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