November 2005 arXiv papers — page 19

Rui-Hua Xie, Jiangbin Gong

Based on a simplest molecular orbital theory of H$_{2}^{+}$, a three-parameter model potential function is proposed to describe ground-state diatomic systems with closed-shell and/or S-type valence-shell constituents over a significantly wide range of internuclear distances. More than 200 weakly and strongly bound diatomics have been studied, including neutr

Kartik Srinivasan, Matthew Borselli, Andreas Stintz, Sanjay Krishna

The quality factor (Q), mode volume (Veff), and room-temperature lasing threshold of microdisk cavities with embedded quantum dots (QDs) are investigated. Finite element method simulations of standing wave modes within the microdisk reveal that Veff can be as small as 2(lambda/n)^3 while maintaining radiation-limited Qs in excess of 10^5. Microdisks of diame

D. Asthagiri, Lawrence R. Pratt, Michael E. Paulaitis

The KcsA potassium channel belongs to a class of K+ channels that is selective for K+ over Na+ at rates of K+ transport approaching the diffusion limit. This selectivity is explained thermodynamically in terms of favorable partitioning of K+ relative to Na+ in a narrow selectivity filter in the channel. One mechanism for selectivity based on the atomic struc

Oliver Pfeiffer, Laurent Nony, Roland Bennewitz, Alexis Baratoff

The dynamic characteristics of a tip oscillating in the nc-AFM mode in close vicinity to a Cu(100)-surface are investigated by means of phase variation experiments in the constant amplitude mode. The change of the quality factor upon approaching the surface deduced from both frequency shift and excitation versus phase curves yield to consistent values. The o

Laurent Nony, Roland Prof. Bennewitz, Oliver Dr. Pfeiffer, Enrico Dr. Gnecco

The adsorption of two kinds of porphyrin (Cu-TBPP) and perylene (PTCDA) derived organic molecules deposited on KBr and Al2O3 surfaces has been studied by non-contact force microscopy in ultra-high vacuum, our goal being the assembly of ordered molecular arrangements on insulating surfaces at room temperature. On a Cu(100) surface, well ordered islands of Cu-

Luc Chevalier, Sylvain Calloch, François Hild, Yann Marco

We present an experimental approach to discriminate models describing the mechanical behavior of polymeric materials. A biaxial loading condition is obtained in a multiaxial testing machine. An evaluation of the displacement field obtained by digital image correlation allows us to evaluate the heterogeneous strain field observed during these tests. We focus

A. K. Popov, J. Brummer, R. S. Tanke, G. Taft

Photo-induced synthesis and control over the size and shape of colloidal silver nanoparticles is investigated in contrast to photo-stimulated aggregation of small nanoparticles into large fractal-type structures. The feasibility of light-driven nanoengineering which enables manipulation of the sizes and shapes of the isolated nanoparticles is studied by vary

C. Hanhart

I review recent insights and open questions connected with the production of eta--mesons from hadrons.

C. E. Alonso, J. M. Arias, L. Fortunato, A. Vitturi

The phase transition around the critical point in the evolution from spherical to deformed gamma-unstable shapes is investigated in odd nuclei within the Interacting Boson Fermion Model. We consider the particular case of an odd j=3/2 particle coupled to an even-even boson core that undergoes a transition from spherical U(5) to gamma-unstable O(6) situation.

K. Kaneko, M. Hasegawa

The partition function by means of the static path approximation (SPA) plus the random-phase approximation (RPA) treatment can be written as a contour integral form without solving the RPA equations for a separable interaction. This method is an efficient way to evaluate numerically the partition function for realistic calculations. As an illustration, we ad

D. N. Basu, P. Roy Chowdhury, C. Samanta

Half lives of the decays of spherical nuclei away from proton drip line by proton emissions are estimated theoretically. The quantum mechanical tunneling probability is calculated within the WKB approximation. Microscopic proton-nucleus interaction potentials are obtained by single folding the densities of the daughter nuclei with M3Y effective interaction s

J. P. Chen, X. Jiang, J. -C. Peng, L. Zhu

Nucleon transversity and single transverse spin asymmetries have been the recent focus of large efforts by both theorists and experimentalists. On-going and planned experiments from HERMES, COMPASS and RHIC are mostly on the proton or the deuteron. Presented here is a planned measurement of the neutron transversity and single target spin asymmetries at Jeffe

A. Kacharava, F. Rathmann, C. Wilkin

It is the aim of the ANKE-COSY spin collaboration to carry out a well directed programme of internationally competitive experiments involving polarised beams and targets, using the outstanding facilities available at the storage ring. These activities, at the same time, are good preparation for our participation in the PAX@FAIR project.

Willard Miller

A classical (or quantum) superintegrable system on an n-dimensional Riemannian manifold is an integrable Hamiltonian system with potential that admits 2n-1 functionally independent constants of the motion that are polynomial in the momenta, the maximum number possible. If these constants of the motion are all quadratic, the system is second order superintegr

T. Kanna, M. Lakshmanan, P. Tchofo Dinda, Nail Akhmediev

A novel kind of shape changing (intensity redistribution) collision with potential application to signal amplification is identified in the integrable $N$-coupled nonlinear Schr{ö}dinger (CNLS) equations with mixed signs of focusing and defocusing type nonlinearity coefficients. The corresponding soliton solutions for N=2 case are obtained by using Hirota&#3

E. Ahmed, A. S. Hegazi, A. S. Elgazzar

The analytical structure of some generalizations of the circle map is given. Also a generalization of off centre reflection is studied. The stability of Ito-Glass coupled map lattice is studied.

H. Makino, S. Tasaki

Extending the argument of Ref.\citen{[4]} to the long-range spectral statistics of classically integrable quantum systems, we examine the level number variance, spectral rigidity and two-level cluster function. These observables are obtained by applying the approach of Berry and Robnik\cite{[0]} and the mathematical framework of Pandey \cite{[2]} to systems

Shamgar Gurevich, Ronny Hadani

In this paper, proof of the {\it Kurlberg-Rudnick supremum conjecture} for the quantum Hannay-Berry model is presented. This conjecture was stated in P. Kurlberg's lectures at Bologna 2001 and Tel-Aviv 2003. The proof is a primer application of a fundamental solution: all the Hecke eigenfunctions of the quantum system are constructed. The main tool in ou

A. Fey, F. Redig

We define stabilizability of an infinite volume height configuration and of a probability measure on height configurations. We show that for high enough densities, a probability measure cannot be stabilized. We also show that in some sense the thermodynamic limit of the uniform measures on the recurrent configurations of the abelian sandpile model (ASM) is a

Janusz Grabowski, Marek Kuś, Giuseppe Marmo

Various problems concerning the geometry of the space $u^*(\cH)$ of Hermitian operators on a Hilbert space $\cH$ are addressed. In particular, we study the canonical Poisson and Riemann-Jordan tensors and the corresponding foliations into Kähler submanifolds. It is also shown that the space $\cD(\cH)$ of density states on an $n$-dimensional Hilbert space $\c

Julien Melleray

We compute here the Borel complexity of the relation of isometry between separable Banach spaces, using results of Gao, Kechris and Weaver.

Robert Easton

The Bogomolov-Miyaoka-Yau inequality asserts that the Chern numbers of a surface X of general type in characteristic 0 satisfy the inequality c_1^2 <= 3c_2, a consequence of which is (K_X^2)/chi(O_X) <= 9. This inequality fails in characteristic p, and here we produce infinite families of counterexamples for large p. Our method parallels a construction of Hi

Lisa Orloff Clark

Suppose $G$ is a second countable, locally compact, Hausdorff groupoid with a fixed left Haar system. Let $\go/G$ denote the orbit space of $G$ and $\cs(G)$ denote the groupoid $C^*$-algebra. Suppose that $G$ is a principal groupoid. We show that $C^*(G)$ is CCR if and only if $\go/G$ is a $T_1$ topological space, and that $C^*(G)$ is GCR if and only if $\go

Lisa Orloff Clark

Suppose $G$ is a second countable, locally compact, Hausdorff groupoid with a fixed left Haar system. Let $\go/G$ denote the orbit space of $G$ and $C^*(G)$ denote the groupoid $C^*$-algebra. Suppose that the isotropy groups of $G$ are amenable. We show that $C^*(G)$ is CCR if and only if $\go/G$ is a $T_1$ topological space and all of the isotropy groups ar

Laurent Fargues

V.Berkovich, K.Fujiwara and R.Huber have proved independently by different methods that the fiber of the vanishing cycles at a point of the special fiber depends only on the formal completion at this point. We refine this result and prove the invariance under formal completion of the perverse monodromy filtration on the fiber of vanishing cycles. This result

Guyan Robertson

Let $Γ$ be a torsion free cocompact lattice in $\aut(\cl T_1)\times\aut(\cl T_2)$, where $\cl T_1$, $\cl T_2$ are trees whose vertices all have degree at least three. The group $H_2(Γ, \bb Z)$ is determined explicitly in terms of an associated 2-dimensional tiling system. It follows that under appropriate conditions the crossed product $C^*$-algebra $\cl A$

A. S. Hegazi, F. Ismail, M. M. Elsofy

In this work we study the induction theory for Hopf group coalgebra. To reach this goal we define a substructure B of a Hopf group coalgebra $H$, called subHopf group coalgebra. Also, we introduced the definition of Hopf group suboalgebra and group coisotropic quantum subgroup of $H$.

Emmanuel Cépa, Dominique Lépingle

Brownian particles in electrostatic interaction may pairwise collide when the interaction parameter is small. But multiple collisions are never possible.

Hugues Lapointe

The i-th eigenvalue of the Laplacian on a surface can be viewed as a functional on the space of Riemannian metrics of fixed area. Extremal points of these functionals correspond to surfaces admitting minimal isometric immersions into spheres. Recently, critical metrics for the first eigenvalue were classified on tori and on Klein bottles. The present paper i

Anne Broise, Frédéric Paulin

Let $\wh K$ be the field of formal Laurent series in $X^{-1}$ over the finite field $k$, and let $A$ be the ring of polynomials in $X$ over $k$. One of the main results of the paper is to give a particularly nice coding of the geodesic flow on the quotient of the Bruhat-Tits tree $\TT$ of ${\rm PGL}\_2(\wh K)$ by ${\rm PGL}\_2(A)$, by using the continued fra

Guillaume Ricotta, T. Vidick

The asymptotic behaviour of the Neron-Tate height of Heegner points on a rational elliptic curve attached to an arithmetically normalized new cusp form f of weight 2, level N and trivial character is studied in this paper. By Gross-Zagier formula, this height is related to the special value at the critical point for the derivative of the Rankin-Selberg convo

Laurent Hauswirth, Frank Pacard

We construct higher genus Riemann&#39;s minimal surfaces properly embedded in the Euclidean space. To do that we glue end by end a Costa-Hoffman-Meeks examples to two halves genus zero Riemann&#39;s minimal surfaces. In first we need to perform a deformation of a Costa-Hoffman-Meeks example to prescribe the flux vector along the catenoidal ends. Then we stud

Ihor Zarichnyi

We show that there exists a natural counterpart of the Gromov-Hausdorff metric in the class of ultrametric spaces. It is proved, in particular, that the space of all ultrametric spaces whose metric take values in a fixed countable set is homeomorphic to the space of irrationals.

N. Aizawa, R. Chakrabarti

Using the corepresentation of the quantum group $ SL_q(2)$ a general method for constructing noncommutative spaces covariant under its coaction is developed. The method allows us to treat the quantum plane and Podleś&#39; quantum spheres in a unified way and to construct higher dimensional noncommutative spaces systematically. Furthermore, we extend the meth

Iain Moffatt

We relate the tree part of the Aarhus integral to Milnor&#39;s mu-invariants of string-links in homology balls thus generalizing results of Habegger and Masbaum.

Stefan Wewers

Lubin-Tate spaces of dimension one are finite etale covers of the non-archimedian open unit disk. We compute certain invariants which measure the ramification of this cover over the boundary of the disk.

E. Freitag, R. Salvati Manni

Some years ago, Borcherds described in [Bo1] two methods for constructing modular forms on modular varieties related to the orthogonal group $Ø(2,n)$. They are the so called Borcherds&#39; additive and multiplicative lifting. The multiplicative lifting has been used by Borcherds himself and other authors to construct modular forms with known vanishing locus

Iain Moffatt

This thesis consists of three self-contained chapters. The first two concern quantum invariants of links and three manifolds and the third contains results on the word problem for link groups. In chapter 1 we relate the tree part of the Aarhus integral to the mu-invariants of string-links in homology balls thus generalizing results of Habegger and Masbaum. T

Olexandr Ganyushkin, Volodymyr Mazorchuk

We obtain several combinatorial results about chains, cycles and orbits of the elements of the symmetric inverse semigroup $\IS_n$ and the set $T_n$ of nilpotent elements in $\IS_n$. We also get some estimates for the growth of $|\IS_n|$ and $|T_n|$, and study random products of elements from $\IS_n$.

Davar Khoshnevisan, David A. Levin

We derive a new coupling of the running maximum of an Ornstein-Uhlenbeck process and the running maximum of an explicit i.i.d. sequence. We use this coupling to verify a conjecture of Darling and Erdos (1956).

Larry Goldstein, Yosef Rinott

We consider a permutation method for testing whether observations given in their natural pairing exhibit an unusual level of similarity in situations where any two observations may be similar at some unknown baseline level. Under a null hypotheses where there is no distinguished pairing of the observations, a normal approximation with explicit bounds and rat

K. A. Dancer

For the last fifteen years quantum superalgebras have been used to model supersymmetric quantum systems. A class of quasi-triangular Hopf superalgebras, they each contain a universal $R$-matrix, which automatically satisfies the Yang--Baxter equation. Applying the vector representation to the left-hand side of a universal $R$-matrix gives a Lax operator. The

Mark B. Villarino

An algebraic transformation of the DeTemple-Wang half-integer approximation to the harmonic series produces the general formula and error estimate for the Ramanujan expansion for the nth harmonic number.

Hiroki Matui

We will show that an equivalence relation on a Cantor set arising from a two-dimensional substitution tiling by polygons is affable in the sense of Giordano, Putnam and Skau.

M. Livernet

In this paper we prove a ``Leray theorem&#39;&#39; for preLie algebras. We define a notion of &#39;&#39;Hopf&#39;&#39; preLie algebra: it is a preLie algebra together with a non associative permutative coproduct D and a compatibility relation between the preLie product and the coproduct D. A nonassociative permutative algebra is a vector space together with

Hans Lindblad, Jacob Sterbenz

We prove that the charge-scalar field (also known as the massless Maxwell-Klein-Gordon) equations are globally stable on (3+1) dimensional Minkowski space for small initial data in certain gauge covariant weighted Sobolev spaces. These spaces can be chosen as to be almost scale invariant with respect to the homogeneity of the equations. This result is valid

Gerald V. Dunne

This talk reports work done in collaboration with Jin Hur, Choonkyu Lee and Hyunsoo Min concerning the computation of the precise mass dependence of the fermion determinant for quarks in the presence of an instanton background. The result interpolates smoothly between the previously known chiral and heavy quark limits of extreme small and large mass. The com

Vikram Vyas

In the planar limit of QCD meson correlation functions can be written as a path-integral for a spin-half particle with each path being weighted by the expectation value of the corresponding Super Wilson Loop. An important quantity in this context is the expectation value of the Super Wilson Loop averaged over loops of fixed length. I obtain the leading and t

Gia Dvali, R. Jackiw, So - Young Pi

Schwinger&#39;s mechanism for mass generation relies on topological structures of a 2-dimensional gauge theory. In the same manner, corresponding 4-dimensional topological entities give rise to topological mass generation in four dimensions.

Tomoko Asaga, Takehisa Fujita

Wilson&#39;s area law in QCD is critically examined. It is shown that the expectation value of the Wilson loop integral $ \exp(\int iA_μdx^μ) $ in the strong coupling limit vanishes when we employ the conjugate Wilson action which has a proper QED action in the continuum limit. The finite value of Wilson loop with the Wilson action is due to the result of th

Ines Cavero-Pelaez, Kimball A. Milton

We present a Green&#39;s dyadic formulation to calculate the Casimir energy for a dielectric-diamagnetic cylinder with the speed of light differing on the inside and outside. Although the result is in general divergent, special cases are meaningful. It is pointed out how the self-stress on a purely dielectric cylinder vanishes through second order in the dev

Raman Sundrum

Introductory lectures on Extra Dimensions delivered at TASI 2004. The emphasis is on basic mechanisms rather than specific models.

P. Callin, C. P. Burgess

Deviations from Newton&#39;s Inverse-Squared Law at the micron length scale are smoking-gun signals for models containing Supersymmetric Large Extra Dimensions (SLEDs), which have been proposed as approaches for resolving the Cosmological Constant Problem. Just like their non-supersymmetric counterparts, SLED models predict gravity to deviate from the invers

Robi Peschanski

Saturation is expected to occur when a high density of partons (mainly gluons)- or equivalently strong fields in Quantum Chromodynamics (QCD) - is realized in the weak coupling regime. A way to reach saturation is through the high-energy evolution of an extended target probed at a fixed hard scale. In this case, the transition to saturation is expected to oc

J. Labbe, A. Barrau, J. Grain

In this brief note, we investigate some possible experimental consequences of the de-Sitter or Anti-de-Sitter background spacetime structure for d-dimensional evaporating black holes. Possible observational signatures in Large Hadron Collider (LHC) events are considered in the framework of the Arkani-Hamed-Dimopoulos-Dvali (ADD) braneworld model. Lower bound

Vincent Mathieu, Claude Semay, Fabian Brau

Assuming that the Casimir scaling hypothesis is well verified in QCD, masses of glueballs and hybrid gluelumps (gluon with a point-like $c\bar c$ pair) are computed within the rotating string formalism. In our model, two gluons are attached by an adjoint string in a glueball while the gluon and the colour octet $c\bar c$ pair are attached by two fundamental

N. Sawado, N. Shiiki, S. Tanaka

The Skyrme-Faddeev-Niemi (SFN) model which is an O(3) $σ$ model in three dimensional space up to fourth-order in the first derivative is regarded as a low-energy effective theory of SU(2) Yang-Mills theory. One can show from the Wilsonian renormalization group argument that the effective action of Yang-Mills theory recovers the SFN in the infrared region. Ho

Brooks Thomas, Manuel Toharia

In Split Supersymmetry scenarios the possibility of having a very heavy gravitino opens the door to alleviate or completely solve the worrisome &#34;gravitino problem&#39;&#39; in the context of supersymmetric baryogenesis models. Here we assume that the gravitino may indeed be heavy and that Majorana masses for neutrinos are forbidden as well as direct Higg

Eric B. Gregory, Alan Irving, Craig McNeile, Steven Miller

Because the propagators of flavor-singlet states incorporate disconnected diagrams, they are uniquely sensitive to any differences in the actions governing sea and valence fermions on the lattice. As such, they present an important test of the validity of the ``fourth-root trick&#39;&#39; in the staggered fermion formulation. The pseudoscalar&#39;s relations

Andrzej Sandacz, the PP2PP Collaboration

We report on the first measurement of the single spin analyzing power ($A\_N$) at $\sqrt{s}=200$ GeV, obtained by the pp2pp experiment using polarized proton beams at the Relativistic Heavy Ion Collider (RHIC). Data points were measured in the four momentum transfer $t$ range $0.01 \leq |t| \leq 0.03$ $\GeVcSq$. Our result is about one standard deviation abo

John G. Baker, Joan Centrella, Dae-Il Choi, Michael Koppitz

We present new techniqes for evolving binary black hole systems which allow the accurate determination of gravitational waveforms directly from the wave zone region of the numerical simulations. Rather than excising the black hole interiors, our approach follows the &#34;puncture&#34; treatment of black holes, but utilzing a new gauge condition which allows

Sergio Dain

The inequality $\sqrt{J}\leq m$ is proved for vacuum, asymptotically flat, maximal and axisymmetric data close to extreme Kerr data. The physical significance of this inequality and its relation to the standard picture of the gravitational collapse are discussed.

F. Cianfrani, G. Montani

In this work we deal with the extension of the Kaluza-Klein approach to a non-Abelian gauge theory; we show how we need to consider the link between the n-dimensional model and a four-dimensional observer physics, in order to reproduce fields equations and gauge transformations in the four-dimensional picture. More precisely, in fields equations any dependen

M. O. Ribas, F. P. Devecchi, G. M. Kremer

In this work it is investigated if fermionic sources could be responsible for accelerated periods during the evolution of a universe where a matter field would answer for the decelerated period. The self-interaction potential of the fermionic field is considered as a function of the scalar and pseudo-scalar invariants. Irreversible processes of energy transf

Matthew R. McKay, Alex J. Grant, Iain B. Collings

We consider multiple-input multiple-output (MIMO) transmit beamforming systems with maximum ratio combining (MRC) receivers. The operating environment is Rayleigh-fading with both transmit and receive spatial correlation. We present exact expressions for the probability density function (p.d.f.) of the output signal-to-noise ratio (SNR), as well as the syste

Young-Woo Son, Jisoon Ihm, Marvin L. Cohen, Steven G. Louie

We present first-principles calculations of quantum transport which show that the resistance of metallic carbon nanotubes can be changed dramatically with homogeneous transverse electric fields if the nanotubes have impurities or defects. The change of the resistance is predicted to range over more than two orders of magnitude with experimentally attainable

M. E. Torio, A. A. Aligia, G. I. Japaridze, B. Normand

We investigate the ground-state phase diagram of the Hubbard model for the AB$_{N-1}$ chain with filling 1/N, where $N$ is the number of atoms per unit cell. In the strong-coupling limit, a charge transition takes place from a band insulator (BI) to a correlated insulator (CI) for increasing on-site repulsion $U$ and positive on-site energy difference $Δ$ (e

Miroslaw Kozlowski, Janina Marciak-Kozlowska

In this paper heat transport in carbon nanotubes is investigated. When the dimension of the structure is of the order of the de Broglie wave length transport phenomena must be analysed by quantum mechanics. In this paper we derived the Dirac type thermal equation .The solution of the equation for the temperature fields for electrons can either be damped or c

J. N. Milstein, K. Burnett

We propose a method for simulating the behaviour of small clusters of particles that explicitly accounts for all mean-field and binary-correlation effects. Our approach leads to a set of variational equations that can be used to study both the dynamics and thermodynamics of these clusters. As an illustration of this method, we explore the BCS-BEC crossover i

D. R. Roy, V. Subramanian, P. K. Chattaraj

Intramolecular electron transfer capability of all metal aromatic and anti-aromatic aluminum cluster compounds is studied in terms of density functional theory based global and local reactivity descriptors. This study will provide important inputs towards the fabrication of the material required for molecular electronics.

Carlo Ruberto, Aleksandra Vojvodic, Bengt I. Lundqvist

Extensive density-functional calculations are performed to understand atomic chemisorption on the TiC(111) and TiN(111) surfaces, in particular the calculated pyramid-shaped trends in the adsorption energies for second- and third-period adatoms. Our previously proposed concerted-coupling model for chemisorption on TiC(111) is tested against new results for a

Michael Galperin, Abraham Nitzan, Mark A. Ratner

Using a model comprising a 2-level bridge connecting free electron reservoirs we show that coupling of a molecular bridge to electron-hole excitations in the leads can markedly effect the source-drain current through a molecular junction.In some cases, e.g. molecules that exhibit strong charge transfer transitions, the contribution from electron-hole excitat

A. Smerzi, P. Sodano, A. Trombettoni

By using a renormalization group analysis, we study the effect of interparticle interactions on the critical temperature at which the Berezinskii-Kosterlitz-Thouless (BKT) transition occurs for Bose-Einstein condensates loaded at finite temperature in a 2D optical lattice. We find that the critical temperature decreases as the interaction energy decreases; w

Y. Ihara, K. Ishida, H. Takeya, C. Michioka

The Co Knight shift was measured in an aligned powder sample of Na_xCoO_2yH_2O, which shows superconductivity at T_c \sim 4.6 K. The Knight-shift components parallel (K_c) and perpendicular to the c-axis (along the ab plane K_{ab}) were measured in both the normal and superconducting (SC) states. The temperature dependences of K_{ab} and K_c are scaled with

Saki Sonoda, Isao Tanaka, Hidekazu Ikeno, Tomoyuki Yamamoto

Considerable efforts have been devoted recently to synthesize diluted magnetic semiconductors having ferromagnetic properties at room temperature because of their technological impacts for spintronic devices. In 2001 successful growth of GaMnN films showing room temperature ferromagnetism and p-type conductivity has been reported. The estimated Curie tempera

V. Ferrari, J. M. Pruneda, Emilio Artacho

The electronic structure and equilibrium geometry of La2/3Sr1/3MnO3 are studied theoretically by means of density functional calculations. The doping is treated by introducing holes and a compensating jellium background. The results for the local density approximation (LDA) agree with previous LDA calculations, with an equilibrium volume 5.3% too small and w

Lorenz S. Cederbaum, Ofir E. Alon, Alexej I. Streltsov

A coupled-cluster approach for systems of $N$ bosons in external traps is developed. In the coupled-cluster approach the exact many-body wavefunction is obtained by applying an exponential operator $\exp{T}$ to the ground configuration $|ϕ_0>$. The natural ground configuration for bosons is, of course, when all reside in a single orbital. Because of this sim

Z. Usatenko

The process of adsorption on a planar repulsive, &#34;marginal&#34; and attractive wall of long-flexible polymer chains with excluded volume interactions is investigated. The performed scaling analysis is based on formal analogy between the polymer adsorption problem and the equivalent problem of critical phenomena in the semi-infinite $|ϕ|^4$ n-vector model

O. Petracic, X. Chen, S. Bedanta, W. Kleemann

Discontinuous magnetic multilayers [CoFe/Al2O3] are studied by use of magnetometry, susceptometry and numeric simulations. Soft ferromagnetic Co80Fe20 nanoparticles are embedded in a diamagnetic insulating a-Al2O3 matrix and can be considered as homogeneously magnetized superspins exhibiting randomness of size (viz. moment), position and anisotropy. Lacking

L. Angelani, C. Conti, G. Ruocco, F. Zamponi

We study the nonlinear dynamics of a multi-mode random laser using the methods of statistical physics of disordered systems. A replica-symmetry breaking phase transition is predicted as a function of the pump intensity. We thus show that light propagating in a random non-linear medium displays glassy behavior, i.e. the photon gas has a multitude of metastabl

D. Stamopoulos, N. Moutis, M. Pissas, D. Niarchos

In this work we present magnetization data on hybrids consisting of multilayers (MLs) of man- ganites [La0.33Ca0.67MnO3/La0.60Ca0.40MnO3]15 in contact with a low-Tc Nb superconductor (SC). Although a pure SC should behave diamagnetically in respect to the external magnetic field in our ML-SC hybrids we observed that the magnetization of the SC follows that o

D. Wegner, A. Bauer, Yu. M. Koroteev, G. Bihlmayer

Most spectroscopic methods for studying the electronic structure of metal surfaces have the disadvantage that either only occupied or only unoccupied states can be probed, and the signal is cut at the Fermi edge. This leads to significant uncertainties, when states are very close to the Fermi level. By performing low-temperature scanning tunneling spectrosco

M. Rizzi, V. Cataudella, R. Fazio

Fully frustrated one-dimensional diamond Josephson chains have been shown [B. Douçot and J. Vidal, Phys. Rev. Lett. {\bf 88}, 227005 (2002)] to posses a remarkable property: The superfluid phase occurs through the condensation of pairs of Cooper pairs. By means of Monte Carlo simulations we analyze quantitatively the Insulator to $4e$-Superfluid transition.

Masayo Inoue, Kunihiko Kaneko

Microorganisms often perform chemotaxis, (i.e., sensing and moving toward a region with a higher concentration of an attractive chemical) by changing the rate of tumbling for random walk. We studied several models with internal adaptive dynamics numerically to examine the validity of the condition for chemotaxis proposed by Oosawa and Nakaoka, which states t

Masashige Matsumoto, Mikito Koga

In PrOs4Sb12, the lowest-lying singlet and triplet states in a Pr 4f^2 configuration hybridize with conduction electrons having local a_u and t_u point-group symmetries. It is shown that for an attractive triplet pairing interaction, the orbital degrees of freedom of the t_u component are important. In addition, the Th point-group symmetry characteristic of

Masashige Matsumoto, Mikito Koga

The most important character of the exotic superconductor PrOs4Sb12 is the existence of low-lying excitations (excitons) with a finite energy gap and it appears as the magnetic field-induced order above 4.5 T. We focus on the a_u conduction band, which hybridizes with a Pr 4f^2 state strongly, coupled to the excitons. It results in an attractive interaction

Christian Maes, Hal Tasaki

Based only on classical Hamiltonian dynamics, we prove the maximum work principle in a system where macroscopic dynamical degrees of freedom are intrinsically coupled to microscopic degrees of freedom. Unlike recent identities between irreversible work and free energy, such as in the Jarzynski relation, the macroscopic dynamics is not governed by an external

Zhibing Li, Weiliang Wang, Shaozhi Deng, Ningsheng Xu

Significant field emission is found theoretically possible from nanorods of semiconductors of wide energy band gaps. If the nanorod has a thin surface layer containing a large number of localized states, a part of nanorod can exhibit an insulator-to-semimetal transition under high enough fields of direction parallel to its axis, so that field emission occurs

H. J. Xiang, Jinlong Yang, J. G. Hou, Qingshi Zhu

We investigate the electronic and magnetic properties of the proposed one-dimensional transition metal (TM=Sc, Ti, V, Cr, and Mn)-benzene (Bz) sandwich polymers by means of density functional calculations. [V(Bz)]$_{\infty}$ is found to be a quasi-half-metallic ferromagnet and half-metallic ferromagnetism is predicted for [Mn(Bz)]$_{\infty}$. Moreover, we sh

H. Sakurai, N. Tsujii, O. Suzuki, H. Kitazawa

Various samples of sodium cobalt oxyhydrate with relatively large amounts of Na$^{+}$ ions were synthesized by a modified soft-chemical process in which a NaOH aqueous solution was added in the final step of the procedure. From these samples, a superconducting phase diagram was determined for a section of a cobalt valence of $\sim$+3.48, which was compared w

H. Sakurai, K. Takada, T. Sasaki, E. Takayama-Muromachi

We synthesized Nax(H3O)zCoO2yH2O samples with various Na/H3O ratios but with the constant Co valence of s = +3.40, and measured their magnetic properties to draw phase diagrams of the system. The superconductivity is very sensitive to the Na/H3O ratio. With varying x under fixed s of +3.40, magnetically ordered phase appears in the intermediate range of x sa

V. Gurarie

We present a study of a gas of bosons confined in one dimension with Feshbach resonant interactions, at zero temperature. Unlike the gas of one dimensional bosons with non-resonant interactions, which is known to be equivalent to a system of interacting spinless fermions and can be described using the Luttinger liquid formalism, the resonant gas possesses no

Igor Goychuk, Peter Hanggi

A large number of multifaceted quantum transport processes in molecular systems and physical nanosystems can be treated in terms of quantum relaxation processes which couple to one or several fluctuating environments. A thermal equilibrium environment can conveniently be modelled by a thermal bath of harmonic oscillators. An archetype situation provides a tw

J. -B. Fouet, A. Laeuchli, S. Pilgram, R. M. Noack

Motivated by the recent discovery of the spin tube [(CuCl$_2$tachH)$_3$Cl]Cl$_2$, we investigate the properties of a frustrated three-leg spin tube with antiferromagnetic intra-ring and inter-ring couplings. We pay special attention to the evolution of the properties from weak to strong inter-ring coupling and show on the basis of extensive density matrix re

A. V. Syromyatnikov, S. V. Maleyev

Dynamical properties of the impurity spin-$\frac12$ in 2D and quasi-2D Heisenberg antiferromagnets (AFs) at $T\ge0$ are discussed. The specific case of an impurity coupled symmetrically to two neighboring host spins is considered. The specific feature of this problem is that the defect is degenerate (frustrated) being located in zero molecular field. It is s

J. Lloyd-Hughes, E. Castro-Camus, M. B. Johnston

We simulate the terahertz emission from laterally-biased InGaAs and InP using a three-dimensional carrier dynamics model in order to optimise the semiconductor material. Incident pump-pulse parameters of current Ti:Sapphire and Er:fibre lasers are chosen, and the simulation models the semiconductor&#39;s bandstructure using parabolic Gamma, L and X valleys,

Marek W. Gutowski

At the very heart of the successful phenomenological model of magnetic hysteresis there is the so called Preisach distribution. In the existing literature it is implicitly assumed, that this distribution has a mirror symmetry. We show, by simple and convincing example, that this common assumption is plainly wrong. Dropping it, we gain the ability to model no

Marco Baiesi, Maya Paczuski, Attilio L. Stella

Introducing thresholds to analyze time series of emission from the Sun enables a new and simple definition of solar flare events, and their interoccurrence times. Rescaling time by the rate of events, the waiting and quiet time distributions both conform to scaling functions that are independent of the intensity threshold over a wide range. The scaling funct

Timothy S. Hamilton, Stefano Casertano, David A. Turnshek

We present results from an archival study of 70 medium-redshift QSOs observed with the Wide Field Planetary Camera 2 on board the Hubble Space Telescope. The QSOs have magnitudes M_V < -23 (total nuclear plus host light) and redshifts 0.06 < z < 0.46. A close relationship between QSO host and nucleus is found by examining multiple parameters at once. A princ

Joshua D. Simon, Leo Blitz, Andrew A. Cole, Martin D. Weinberg

We have used infrared and radio observations to search for a dwarf galaxy associated with the high-velocity cloud (HVC) known as Complex H. Complex H is a large (> 400 deg^2) and probably nearby (d = 27 kpc) HVC whose location in the Galactic plane has hampered previous investigations of its stellar content. The HI mass of the cloud is 2.0 x 10^7 (d/27 kpc)^