May 1999 arXiv papers — page 2
Showing 101–200 of 2,202 papers
Richard Nisius
Measurements of the QED structure of the photon based on the reaction ee --> ee \gamma(*)(P^2)\gamma*(Q^2) --> ee mumu are discussed. This review is an update of the discussion of the results on the QED structure of the photon presented in Refs.[1], and covers the published measurements of the photon structure functions F_2, F_A nd F_B and of the differentia
Lior M. Burko
We discuss a piecewise-conserved constant of motion for a simple dissipative oscillatory mechanical system. The system is a harmonic oscillator with sliding (dry) friction. The piecewise-conserved constant of motion corresponds to the time average of the energy of the system during one half-period of the motion, and changes abruptly at the turning points of
Z-Measures on partitions, Robinson-Schensted-Knuth correspondence, and beta=2 random matrix ensembles
math.COAlexei Borodin, Grigori Olshanski
We suggest an hierarchy of all the results known so far about the connection of the asymptotics of combinatorial or representation theoretic problems with ``beta=2 ensembles'' arising in the random matrix theory. We show that all such results are, essentially, degenerations of one general situation arising from so-called generalized regular represent
Luis A. Cordero, Phillip E. Parker
We begin a systematic study of these spaces, initially following along the lines of Eberlein's comprehensive study of the Riemannian case. In particular, we integrate the geodesic equation, discuss the structure of the isometry group, and make a study of lattices and periodic geodesics. Some major differences from the Riemannian theory appear. There are
Jonathan Gratus
A noncommutative algebra $A$, called an algebraic noncommutative geometry, is defined, with a parameter $ε$ in the centre. When $ε$ is set to zero, the commutative algebra $A^0$ of algebraic functions on an algebraic manifold $M$ is obtained. This $A^0$ is a subalgebra of $C(M)$, which is dense if $M$ is compact. The generators of $A$ define an immersion of
Vilma A. S. Sant'Anna, Adonai S. Sant'Anna
We discuss the babylonian method of extracting the root square of a number, from the point of view of modern mathematics. We also speculate that the babylonian mathematics was rich enough for a generalization of this method, despite the lack of general statements and justified procedures in their mathematics.
Jean Renault
The usual crossed product construction which associates to the homeomorphism $T$ of the locally compact space $X$ the C$^*$-algebra $C^*(X,T)$ is extended to the case of a partial local homeomorphism $T$. For example, the Cuntz-Krieger algebras are the C$^*$-algebras of the one-sided Markov shifts. The generalizations of the Cuntz-Krieger algebras (graph alg
Dmitri Zaitsev
We construct a birational equivalence between certain quotients of s-tuples of equidimensional linear subspaces of $C^n$ and some quotients of products of square matrices modulo diagonal conjugations. In particular, we prove the rationality of the quotient space of s-tuples of linear 2-planes in $C^n$ modulo the diagonal $\gl_n(C)$-action . Furthermore, we c
Wilhelm Kaup, Dmitri Zaitsev
A joint generalization of real smooth as well of complex manifolds are the Cauchy-Riemann manifolds. The main objective of the paper is to inroduce a class of symmetric CR manifolds containing both classes of Riemannian and Hermitian symmetric spaces. It turns out that the classical requirement of isolated fixed points for the symmetries is no longer adequat
D. P. Roy
The hadronic tau decay channel offers by far the best signature for heavy charged Higgs boson search at the LHC in the large $\tanβ$ region. By exploiting the distinct polarization of the tau and its large transverse mass, along with the accompanying missing--$p_T$, one can probe for a charged Higgs boson up to a mass of about 600 GeV in an essentially backg
George W. S. Hou
A Discovery Voyage into The Age of: PENGUINS (chubby little figure).
S. Pakvasa
I review explanations for the three neutrino anomalies (solar, atmospheric and LSND) which go beyond the ``conventional'' neutrino oscillations induced by mass-mixing. Several of these require non-zero neutrino masses as well.
Rajiv V. Gavai, Manu Mathur
The paper has been withdrawn
R. N. Bannister, N. d'Ambrumenil
We study the effect of varying the boundary condition on the spectral function of a finite 1D Hubbard chain, which we compute using direct (Lanczos) diagonalization of the Hamiltonian. By direct comparison with the two-body response functions and with the exact solution of the Bethe Ansatz equations, we can identify both spinon and holon features in the spec
Theory of Hall Effect and Electrical Transport in High-Tc Cuprates: Effects of Antiferromagnetic Spin Fluctuations
cond-mat.supr-conKazuki Kanki, Hiroshi Kontani
In the normal state of high-Tc cuprates, the Hall coefficient shows remarkable temperature dependence, and its absolute value is enhanced in comparison with that value simply estimated on the basis of band structure. It has been recognized that this temperature dependence of the Hall coefficient is due to highly anisotropic quasiparticle damping rate on the
Hall Effect and Resistivity in High-Tc Superconductors: The Conserving Approximation
cond-mat.supr-conHiroshi Kontani, Kazuki Kanki, Kazuo Ueda
The Hall coefficient (R_H) of high-Tc cuprates in the normal state shows the striking non-Fermi liquid behavior: R_H follows a Curie-Weiss type temperature dependence, and |R_H|>>1/|ne| at low temperatures in the under-doped compounds. Moreover, R_H is positive for hole-doped compounds and is negative for electron-doped ones, although each of them has a simi
Testing quantum correlations in a confined atomic cloud by scattering fast atoms: Direct and time reversed processes
cond-mat.softA. B. Kuklov, B. V. Svistunov
We suggest measuring the one-particle density matrix of a trapped ultracold atomic cloud by scattering fast atoms in a pure momentum state off the cloud. The lowest-order probability for the process, resulting in a pair of outcoming fast atoms for each incoming one, as well as of its time reversed counterpart, turns out to be given by the Fourier transform o
P. Lundqvist, J. Sollerman, C. Kozma, B. Larsson
We report on observations of SN 1987A with ISO SWS/LWS made 9 - 11 years after the explosion. No emission from the supernova was seen. In particular, the upper limits on the fluxes of [Fe I] 24.05 microns and [Fe II] 25.99 microns on day 3999 are roughly 1.1 Jy and 1.4 Jy, respectively. Assuming a homogeneous distribution of Ti-44 inside 2000 km/s, we have m
Chris J. Willott, Steve Rawlings, Katherine M. Blundell, Mark Lacy
We have used narrow emission line data from the new 7C Redshift Survey to investigate correlations between the narrow-line luminosities and the radio properties of radio galaxies and steep-spectrum quasars. The 7C Redshift Survey is a low-frequency (151 MHz) selected sample with a flux-density limit about 25-times fainter than the 3CRR sample. By combining t
Sean M. Carroll, Simeon Hellerman, Mark Trodden
We study N=1 SUSY theories in four dimensions with multiple discrete vacua, which admit solitonic solutions describing segments of domain walls meeting at one-dimensional junctions. We show that there exist solutions preserving one quarter of the underlying supersymmetry -- a single Hermitian supercharge. We derive a BPS bound for the masses of these solutio
M. G. Moore, P. Meystre
In a recent MIT experiment, a new form of superradiant Rayleigh scattering was observed in Bose-Einstein condensates. We present a detailed theory of this phenomena in which the directional dependence of the scattering rate and condensate depletion lead to mode competition which is ultimately responsible for superradiance. The nonlinear response of the syste
Xinwei Kong, Finn Ravndal
Next to leading order contributions to the pionium lifetime are considered within non-relativistic effective field theory. A more precise determination of the coupling constants is then needed in order to be consistent with the relativistic pion-pion scattering amplitude which can be obtained from chiral perturbation theory. The relativistic correction is fo
Keplerian Motion of Broad-Line Region Gas as Evidence for Supermassive Black Holes in Active Galactic Nuclei
astro-phBradley M. Peterson, Amri Wandel
Emission-line variability data on NGC 5548 argue strongly for the existence of a mass of order 7 x 10^7 solar masses within the inner few light days of the nucleus in the Seyfert 1 galaxy NGC 5548. The time-delayed response of the emission lines to continuum variations is used to infer the size of the line-emitting region, and these determinations are combin
Mikhail G. Revnivtsev, Konstantin N. Borozdin, William C. Priedhorsky, Alexey Vikhlinin
We present the results of Rossi X-ray Timing Explorer observations of GS 1354-644 during a modest outburst in 1997-1998. The source is one of a handful of black hole X-ray transients that are confirmed to be recurrent in X-rays. A 1987 outburst of the same source observed by Ginga was much brighter, and showed a high/soft spectral state. In contrast the 1997
Measurement of the Proton Structure Function F2 and of the Total Photon-Proton Cross Section sigma(tot) at Very Low Q2 and Very Low x
hep-exChristoph Amelung
The proton structure function F2 has been measured in the range 0.045 GeV2 < Q2 < 0.65 GeV2 and 6*10**-7 < x < 1*10**-3 using 3.9 pb-1 of ep->eX reactions recorded with the ZEUS detector in 1997. The analysis is based on data from the Beam Pipe Calorimeter (BPC) and the Beam Pipe Tracker (BPT). Compared to our previous analysis, the BPT permits improved back
Guido Altarelli, Ferruccio Feruglio
We briefly review the recent activity on neutrino masses and mixings which was prompted by the confirmation of neutrino oscillations by the Superkamiokande experiment.
C. S. Kim, Yeong Gyun Kim
We consider $b \to s γ$ decays in the Left-Right Symmetric Model. Values of observables sensitive to chiral structure such as the $Λ$ polarization in the $Λ_b \to Λγ$ decays and the mixing-induced CP asymmetries in the $B_{d,s} \to M^0 γ$ decays can deviate in the LRSM significantly from the SM values. The combined analysis of $P_Λ$ and $A_{CP}$ as well as $
V. Dzhunushaliev, D. Singleton
5D Kaluza-Klein gravity has several nonasymptotically flat solutions which generally, possessed both electric and magnetic charges. In this paper we suggest that these solutions can act as quantum virtual handles (wormholes) in spacetime foam models. By applying a sufficently large, external electric and/or magnetic field it may be possible to ``inflate'
Y. Nakahara, M. Asakawa, T. Hatsuda
QCD spectral functions of hadrons in the pseudo-scalar and vector channels are extracted from lattice Monte Carlo data of the imaginary time Green's functions. The maximum entropy method works well for this purpose, and the resonance and continuum structures in the spectra are obtained in addition to the ground state peaks.
A. J. Bracken, H. -D. Doebner, J. G. Wood
The integral of the Wigner function over a subregion of the phase-space of a quantum system may be less than zero or greater than one. It is shown that for systems with one degree of freedom, the problem of determining the best possible upper and lower bounds on such an integral, over all possible states, reduces to the problem of finding the greatest and le
Electron Spin Resonance Transistors for Quantum Computing in Silicon-Germanium Heterostructures
quant-phRutger Vrijen, Eli Yablonovitch, Kang Wang, Hong Wen Jiang
We apply the full power of modern electronic band structure engineering and epitaxial heterostructures to design a transistor that can sense and control a single donor electron spin. Spin resonance transistors may form the technological basis for quantum information processing. One and two qubit operations are performed by applying a gate bias. The bias elec
J. Mark Ettinger, Peter Hoyer
We present the view of quantum algorithms as a search-theoretic problem. We show that the Fourier transform, used to solve the Abelian hidden subgroup problem, is an example of an efficient elimination observable which eliminates a constant fraction of the candidate secret states with high probability. Finally, we show that elimination observables do not alw
Akihiro Ogura
Using the post-Gaussian trial functions, we calculate the variational solutions to the quantum-mechanical anharmonic oscillator. We evaluate not only the ground state but also some excited energies, and compare them with numerical results.
Progetto per la costituzione del centro di divulgazione della cultura scientifica a Sesto Fiorentino
physics.ed-phMassimo Materassi, Marco Ulivi
Two Italian non-profit organizations (Set and Galea) are working together to realize a center (Cdcs) supported by the town administration of Sesto Fiorentino (a little town not far from Florence, Italy), for the divulgation of the scientific culture in the schools and among people. This is their project: the key idea is to let the non-profit organizations in
I. V. Barashenkov, E. V. Zemlyanaya
It has been known for some time that solitons of the externally driven, damped nonlinear Schrödinger equation can only exist if the driver's strength, $h$, exceeds approximately $(2/ π) γ$, where $γ$ is the dissipation coefficient. Although this perturbative result was expected to be correct only to the leading order in $γ$, recent studies have demonstra
J. L. Forest
The off-shell aspects of the one-pion-exchange potential (OPEP) are discussed. Relativistic Hamiltonians containing relativistic kinetic energy, relativistic OPEP with various off-shell behaviors and Argonne $v_{18}$ short-range parameterization are used to study the deuteron properties. The OPEP off-shell behaviors depend on whether a pseudovector or pseudo
V. Pascalutsa, J. A. Tjon
We show how the invariance under the charge conjugation and CPT symmetry, present in the Bethe-Salpeter equation, is lost in the reduction to certain relativistic three-dimensional equations. This in particular leads to the breakdown of the standard Lorentz structure and renormalization procedures for the resulting single-particle propagators. We formulate t
T. Engeland, M. Hjorth-Jensen, E. Osnes
We present results of shell model calculations for the proton drip line nucleus $^{106}$Sb. The shell model calculations were performed based on an effective interaction for the $2s1d0g_{7/2}0h11_{11/2}$ shells employing modern models for the nucleon-nucleon interaction. The results are compared with the recently proposed experimental yrast states. A good ag
Jasper Scholten
In this paper it is explained how one can construct non-selfdual 4-dimensional $\ell$-adic Galois representations of Hodge type $h^{3,0}=h^{2,1}=h^{1,2}=h^{0,3}=1$, assuming a hypothesis concerning the cohomology of a certain threefold. For one such a representation the first 80000 coefficients of its $L$-function are computed, and it is numerically verified
Roland Queme
Let K/Q be a cyclic extension. In this paper, we give several congruences connecting the prime divisors of the degree g= [K:Q] with the prime divisors of the class number h of K/Q. As an exemple, the theorem: Let K/Q be a cyclic extension with [K:Q]=g. Suppose that g is not divisible by 2 . Let g_j, j=1,...m, be the prime divisors of g. Let h_i, i=1,...r, be
Graham Everest
A new proof is given for the explicit formulae for the non-archimedean canonical height on an elliptic curve. This arises as a direct calculation of the Haar integral in the elliptic Jensen formula.
Thomas G. Goodwillie, Michael Weiss
Let M and N be smooth manifolds. For an open V of M let emb(V,N) be the space of embeddings from V to N. By results of Goodwillie and Goodwillie-Klein, the cofunctor V |--> emb(V,N) is analytic if dim(N)-dim(M) > 2. We deduce that its Taylor series converges to it. For details about the Taylor series, see Part I.
Michael Weiss
Let M and N be smooth manifolds without boundary. Immersion theory suggests that an understanding of the space of smooth embeddings emb(M,N) should come from an analysis of the cofunctor V |--> emb(V,N) from the poset O of open subsets of M to spaces. We therefore abstract some of the properties of this cofunctor, and develop a suitable calculus of such cofu
L. Paris
We prove in this paper that the action of the mapping class group on the complex of curves has noncommensurable stabilizers. Following a method due to Burger and de la Harpe, this action leads to constructions of irreducible unitary representations of the mapping class group.
Bumsig Kim
The quantum hyperplane section theorem is explained for nonnegative decomposable concavex bundle spaces over generalized flag manifolds.
Osvaldo Chandia
We write the BRST operator of the N=2 superstring as $Q= e^{-R} (\oint \frac{dz}{2πi} ~ b γ_+ γ_-)e^R$ where $b$ and $gamma_\pm$ are super-reparameterization ghosts. This provides a trivial proof of the nilpotence of this operator.
Bo-yu Hou, Kang-jie Shi, Yan-shen Wang, Wen-li Yang
Boundary operators and boundary ground states in sine-Gordon model with a fixed boundary condition are studied using bosonization and q-deformed oscillators.We also obtain the form-factors of this model.
Martin R. Zirnbauer
A solution to the long-standing problem of identifying the conformal field theory governing the transition between quantized Hall plateaus of a disordered noninteracting 2d electron gas, is proposed. The theory is a nonlinear sigma model with a Wess-Zumino-Novikov-Witten term, and fields taking values in a Riemannian symmetric superspace based on H^3 x S^3.
Sebastian Jaimungal, Ariel R. Zhitnitsky
A novel Coulomb gas (CG) description of low energy QCD_4(N_c) is constructed. The construction is based on the dual transformation of the QCD effective Lagrangian. By considering a large gauge transformation, the charges of this statistical system are identified with magnetic monopoles which carry fractional charges of strength 1/N_c. Furthermore, the creati
D. M. Jansen, M. Albrow, R. Brugnera
Experimental results on diffraction, which were presented at the 7th International Workshop on Deep Inelastic Scattering and QCD (DIS99), are summarized.
M. Boglione, P. J. Mulders
Estimates of the T-odd fragmentation and distribution functions, $H_1^\perp$ and $f_{1T}^{\perp}$, are presented. Our evaluations are based on a fit on experimental data of polarized proton-proton scattering. We use our estimates to make predictions for electron polarized-proton azimuthal asymmetries.
Marcello Ciafaloni
I report on the recent proposal of a generalized small-x equation which, in addition to exact leading and next-to-leading BFKL kernels, incorporates renormalization group constraints in the relevant collinear limits.
Eugene Levin
This talk,given at Monte Carlo Workshop, is a review of news in low $x$ physics which, I think, would be useful for writing of the Monte Carlo codes. The following topics are discussed here: (i) the next-to-leading order BFKL Pomeron; (ii) two indications for shadowing corrections (SC) in DIS from HERA data; (iii) matching of "soft" and "hard"
Ken Kiers, Michel H. G. Tytgat
I review our proof that long range forces induced by the exchange of massless neutrino-antineutrino pairs do not affect the stability of neutron stars.
Daniel de Florian
In this talk I present a review on the theoretical status of polarized fragmentation functions and the prospects for conceivable future semi-inclusive deep-inelastic scattering and proton-proton collision experiments to measure them.
Katuhiko Suzuki, Noriaki Nakajima, H. Toki, K. -I. Kubo
Analyzing powers in inclusive pion production in high energy transversely polarized proton-proton collisions are studied theoretically in the framework of the quark recombination model. Calculations by assuming the SU(6) spin-flavor symmetry for the nucleon structure disagree with the experiments. We solve this difficulty by taking into account the %We overc
C. S. Kim, Yeong Gyun Kim, T. Morozumi
We present a model-independent analysis of rare B decays, $B \to K^{(*)} νν$. The effect of possible new physics is written in terms of dimension-6 four-fermi interactions. The lepton number violating scalar- and tensor-type interactions are included, and they induce $B \to K^{(*)} νν({\bar ν} {\bar ν})$ decays. We show systematically how the branching ratio
The SLD Collaboration, Danning Dong
We present preliminary results on three SLD analyses: the gluon energy spectrum in 3-jet bbg events, the rate of g->bb, and the b fragmentation function in Z0 decays. The gluon energy spectrum, measured over the full kinematic range, is compared with perturbative QCD predictions. We set new 95% C.L. limits on the anomalous chromomagnetic coupling of the b qu
A preliminary measurement of the gluon splitting rate into $b\bar{b}$ pairs in hadronic $Z^0$ decays
hep-exToshinori Abe, representing the SLD Collaboration
We present a measurement of the rate of gluon splitting into bottom quarks, $g \to b\bar{b}$, in hadronic $Z^0$ decays collected by SLD from 1996 to 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary flavor. A topological vertex mass technique was used to tag the two jets with the smallest angle between
B. H. Behrens
Using a sample of 3.3 million Upsilon(4S) -> BBbar events collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR), we measure the branching fraction for B -> rho l nu, |V_ub|, and the partial rate (Delta Gamma) in three bins of q^2 = (p_B-p_rho)^2. We find B(B^0 -> rho^- l^+ nu)=(2.69 +- 0.41^+0.35_-0.40 +- 0.50) 10^-4, |V_ub|=(3.23 +
SLD Collaboration, Danning Dong
We present a new preliminary measurement of the b quark fragmentation function in Z0 decays using a novel kinematic B hadron energy reconstruction technique. The measurement is performed using 150,000 hadronic Z0 events recorded in the SLD experiment at SLAC between 1996 and 1997. The small and stable SLC beam spot and the CCD-based vertex detector are used
Michael Duren
This paper summarizes the contributions to the experimental sessions on polarized lepton nucleon scattering at the DIS 99 workshop. Results are reported about the flavor decomposition of the quark polarization, a first direct measurement of a positive gluon polarization, the observation of a double-spin asymmetry in diffractive rho production, the polarizati
Alexei Nesteruk
We present a simple, exact and self-consistent cosmology with a phenomenological model of quantum creation of radiation due to decay of the scalar field. The decay drives a non-isentropic inflationary epoch, which exits smoothly to the radiation era, without reheating. The initial vacuum for radiation is a regular Minkowski vacuum. The created radiation obey
H. -J. Schmidt
A contribution linear in r to the gravitational potential can be created by a suitable conformal duality transformation: the conformal factor is 1/(1+r)^2 and r will be replaced by r/(1+r), where r is the Schwarzschild radial coordinate. Thus, every spherically symmetric solution of conformal Weyl gravity is conformally related to an Einstein space. This res
NMR studies of the original magnetic properties of cuprates: effect of impurities and defects
cond-mat.supr-conH. Alloul, J. Bobroff, A. Mahajan, P. Mendels
Substitutional impurities in the CuO2 planes of the cuprates allow us to probe the electronic properties of the host material. The pseudo-gap in the underdoped regime is unmodified far from the impurities even though Tc is greatly reduced. The spin polarisation induced by magnetic impurities has an oscillatory behaviour reflecting the existing AF correlation
Catalina Mayol, Raul Toral, Claudio R. Mirasso
We describe the dynamical behavior of both class A and class B lasers in terms of a Lyapunov potential. For class A lasers we use the potential to analyze both deterministic and stochastic dynamics. In the stochastic case it is found that the phase of the electric field drifts with time in the steady state. For class B lasers, the potential obtained is valid
Efficient Real Space Solution of the Kohn-Sham Equations with Multiscale Techniques
cond-mat.mtrl-sciJian Wang, Thomas L. Beck
We present a multigrid algorithm for self consistent solution of the Kohn-Sham equations in real space. The entire problem is discretized on a real space mesh with a high order finite difference representation. The resulting self consistent equations are solved on a heirarchy of grids of increasing resolution with a nonlinear Full Approximation Scheme, Full
Andras Suto
We investigate the properties of the ground state of a system of interacting bosons on regular lattices with coordination number $k\geq 2$. The interaction is a pure, infinite, on-site repulsion. Our concern is to give an improved upper bound on the ground state energy per site. For a density $ρ$ a trivial upper bound is known to be $-kρ(1-ρ)$. We obtain a s
D. Guery-Odelin, G. V. Shlyapnikov
We find that inelastic collisional processes in Bose-Einstein condensates induce local variations of the mean-field interparticle interaction and are accompanied by the creation/annihilation of elementary excitation. The physical picture is demonstrated for the case of three body recombination in a trapped condensate. For a high trap barrier the production o
Mario S. C. Mazzoni, Helio Chacham, Pablo Ordejon, Daniel Sanchez-Portal
We apply first principles calculations to study the opening of single-wall carbon nanotubes (SWNT's) by oxidation. We show that an oxygen rim can stabilize the edge of the open tube. The sublimation of CO$_2$ molecules from the rim with the subsequent closing of the tube changes from endothermic to exothermic as the tube radius increases, within the rang
Born Effective Charge Reversal and Metallic Threshold State at a Band Insulator-Mott Insulator Transition
cond-matN. Gidopoulos S. Sorella, E. Tosatti
We study the quantum phase transition between a band (``ionic'') insulator and a Mott-Hubbard insulator, realized at a critical value U=Uc in a bipartite Hubbard model with two inequivalent sites, whose on-site energies differ by an offset Delta. The study is carried out both in D=1 and D=2 (square and honeycomb lattices), using exact Lanczos diagona
Spatial distribution of atoms in gas-covered Pd-X nanoparticles (X= Ag, Cu, Ni, Pt)
cond-mat.mtrl-sciMahesh Menon, Badal C. Khanra
A Monte-carlo (MC) simulation procedure has been developed where the pair bond energies are allowed to take into account the various coordination numbers of surface atoms and the presence of adsorbates. The pair bond energies are calculated from partial bond energies of atoms which, in turn, are calculated from modified tight binding model in the second mome
Magnetic behaviour of Eu_2CuSi_3: Large negative magnetoresistance above Curie temperature
cond-mat.str-elSubham Majumdar, R. Mallik, E. V. Sampathkumaran, Kirsten Rupprecht
We report here the results of magnetic susceptibility, electrical-resistivity, magnetoresistance (MR), heat-capacity and ^{151}Eu Mossbauer effect measurements on the compound, Eu_2CuSi_3, crystallizing in an AlB_2-derived hexagonal structure. The results establish that Eu ions are divalent, undergoing long-range ferromagnetic-ordering below (T_C=) 37 K. An
Spin transport properties of the quantum one-dimensional non-linear sigma model : an application to Haldane gap systems
cond-mat.str-elSatoshi Fujimoto
Spin transport properties of the quantum one-dimensional non-linear sigma model are studied based upon the Bethe ansatz exact solution for the O(3) sigma model and the 1/N-expansion approach for the O(N) sigma model. It is shown that the spin transport at finite temperatures is ballistic and there is no spin diffusion in this system. A possible mechanism for
Identification of the Chemical Potential of an Open System at 0 K with Functional Derivatives of the Integer-State Energy Density Functionals
cond-mat.mtrl-sciSteven M. Valone
Open-system density functional theory may be formulated in terms of ensemble averages arising from interaction with a bath. The system is allowed to exchange particles with the bath and the states in the ensemble average are those corresponding to integer numbers of particles. The weights in the ensemble average are typically equated with time-averaged value
R. Cruz, R. Mulet, E. Altshuler
In this work the robustness of a simple cellular automaton developed by Bassler and Paczuski to describe the critical state in type-II superconductors is studied. Two different configurations of pinning centers are introduced and a new universality class is found. The numerical values of the critical exponents were calculated following two scaling techniques
B. Kaulakys, F. Ivanauskas, T. Meskauskas
An analysis of transition from chaotic to nonchaotic behavior and synchronization in an ensemble of systems driven by identical random forces is presented. The synchronization phenomenon is investigated in the ensemble of particles moving with friction in the time-dependent potential and driven by the identical noise. The threshold values of the parameters f
Y. -Z. Qian, P. Vogel, G. J. Wasserburg
We estimate gamma-ray fluxes due to the decay of nuclei beyond Bi209 from a supernova or a supernova remnant assuming that the r-process occurs in supernovae. We find that a detector with a sensitivity of about 10**(-7) photons/cm**2/s at energies of 40 keV to 3 MeV may detect fluxes due to the decay of Ra226, Th229, Am241, Am243, Cf249, and Cf251 in the new
J. Loveday, L. Tresse, S. Maddox
We study the luminosity function and clustering properties of subsamples of local galaxies selected from the Stromlo-APM survey by the rest-frame equivalent width (EW) of the Halpha emission line. The b_J luminosity function of star-forming galaxies has a significantly steeper faint-end slope than that for quiescent galaxies: the majority of sub-L* galaxies
Spectral Analysis of the Stromlo-APM Survey II. Galaxy luminosity function and clustering by spectral type
astro-phJ. Loveday, L. Tresse, S. Maddox
We study the luminosity function and clustering properties of subsamples of local galaxies selected from the Stromlo-APM survey by the rest-frame equivalent widths of their Halpha and Oii emission lines. The b_J luminosity function of star-forming galaxies has a significantly steeper faint-end slope than that for quiescent galaxies: the majority of sub-L* ga
L. Tresse, S. Maddox, J. Loveday, C. Singleton
We analyze spectral properties of 1671 galaxies from the Stromlo-APM survey, selected to have 15 < b_J < 17.15 and having a mean redshift z = 0.05. This is a representative local sample of field galaxies, so the global properties of the galaxy population provide a comparative point for analysis of more distant surveys. We measure Halpha, Oii 3727, Sii 6716,
Paolo Padoan, John Bally, Youssef Billawala, Mika Juvela
We compare the statistical properties of J=1-0 13CO spectra observed in the Perseus Molecular Cloud with synthetic J=1-0 13CO spectra, computed solving the non-LTE radiative transfer problem for a model cloud obtained as solutions of the three dimensional magneto-hydrodynamic (MHD) equations. The model cloud is a randomly forced super-Alfvenic and highly sup
C. D. Impey, C. E. Petry, K. P. Flint
Spectroscopy of ten quasars obtained with the Goddard High Resolution Spectrograph (GHRS) of the Hubble Space Telescope (HST) is presented. A clustering analysis reveals an excess of nearest neighbor line pairs on velocity scales of 250-750 km/s at a 95-98% confidence level. The hypothesis that the absorbers are randomly distributed in velocity space can be
The transition phase in Nova Muscae 1998, the dust formation in classical novae and a possible link to intermediate polar systems
astro-phA. Retter, W. Liller, G. Garradd
We present results of continuous CCD photometry of Nova Muscae 1998 during 17 nights obtained mainly during the transition phase in the light curve of the young nova. We discovered a periodical oscillation with the period 0.16930 day. This result is important for understanding this peculiar stage in the light curve of certain classical novae. We also note a
A. Retter, T. Naylor
We suggest new evolutionary scenarios for non-magnetic short orbital period CVs. The first model is the analogy of the `hibernation scenario' or the `modern hibernation scenario'. The second one is an extension of Mukai and Naylor (1995) ideas. All models imply a tight connection between permanent superhump systems and classical novae. We highlight t
Thomas M. Brown
The rest-frame UV contains the most sensitive indicators of age for elliptical galaxies. While the near-UV flux from young ellipticals isolates the main sequence turnoff, the far-UV flux in old ellipticals is dominated by hot horizontal branch (HB) stars. This evolved population was first revealed by early UV observations showing a sharp flux increase shortw
A. Retter, C. Hellier
Re-examination of photometric data of TV Col (Hellier, 1993) reveals positive superhumps in addition to the negative superhumps previously known. The superhump period is 0.265+/-0.005 day - about 16 percent longer than the orbital period - which obeys the relation between superhump-period excess and orbital period (Stolz and Schoembs 1984). As a confirmed pe
An Irradiation Effect in Nova DN Gem 1912 and the Significance of the Period Gap for Classical Novae
astro-phA. Retter, E. M. Leibowitz, T. Naylor
Continuous CCD photometry of the classical nova DN Gem during 52 nights in the years 1992-98 reveals a modulation with a period 0.127844 d. The semi-amplitude is about 0.03 mag. The stability of the variation suggests that it is the orbital period of the binary system. This interpretation makes DN Gem the fourth nova inside the cataclysmic variable (CV) peri
Upper limit on C60 and C60+ features in the ISO-SWS spectrum of the reflection nebula NGC 7023
astro-phC. Moutou, K. Sellgren, L. Verstraete, A. Leger
We present here the 7.0-8.7 micron spectrum of the bright reflection nebula NGC 7023. Our observations are made with the Short Wavelength Spectrometer (SWS) on the European satellite Infrared Space Observatory (ISO). The vibrational bands of the ionized fullerene C60+ are expected at 7.11 and 7.51 microns, while those of the neutral fullerene C60 are expecte
Hyun Kyu Lee, R. A. M. J. Wijers, G. E. Brown
We investigate the possibility that gamma-ray bursts are powered by a central engine consisting of a black hole with an external magnetic field supported by a surrounding disk or torus. The rotational energy of the black hole can be extracted electromagnetically as a Poynting flux, a mechanism proposed by Blandford and Znajek(1977). Recently observed magneta
Yi Li, Rick Riolo, Robert Savit
We continue our study of evolution in minority games by examining games in which agents with poorly performing strategies can trade in their strategies for new ones from a different strategy space. In the context of the games discussed in this paper, this means allowing for strategies that use information from different numbers of time lags, m. We find, in a
Nemanja Kaloper
We consider domain walls embedded in curved backgrounds as an approximation for braneworld scenarios. We give a large class of new exact solutions, exhausting the possibilities for describing one and two walls for the cases where the curvature of both the bulk and the wall is locally constant. In the case of two walls, we find solutions where each wall has p
The Impact of Atmospheric Fluctuations on Degree-scale Imaging of the Cosmic Microwave Background
astro-phOliver P. Lay, Nils W. Halverson
Fluctuations in the brightness of the Earth's atmosphere originating from water vapor are an important source of noise for ground-based instruments attempting to measure anisotropy in the Cosmic Microwave Background. This paper presents a model for the atmospheric fluctuations and derives simple expressions to predict the contribution of the atmosphere t
Amihay Hanany, Yang-Hui He
We here present, in modern notation, the classification of the discrete finite subgroups of SU(4) as well as the character tables for the exceptional cases thereof (Cf. https://github.com/yanghuihe/SU4Subgroups). We hope this catalogue will be useful to works on string orbifold theories, quiver theories, WZW modular invariants, Gorenstein resolutions, nonlin
Andrew Belmonte, Bian Martin, Walter I. Goldburg
An experimental study of Taylor's hypothesis in a quasi-two-dimensional turbulent soap film is presented. A two probe laser Doppler velocimeter enables a non-intrusive simultaneous measurement of the velocity at spatially separated points. The breakdown of Taylor's hypothesis is quantified using the cross correlation between two points displaced in b
L. E. Guerrero, A. Bellorin, J. A. Gonzalez
We show that soliton interaction with finite-width inhomogeneities can activate a great number of soliton internal modes. We obtain the exact stationary soliton solution in the presence of inhomogeneities and solve exactly the stability problem. We present a Karhunen-Loeve analysis of the soliton structure dynamics as a time-dependent force pumps energy into
Deog Ki Hong
We study an effective theory of QCD at high density in detail, including the finite temperature effects and the leading order correction in $1/μ$ expansion. We investigate the Cooper pair gap equation and find that the color-flavor locking phase is energetically preferred at high density. We also find the color-superconducting phase transition occurs in dens
L. E. Guerrero, J. A. Gonzalez
The nonlinear Klein-Gordon equation with a different potential that satisfies the degeneracy properties discussed in this paper possesses solitonic solutions that interact with long-range forces. We generalize the Ginzburg-Landau equation in such a way that the topological defects supported by this equation present long-range interaction both in D = 1 and D
Ruth Britto-Pacumio, Andrew Strominger, Anastasia Volovich
M/string theory on noncompact, negatively curved, cosets which generalize $AdS_{D+1}=SO(D,2)/SO(D,1)$ is considered. Holographic descriptions in terms of a conformal field theory on the boundary of the spacetime are proposed. Examples include $SU(2,1)/U(2)$, which is a Euclidean signature (4,0) space with no supersymmetry, and $SO(2,2)/SO(2)$ and $SO(3,2)/SO
Malcolm Butler, Jiunn-Wei Chen
The differential cross-sections for elastic and inelastic neutrino-deuteron scattering are calculated analytically using nucleon-nucleon effective field theory. For elastic scattering, the deuteron axial form factor and the deuteron strange magnetic moment form factor are computed to next-to-leading order, including two-body currents. For inelastic scatterin