4 research outputs found
Composite Fermion Metals from Dyon Black Holes and S-Duality
We propose that string theory in the background of dyon black holes in
four-dimensional anti-de Sitter spacetime is holographic dual to conformally
invariant composite Dirac fermion metal. By utilizing S-duality map, we show
that thermodynamic and transport properties of the black hole match with those
of composite fermion metal, exhibiting Fermi liquid-like. Built upon
Dirac-Schwinger-Zwanziger quantization condition, we argue that turning on
magnetic charges to electric black hole along the orbit of Gamma(2) subgroup of
SL(2,Z) is equivalent to attaching even unit of statistical flux quanta to
constituent fermions. Being at metallic point, the statistical magnetic flux is
interlocked to the background magnetic field. We find supporting evidences for
proposed holographic duality from study of internal energy of black hole and
probe bulk fermion motion in black hole background. They show good agreement
with ground-state energy of composite fermion metal in Thomas-Fermi
approximation and cyclotron motion of a constituent or composite fermion
excitation near Fermi-point.Comment: 30 pages, v2. 1 figure added, minor typos corrected; v3. revised
version to be published in JHE
Preparation, characterization, and photocatalytic performance of polyvinylidene fluoride membrane modified with TiO2-C hybrid aerogels
TiO2-C hybrid aerogels containing submicrometer anatase and carbon
nanoparticles were prepared with TiCl4 and resorcinol-furfural. A modified
polyvinylidene fluoride (PVDF) ultrafiltration membrane was prepared through
phase inversion after dispersing the TiO2-C hybrid aerogel into a PVDF
solution. The surface features, structure, and hydrophilicity of the membrane
were characterized by scanning electron microscopy, X-ray diffraction,
Fourier transform infrared spectroscopy, contact angle measurement, and pure
water flux. The mechanical strength of this membrane was also determined. The
photocatalytic performance of the modified membrane was investigated using
reactive brilliant red (X-3B) as a representative contaminant.
Characterization results indicated that the TiO2-C hybrid aerogels were
distributed evenly in the PVDF membrane, showing enhanced hydrophilicity,
mechanical strength, and pure water flux. Furthermore, the photodegradation
rate of X-3B through the modified membrane was significantly high owing to
the photocatalytic action of the TiO2-C hybrid aerogels distributed in the
modified membrane