A simple method for the Kramers-Kronig analysis of reflectance spectra measured with diamond anvil cell

When the optical reflectance spectrum of a sample under high pressure is studied with a diamond anvil cell, it is measured at a sample/diamond interface. Due to the large refractive index of diamond, the resulting reflectance Rd(w) may substantially differ from that measured in vacuum. To obtain optical constants from Rd(w), therefore, the usual Kramers-Kronig (KK) transform cannot be straightforwardly applied, and either a spectral fitting or a modified KK transform has been used. Here we describe an alternative method to perform KK analysis on Rd(w). This method relies on the usual KK transform with an appropriate cutoff and extrapolation to Rd(w), and may offer a simpler approach to obtain infrared conductivity from measured Rd(w).Comment: 6 pages, 2 figures, to appear in the Proceedings of 6th WIRMS Conference (J. Phys. Conf. Ser.

Renormalization-group and numerical analysis of a noisy Kuramoto-Sivashinsky equation in 1+1 dimensions

The long-wavelength properties of a noisy Kuramoto-Sivashinsky (KS) equation in 1+1 dimensions are investigated by use of the dynamic renormalization group (RG) and direct numerical simulations. It is shown that the noisy KS equation is in the same universality class as the Kardar-Parisi-Zhang (KPZ) equation in the sense that they have scale invariant solutions with the same scaling exponents in the long-wavelength limit. The RG analysis reveals that the RG flow for the parameters of the noisy KS equation rapidly approach the KPZ fixed point with increasing the strength of the noise. This is supplemented by the numerical simulations of the KS equation with a stochastic noise, in which the scaling behavior of the KPZ equation can be easily observed even in the moderate system size and time.Comment: 12pages, 7figure

Mirror effect induced by the dilaton field on the Hawking radiation

We discuss the string creation in the near-extremal NS1 black string solution. The string creation is described by an effective field equation derived from a fundamental string action coupled to the dilaton field in a conformally invariant manner. In the non-critical string model the dilaton field causes a timelike mirror surface outside the horizon when the size of the black string is comparable to the Planck scale. Since the fundamental strings are reflected by the mirror surface, the negative energy flux does not propagate across the surface. This means that the evaporation stops just before the naked singularity of the extremal black string appears even though the surface gravity is non-zero in the extremal limit.Comment: 15 page

Number Density of Bright Lyman-Break Galaxies at z~6 in the Subaru Deep Field

We report on the bright Lyman-break galaxies (LBGs) selected in a 767 arcmin^2 area of the Subaru Deep Field. The selection is made in the i-zR vs zB-zR plane, where zB and zR are new bandpasses with a central wavelength of 8842A and 9841A, respectively. This set of bandpasses enables us to separate well z~6 LBGs from foreground galaxies and Galactic cool stars. We detect 12 LBG candidates down to zR=25.4, and calculate the normalization of the rest-frame far-ultraviolet (FUV: 1400A) luminosity function at MFUV = -21.6 to be \phi(-21.6) = (2.6+/-0.7) x 10^{-5} mag^{-1} Mpc^{-3}. This must be the most reliable measurement ever obtained of the number density of bright z~6 LBGs, because it is more robust against both contamination and cosmic variance than previous values. The FUV luminosity density contributed from LBGs brighter than MFUV = -21.3 is (2.8+/-0.8) x 10^{24} ergs/s/Hz/Mpc^3, which is equivalent to a star formation rate density of (3.5+/-1.0) x 10^{-4} Msun/yr/Mpc^3. Combining our measurement with those at z<6 in the literature, we find that the FUV luminosity density of bright galaxies increases by an order of magnitude from z~6 to z~3 and then drops by 10^3 from z~3 to the present epoch, while the evolution of the total luminosity density is much milder. The evolutionary behavior of bright LBGs resembles that of luminous dusty star-forming galaxies and bright QSOs. The redshift of z~3 appears to be a remarkable era in the cosmic history when massive galaxies were being intensively formed.Comment: 12 pages, accepted for PASJ, a high resolution version is available at http://hikari.astron.s.u-tokyo.ac.jp/~shima/z6LBGs

Characterisation of polymorphic microsatellite loci for the bryozoan Fredericella sultana, the primary host of the causative agent of salmonid proliferative kidney disease

0000-0001-7279-715X© Springer Science+Business Media Dordrecht 2014. The attached document is the authors' final accepted version of the journal article. You are advised to consult the publisher's version if you wish to cite from it

Pressure Tuning of an Ionic Insulator into a Heavy Electron Metal: An Infrared Study of YbS

Optical conductivity [$\sigma(\omega)$] of YbS has been measured under pressure up to 20 GPa. Below 8 GPa, $\sigma(\omega)$ is low since YbS is an insulator with an energy gap between fully occupied 4$f$ state and unoccupied conduction ($c$) band. Above 8 GPa, however, $\sigma(\omega)$ increases dramatically, developing a Drude component due to heavy carriers and characteristic infrared peaks. It is shown that increasing pressure has caused an energy overlap and hybridization between the $c$ band and 4$f$ state, thus driving the initially ionic and insulating YbS into a correlated metal with heavy carriers

Optical Conductivity and Electronic Structure of CeRu4Sb12 under High Pressure

Optical conductivity [s(w)] of Ce-filled skutterudite CeRu4Sb12 has been measured at high pressure to 8 GPa and at low temperature, to probe the pressure evolution of its electronic structures. At ambient pressure, a mid-infrared peak at 0.1 eV was formed in s(w) at low temperature, and the spectral weight below 0.1 eV was strongly suppressed, due to a hybridization of the f electron and conduction electron states. With increasing external pressure, the mid-infrared peak shifts to higher energy, and the spectral weight below the peak was further depleted. The obtained spectral data are analyzed in comparison with band calculation result and other reported physical properties. It is shown that the electronic structure of CeRu4Sb12 becomes similar to that of a narrow-gap semiconductor under external pressure.Comment: 8 pages, 9 figure

Photogenerated Carriers in SrTiO3 Probed by Mid-Infrared Absorption

Infrared absorption spectra of SrTiO$_3$ have been measured under above-band-gap photoexcitations to study the properties of photogenerated carriers, which should play important roles in previously reported photoinduced phenomena in SrTiO$_3$. A broad absorption band appears over the entire mid-infrared region under photoexcitation. Detailed energy, temperature, and excitation power dependences of the photoinduced absorption are reported. This photo-induced absorption is attributed to the intragap excitations of the photogenerated carriers. The data show the existence of a high density of in-gap states for the photocarriers, which extends over a wide energy range starting from the conduction and valence band edges.Comment: 5 pages, 5 figures, submitted to J. Phys. Soc. Jp