Universiteit Leiden

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Strings and AdS/CFT at finite density

Promotores: J. Zaanen, A. Parnachev

M. Goykhman
24 juni 2014
Thesis in Leiden Repository

This thesis is devoted to applications of string theoretic methods of holography to strongly coupled phases of quantum field theories. In chapter 2 we consider a finite-density system of quarks, realized holographically by a probe brane in Anti-de Sitter space, with a non-trivial gauge field background on its world-volume. We reproduce the holographic zero-sound in the longitudinal channel of the current-current correlation function. We generalize this result to the case of a non-vanishing background magnetic field. This field leads to a gap in the zero-sound mode, which scales proportionally to the magnitude of the field when it is small. In chapter 3 we study the classical dynamics of the tachyon field in an AdS background described by the tachyon-Dirac-Born-Infeld action. By considering a black hole in AdS space and switching on a non-vanishing background gauge field we obtained a holographic model of conformal symmetry breaking in a strongly coupled system at finite temperature and charge density. In chapter 4 we provide the exact string theoretic description of a quantum field theory at finite temperature and charge density.