Triangle Seminars
Wednesday, 14 Apr 2010
Holographic QCD
Nick Evans
(Southampton)
Abstract:
The D3/D7 system provides a simple holographic description of a strongly coupled gauge theory with quarks. By introducing a range of deformations of the AdS5 space a variety of familair phenomena in gauge theory can be investigated quantitatively. These include a running gauge coupling, temperature, chemical potential, and magnetic fields leading to confinement and chiral symmetry breaking, as well as bound mesons and their melting. I'll illustrate these phenomena with examples and derive the phase diagram of a chiral symmetry breaking theory. Finally I shall discuss how hadronization can be modelled in such set ups and propose that rho meson emission should be described by a simple EM radiation problem.
The D3/D7 system provides a simple holographic description of a strongly coupled gauge theory with quarks. By introducing a range of deformations of the AdS5 space a variety of familair phenomena in gauge theory can be investigated quantitatively. These include a running gauge coupling, temperature, chemical potential, and magnetic fields leading to confinement and chiral symmetry breaking, as well as bound mesons and their melting. I'll illustrate these phenomena with examples and derive the phase diagram of a chiral symmetry breaking theory. Finally I shall discuss how hadronization can be modelled in such set ups and propose that rho meson emission should be described by a simple EM radiation problem.
Posted by: QMW
Thursday, 15 Apr 2010
Covariant vertex operators for cosmic strings
Dimitri Skliros
(Sussex)
Abstract:
I will discuss the first construction of coherent states (and other
massive states with arbitrarily exited harmonics) in the covariant
formalism for both open and closed strings with applications to cosmic
strings in mind. Furthermore, I provide an explicit map that relates
three different descriptions of cosmic strings: classical strings,
lightcone gauge quantum states and covariant vertex operators,
highlighting the virtues and shortcomings of each. I will then go on to
discuss applications and future directions: string amplitude computations
with such vertices and in particular decays of (the phenomenologically
promising) cosmic strings with non-degenerate cusps in a framework that
naturally incorporates the effects of gravitational backreaction.
I will discuss the first construction of coherent states (and other
massive states with arbitrarily exited harmonics) in the covariant
formalism for both open and closed strings with applications to cosmic
strings in mind. Furthermore, I provide an explicit map that relates
three different descriptions of cosmic strings: classical strings,
lightcone gauge quantum states and covariant vertex operators,
highlighting the virtues and shortcomings of each. I will then go on to
discuss applications and future directions: string amplitude computations
with such vertices and in particular decays of (the phenomenologically
promising) cosmic strings with non-degenerate cusps in a framework that
naturally incorporates the effects of gravitational backreaction.
Posted by: QMW