ABJM Theory at Finite Density: Symmetry Breaking, Charge Oscillations, and Fermion Response
OKC/Nordita High-Energy Physics Theory seminar
Monday 28 November 2016
to 14:15 at
Nordita East Building
Christopher Rosen (Imperial)
The gauge/gravity correspondence has been celebrated by some as a promising avenue towards an understanding of the possible phases of strongly interacting matter. By now this avenue has been well trodden, and a variety of examples of novel condensed matter phenomena have been realized holographically. Appealing to both efficacy and ease, many of these examples appeared first in gravitational models that do not descend from any known consistent string or supergravity theory. Thus it is natural to wonder to what extent such results are actually teaching us about the physics of strongly coupled bosons and fermions.
We investigate some of these phenomena by appealing directly to maximal gauged supergravity, focusing for the purposes of presentation on the N=8 theory in 3+1 dimensions. Under appropriate circumstances, this theory holographically describes ABJM theory in 2+1 dimensions, and serves as an excellent testing ground for many surprising holographic results. In particular, we will discuss features of spectral functions of fermionic operators in the ABJM theory, evaluated in states with and without broken global symmetries. Such spectral functions can be used to diagnose where the fermionic degrees of freedom reside in a finite density phase, and how they disperse. We will also attempt to reconcile some results of these fermionic correlation functions with non-analyticities in the static susceptibility, which can lead to oscillations of the charge density in the same state.