Quantum phase transitions with dynamical flavors

TL;DR

This paper investigates quantum phase transitions in a holographic model with dynamical flavors, revealing a change in brane embedding topology and characterizing the order and critical behavior of the transition.

Contribution

It demonstrates how dynamical quarks influence the order and nature of quantum phase transitions in the ABJM holographic setup, including critical exponents and scaling behavior.

Findings

Second order transition in unflavored case at zero charge density

First order transition with dynamical quarks at non-zero charge density

Discontinuities in physical quantities depend on the number of unquenched quarks

Abstract

We study the properties of a D6-brane probe in the ABJM background with smeared massless dynamical quarks in the Veneziano limit. Working at zero temperature and non-vanishing charge density, we show that the system undergoes a quantum phase transition in which the topology of the brane embedding changes from a black hole to a Minkowski embedding. In the unflavored background the phase transition is of second order and takes place when the charge density vanishes. We determine the corresponding critical exponents and show that the scaling behavior near the quantum critical point has multiplicative logarithmic corrections. In the background with dynamical quarks the phase transition is of first order and occurs at non-zero charge density. In this case we compute the discontinuity of several physical quantities as functions of the number $N_f$ of unquenched quarks of the background.