29 research outputs found
Dissipative Charged Fluid in a Magnetic Field
We study the collective excitations in a dissipative charged fluid at zero
chemical potential when an external magnetic field is present. While in the
absence of magnetic field, four collective excitations appear in the fluid, we
find five hydrodynamic modes in presence of magnetic field. This implies that
the magnetic field splits the degeneracy between the transverse shear modes.
Using linear response theory, we then compute the retarded response functions.
In particular, it turns out that the correlation between charge and the energy
fluctuations will no longer vanish, even at zero chemical potential. By use of
the response functions, we also derive the relevant Kubo formulas for the
transport coefficients.Comment: 6 page
On Butterfly effect in Higher Derivative Gravities
We study butterfly effect in -dimensional gravitational theories
containing terms quadratic in Ricci scalar and Ricci tensor. One observes that
due to higher order derivatives in the corresponding equations of motion there
are two butterfly velocities. The velocities are determined by the dimension of
operators whose sources are provided by the metric. The three dimensional TMG
model is also studied where we get two butterfly velocities at generic point of
the moduli space of parameters. At critical point two velocities coincide.Comment: 16 pages, references adde
On AdS/CFT of Galilean Conformal Field Theories
We study a new contraction of a d+1 dimensional relativistic conformal
algebra where n+1 directions remain unchanged. For n=0,1 the resultant algebras
admit infinite dimensional extension containing one and two copies of Virasoro
algebra, respectively. For n> 1 the obtained algebra is finite dimensional
containing an so(2,n+1) subalgebra. The gravity dual is provided by taking a
Newton-Cartan like limit of the Einstein's equations of AdS space which singles
out an AdS_{n+2} spacetime. The infinite dimensional extension of n=0,1 cases
may be understood from the fact that the dual gravities contain AdS_2 and AdS_3
factor, respectively. We also explore how the AdS/CFT correspondence works for
this case where we see that the main role is playing by AdS_{n+2} base
geometry.Comment: new references adde
Fermions in non-relativistic AdS/CFT correspondence
We extend the non-relativistic AdS/CFT correspondence to the fermionic
fields. In particular we study the two point function of a fermionic operator
in non-relativistic CFTs by making use of a massive fermion propagating in
geometries with Schrodinger group isometry. Although the boundary of the
geometries with Schrodinger group isometry differ from that in AdS geometries
where the dictionary of AdS/CFT is established, using the general procedure of
AdS/CFT correspondence, we see that the resultant two point function has the
expected form for fermionic operators in non-relativistic CFTs, though a
non-trivial regularization may be needed.Comment: 12 pages,Latex file; V2: typos corrected, refs adde