Tau-Function Theory of Chaotic Quantum Transport with β = 1, 2, 4

We study the cumulants and their generating functions of the probability distributions of the conductance, shot noise and Wigner delay time in ballistic quantum dots. Our approach is based on the integrable theory of certain matrix integrals and applies to all the symmetry classes ${\beta \in \{1, 2, 4\}}$ of Random Matrix Theory. We compute the weak localization corrections to the mixed cumulants of the conductance and shot noise for β = 1, 4, thus proving a number of conjectures of Khoruzhenko et al. (in Phys Rev B 80:(12)125301, 2009). We derive differential equations that characterize the cumulant generating functions for all ${\beta \in \{1, 2, 4 \} }$ . Furthermore, when β = 2 we show that the cumulant generating function of the Wigner delay time can be expressed in terms of the Painlevé III′ transcendant. This allows us to study properties of the cumulants of the Wigner delay time in the asymptotic limit ${n \to \infty}$ . Finally, for all the symmetry classes and for any number of open channels, we derive a set of recurrence relations that are very efficient for computing cumulants at all orders.     

Experimental constraints onJ PC=1−+,I=1, Hybrid mesons

Using data on coherent production of π⁺π⁺π^- systems in π⁺ collisions with nuclei we exclude the existence ofJ ^PC=1^?+,I=1, exotic hybrid mesons with masses below 1.5 GeV and widths greater than 20 MeV, provided that their primary coupling is to πρ systems. Hybrid states with just such properties have recently been predicted from arguments based on QCD sum rules. Our experimental limit is based on Primakoff production of these states, and on an argument using vector dominance to relate their radiative widths to πρ channels. There has been increasing interest of late in the existence of hybrid states, which, in the case of mesons, contain a valence gluon in addition to aq \(\bar q\) pair in a color-octet state [1–5]. The pursuit of spectroscopic gluon degrees of freedom has been strongly motivated by the general QCD picture of hadrons, as well as by many specific calculations based on QCD sum rules, lattice simulations, and more phenomenological approaches such as QCD-bag models. Although much effort, both thoretical and experimental, has been devoted to the spectroscopy of glueballs, for which several candidates exist [6], it has also been realized that hybrid states may be as amenable to discovery, and perhaps less ambiguous to interpretation.     

Isotope dependent predissociation in the C 1 Σ + , v =0 and v =1 states of CO

Rotationally resolved spectral lines in the C - X (1, 0) band of carbon monoxide are investigated under high resolution using a coherent vacuum ultraviolet laser source, continuously tunable near 107 nm. Transition frequencies are determined by calibrating against a reference standard of iodine lines, recorded with saturation spectroscopy in the visible range, yielding an absolute accuracy of 0.003 cm^-1 in the vacuum ultraviolet. Improved molecular constants for the excited state are derived and no effects of perturbation are found at the present level of accuracy. Line broadening measurements result in information on the excited state lifetime of the C ¹ Σ ⁺ , v = 1 state for five natural isotopomers of carbon monoxide: τ( ¹² C ¹⁷ O ) = 280 ps, τ( ¹² C ¹⁸ O ) = 210 ps, τ( ¹³ C ¹⁶ O ) = 295 ps, τ( ¹³ C ¹⁷ O ) = 160 ps, and τ( ¹³ C ¹⁸ O ) = 150 ps. Within the accuracy of the present measurements no effects of J-dependent lifetimes were observed, for neither of the isotopomers. In addition direct time domain measurements of the lifetime of the C ¹ Σ ⁺ , v = 0 and v = 1 states of the main isotopomer are performed in a pump-probe experiment using a picosecond VUV-laser, yielding τ( ¹² C ¹⁶ O ) = 1780 ps for v = 0 and τ( ¹² C ¹⁶ O ) = 625 ps for v = 1. For C ¹ Σ ⁺ , v = 0 in ¹²C¹⁶O and ¹³C¹⁶O the same lifetime is found; this lifetime matches experimental values of the oscillator strength and hence supports previous results showing pure radiative decay in this state; the error margins however do not exclude some low level of predissociation. The measurements indicate that the C ¹ Σ ⁺ , v = 0 state of the ¹³C¹⁸O isotopomer is predissociated with an estimated yield of 17% (i.e. above the level of predissociation for ¹²C¹⁶O.) From the combined data predissociation yields upon excitation of the C ¹ Σ ⁺ , v = 1 state are derived, lying in the range 0.84-0.91 for the five less abundant isotopomers; for the main ¹²C¹⁶O isotopomer a strongly deviating predissociation yield of 0.65 is deduced. Received 21 December 2000 and Received in final form 26 March 2001     

BPS States of D=4 ␣N=1 Supersymmetry

We find the combinations of momentum and domain-wall charges corresponding to BPS states preserving 1/4, 1/2 or 3/4 of D=4 N=1 supersymmetry, and we show how the supersymmetry algebra implies their stability. These states form the boundary of the convex cone associated with the Jordan algebra of 4× 4 real symmetric matrices, and we explore some implications of the associated geometry. For the Wess–Zumino model we derive the conditions for preservation of 1/4 supersymmetry when one of two parallel domain-walls is rotated and in addition show that this model does not admit any classical configurations with 3/4 supersymmetry. Our analysis also provides information about BPS states of N=1 D=4 anti-de Sitter supersymmetry. Received: 6 April 2000/ Accepted: 10 September 2000     

Magnetic Properties of Hydrides of RNi1 – xSix Compounds (R = Dy,Gd, x = 0.05, 0.02)

Physics of the Solid State - The magnetic properties of intermetallic compounds GdNi0.98Si0.02 and DyNi0.95Si0.05 and hydrides based on them have been studied. It is found that a partial...     

Design of a β=0.45, f=350 MHz Spoke Cavity

Recently intensive studies have been done on superconducting cavities (e.g. spoke cavity, reentrant cavity, and ch cavity), which are used as accelerating structures in the low and medium energy part of high power high intensity proton or ion accelerators. many experiments have shown that spoke cavity is a good candidate for low energy part. it is also promising to be used for the medium β area. so a β=0.45 spoke cavity is being studied at Peking university. in this paper, the structural and electromagnetic design of a β=0.45, f=350mhz spoke cavity is reported in detail. the calculated rf parameters (e.g. Q, r/Q, peak surface fields and dissipated power) indict a potential of good acceleration.     

∧ BARYONS(S=-1,I=0)∧~0=uds

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激发态H2(X1∑+g,v=1,J=1)之间的碰撞能量合并

受激拉曼激发H2(0,1)基态的Q支得到H2(1,1)能级.在室温条件下,利用反斯托克斯拉曼散射(CARS)探测技术测量了碰撞能量合并(EP)过程H2(1,1)+H2(1,1)→H2(2,J)+H2(0,J″)及H2(1,1)与H2(1,J)转动能级间的碰撞转移速率系数.扫描CARS谱表明在H2(1,1)能级的碰撞能量...     

First-Principles Study of Electronic and Optical Properties of Y1-xCaxTiO3 （x=0, 0.25, 0.5, 0.75）

The full potential linearized augmented plane wave （FP-LAPW） method with the generalized gradient approximation （GGA） is applied to study the electronic and optical properties of perovskite-type compounds Y1-xCaxTiO3. The lattice parameters, magnetic moment, band structure, density of states and optical conductivity are obtained. The results show that the Ca ion plays an important role in the electronic properties and optical responses. Moreover, the optical properties including the dielectric function, absorption spectrum, extinction coefficient, energy-loss spectrum and refractive index are also discussed.     

∑BARYONS(S=-1,I=1)∑~+=uus,∑~0=uds,∑~-=dds

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Structure and stability of AgXen Z({\sf n=1}–3, {\sf Z=-1}, 0, +1) clusters. Theoretical insights

The structure and stability of AgXe_n ^Z(n=1–3, Z=-1, 0, +1) cluster series at CCSD(T) theoretical level have been investigated. It is shown that the cations are more stable and have more compact geometries than the anions and neutrals. The role of the interaction was explained using the natural bond orbital (NBO) analysis.     

Observation of Δn=1 dielectronic recombination resonances of boronlike argon

We report here an observation ofn=1 dielectronic recombination resonances of boron-like argon in the energy region 140–195 eV. With the cooler's electron beam as a target, a resolution of approximately 0.6 eV FWHM was obtained in the observed energy range. The energies of the doubly excited states were estimated with a Hartree-Fock calculation, which indicates that the observed resonances are from Ar¹³⁺(1s²2s²2p) to Ar¹²⁺(1s²2s²3l3l) and Ar¹²⁺(1s²2s2p3l3l) transitions.     

Fusion rules of U q(sl(2, ℂ)), q m = 1

The decomposition of multiple tensor products of finite-dimensional irreducible representations of U _q(sl(2, )), for q's which are roots of 1, is studied in detail.     

Quantum-chemical modeling of the electronic structure and magnetic properties of Sn1 − x − y M x Sb y O2, M = Cr, Mn, Co, or Ni (x = 0.25; y = 0, 0.25)

The electronic and magnetic structures of the Sn_0.75 M _0.25O₂ and Sn_0.5 M _0.25Sb_0.25O₂ (M = Cr, Mn, Co, Ni) compounds with a structure that is derivative of the rutile structure are modeled using the ab initio spin-polarized tight-binding linear muffin-tin orbital (TB-LMTO) method. The magnetic moments of the transition metal atoms are calculated. The data obtained are used to analyze the influence of the composition of Sn_{1 ? x ? y} M _x Sb _y O₂ phases on their electronic spectra and the magnetic and transport characteristics.     

High resolution FTIR spectra of AsD3 in the 20-1000 cm−1 region. The ground, 98, v2 = 1 and v4 = 1 states

The pure rotational spectrum of the near-spherical oblate symmetric top AsD₃ has been recorded in the 20–120cm^?′ region with a resolution of 2.3 × 10^?3 m^?1 employing an FT interferometer. Rotational transitions with 5 ? J ? 29 and 0 ? X ? 25 of the ground state (GS) and the v₂ = 1 and v₄ = 1 excited states have been assigned. Splittings were observed for the GS, 98, K = 3 and 6 levels, the K = 3 levels of v₂ and the kl = ?2, 1, 4 and 7 levels of v₄. Furthermore the x,y Coriolis coupled v₂ and v₄ bands, v ⁰ ₂ = 654.4149cm^?1, and v ⁰ ₄ = 714.3399 cm^?1, have been examined with a resolution of 2.4 × 10^?3 cm^?1, and ca. 2500 allowed and 336 ‘forbidden’ lines with J′_max = 31 and K′_max = 28 have been assigned. Appropriately weighted GS data comprising FIR lines, allowed and ‘forbidden’ (up to ΔK = ±6) GS combination differences, mmw data, and ΔJ = 0, ΔK = ±1 distortion moment transitions were fitted together, and GS parameters complete through H parameters have been determined. Two different reductions of the Hamiltonian, either with ΔK = ±6 (h₃) or ΔK = ±3 (ε) off-diagonal elements, have been employed. Equivalence of these reductions up to J = 22 was established while for J > 22 the ε reduction is superior. The v₂ and v₄ data have been fitted with two equivalent models based on different reductions of the rovibrational Hamiltonian. In addition to the dominating x,y Coriolis resonance, ζ ^y ₂₄ 0.520, Δ(k ? l) = ±3 and ±6 interactions are important and were accounted for by the models. The transition moment ratio |M₄: M₂| =0.75 has been determined, with a positive sign of the product M ₂ζ ^y ₂₄ M ₄. An improved r₀ structure, r₀(AsD) = 1.51753 Å and α₀(DAsD) = 92.000°, has been determined.     

DFT studies on the interaction of PtxRuyMz (M = Fe,Ni, Cu,Mo, Sn,x + y + z = 4, x ≥ 1, y ≥ 1) alloy clusters with O2

The reaction mechanism of O₂ dissociation on Pt_xRu_yM_z (M = Fe, Ni, Cu, Mo, Sn, x + y + z = 4, x ≥ 1, y ≥ 1) alloy catalysts have been investigated with density functional theory calculations in this work. For bare alloy clusters, bimetallic clusters are more stable than the ternary alloy clusters. The geometries of the Pt_xRu_yM_z–O₂ system, O–O bond stretching frequency and electronic-structure details have been investigated. The energies of O₂ adsorption on PtRu clusters are slightly higher than those on Pt_xRu_yM_z clusters, and the more charge transfer to O₂ from the metal cluster, the higher O₂ the adsorption energy obtains. The reaction barriers show that the catalytic performance of trimetallic clusters are better than those of bimetallic clusters, and Pt₂RuM clusters exhibit superior catalytic activity for O₂ dissociation. The different performance of these alloy clusters for O₂ dissociation is scrutinised with aid of molecular orbital and natural bond orbital population analysis.     

Spectroscopic parameters of theJ π=1+,T=0 excited6Li level

An analysis of thed- coincidence spectra of the⁷Li(³He, d)⁴He reaction at incident energy of 5.0 MeV and at various detector angles has been carried out. The values of the spectroscopic parameters of theJ =1⁺,T=0⁶Li state at excitation energy of 5.65 MeV have been deduced. The results, considering the experimental errors, do not appear to be dependent on the geometry and are in line with the ones adopted in literature.     

Magnetic structures of non-stoichiometric hexagonal RNi1−xIn1+x (R=Dy,Ho, Er) compounds

Results of neutron diffraction studies of DyNi_0.9In_1.1, HoNi_0.8In_1.2 and ErNi_0.9In_1.1 compounds crystallizing in the hexagonal ZrNiAl-type structure are reported. Previously published data for stoichiometric 1–1–1 compounds indicate that HoNiIn and ErNiIn compounds are ferromagnets (ordering along the c-axis) with T_C of 22 and 9 K, respectively, while DyNiIn was found to be an antiferromagnet with T_N of 32 K (J. Magn. Magn. Mater. 262 (2003) L177; J. Magn. Magn. Mater., in press). DC bulk magnetic measurements show that with the rise of the x parameter the ordering temperature is lowered; moreover changes in the magnetic ordering occur. At 1.5 K the HoNi_0.8In_1.2 compound has a non-collinear magnetic structure, for the ErNi_0.9In_1.1 compound an additional sine-modulated component lying in the basal plane was found. For the DyNi_0.9In_1.1 compound the antiferromagnetic character of magnetic coupling is conserved, but some changes in comparison to 1–1–1 stoichiometry were noticed.