Results for "C. Armendariz-Picon"

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On the Scale of InflationOct 27 2015Nov 03 2015Because the scale of inflation is conformal frame dependent, in order to fully characterize it one should quote its value in terms of all the independent equal-time dimensionless ratios in the theory. We argue that when couplings depend on the inflaton ... More
When Does the Inflaton Decay?Aug 31 2017Sep 05 2017In order for the inflaton to decay into radiation at the end of inflation, it needs to couple to light matter fields. In this article we determine whether such couplings cause the inflaton to decay during inflation rather than after it. We calculate decay ... More
On the Expected Production of Gravitational Waves During PreheatingMay 14 2019The existing predictions of the energy density of gravitational waves produced during preheating mostly rely on computer simulations in which the matter field inhomogeneities essentially behave classically. In this article we follow instead a full quantum ... More
Anisotropic Inflation and the Origin of Four Large DimensionsMay 27 2003Aug 20 2003In the context of (4+d)-dimensional general relativity, we propose an inflationary scenario wherein 3 spatial dimensions grow large, while d extra dimensions remain small. Our model requires that a self-interacting d-form acquire a vacuum expectation ... More
k-InflationApr 09 1999It is shown that a large class of higher-order (i.e. non-quadratic) scalar kinetic terms can, without the help of potential terms, drive an inflationary evolution starting from rather generic initial conditions. In many models, this kinetically driven ... More
Spinors, Inflation, and Non-Singular Cyclic CosmologiesJan 20 2003We consider toy cosmological models in which a classical, homogeneous, spinor field provides a dominant or sub-dominant contribution to the energy-momentum tensor of a flat Friedmann-Robertson-Walker universe. We find that, if such a field were to exist, ... More
Scale Invariance without Inflation?Jul 07 2003Sep 04 2003We propose a new alternative mechanism to seed a scale invariant spectrum of primordial density perturbations that does not rely on inflation. In our scenario, a perfect fluid dominates the early stages of an expanding, non-inflating universe. Because ... More
Haloes of k-EssenceMay 10 2005Jun 20 2005We study gravitationally bound static and spherically symmetric configurations of k-essence fields. In particular, we investigate whether these configurations can reproduce the properties of dark matter haloes. The classes of Lagrangians we consider lead ... More
Vacuum Choices and the Predictions of InflationMar 11 2003In the presence of a short-distance cutoff, the choice of a vacuum state in an inflating, non-de Sitter universe is unavoidably ambiguous. The ambiguity is related to the time at which initial conditions for the mode functions are specified and to the ... More
A Dynamical Solution to the Problem of a Small Cosmological Constant and Late-time Cosmic AccelerationApr 11 2000Increasing evidence suggests that most of the energy density of the universe consists of a dark energy component with negative pressure, a ``cosmological constant" that causes the cosmic expansion to accelerate. In this paper, we address the puzzle of ... More
Essentials of k-essenceJun 27 2000We recently introduced the concept of "k-essence" as a dynamical solution for explaining naturally why the universe has entered an epoch of accelerated expansion at a late stage of its evolution. The solution avoids fine-tuning of parameters and anthropic ... More
BRST Quantization of Cosmological PerturbationsJun 13 2016BRST quantization is an elegant and powerful method to quantize theories with local symmetries. In this article we study the Hamiltonian BRST quantization of cosmological perturbations in a universe dominated by a scalar field, along with the closely ... More
Quantum Equivalence Principle Violations in Scalar-Tensor TheoriesAug 30 2011We study the equivalence principle and its violations by quantum effects in scalar-tensor theories that admit a conformal frame in which matter only couples to the spacetime metric. These theories possess Ward identities that guarantee the validity of ... More
BRST Quantization of Cosmological PerturbationsJun 13 2016Nov 09 2016BRST quantization is an elegant and powerful method to quantize theories with local symmetries. In this article we study the Hamiltonian BRST quantization of cosmological perturbations in a universe dominated by a scalar field, along with the closely ... More
Measuring the Speed of Sound of QuintessenceDec 19 2001Quintessence, a time-varying energy component that may account for the accelerated expansion of the universe, can be characterized by its equation of state and sound speed. In this paper, we show that if the quintessence density is at least one percent ... More
How Cold is Cold Dark Matter?Sep 26 2013Mar 31 2014If cold dark matter consists of particles, these must be non-interacting and non-relativistic by definition. In most cold dark matter models however, dark matter particles inherit a non-vanishing velocity dispersion from interactions in the early universe, ... More
Aether UnleashedApr 06 2009Nov 20 2009We follow a low-energy effective theory approach to identify the general class of theories that describes a vector field (of unconstrained norm) coupled to gravity. The resulting set may be regarded as a generalization of the conventional vector-tensor ... More
Where does Cosmological Perturbation Theory Break Down?May 01 2008We apply the effective field theory approach to the coupled metric-inflaton system, in order to investigate the impact of higher dimension operators on the spectrum of scalar and tensor perturbations in the short-wavelength regime. In both cases, effective ... More
General Covariance Constraints on Cosmological CorrelatorsOct 31 2014We study the extent to which diffeomorphism invariance restricts the properties of the primordial perturbations in single scalar field models. We derive a set of identities that constrain the connected correlators of the cosmological perturbations, as ... More
Preheating in Derivatively-Coupled Inflation ModelsJul 16 2007Nov 27 2007We study preheating in theories where the inflaton couples derivatively to scalar and gauge fields. Such couplings may dominate in natural models of inflation, in which the flatness of the inflaton potential is related to an approximate shift symmetry ... More
Effective Theory Approach to the Spontaneous Breakdown of Lorentz InvarianceApr 30 2010We generalize the coset construction of Callan, Coleman, Wess and Zumino to theories in which the Lorentz group is spontaneously broken down to one of its subgroups. This allows us to write down the most general low-energy effective Lagrangian in which ... More
Primordial Perturbations in Einstein-Aether and BPSH TheoriesMar 05 2010Mar 22 2010We study the primordial perturbations generated during a stage of single-field inflation in Einstein-aether theories. Quantum fluctuations of the inflaton and aether fields seed long wavelength adiabatic and isocurvature scalar perturbations, as well ... More
The Impact of Molecular Polarization on the Electronic Properties of Molecular SemiconductorsJun 13 2003Oct 15 2003In a molecular semiconductor, the carrier is dressed with a polarization cloud that we treat as a quantum field of Frenkel excitons coupled to it. The consequences of the existence of this electronic polaron on the dynamics of an extra charge in a material ... More
Regularity of maximal functions on Hardy-Sobolev spacesNov 04 2017Apr 22 2018We prove that maximal operators of convolution type associated to smooth kernels are bounded in the homogeneous Hardy-Sobolev spaces $\dot{H}^{1,p}(\mathbb{R}^d)$ when $1/p < 1+1/d$. This range of exponents is sharp. As a by-product of the proof, we obtain ... More
Fundamental Physics at the Intensity FrontierMay 11 2012The Proceedings of the 2011 workshop on Fundamental Physics at the Intensity Frontier. Science opportunities at the intensity frontier are identified and described in the areas of heavy quarks, charged leptons, neutrinos, proton decay, new light weakly-coupled ... More
Evolution of event-by-event transverse-energy fluctuations over collision centrality in RHIC interactionsJan 10 2007Preliminary results are presented for two analyses of transverse energy (ET) production measured with the electromagnetic calorimeters of the Pioneering High Energy Nuclear Interaction Experiment (PHENIX), in nuclear interactions in Au+Au heavy-ion collisions ... More
Fractional Hardy-Sobolev inequalities for canceling elliptic differential operatorsSep 22 2018Let $A(D)$ be an elliptic homogeneous linear differential operator of order $\nu$ on $\mathbb{R}^{N}$, $N \geq 2$, from a complex vector space E to a complex vector space F. In this paper we show that if $\ell\in \mathbb{R}$ satisfies $0< \ell <N$ and ... More
Continuous solutions for divergence-type equations associated to elliptic systems of complex vector fieldsJan 11 2017In this paper, we characterize all the distributions $F \in \mathcal{D}'(U)$ such that there exists a continuous weak solution $v \in C(U,\mathbb{C}^{n})$ (with $U \subset \Omega$) to the divergence-type equation $$L_{1}^{*}v_{1}+...+L_{n}^{*}v_{n}=F,$$ ... More
Analytic evaluation of Hecke eigenvalues for classical modular formsJun 05 2018We describe an efficient method for computing approximations to the Hecke eigenvalues of classical modular eigenforms, describe its implementation in SageMath and compare it to the modular symbols method.
A Quantum Field Theory Twist to Photon Angular MomentumSep 06 2005A quantum field theory approach is put forward to generalize the concept of classical spatial light beams carrying orbital angular momentum to the single-photon level. This quantization framework is carried out both in the paraxial and nonparaxial regimes. ... More
Pseudodifferential Operators, Rellich-Kondrachov Theorem and Hardy-Sobolev SpacesMar 31 2017Oct 09 2018We will present versions of the Rellich-Kondrachov theorem for pseudo-differential operators acting on localizable Hardy spaces. One of the techniques includes boundedness properties for pseudodifferential operators with symbols in the H\"ormander class, ... More
Contractions of Filippov algebrasSep 02 2010Jan 11 2011We introduce in this paper the contractions $\mathfrak{G}_c$ of $n$-Lie (or Filippov) algebras $\mathfrak{G}$ and show that they have a semidirect structure as their $n=2$ Lie algebra counterparts. As an example, we compute the non-trivial contractions ... More
The critical exponent(s) for the semilinear fractional diffusive equationSep 11 2017In this paper we show that there exist two different critical exponents for global small data solutions to the semilinear fractional diffusive equation with Caputo fractional derivative in time. The second critical exponent appears if the second data ... More
Supersolid phase with cold polar molecules on a triangular latticeJun 11 2009We study a system of heteronuclear molecules on a triangular lattice and analyze the potential of this system for the experimental realization of a supersolid phase. The ground state phase diagram contains superfluid, solid and supersolid phases. At finite ... More
Phase separation versus supersolid behavior in frustrated antiferromagnetsMay 04 2010May 10 2011We investigate the competition between spin-supersolidity and phase separation in a frustrated spin-half model of weakly coupled dimers. We start by considering systems of hard-core bosons on the square lattice, onto which the low-energy physics of the ... More
Quantum coherence and carriers mobility in organic semiconductorsSep 19 2006Jan 24 2007We present a model of charge transport in organic molecular semiconductors based on the effects of lattice fluctuations on the quantum coherence of the electronic state of the charge carrier. Thermal intermolecular phonons and librations tend to localize ... More
Statistics of the electromagnetic response of a chaotic reverberation chamberSep 20 2014This article presents a study of the electromagnetic response of a chaotic reverberation chamber (RC) in the presence of losses. By means of simulations and of experiments, the fluctuations in the maxima of the field obtained in a conventional mode-stirred ... More
Unconventional magnetization plateaus in a Shastry-Sutherland spin tubeMar 08 2010Jun 21 2011Using density matrix renormalization group (DMRG) and perturbative continuous unitary transformations (PCUTs), we study the magnetization process in a magnetic field for all coupling strengths of a quasi-1D version of the 2D Shastry-Sutherland lattice, ... More
Extensions, expansions, Lie algebra cohomology and enlarged superspacesJan 07 2004Jan 08 2004After briefly reviewing the methods that allow us to derive consistently new Lie (super)algebras from given ones, we consider enlarged superspaces and superalgebras, their relevance and some possible applications.
On BPS preons, generalized holonomies and D=11 supergravitiesDec 22 2003Feb 10 2004We develop the BPS preon conjecture to analyze the supersymmetric solutions of D=11 supergravity. By relating the notions of Killing spinors and BPS preons, we develop a moving G-frame method (G=GL(32,R), SL(32,R) or Sp(32,R)) to analyze their associated ... More
Mechanisms for Spin-Supersolidity in S=1/2 Spin-Dimer AntiferromagnetsJul 25 2008Using perturbative expansions and the contractor renormalization (CORE) algorithm, we obtain effective hard-core bosonic Hamiltonians describing the low-energy physics of $S=1/2$ spin-dimer antiferromagnets known to display supersolid phases under an ... More
Expansions of algebras and superalgebras and some applicationsMar 02 2007After reviewing the three well-known methods to obtain Lie algebras and superalgebras from given ones, namely, contractions, deformations and extensions, we describe a fourth method recently introduced, the expansion of Lie (super)algebras. Expanded (super)algebras ... More
Transverse-energy distributions at midrapidity in $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at $\sqrt{s_{_{NN}}}=62.4$--200~GeV and implications for particle-production modelsDec 23 2013Measurements of the midrapidity transverse energy distribution, $d\Et/d\eta$, are presented for $p$$+$$p$, $d$$+$Au, and Au$+$Au collisions at $\sqrt{s_{_{NN}}}=200$ GeV and additionally for Au$+$Au collisions at $\sqrt{s_{_{NN}}}=62.4$ and 130 GeV. The ... More
Measurement of neutral mesons in p+p collisions at sqrt(s) = 200 GeV and scaling properties of hadron productionMay 20 2010The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the invariant differential cross section for production of K^0_S , \omega, \eta prime, and \phi mesons in p + p collisions at = 200 GeV. Measurements \omega and \phi production ... More
Supersymmetric string model with 30 kappa--symmetries in an extended D=11 superspace and 30/ 32 BPS statesJul 11 2003Dec 23 2003A supersymmetric string model in the D=11 superspace maximally extended by antisymmetric tensor bosonic coordinates, $\Sigma^{(528|32)}$, is proposed. It possesses 30 $\kappa$-symmetries and 32 target space supersymmetries. The usual preserved supersymmetry-$\kappa$-symmetry ... More
Generalized curvature and the equations of D=11 supergravityJan 03 2005Apr 11 2005It is known that, for zero fermionic sector, the bosonic equations of Cremmer-Julia-Scherk eleven-dimensional supergravity can be collected in a compact expression which is a condition on the curvature of the generalized connection. Here we peresent the ... More
On the formulation of D=11 supergravity and the composite nature of its three-from fieldSep 08 2004May 05 2005The underlying gauge group structure of the D=11 Cremmer-Julia-Scherk supergravity becomes manifest when its three-form field A_3 is expressed through a set of one-form gauge fields. These are associated with the generators of the elements of a family ... More
On the underlying gauge group structure of D=11 supergravityJun 02 2004The underlying gauge group structure of D=11 supergravity is revisited (see paper for detailed abstract).
Inclusive cross sections, charge ratio and double-helicity asymmetries for $π^+$ and $π^-$ production in $p$$+$$p$ collisions at $\sqrt{s}$=200 GeVSep 05 2014We present the midrapidity charged pion invariant cross sections and the ratio of $\pi^-$-to-$\pi^+$ production ($5<p_T<13$ GeV/$c$), together with the double-helicity asymmetries ($5<p_T<12$ GeV/$c$) in polarized $p$$+$$p$ collisions at $\sqrt{s} = 200$ ... More
Frustration induced plateaux in S>=1/2 Heisenberg spin laddersJul 09 2009Dec 07 2009We study the T = 0 magnetization of frustrated two-leg spin ladders with arbitrary value of the spin S. In the strong rung limit, we use degenerate perturbation theory to prove that frustration leads to magnetization plateaux at fractional values of the ... More
Generating Lie and gauge free differential (super)algebras by expanding Maurer-Cartan forms and Chern-Simons supergravityDec 31 2002We study how to generate new Lie algebras $\mathcal{G}(N_0,..., N_p,...,N_n)$ from a given one $\mathcal{G}$. The (order by order) method consists in expanding its Maurer-Cartan one-forms in powers of a real parameter $\lambda$ which rescales the coordinates ... More
Cold-nuclear-matter effects on heavy-quark production at forward and backward rapidity in d+Au collisions at sqrt(s_NN)=200 GeVOct 03 2013The PHENIX experiment has measured open heavy-flavor production via semileptonic decay muons over the transverse momentum range 1 < pT < 6 GeV/c at forward and backward rapidity (1.4 < |y| < 2.0) in d+Au and p+p collisions at ?sNN = 200 GeV. In central ... More
Cross Section and Parity Violating Spin Asymmetries of W^+/- Boson Production in Polarized p+p Collisions at sqrt(s)=500 GeVSep 02 2010Sep 03 2010Large parity violating longitudinal single spin asymmetries A^{e^-}_L= -0.86^{+0.14}_{-0.30} and A^{e^+}_L= 0.88^{+0.12}_{-0.71} are observed for inclusive high transverse momentum electrons and positrons in polarized pp collisions at a center of mass ... More
Double Spin Asymmetry of Electrons from Heavy Flavor Decays in p+p Collisions at sqrt(s)=200 GeVSep 14 2012We report on the first measurement of double-spin asymmetry, A_LL, of electrons from the decays of hadrons containing heavy flavor in longitudinally polarized p+p collisions at sqrt(s)=200 GeV for p_T= 0.5 to 3.0 GeV/c. The asymmetry was measured at mid-rapidity ... More
Systematic Study of Azimuthal Anisotropy in Cu$+$Cu and Au$+$Au Collisions at $\sqrt{s_{_{NN}}} = 62.4$ and 200 GeVDec 02 2014Sep 18 2015We have studied the dependence of azimuthal anisotropy $v_2$ for inclusive and identified charged hadrons in Au$+$Au and Cu$+$Cu collisions on collision energy, species, and centrality. The values of $v_2$ as a function of transverse momentum $p_T$ and ... More
Measurement of long-range angular correlation and quadrupole anisotropy of pions and (anti)protons in central $d$$+$Au collisions at $\sqrt{s_{_{NN}}}$=200 GeVApr 29 2014Apr 01 2015We present azimuthal angular correlations between charged hadrons and energy deposited in calorimeter towers in central $d$$+$Au and minimum bias $p$$+$$p$ collisions at $\sqrt{s_{_{NN}}}=200$ GeV. The charged hadron is measured at midrapidity $|\eta|<0.35$, ... More
Identified charged hadron production in p+p collisions at sqrt(s)=200 and 62.4 GeVFeb 03 2011Transverse momentum distributions and yields for $\pi^{\pm}$, $K^{\pm}$, $p$ and $\bar{p}$ in $p+p$ collisions at $\sqrt{s}$=200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC). These data ... More
Inclusive double-helicity asymmetries in neutral pion and eta meson production in $\vec{p}+\vec{p}$ collisions at $\sqrt{s}=200$ GeVFeb 25 2014Results are presented from data recorded in 2009 by the PHENIX experiment at the Relativistic Heavy Ion Collider for the double-longitudinal spin asymmetry, $A_{LL}$, for $\pi^0$ and $\eta$ production in $\sqrt{s} = 200$ GeV polarized $p$$+$$p$ collisions. ... More
Nuclear-Modification Factor for Open-Heavy-Flavor Production at Forward Rapidity in Cu+Cu Collisions at sqrt(s_NN)=200 GeVApr 03 2012Background: Heavy-flavor production in p+p collisions tests perturbative-quantum-chromodynamics (pQCD) calculations. Modification of heavy-flavor production in heavy-ion collisions relative to binary-collision scaling from p+p results, quantified with ... More
The ALPS project release 2.0: Open source software for strongly correlated systemsJan 13 2011May 23 2011We present release 2.0 of the ALPS (Algorithms and Libraries for Physics Simulations) project, an open source software project to develop libraries and application programs for the simulation of strongly correlated quantum lattice models such as quantum ... More
System-size dependence of open-heavy-flavor production in nucleus-nucleus collisions at $\sqrt{s_{_{NN}}}$=200 GeVOct 30 2013The PHENIX Collaboration at the Relativistic Heavy Ion Collider has measured open heavy flavor production in Cu$+$Cu collisions at $\sqrt{s_{_{NN}}}$=200 GeV through the measurement of electrons at midrapidity that originate from semileptonic decays of ... More
Measurement of Direct Photons in Au+Au Collisions at sqrt(s_NN) = 200 GeVMay 25 2012We report the measurement of direct photons at midrapidity in Au+Au collisions at sqrt{s_NN} = 200 GeV. The direct photon signal was extracted for the transverse-momentum range of 4 GeV/c < p_T < 22 GeV/c, using a statistical method to subtract decay ... More
High p_T Direct Photon and pi^0 Triggered Azimuthal Jet Correlations in sqrt(s)=200 GeV p+p CollisionsJun 07 2010Correlations of charged hadrons of 1 < pT < 10 GeV/c with high pT direct photons and pi^ 0 mesons in the range 5 <pT < 15 GeV/c are used to study jet fragmentation in the photon+jet and di-jet channels, respectively. The magnitude of the partonic transverse ... More
Cross section and double helicity asymmetry for eta mesons and their comparison to neutral pion production in p+p collisions at sqrt(s)=200 GeVSep 30 2010Oct 01 2010Measurements of double-helicity asymmetries for inclusive hadron production in polarized p+p collisions are sensitive to helicity--dependent parton distribution functions, in particular to the gluon helicity distribution, Delta(g). This study focuses ... More
Heavy Quark Production in p+p and Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at sqrt(s_NN)=200 GeVMay 10 2010May 17 2010Transverse momentum (p^e_T) spectra of electrons from semileptonic weak decays of heavy flavor mesons in the range of 0.3 < p^e_T < 9.0 GeV/c have been measured at mid-rapidity (|eta| < 0.35) by the PHENIX experiment at the Relativistic Heavy Ion Collider ... More
Production of omega mesons in p+p, d+Au, Cu+Cu, and Au+Au collisions at sqrt(s_NN)=200 GeVMay 17 2011The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has measured omega meson production via leptonic and hadronic decay channels in p+p, d+Au, Cu+Cu, and Au+Au collisions at sqrt(s_NN) = 200 GeV. The invariant transverse momentum spectra ... More
Event Structure and Double Helicity Asymmetry in Jet Production from Polarized p+p Collisions at sqrt(s) = 200 GeVSep 24 2010We report on event structure and double helicity asymmetry ($A_LL$) of jet production in longitudinally polarized p+p collisions at $\sqrt{s}$=200 GeV. Photons and charged particles were measured at midrapidity $|\eta| < 0.35$ with the requirement of ... More
Direct photon production in d+Au collisions at sqrt(s_NN)=200 GeVAug 06 2012Direct photons have been measured in sqrt(s_NN)=200 GeV d+Au collisions at midrapidity. A wide p_T range is covered by measurements of nearly-real virtual photons (1<p_T<6 GeV/c) and real photons (5<p_T<16 GeV/c). The invariant yield of the direct photons ... More
Low-mass vector-meson production at forward rapidity in $p$$+$$p$ collisions at $\sqrt{s}=200$ GeVMay 16 2014The PHENIX experiment at the Relativistic Heavy Ion Collider has measured low mass vector meson, $\omega$, $\rho$, and $\phi$, production through the dimuon decay channel at forward rapidity ($1.2<|y|<2.2$) in $p$$+$$p$ collisions at $\sqrt{s}=200$ GeV. ... More
Nuclear modification factors of phi mesons in d+Au, Cu+Cu and Au+Au collisions at sqrt(S_NN)=200 GeVApr 20 2010Apr 21 2010The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has performed systematic measurements of phi meson production in the K+K- decay channel at midrapidity in p+p, d+Au, Cu+Cu and Au+Au collisions at sqrt(S_NN)=200 GeV. Results are presented ... More
$φ$ meson production in the forward/backward rapidity region in Cu$+$Au collisions at $\sqrt{s_{NN}}=200$ GeVSep 21 2015Feb 04 2016The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) has measured $\phi$ meson production and its nuclear modification in asymmetric Cu$+$Au heavy-ion collisions at $\sqrt{s_{NN}}=200$ GeV at both forward Cu-going direction ($1.2<y<2.2$) ... More
Medium modification of jet fragmentation in Au+Au collisions at sqrt(s_NN)=200 GeV measured in direct photon-hadron correlationsDec 13 2012Dec 17 2012The jet fragmentation function is measured with direct photon-hadron correlations in p+p and Au+Au collisions at sqrt(s_NN)=200 GeV. The p_T of the photon is an excellent approximation to the initial p_T of the jet and the ratio z_T=p_T^h/p_T^\gamma is ... More
COOLL: Controlled On/Off Loads Library, a Public Dataset of High-Sampled Electrical Signals for Appliance IdentificationNov 17 2016This paper gives a brief description of the Controlled On/Off Loads Library (COOLL) dataset. This latter is a dataset of high-sampled electrical current and voltage measurements representing individual appliances consumption. The measurements were taken ... More
Upsilon (1S+2S+3S) production in d+Au and p+p collisions at sqrt(s_NN)=200 GeV and cold-nuclear matter effectsNov 16 2012The three Upsilon states, Upsilon(1S+2S+3S), are measured in d+Au and p+p collisions at sqrt(s_NN)=200 GeV and rapidities 1.2<|y|<2.2 by the PHENIX experiment at the Relativistic Heavy-Ion Collider. Cross sections for the inclusive Upsilon(1S+2S+3S) production ... More
Low-momentum direct photon measurement in Cu$+$Cu collisions at $\sqrt{s_{_{NN}}}=200$ GeVMay 10 2018Oct 19 2018We have measured direct photons for $p_T<5~$GeV/$c$ in minimum bias and 0\%--40\% most central events at midrapidity for Cu$+$Cu collisions at $\sqrt{s_{_{NN}}}=200$ GeV. The $e^{+}e^{-}$ contribution from quasi-real direct virtual photons has been determined ... More
A theorem of Mislin for cohomology of fusion systems and applications to block algebras of finite groupsNov 15 2013Dec 10 2014We give an algebraic proof for a theorem of Mislin in the case of cohomology of saturated fusion systems defined on p-groups when p is odd. Some applications of this theorem to block algebras of finite groups are also given.
Stückelberg Field Shiftting Quantization of Free-Particle on D-Dimensional SphereAug 11 2000In this paper we quantize the free-particle on a D-dimensional sphere in an unambiguous way by converting the second-class constraint using St\"uckelberg field shiftting formalism. Further, we argument that this formalism is equivalent to the BFFT constraint ... More
Entanglement and topological entropy of the toric code at finite temperatureApr 27 2007Nov 01 2007We calculate exactly the von Neumann and topological entropies of the toric code as a function of system size and temperature. We do so for systems with infinite energy scale separation between magnetic and electric excitations, so that the magnetic closed ... More
Dynamical shift conditions for the Z4 and BSSN hyperbolic formalismsJan 07 2004Mar 22 2004A class of dynamical shift conditions is shown to lead to a strongly hyperbolic evolution system, both in the Z4 and in the BSSN Numerical Relativity formalisms. This class generalizes the harmonic shift condition, where light speed is the only non-trivial ... More
Auger recombination and carrier multiplication in embedded silicon and germanium nanocrystalsSep 10 2007Apr 16 2008For Si and Ge nanocrystals (NCs) embedded in wide band-gap matrices, Auger recombination (AR) and carrier multiplication (CM) lifetimes are computed exactly in a three-dimensional real space grid using empirical pseudopotential wave functions. Our results ... More
Theoretical study of the insulating oxides and nitrides: SiO2, GeO2, Al2O3, Si3N4, and Ge3N4Oct 06 2006Jul 23 2007An extensive theoretical study is performed for wide bandgap crystalline oxides and nitrides, namely, SiO_{2}, GeO_{2}, Al_{2}O_{3}, Si_{3}N_{4}, and Ge_{3}N_{4}. Their important polymorphs are considered which are for SiO_{2}: $\alpha$-quartz, $\alpha$- ... More
A simple stochastic model for the evolution of protein lengthsMar 26 2007Mar 26 2007We analyse a simple discrete-time stochastic process for the theoretical modeling of the evolution of protein lengths. At every step of the process a new protein is produced as a modification of one of the proteins already existing and its length is assumed ... More
Staggered Chiral Perturbation TheoryAug 28 2003We discuss how to formulate a staggered chiral perturbation theory. This amounts to a generalization of the Lee-Sharpe Lagrangian to include more than one flavor (i.e. multiple staggered fields), which turns out to be nontrivial. One loop corrections ... More
Dark Matter in a single-metric universeJan 04 2016Mar 01 2016A few years ago Baker proposed a metric, implementing the Bona-Stela construction, which interpolates smoothly between the Schwarzschild metric at small scales and the Friedmann-Robertson-Walker (FRW) metric at large scales. As it stands, by enforcing ... More
Eccentric Binary Millisecond PulsarsJul 18 2009In this paper we review the recent discovery of several millisecond pulsars (MSPs) in eccentric binary systems. Timing these MSPs we were able to estimate (and in one case precisely measure) their masses. These results suggest that, as a class, MSPs have ... More
Understanding Convolutional Neural Networks with A Mathematical ModelSep 14 2016Nov 02 2016This work attempts to address two fundamental questions about the structure of the convolutional neural networks (CNN): 1) why a non-linear activation function is essential at the filter output of every convolutional layer? 2) what is the advantage of ... More
Light-front representation of chiral dynamics in peripheral transverse densitiesMar 16 2015The nucleon's electromagnetic form factors are expressed in terms of the transverse densities of charge and magnetization at fixed light-front time. At peripheral transverse distances $b = O(M_\pi^{-1})$ the densities are governed by chiral dynamics and ... More
On the density of the sum of two independent Student t-random vectorsJun 16 2009In this paper, we find an expression for the density of the sum of two independent $d-$dimensional Student $t-$random vectors $\mathbf{X}$ and $\mathbf{Y}$ with arbitrary degrees of freedom. As a byproduct we also obtain an expression for the density ... More
Detection of Optical Synchrotron Emission from the Radio Jet of 3C279Oct 08 2002Nov 05 2002We report the detection of optical and ultraviolet emission from the kiloparsec scale jet of the well-known quasar 3C~279. A bright knot, discovered in archival V and U band {\it Hubble Space Telescope} Faint Object Camera images, is coincident with a ... More
Some General Expressions for the Coefficient of the 14th Chern FormMay 03 1999Some general expressions are given for the coefficient of the 14th Chern form in terms of the Riemann-Christoffel curvature tensor and some of its concomitants (e.g., Pontrjagin's characteristic tensors) for n-dimensional differentiable manifolds having ... More
Simple Formulas for Generating Chern-Simons Basic Invariant Polynomials by Repeated Exterior DifferentiationOct 14 1998Simple formulas are given for generating Chern-Simons basic invariant polynomials by repeated exterior differentiation for n-dimensional differentiable manifolds having a general linear connection.
A General Expression for the Quartic Lovelock TensorMar 27 1997A general expression is given for the quartic Lovelock tensor in terms of the Riemann-Christoffel and Ricci curvature tensors and the Riemann curvature scalar for n-dimensional differentiable manifolds having a general linear connection. In addition, ... More
Pioneer 10/11 clock acceleration from Schwarzschild metric and Flyby energy IncreaseJul 01 2019Jul 05 2019We find that a velocity dependent component from the Schwarzschild metric factor could lead to a significant clock acceleration when the spacecraft has a sufficiently large radial velocity. For Pioneer 10, this acceleration is about $40\%$ of the observed ... More
On the numerical evaluation of algebro-geometric solutions to integrable equationsJul 11 2011Dec 06 2011Physically meaningful periodic solutions to certain integrable partial differential equations are given in terms of multi-dimensional theta functions associated to real Riemann surfaces. Typical analytical problems in the numerical evaluation of these ... More
Understanding Convolutional Neural Networks with A Mathematical ModelSep 14 2016This work attempts to address two fundamental questions about the structure of the convolutional neural networks (CNN): 1) why a non-linear activation function is essential at the filter output of every convolutional layer? 2) what is the advantage of ... More
Threshold effects in open-string theoryMay 05 1996May 14 1996We analyze the one-loop effective gauge-field action in $Z_2$-orbifold compactifications of type-I theory. We show how, for non-abelian group factors, the threshold effects are ultraviolet finite though given entirely by a six-dimensional field theory ... More
Hidden Symmetry of a Fluid Dynamical ModelMay 28 2001A connection between solutions of the relativistic d-brane system in (d+1) dimensions with the solutions of a Galileo invariant fluid in d-dimensions is by now well established. However, the physical nature of the light-cone gauge description of a relativistic ... More
A quantum topological phase transition at the microscopic levelJul 13 2007Mar 01 2008We study a quantum phase transition between a phase which is topologically ordered and one which is not. We focus on a spin model, an extension of the toric code, for which we obtain the exact ground state for all values of the coupling constant that ... More
Explicit Gravitational Radiation in Hyperbolic Systems for Numerical RelativityFeb 14 2002Feb 28 2002A method for studying the causal structure of space-time evolution systems is presented. This method, based on a generalization of the well known Riemann problem, provides intrinsic results which can be interpreted from the geometrical point of view. ... More