Gauge/Gravity Duality 2015

Session

Morning session

Apr 15, 2015, 9:00 AM

The Galileo Galilei Institute for Theoretical Physics (GGI)

53. Holographic Quantum Hall Ferromagnetism

Charlotte Kristjansen

4/15/15, 9:00 AM

56. Is the composite fermion a Dirac particle?

Dam Thanh Son

4/15/15, 9:40 AM

The theory of the fractional quantum Hall effect is based on the notion of the composite fermion, which is the low-energy quasiparticle for filling factor close to 1/2. I will show that the particle-hole symmetry of the half-filled Landau level implies that the composite fermion is a Dirac particle, characterized by a Berry phase of $pi$ around the Fermi surface. Physical consequences are discussed.

57. Holographic graphene bilayers

Gianluca Grignani

4/15/15, 10:50 AM

The possibility of inter-layer exciton condensation in holographic models of a strongly coupled double monolayer Dirac semi-metal are studied in detail. It is showed that, when the charge densities on the layers are exactly balanced so that, at weak coupling, the Fermi surfaces of electrons in one monolayer and holes in the other monolayer would be perfectly nested, inter-layer condensates can...

59. Monopoles and magnetic oscillations in holographic liquids

Valentina Giangreco Puletti

4/15/15, 11:20 AM

We study monopoles and the role of magnetic field in holographic models of compressible phases of quantum matter, both from a bottom-up and a top-down approach. The former extends previous electron star models to include a magnetic field at finite temperature, while the latter is based on D-brane constructions. I will present these models and their most interesting features, such as quantum...

62. Diffusion and incoherence

Daniele Musso

4/15/15, 11:50 AM

Charge and heat diffusion are essential handles to grasp the transport of strongly coupled systems where momentum is quickly dissipated. Holography without momentum conservation allows to compute the diffusion constants and explore the formulation of (possibly general) bounds in analogy with the eta/s bound. The talk focuses on the description of the diffusion constants computation and...

64. Semiholography, conductivity and Ward identities

Umut Gursoy

4/15/15, 12:20 PM

In semiholography, a strongly-coupled conformal field theory with a holographic dual is coupled to another theory that is weakly interacting. We show how semiholography is set up in accordance with the Ward identities of the total theory. As an example, we charge fermions in the total theory under a U(1) gauge field, and compute the total electrical conductivity and Ward identity corresponding...