3 research outputs found
A Non-Fermi Liquid from a Charged Black Hole; A Critical Fermi Ball
Using the AdS/CFT correspondence, we calculate a fermionic spectral function
in a 2+1 dimensional non-relativistic quantum field theory which is dual to a
gravitational theory in the background with a charged black hole. The
spectral function shows no quasiparticle peak but the Fermi surface is still
well defined. Interestingly, all momentum points inside the Fermi surface are
critical and the gapless modes are defined in a {\it critical Fermi ball} in
the momentum space.Comment: v3) discussion on the singular nature of the zero energy peak added;
to appear in Phys. Rev.
Hall Anomaly and Vortex-Lattice Melting in Superconducting Single Crystal YBa2Cu3O7-d
Sub-nanovolt resolution longitudinal and Hall voltages are measured in an
ultra pure YBa2Cu3O7-d single crystal. The Hall anomaly and the first-order
vortex-lattice melting transition are observed simultaneously. Changes in the
dynamic behavior of the vortex solid and liquid are correlated with features of
the Hall conductivity sxy. With the magnetic field oriented at an angle from
the twin-boundaries, the Hall conductivity sharply decreases toward large
negative values at the vortex-lattice melting transition.Comment: 6 pages, 2 figures included, Postscript, to appear in Phys. Rev. Let