336 research outputs found
Symmetry Energy from Holographic QCD
We review the symmetry energy in the context of AdS/CFT correspondence. After
constructing brane configurations corresponding to dense system in boundary
theory, we calculate the symmetry energy by solving DBI action of branes in
confining and deconfining phase. We conclude the density dependence of the
symmetry energy has scaling law whose power depends only on dimensionality of
the branes and space-time.Comment: 9 pages, 5 figures. Some compile errors are corrected. arXiv admin
note: substantial text overlap with arXiv:1201.045
Small Fermi Surfaces and Strong Correlation Effects in Dirac Materials with Holography
Recent discovery of transport anomaly in graphene demonstrated that a system
known to be weakly interacting may become strongly correlated if system
parameter(s) can be tuned such that fermi surface is sufficiently small. We
study the strong correlation effects in the transport coefficients of Dirac
materials doped with magnetic impurity under the magnetic field using
holographic method. The experimental data of magneto-conductivity are well fit
by our theory, however, not much data are available for other transports of
Dirac material in such regime. Therefore, our results on heat
transport,thermo-electric power and Nernst coefficients are left as predictions
of holographic theory for generic Dirac materials in the vicinity of charge
neutral point with possible surface gap. We give detailed look over each
magneto-transport observable and 3Dplots to guide future experiments.Comment: 32 pages, 24 figure
A New Phase at Finite Quark Density from AdS/CFT
We explore phases of N=2 super Yang-Mills theory at finite quark density by
introducing quark chemical potential in a D3-D7 setup. We formulate the
thermodynamics of brane embeddings and find that we need to renormalize the
finite chemical potential due to the divergence of the thermodynamic potentials
and we find that the density versus chemical potential equation of state has
rich structure. This yields two distinct first order phase transitions in a
small window of quark density. In order words, there is a new first order phase
transition in the region of deconfined quarks. In this new phase, the chemical
potential is a decreasing function of the density. We suggest that this might
be relevant to the difference in sQGP--wQGP phases of QCD.Comment: 4 pages, revte
Mott transition with Holographic Spectral function
We show that the Mott transition can be realized in a holographic model of a
fermion with bulk mass, , and a dipole interaction of coupling strength .
The phase diagram contains gapless, pseudo-gap and gapped phases and the first
one can be further divided into four sub-classes. We compare the spectral
densities of our holographic model with the Dynamical Mean Field Theory (DMFT)
results for Hubbard model as well as the experimental data of Vanadium Oxide
materials. Interestingly, single-site and cluster DMFT results of Hubbard model
share some similarities with the holographic model of different parameters,
although the spectral functions are quite different due to the asymmetry in the
holography part. The theory can fit the X-ray absorption spectrum (XAS) data
quite well, but once the theory parameters are fixed with the former it can fit
the photoelectric emission spectrum (PES) data only if we symmetrize the
spectral function.Comment: 22 pages, 21 figures, v2 symmetrization arguments are abandoned, the
argument of Mott transition is still valid, but comparison with Hubbard model
is modified. Title is change
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