ASCA Observation of the Lyman-limit Quasar PKS2145+067

X-ray observation of a famous Lyman-limit quasar PKS2145+067at z_em= 0.990 was carried with ASCA. The source showed a 2-10 keV flux of 1.3 E-11 erg cm^-2 sec^-1 (L_X = 2.5 E46 erg sec^-1 for H_0=50 km s^-1 Mpc^-1) described by a power-law spectrum with a photon index Gamma=1.63 +/- 0.04 . In the ASCA energy band, no excess absorption was detected implying the absorption column density at z_ ab=0.791 was less than 1.6 E21 cm^-2 if absorbing medium had a metal abundance of 0.5 solar. Comparison with previous Einstein and ROSAT observations shows that PKS2145+067 has increased its luminosity by a factor of 2--3 between 1991 and 1998.Comment: 15 pages, 3figures, Latex(PASJadd,sty, PASJ95.sty) accepted in PAS

Alignment and orientation of an adsorbed dipole molecule

Half-cycle laser pulse is applied on an absorbed molecule to investigate its alignment and orientation behavior. Crossover from field-free to hindered rotation motion is observed by varying the angel of hindrance of potential well. At small hindered angle, both alignment and orientation show sinusoidal-like behavior because of the suppression of higher excited states. However, mean alignment decreases monotonically as the hindered angle is increased, while mean orientation displays a minimum point at certain hindered angle. The reason is attributed to the symmetry of wavefunction and can be explained well by analyzing the coefficients of eigenstates.Comment: 4 pages, 4 figures, to appear in Phys. Rev. B (2004

Correlation Functions in Two-Dimensional Dilaton Gravity

The Liouville approach is applied to the quantum treatment of the dilaton gravity in two dimensions. The physical states are obtained from the BRST cohomology and correlation functions are computed up to three-point functions. For the $N=0$ case (i.e., without matter), the cosmological term operator is found to have the discrete momentum that plays a special role in the $c=1$ Liouville gravity. The correlation functions for arbitrary numbers of operators are found in the $N=0$ case, and are nonvanishing only for specific ``chirality'' configurations.Comment: 14 pages, TIT/HEP-204, STUPP-92-13

Optical probe of carrier doping by X-ray irradiation in organic dimer Mott insulator κ\kappa-(BEDT-TTF)2_{2}Cu[N(CN)2]_{2}]Cl

We investigated the infrared optical spectra of an organic dimer Mott insulator $\kappa$-(BEDT-TTF)$_{2}$Cu[N(CN)$_{2}$]Cl, which was irradiated with X-rays. We observed that the irradiation caused a large spectral weight transfer from the mid-infrared region, where interband transitions in the dimer and Mott-Hubbard bands take place, to a Drude part in a low-energy region; this caused the Mott gap to collapse. The increase of the Drude part indicates a carrier doping into the Mott insulator due to irradiation defects. The strong redistribution of the spectral weight demonstrates that the organic Mott insulator is very close to the phase border of the bandwidth-controlled Mott transition.Comment: 4 pages, 4 figure

Single particle momentum and angular distributions in hadron-hadron collisions at ultrahigh energies

The forward-backward charged multiplicity distribution (P n sub F, n sub B) of events in the 540 GeV antiproton-proton collider has been extensively studied by the UA5 Collaboration. It was pointed out that the distribution with respect to n = n sub F + n sub B satisfies approximate KNO scaling and that with respect to Z = n sub F - n sub B is binomial. The geometrical model of hadron-hadron collision interprets the large multiplicity fluctuation as due to the widely different nature of collisions at different impact parameters b. For a single impact parameter b, the collision in the geometrical model should exhibit stochastic behavior. This separation of the stochastic and nonstochastic (KNO) aspects of multiparticle production processes gives conceptually a lucid and attractive picture of such collisions, leading to the concept of partition temperature T sub p and the single particle momentum spectrum to be discussed in detail