Aspects of the holographic study of flavor dynamics.

摘要

This thesis is dedicated to the holographic study of flavor dynamics. The technique employed is a D7-brane probing of various D3-brane backgrounds. The first topic covered studies the influence of an external magnetic field on a flavored large N Yang-Mills theory. The theory exhibits spontaneous chiral symmetry breaking. A discrete self-similar structure of the spontaneous symmetry breaking mechanism is observed, this structure is reflected in the meson spectrum. The meson spectrum exhibits Zeeman splitting and characteristic GMOR relation. The second topic examines thermal properties of the dual gauge theory. The study reveals a first order phase transition associated to the melting of mesons. The critical ratio of the bare quark mass and temperature at which the transition happens is computed. The third topic studies the phase structure of the finite temperature dual gauge theory in the presence of magnetic field. A phase diagram of the theory is obtained. The temperature restores the chiral symmetry while the magnetic field has a freezing effect on the meson melting. The meson spectrum exhibits Zeeman splitting and characteristic GMOR relation. Thermodynamic quantities such as free energy, entropy, and magnetization are computed. The fourth topic studies the addition of an external electric field. The observed effect is dissociation of the bound quarks, favoring the meson melting. For sufficiently strong electric fields a global electric current is induced. Thus, the dissociation of mesons corresponds to an insulator/conductor phase transition. This transition persists at vanishing temperature. The fifth topic studies the addition of an R-charge chemical potential via brane probing of the spinning D3-brane geometry. The corresponding phase diagram is obtained. The chemical potential favors the dissociation of mesons. For high chemical potential, a finite phase difference between the bare quark mass and the quark condensate is induced. The last topic explores universal properties of gauge theories dual to the Dp/Dq system. A universal discrete self-similar behavior associated to the insulator/conductor phase transition is observed and the corresponding scaling exponents are computed. A similarity between the electric field and R-charge chemical potential cases is discussed.