Results for "A. J. Sigillito"

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Anisotropic Stark Effect and Electric-Field Noise Suppression for Phosphorus Donor Qubits in SiliconSep 11 2014Mar 08 2015We report the use of novel, capacitively terminated coplanar waveguide (CPW) resonators to measure the quadratic Stark shift of phosphorus donor qubits in Si. We confirm that valley repopulation leads to an anisotropic spin-orbit Stark shift depending ... More
Electron Spin Resonance at the Level of 10000 Spins Using Low Impedance Superconducting ResonatorsAug 17 2016We report on electron spin resonance (ESR) measurements of phosphorus donors localized in a 200 square micron area below the inductive wire of a lumped element superconducting resonator. By combining quantum limited parametric amplification with a low ... More
Addressing spin transitions on 209Bi donors in silicon using circularly-polarized microwavesJan 21 2016Jan 22 2016Over the past decade donor spin qubits in isotopically enriched $^{28}$Si have been intensely studied due to their exceptionally long coherence times. More recently bismuth donor electron spins have become popular because Bi has a large nuclear spin which ... More
Large Stark tuning of donor electron spin quantum bits in germaniumJun 10 2016Jun 30 2016Donor electron spins in semiconductors make exceptional quantum bits because of their long coherence times and compatibility with industrial fabrication techniques. Despite many advances in donor-based qubit technology, it remains difficult to selectively ... More
Site-selective quantum control in an isotopically enriched 28Si/SiGe quadruple quantum dotMar 14 2019Silicon spin qubits are a promising quantum computing platform offering long coherence times, small device sizes, and compatibility with industry-backed device fabrication techniques. In recent years, high fidelity single-qubit and two-qubit operations ... More
High-fidelity quantum gates in Si/SiGe double quantum dotsNov 02 2017Motivated by recent experiments of Zajac et al. [arXiv:1708.03530], we theoretically describe high-fidelity two-qubit gates using the exchange interaction between the spins in neighboring quantum dots subject to a magnetic field gradient. We use a combination ... More
Quantum CNOT Gate for Spins in SiliconAug 11 2017Single qubit rotations and two-qubit CNOT operations are crucial ingredients for universal quantum computing. While high fidelity single qubit operations have been achieved using the electron spin degree of freedom, realizing a robust CNOT gate has been ... More
Fast high-fidelity entangling gates in Si double quantum dotsFeb 06 2019Implementing high-fidelity two-qubit gates in single-electron spin qubits in silicon double quantum dots is still a major challenge. In this work, we employ analytical methods to design control pulses that generate high-fidelity entangling gates for quantum ... More
Electron spin coherence of shallow donors in natural and isotopically enriched germaniumJun 18 2015Nov 07 2015Germanium is a widely used material for electronic and optoelectronic devices and recently it has become an important material for spintronics and quantum computing applications. Donor spins in silicon have been shown to support very long coherence times ... More
Fast, low-power manipulation of spin ensembles in superconducting microresonatorsFeb 28 2014May 02 2014We demonstrate the use of high-Q superconducting coplanar waveguide (CPW) microresonators to perform rapid manipulations on a randomly distributed spin ensemble using very low microwave power (400 nW). This power is compatible with dilution refrigerators, ... More
Volume fluctuations and linear response in a simple model of compactionMar 01 2007Jul 10 2007By means of a simple model system, the total volume fluctuations of a tapped granular material in the steady state are studied. In the limit of a system with a large number of particles, they are found to be Gaussian distributed, and explicit expressions ... More
Slow logarithmic relaxation in models with hierarchically constrained dynamicsJun 27 2000Nov 06 2000A general kind of models with hierarchically constrained dynamics is shown to exhibit logarithmic anomalous relaxation, similarly to a variety of complex strongly interacting materials. The logarithmic behavior describes most of the decay of the response ... More
The Kovacs effect: a master equation analysisNov 20 2009Jan 14 2010The Kovacs or crossover effect is one of the peculiar behaviours exhibited by glasses and other complex, slowly relaxing systems. Roughly it consists in the non-monotonic relaxation to its equilibrium value of a macroscopic property of a system evolving ... More
Closed model for granular compaction under weak tappingOct 30 2003A one dimensional lattice model is formulated to study tapping dynamics and the long time steady distribution in granular media. The dynamics conserves the number of particles in the system, and density changes are associated to the creation and destruction ... More
An exact algorithm for spin correlation functions of the two dimensional +/-J Ising spin glass in the ground stateApr 18 2005We introduce an exact algorithm for the computation of spin correlation functions for the two dimensional +/-J Ising spin glass in the ground state. Unlike with the transfer matrix method, there is no particular restriction on the shape of the lattice ... More
The nature of ZZ branesJul 23 2007Dec 04 2007In minimal non-critical string theory we show that the principal (r,s) ZZ brane can be viewed as the basic (1,1) ZZ boundary state tensored with the (r,s) Cardy boundary state. In this sense there exists only one ZZ boundary state, the basic (1,1) boundary ... More
Particle Energy And Acceleration Efficiencies In Highly Relativistic ShocksJan 15 2001Jan 23 2001In this paper we present an investigation of numerical Monte Carlo simulations of the diffusive shock acceleration in the test particle limit. Very high gamma flow astrophysical plasmas, have been used, from $\gamma_{up}$ $\sim50$ up to $\gamma_{up}$ ... More
Reduced phase space and toric variety coordinatizations of Delzant spacesApr 03 2007In this note we describe the natural coordinatizations of a Delzant space defined as a reduced phase space (symplectic geometry view-point) and give explicit formulas for the coordinate transformations. For each fixed point of the torus action on the ... More
Higgs triplet effects in purely leptonic processesNov 11 1995We consider the effect of complex Higgs triplets on purely leptonic processes and survey the experimental constraints on the mass and couplings of their single and double charge members. Present day experiments tolerate values of the Yukawa couplings ... More
Self-passivation of vacancies in α-PbOFeb 06 2013We introduce a self-passivation of single lead (Pb) and oxygen (O) vacancies in the \alpha-PbO compound through formation of a Pb-O vacancy pair. The preferential mechanism for pair formation involves initial development of the single Pb vacancy which, ... More
Compilation of relations for the antisymmetric tensors defined by the Lie algebra cocycles of $su(n)$Jun 27 2000May 17 2001This paper attempts to provide a comprehensive compilation of results, many new here, involving the invariant totally antisymmetric tensors (Omega tensors) which define the Lie algebra cohomology cocycles of $su(n)$, and that play an essential role in ... More
Pomeranchuk and Topological Fermi Surface Instabilities from Central InteractionsJan 05 2006Sep 29 2006We address at the mean field level the emergence of a Pomeranchuk instability in a uniform Fermi liquid with \emph{central} particle-particle interactions. We find that Pomeranchuk instabilities with all symmetries except $l=1$ can take place if the interaction ... More
Electrodynamics of Abrikosov vortices: the Field Theoretical FormulationJun 20 2011Electrodynamic phenomena related to vortices in superconductors have been studied since their prediction by Abrikosov, and seem to hold no fundamental mysteries. However, most of the effects are treated separately, with no guiding principle. We demonstrate ... More
The emergence of gauge invariance: the stay-at-home gauge versus local-global dualityAug 13 2011In condensed matter physics gauge symmetries other than the U(1) of electromagnetism are of an emergent nature. Two emergence mechanisms for gauge symmetry are well established: the way these arise in Kramers-Wannier type local-global dualities, and as ... More
Adsorption of a binary mixture of monomers with nearest-neighbour cooperative effectsMay 04 2005Jun 28 2005A model for the adsorption of a binary mixture on a one-dimensional infinite lattice with nearest neighbour cooperative effects is considered. The particles of the two species are both monomers but differ in the repulsive interaction experienced by them ... More
Is nonsymmetric gravity related to string theory?Oct 21 1996In this work we raise the question whether nonsymmetric gravity and string theory are related. We start making the observation, that the gravitational field $ g_{\mu\nu}$ and the nonsymmetric gauge field $ A_{\mu\nu}$ arising in the low energy limit in ... More
Breakdown of weak-field magnetotransport at a metallic quantum critical pointJul 11 2005We show how the collapse of an energy scale in a quantum critical metal can lead to physics beyond the weak-field limit usually used to compute transport quantities. For a density-wave transition we show that the presence of a finite magnetic field at ... More
Pressure Support in Galaxy Disks: Impact on Rotation Curves and Dark Matter Density ProfilesJul 15 2010Rotation curves constrain a galaxy's underlying mass density profile, under the assumption that the observed rotation produces a centripetal force that exactly balances the inward force of gravity. However, most rotation curves are measured using emission ... More
Fermionic realisations of simple Lie algebrasMar 14 2000We study the representation ${\cal D}$ of a simple compact Lie algebra $\g$ of rank l constructed with the aid of the hermitian Dirac matrices of a (${\rm dim} \g$)-dimensional euclidean space. The irreducible representations of $\g$ contained in ${\cal ... More
s-wave superconductivity in the presence of local Coulomb correlationsJul 28 1999We derive the superconductiong mean-field equations for an attractive interaction, V, in the s-wave channel when local Coulomb interactions are taken into account for any value of U. Our results show that the Coulomb repulsion is detrimental to the critical ... More
Tests of mode coupling theory in a simple model for two-component miscible polymer blendsAug 06 2007Sep 26 2007We present molecular dynamics simulations on the structural relaxation of a simple bead-spring model for polymer blends. The introduction of a different monomer size induces a large time scale separation for the dynamics of the two components. Simulation ... More
Type-II Bose-Mott insulatorsJul 02 2012Sep 25 2012The Mott insulating state formed from bosons is ubiquitous in solid He-4, cold atom systems, Josephson junction networks and perhaps underdoped high-Tc superconductors. We predict that close to the quantum phase transition to the superconducting state ... More
A fractal set from the binary reflected Gray codeOct 14 2005The permutation associated with the decimal expression of the binary reflected Gray code with $N$ bits is considered. Its cycle structure is studied. Considered as a set of points, its self-similarity is pointed out. As a fractal, it is shown to be the ... More
Substrate concentration dependence of the diffusion-controlled steady-state rate constantDec 20 2004The Smoluchowski approach to diffusion-controlled reactions is generalized to interacting substrate particles by including the osmotic pressure and hydrodynamic interactions of the nonideal particles in the Smoluchoswki equation within a local-density ... More
Symplectic torus actions with coisotropic principal orbitsNov 28 2005Jan 10 2006In this paper we completely classify symplectic actions of a torus $T$ on a compact connected symplectic manifold $(M, \sigma)$ when some, hence every, principal orbit is a coisotropic submanifold of $(M, \sigma)$. That is, we construct an explicit model, ... More
A fast and accurate algorithm for solving Bernstein-Vandermonde linear sytemMay 22 2006Sep 27 2006A fast and accurate algorithm for solving a Bernstein-Vandermonde linear system is presented. The algorithm is derived by using results related to the bidiagonal decomposition of the inverse of a totally positive matrix by means of Neville elimination. ... More
Theory of incompressible MHD turbulence with scale-dependent alignment and cross-helicityMar 29 2009Feb 06 2010(Abridged) An anisotropic theory of MHD turbulence with nonvanishing cross-helicity is constructed based on Boldyrev's alignment hypothesis and probabilities p and q for fluctuations v and b to be positively or negatively aligned. Guided by observations ... More
Effects of dynamical evolution on the distribution of substructuresDec 15 2004We develop a semi-analytical model that determines the evolution of the mass, position and internal structure of dark matter substructures orbiting in dark matter haloes. We apply this model to the case of the Milky Way. We focus in particular on the ... More
Particle acceleration in ultra-relativistic parallel shock wavesDec 13 2002Monte-Carlo computations for highly relativistic parallel shock particle acceleration are presented for upstream flow gamma factors, $\Gamma=(1-V_{1}^{2}/c^{2})^{-0.5}$ with values between 5 and $10^{3}$. The results show that the spectral shape at the ... More
Pair Multiplicities and Pulsar DeathFeb 09 2001Through a simple model of particle acceleration and pair creation above the polar caps of rotation-powered pulsars, we calculate the height of the pair-formation front (PFF) and the dominant photon emission mechanism for the pulsars in the Princeton catalog. ... More
Quantum Weyl algebrasOct 30 1993For any Hecke symmetry $R$ there is a natural quantization $A_n(R)$ of the Weyl algebra $A_n$. The aim of this paper is to study some general ring-theoretic aspects of $A_n(R)$ and its relations to formal deformations of $A_n$. We also obtain further ... More
Seifert fibred knot manifoldsJan 09 2013Aug 05 2013We consider the question of when is the closed manifold obtained by elementary surgery on an $n$-knot Seifert fibred over a 2-orbifold. After some observations on the classical case, we concentrate on the cases n=2 and 3. We have found a new family of ... More
Origin of n- and p-type conductivity in undoped $α$-PbO: role of defectsApr 16 2013Nov 05 2013The first principles calculations (GGA) have been applied to study the crystallographic defects in $\alpha$-PbO in order to understand an origin of $n$- and $p$-type conductivity in otherwise undoped $\alpha$-PbO. It was found that deposition in the oxygen-deficient ... More
Comment on "Superconducting phases in the presence of Coulomb interaction: From weak to strong correlations''Mar 24 1999We examine the paper basic equations of T. Doma\'nski and K.I. Wysoki\'nski [Phys. Rev. B {\bf 59}, 173 (1999)], who calculated the critical superconducting temperature, T_c, in function of Coulomb correlations (U) for s- and d-wave order parameter symmetries. ... More
Scalar-Tensor Quantum Gravity in Two DimensionsJan 12 1992Jan 24 1992We discuss some classical and quantum properties of 2d gravity models involving metric and a scalar field. Different models are parametrized in terms of a scalar potential. We show that a general Liouville-type model with exponential potential and linear ... More
Domain Walls in Superfluid 3He-BAug 20 2004We consider domain walls between regions of superfluid 3He-B in which one component of the order parameter has the opposite sign in the two regions far from one another. We report calculations of the order parameter profile and the free energy for two ... More
Theory of Transition Temperature of Magnetic Double PerovskitesJun 13 2000We formulate a theory of double perovskite coumpounds such as Sr$_2$FeReO$_6$ and Sr$_2$FeMoO$_6$ which have attracted recent attention for their possible uses as spin valves and sources of spin polarized electrons. We solve the theory in the dynamical ... More
Dynamical Mean-Field Theory of Electron-Phonon Interactions in Correlated Systems: Application to Isotope Effects on Electronic PropertiesNov 26 2001Feb 09 2002We use a recently developed formalism (combining an adiabatic expansion and dynamical mean-field theory) to obtain expressions for isotope effects on electronic properties in correlated systems. As an example we calculate the isotope effect on electron ... More
String Theory and the Donaldson PolynomialAug 26 1991It is shown that the scattering of spacetime axions with fivebrane solitons of heterotic string theory at zero momentum is proportional to the Donaldson polynomial.
Proposition Algebra with Projective LimitsJul 23 2008Feb 19 2010Sequential propositional logic deviates from ordinary propositional logic by taking into account that during the sequential evaluation of a propositional statement,atomic propositions may yield different Boolean values at repeated occurrences. We introduce ... More
Finite temperature effects on anisotropic pressure and equation of state of dense neutron matter in an ultrastrong magnetic fieldJan 03 2013Jan 04 2013Spin polarized states in dense neutron matter with recently developed Skyrme effective interaction (BSk20 parametrization) are considered in the magnetic fields $H$ up to $10^{20}$ G at finite temperature. In a strong magnetic field, the total pressure ... More
Power correlations in cosmology: limits on primordial non-Gaussian density fieldsAug 15 1996We probe the statistical nature of the primordial density field by measuring correlations between the power in adjacent Fourier modes. For certain types of non-Gaussian field, these k-space correlations would be expected to be more extended than for a ... More
Green-Schwarz superstring action in a curved magnetic Ramond-Ramond backgroundApr 09 1998Apr 20 1998We derive the complete covariant action for the type IIA superstring in a simple D=10 background which represents a 7-brane with a magnetic Ramond-Ramond vector field (and is U-dual to the Kaluza-Klein Melvin solution). This curved background can be obtained ... More
One-loop four-graviton amplitude in eleven-dimensional supergravityJul 14 1997Jul 22 1997We find explicit expression for the one-loop four-graviton amplitude in eleven-dimensional supergravity compactified on a circle. Represented in terms of the string coupling (related to the compactification radius) it takes the form of an infinite sum ... More
Systematics of intermediate-energy single-nucleon removal cross sectionsSep 23 2014Oct 08 2014There is now a large and increasing body of experimental data and theoretical analyses for reactions that remove a single nucleon from an intermediate-energy beam of neutron- or proton-rich nuclei. In each such measurement, one obtains the inclusive cross ... More
Distinguishing Dark Matter from Modified GravitySep 28 2001Dynamical mass discrepancies in galaxies have two possible explanations: the existence of large amounts of dark matter or the breakdown of Newtonian gravity. True dark matter halos of galaxies could differ in several respects from apparent halos inferred ... More
Theory of electrically controlled exhibition of circular Bragg phenomenon by an obliquely excited structurally chiral material. Part 2: arbitrary dc electric fieldNov 01 2006Numerical examination of the solution of the boundary--value problem of the reflection and transmission of a plane wave due to a slab of an electro--optic structurally chiral material (SCM) indicates that the exhibition of the circular Bragg phenomenon ... More
Theory of electrically controlled exhibition of circular Bragg phenomenon by an obliquely excited structurally chiral materialOct 10 2006The boundary-value problem of the reflection and transmission of a plane wave due to a slab of an electro-optic structurally chiral material (SCM) is formulated in terms of a 4x4 matrix ordinary differential equation. The SCM slab can be locally endowed ... More
Spin polarized states in neutron matter at a strong magnetic fieldAug 10 2009Dec 28 2009Spin polarized states in neutron matter at a strong magnetic field are considered in the model with the Skyrme effective interaction (SLy4, SLy7 parametrizations). Analyzing the self-consistent equations at zero temperature, it is shown that a thermodynamically ... More
Spin ordered phase transitions in neutron matter under the presence of a strong magnetic fieldMar 01 2011In dense neutron matter under the presence of a strong magnetic field, considered in the model with the Skyrme effective interaction, there are possible two types of spin ordered states. In one of them the majority of neutron spins are aligned opposite ... More
Unbiased estimation of multi-fractal dimensions of finite data setsFeb 01 1996We present a novel method for determining multi-fractal properties from experimental data. It is based on maximising the likelihood that the given finite data set comes from a particular set of parameters in a multi-parameter family of well known multi-fractals. ... More
Massive neutrinos and lepton-flavour-violating processesSep 18 2001If neutrino masses and mixings are suitable to explain the atmospheric and solar neutrino fluxes, this amounts to contributions to FCNC processes, in particular $\mu\to e, \gamma$. If the theory is supersymmetric and the origin of the masses is a see-saw ... More
A Measurement of the Exclusive 3He(e,e'p) Reaction Below the Quasi-Elastic PeakOct 21 2003Aug 06 2004New, high-precision measurements of the 3He(e,e'p) reaction using the A1 collaboration spectrometers at the Mainz microtron MAMI are presented. These were performed in antiparallel kinematics at energy transfers below the quasi-elastic peak, and at a ... More
A Rainich-like approach to the Killing-Yano tensorsDec 20 2002Jan 17 2003The Rainich problem for the Killing-Yano tensors posed by Collinson \cite{col} is solved. In intermediate steps, we first obtain the necessary and sufficient conditions for a 2+2 almost-product structure to determine the principal 2--planes of a skew-symmetric ... More
Single particle nonlocality with completely independent reference statesJul 01 2008We describe a scheme to demonstrate the nonlocal properties of a single particle by showing a violation of Bell's inequality. The scheme is experimentally achievable as the only inputs are number states and mixed states, which serve as references to `keep ... More
Comment on ``Relativistic cluster dynamics of nucleons and mesons. II. Formalism and examples''Apr 07 1995In a recent paper [Phys.\ Rev.\ C{\bf 49}, 2142 (1994)], Haberzettl presented cluster N-body equations for arbitrarily large systems of nucleons and mesons. Application to the three-nucleon system is claimed to yield a new kind of three-nucleon force. ... More
Dark Matter Halo Mergers I: Dependence on Environment & Redshift EvolutionFeb 26 2009This paper presents a study of the specific merger rate as a function of group membership, local environment, and redshift in a very large, $500h^{-1} Mpc$, cosmological N-body simulation, the \textit{Millennium Simulation}. The goal is to provide environmental ... More
Does Dark Matter Exist?Sep 05 2000The success of the Lambda-CDM model on large scales does not extend down to galaxy scales. We list a dozen problems of the dark matter hypothesis, some of which arise in specific models for the formation of structure in the universe, while others are ... More
Guiding-center recursive Vlasov and Lie-transform methods in plasma physicsMar 25 2009The gyrocenter phase-space transformation used to describe nonlinear gyrokinetic theory is rediscovered by a recursive solution of the Hamiltonian dynamics associated with the perturbed guiding-center Vlasov operator. The present work clarifies the relation ... More
Anisotropic pressure in strange quark matter under the presence of a strong magnetic fieldOct 11 2012Jan 03 2013Thermodynamic properties of strange quark matter in strong magnetic fields $H$ up to $10^{20}$ G are considered within the MIT bag model at zero temperature implying the constraints of total baryon number conservation, charge neutrality and chemical equilibrium. ... More
Spin polarization phenomena in dense neutron matter at a strong magnetic fieldNov 04 2010Spin polarized states in neutron matter at strong magnetic fields up to $10^{18}$ G are considered in the model with the Skyrme effective interaction. Analyzing the self-consistent equations at zero temperature, it is shown that a thermodynamically stable ... More
Structural and electronic changes of pentacene induced by potassium dopingFeb 14 2017Potassium is introduced into the crystalline herringbone structure of pentacene searching for a compound showing metallic electronic transport properties and, hopefully, superconductivity at small enough temperatures. Several possible structures for stoichiometric ... More
Ultrafast single electron spin manipulation in 2D semiconductor quantum dots with optimally controlled time-dependent electric fields through spin-orbit couplingOct 23 2014We have studied theoretically the possibility of ultra-fast manipulation of a single electron spin in 2D semiconductor quantum dots, by means of high-frequency time-dependent electric fields. The electron spin degree of freedom is excited through spin-orbit ... More
The one-loop elastic coefficients for the Helfrich membrane in higher dimensionsMay 18 2004Jan 26 2005Using a covariant geometric approach we obtain the effective bending couplings for a 2-dimensional rigid membrane embedded into a $(2+D)$-dimensional Euclidean space. The Hamiltonian for the membrane has three terms: The first one is quadratic in its ... More
Schubert varieties and cycle spacesApr 02 2002Oct 02 2002Complex geometric properties of the orbits of a non-compact real form $G_0$ in a flag manifold $Z=G/Q$ of a complex semi-simple groups $G=G_0^\mathbb C$ are studied. Schubert varieties are used to construct a complex submanifold with optimal slice properties ... More
Superfluid phases of $^3$He in nano-scale channelsOct 06 2015Confinement of superfluid $^3$He on length scales comparable to the radial size of the p-wave Cooper pairs can greatly alter the phase diagram by stabilizing broken symmetry phases not observed in bulk $^3$He. We consider superfluid $^3$He confined within ... More
Disk heating and stellar migration in galaxiesMar 14 2000Jul 27 2000The paper claimed that significant radial migration of stars in a stellar disk like that of the Milky Way could not occur. We now think that while the treatment of the effects of molecular clouds was correct, the paper seriously underestimated the ability ... More
Gravito-magnetic vacuum spacetimes: kinematic restrictionsMar 12 2003We show that there are no vacuum solutions with a purely magnetic Weyl tensor with respect to an observer submitted to kinematic restrictions involving first order differential scalars. This result generalizes previous ones for the vorticity-free and ... More
On the classification of type D spacetimesDec 20 2002We give a classification of the type D spacetimes based on the invariant differential properties of the Weyl principal structure. Our classification is established using tensorial invariants of the Weyl tensor and, consequently, besides its intrinsic ... More
Electron-Phonon Interactions in Correlated Systems: Adiabatic Expansion of the Dynamical Mean-Field TheoryApr 12 2000Jan 29 2002We use the dynamical mean field theory to develop a systematic and computationally tractable method for studying electron-phonon interactions in systems with arbitrary electronic correlations. The method is formulated as an adiabatic expansion around ... More
Anisotropic pressure in dense neutron matter under the presence of a strong magnetic fieldDec 22 2011Dense neutron matter with recently developed BSk19 and BSk21 Skyrme effective forces is considered in magnetic fields up to $10^{20}$ G at zero temperature. The breaking of the rotational symmetry by the magnetic field leads to the differentiation between ... More
Finite temperature effects on spin polarization of neutron matter in a strong magnetic fieldMar 03 2010Sep 15 2010Spin polarization of neutron matter at finite temperatures and strong magnetic fields up to $10^{18}$ G is studied in the model with the Skyrme effective interaction. It is shown that, together with the thermodynamically stable branch of solutions for ... More
Oscillating neutrinos and mu --> e, gammaMar 06 2001Nov 07 2001If neutrino masses and mixings are suitable to explain the atmospheric and solar neutrino fluxes, this amounts to contributions to FCNC processes, in particular mu --> e, gamma. If the theory is supersymmetric and the origin of the masses is a see-saw ... More
Chaotic dynamics with MaximaJan 15 2013We present an introduction to the study of chaos in discrete and continuous dynamical systems using the CAS Maxima. These notes are intended to cover the standard topics and techniques: discrete and continuous logistic equation to model growth population, ... More
Dynamics of Barred GalaxiesAug 30 2006Some 30% of disc galaxies have a pronounced central bar feature in the disc plane and many more have weaker features of a similar kind. Kinematic data indicate that the bar constitutes a major non-axisymmetric component of the mass distribution and that ... More
Study of the glass transition in the amorphous interlamellar phase of highly crystallized poly(ethylene terephthalate)Jul 21 2009Jun 01 2010Poly(ethylene terephthalate) (PET) is a semi--crystalline polymer that can be crystallized to different degrees heating from the amorphous state. Even when primary crystallization has been completed, secondary crystallization can take place with further ... More
Electronic Transmission Through Metallic Nanowires: Generalized Scattering Matrix ApproachDec 14 2000An easy to implement and powerful method for the solution of 3D scattering problems that can be well described by Helmholtz equation is presented. The matrix algebra used provides excellent stability versus the number of junctions as well as great computational ... More
A consistent formalism for the Thomas-Ehrman Level DisplacementApr 26 2007Usage of the Thomas-Ehrman Level Displacement formalism has been examined. Mistakes and inconsistencies are found in several papers, being repeated in subsequent works. Here, we present a complete formalism with a consistent set of definitions. Full algorithms ... More
Radial Mixing in Galactic DiscsMar 28 2002Jul 03 2002We show that spiral waves in galaxy discs churn the stars and gas in a manner that largely preserves the overall angular momentum distribution and leads to little increase in random motion. Changes in the angular momenta of individual stars are typically ... More
Particle acceleration in ultra-relativistic oblique shock wavesDec 13 2002We perform Monte Carlo simulations of diffusive shock acceleration at highly relativistic oblique shock waves. High upstream flow Lorentz gamma factors are used, which are relevant to models of ultra relativistic particle shock acceleration in Active ... More
Soldered Bundle Background for the De Sitter TopMay 18 2005Aug 12 2005We prove that the mathematical framework for the de Sitter top system is the de Sitter fiber bundle. In this context, the concept of soldering associated with a fiber bundle plays a central role. We comment on the possibility that our formalism may be ... More
The de Sitter Relativistic Top TheoryMay 27 2004Aug 16 2004We discuss the relativistic top theory from the point of view of the de Sitter (or anti de Sitter) group. Our treatment rests on Hanson-Regge's spherical relativistic top lagrangian formulation. We propose an alternative method for studying spinning objects ... More
Self-dual gravity and self-dual Yang-Mills in the context of Macdowell-Mansouri formalismJul 20 1998In this work we propose an action which unifies self-dual gravity and self-dual Yang-Mills in the context of the Macdowell-Mansouri formalism. We claim that such an action may be used to find the S-dual action for both self-dual gravity and self-dual ... More
Glass-like dynamical behavior in hierarchical models submitted to continuous cooling and heating processesMar 15 2001Jul 02 2001The dynamical behavior of a kind of models with hierarchically constrained dynamics is investigated. The models exhibit many properties resembling real structural glasses. In particular, we focus on the study of time-dependent temperature processes. In ... More
Dynamics and steady state of a vibrated granular binary mixture modelApr 29 2003Sep 15 2003A model for the dynamical evolution of a granular binary mixture is analyzed. This system is submitted to a tapping procedure, similarly to what is done in real experiments. In the weak vibration limit, an effective dynamics for the tapping process is ... More
Pair-production multiplicities in rotation-powered pulsarsJul 11 2001We discuss the creation of electron-positron cascades in the context of pulsar polar cap acceleration models and derive several useful analytic and semi-analytic results for the spatial extent and energy response of the cascade. Instead of Monte Carlo ... More
Ab initio study on lattice thermal conductivity of Cu$_2$O using GGA and hybrid density functional methodsJul 03 2017Lattice thermal conductivity of Cu$_2$O was studied using ab initio density functional methods. The performance of generalized gradient approximation, GGA-PBE, and PBE0 exchange-correlation functionals was compared for various electronic and phonon-related ... More
Optimisation of out-vessel magnetic diagnostics for plasma boundary reconstruction in tokamaksJan 31 2013To improve the low frequency spectrum of magnetic field measurements of future tokamak reactors such as ITER, several steady state magnetic sensor technologies have been considered. For all the studied technologies it is always advantageous to place the ... More
Resolving the Reactor Neutrino Anomaly with the KATRIN Neutrino ExperimentMay 06 2011The KArlsruhe TRItium Neutrino experiment (KATRIN) combines an ultra-luminous molecular tritium source with an integrating high-resolution spectrometer to gain sensitivity to the absolute mass scale of neutrinos. The projected sensitivity of the experiment ... More
The Metallicity Dependence of Wolf-Rayet Mass LossOct 31 2007We produce models of early WN, WC, and WO stars as a function of metallicity Z using an analytic CAK-type approach. At log(Z / Z_sun) >= -2 both WN and WC stars have the approximate dependence Mdot \propto Z^{0.5}. For a WN wind the mass-loss rate drops ... More