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Results for "R. E. Sagastizabal"

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Low-cost error mitigation by symmetry verificationJul 26 2018Jan 02 2019We investigate the performance of error mitigation via measurement of conserved symmetries on near-term devices. We present two protocols to measure conserved symmetries during the bulk of an experiment, and develop a zero-cost post-processing protocol ... More
Calculating energy derivatives for quantum chemistry on a quantum computerMay 09 2019Modeling chemical reactions and complicated molecular systems has been proposed as the `killer application' of a future quantum computer. Accurate calculations of derivatives of molecular eigenenergies are essential towards this end, allowing for geometry ... More
Calculating energy derivatives for quantum chemistry on a quantum computerMay 09 2019Jun 17 2019Modeling chemical reactions and complicated molecular systems has been proposed as the `killer application' of a future quantum computer. Accurate calculations of derivatives of molecular eigenenergies are essential towards this end, allowing for geometry ... More
Time-domain characterization and correction of on-chip distortion of control pulses in a quantum processorJul 10 2019We introduce Cryoscope, a method for sampling on-chip baseband pulses used to dynamically control qubit frequency in a quantum processor. We specifically use Cryoscope to measure the step response of the dedicated flux control lines of two-junction transmon ... More
Error Mitigation by Symmetry Verification on a Variational Quantum EigensolverFeb 28 2019Variational quantum eigensolvers offer a small-scale testbed to demonstrate the performance of error mitigation techniques with low experimental overhead. We present successful error mitigation by applying the recently proposed symmetry verification technique ... More
Chip-to-chip entanglement of transmon qubits using engineered measurement fieldsDec 17 2017While the on-chip processing power in circuit QED devices is growing rapidly, an open challenge is to establish high-fidelity quantum links between qubits on different chips. Here, we show entanglement between transmon qubits on different cQED chips with ... More
Experimentally simulating the dynamics of quantum light and matter at ultrastrong couplingOct 31 2016The quantum Rabi model describing the fundamental interaction between light and matter is a cornerstone of quantum physics. It predicts exotic phenomena like quantum phase transitions and ground-state entanglement in the ultrastrong-coupling (USC) regime, ... More
Constraints on Cosmic Strings due to Black Holes Formed from Collapsed Cosmic String LoopsJun 03 1993The cosmological features of primordial black holes formed from collapsed cosmic string loops are studied. Observational restrictions on a population of primordial black holes are used to restrict $f$, the fraction of cosmic string loops which collapse ... More
Flavor content of the nucleon in an unquenched quark modelDec 02 2008We discuss the flavor content of the nucleon in an unquenched quark model in which the effects of quark-antiquark pairs (up, down and strange) are taken into account in an explicit form. It is shown that the inclusion of quark-antiquark pairs leads to ... More
Dynamics of Axisymmetric Truncated Dynamo ModelsAug 20 1998An important question regarding the study of mean field dynamo models is how to make precise the nature of their underlying dynamics. This is difficult both because relatively little is known about the dynamical behaviour of infinite dimensional systems ... More
Mean Field theory of the spin-Peierls transitionJul 21 2004Oct 07 2004We revisit the problem of the spin-Peierls instability in a one dimensional spin-1/2 chain coupled to phonons. The phonons are treated within the mean field approximation. We use bosonization techniques to describe the gapped spin chain and then use the ... More
Charge Density Waves and Bond Order Waves in a quarter filled extended Hubbard ladderFeb 17 2003Mar 15 2003We investigate the phase diagram of a quarter filled Hubbard ladder with nearest-neighbor Coulomb repulsion using bosonization and renormalization group approach. Focusing on the strong-repulsion regime, we discuss the effect of an interchain exchange ... More
Raman Scattering from Magnetic Excitations in coupled Spin LaddersDec 06 2000We consider Raman scattering of coupled two leg spin ladders in the Fleury-Loudon regime. We derive the dependence of the intensity with polarization of the incoming light and temperature and discuss the effect of interaction of the elementary excitations ... More
Raman Scattering cross section of Spin LaddersFeb 16 2000The Raman scattering spectra from magnetic excitations in an antiferromagnetic spin-1/2 two leg ladder is investigated for weak and strong interladder coupling. In the first case, a cusp in the Raman intensityis obtained at a frequency twice the gap. ... More
Non-renormalization theorems without supergraphs: The Wess-Zumino modelJul 15 1999Nov 03 1999The non-renormalization theorems of chiral vertex functions are derived on the basis of an algebraic analysis. The property, that the interaction vertex is a second supersymmetry variation of a lower dimensional field monomial, is used to relate chiral ... More
Properties of convective motions in facular regionsJul 18 2012In this paper, we study the properties of solar granulation in a facular region from the photosphere up to the lower chromosphere. Our aim is to investigate the dependence of granular structure on magnetic field strength. We use observations obtained ... More
One-loop effective multi-gluon Lagrangian in arbitrary dimensionsSep 29 1997We exhibit the one-loop multi-gluon effective Lagrangian in any dimension for a field theory with a quasilocal background, using the background-field formalism. Specific results, including counter terms (up to 12 spacetime dimensions), have been derived, ... More
Equivalent width, shape and proper motion of the iron fluorescent line emission from the molecular clouds as an indicator of the illuminating source X-ray flux historyMay 05 1998Observations of the diffuse emission in the 8--22 keV energy range, elongated parallel to the Galactic plane (Sunyaev et al. 1993) and detection of the strong 6.4 keV fluorescent line with $\sim$ 1 keV equivalent width from some giant molecular clouds ... More
Interplay of superconductivity with structural phases in a generalized t-J modelApr 04 2000The phase diagram of the t-J-V model is discussed using a 1/N expansion in terms of X operators. It is shown that a flux phase of d-wave symmetry is stabilized by the Coulomb interaction V at intermediate dopings and competes with d-wave superconductivity. ... More
Impurity Effects on the Flux Phase Quantum Critical Point ScenarioDec 08 1999Impurity substitution of Zn in La-214 and (Y,Ca)-123 high-T_c superconductors suppresses T_c but does not affect appreciably the onset of the pseudogap phase in the underdoped region nor optimal doping or the position of the inferred quantum critical ... More
What kind of energy is the mass?Feb 07 2013Jul 01 2013In 1905, Einstein discovered the famous equation: E=mc^2, which means that the rest mass of a particle is some kind of energy. This energy is generally referred to as "rest energy", since the particle is believed to be at rest. This paper proposes a new ... More
A quantum mechanical interpretation for the relativity of the space-timeJul 15 2013In special relativity theory the physical quantities are generally expressed as function of the velocity. In the particular case of an extended object, the factor 1/gamma of Lorentz contraction of its length in the direction of motion is written as a ... More
Activated and non activated dephasing demonstrated in NV center dynamicsNov 03 2015We analyze different decoherence processes in a system coupled to a bath. Apart from the well known standard dephasing mechanism which is temperature dependent an alternative mechanism is presented, the spin-swap dephasing which does not need initial ... More
Chandra imaging spectroscopy of 1E 1740.7 - 2942Aug 15 2002We have observed the black hole candidate 1E 1740.7 - 2942, the brightest persistent hard X-ray source within a few degrees of the Galactic centre, for 10 ksec with Chandra (ACIS-I) on August 2000. Attempting to compensate for pile-up effects we found ... More
Currents on Grassmann algebrasOct 22 1993We define currents on a Grassmann algebra $Gr(N)$ with $N$ generators as distributions on its exterior algebra (using the symmetric wedge product). We interpret the currents in terms of ${\Z}_2$-graded Hochschild cohomology and closed currents in terms ... More
Global simulations of magnetorotational turbulence III: influence of field configuration and mass injectionApr 10 2014The stresses produced by magnetorotational turbulence can provide effective angular momentum transport in accretion disks. However, questions remain about the ability of simulated disks to reproduce observationally inferred stress-to-gas-pressure ratios. ... More
Diffusion of Tagged Particle in an Exclusion ProcessJan 05 2010We study the diffusion of tagged hard core interacting particles under the influence of an external force field. Using the Jepsen line we map this many particle problem onto a single particle one. We obtain general equations for the distribution and the ... More
Quantum vs Classical Integrability in Calogero-Moser SystemsApr 04 2002Calogero-Moser systems are classical and quantum integrable multi-particle dynamics defined for any root system $\Delta$. The {\em quantum} Calogero systems having $1/q^2$ potential and a confining $q^2$ potential and the Sutherland systems with $1/\sin^2q$ ... More
On the importance of grain boundaries in high-Tc films: simulation resultsJan 26 2000The importance of the distribution and ``weakness'' of grain boundary junctions in the magnetic field dependence of the transport critical current in HTc films is assessed through simulations. The system is studied with the applied field either parallel ... More
Path Integral Monte Carlo Study of a Model 2D Quantum ParaelectricJul 17 1993We have begun a study of quantum ferroelectrics and paraelectrics. Simple 2D short-range lattice model hamiltonians are constructed, keeping in mind the phenomenology of real perovskite systems, like $SrTiO_{3}$ and $KTaO_{3}$. Pertinent quantum tunneling ... More
Beyond ComplementarityJan 27 2016Mar 06 2016It is argued that Niels Bohr ultimately arrived at positivistic and antirealist-flavored statements because of weaknesses in his initial objective of accounting for measurement in physical terms. Bohr's investigative approach faced a dilemma, the choices ... More
Measurement: still a problem in standard quantum theoryAug 20 2013Aug 21 2013It is argued that recent claims by A. Hobson that standard quantum theory has no measurement problem cannot be sustained. Moreover, it is pointed out that taking the reduced density operator of a component system as an epistemic (ignorance-based) mixture ... More
On Delayed Choice and Contingent Absorber ExperimentsMay 15 2012It is pointed out that a slight variation on the Wheeler Delayed Choice Experiment presents the same challenge to orthodox quantum mechanics as Maudlin-type contingent absorber experiments present to the Transactional Interpretation (TI). Therefore, the ... More
Comment on "Comment on 'On Visibility in the Afshar Two-Slit Experiment' "Feb 22 2010Tabish Qureshi (2010) has recently objected to an aspect of my discussion of a thought experiment by Srikanth (2001). I believe his objection is based on a misunderstanding about my presentation, but I accept responsibility for not being more clear. Here ... More
Shutters, Boxes, But No Paradoxes: Time Symmetry Puzzles in Quantum TheoryJul 11 2002May 18 2004The ``N-Box Experiment'' is a much-discussed thought experiment in quantum mechanics. It is claimed by some authors that a single particle prepared in a superposition of N+1 box locations and which is subject to a final ``post-selection'' measurement ... More
Closing a Loophole in the Case Against the Counterfactual Usage of the ABL RuleJul 05 1998Jul 08 1998A currently discussed interpretation of quantum theory, Time-Symmetrized Quantum Theory, makes certain claims about the properties of systems between pre- and post- selection measurements. These claims are based on a counterfactual usage of the Aharonov-Bergmann-Lebowitz ... More
Haag's Theorem as a Reason to Reconsider Direct-Action TheoriesFeb 12 2015Mar 09 2015It is argued that the severe consequences of Haag's inconsistency theorem for relativistic quantum field theories can be successfully evaded in the direct-action approach. Some recent favorable comments of John Wheeler, often mistakenly presumed to have ... More
On Real and Virtual Photons in the Davies Theory of Time-Symmetric Quantum ElectrodynamicsDec 14 2013Oct 27 2016This paper explores the distinction between virtual and real photons in the context of the Davies quantum relativistic extension of the Wheeler-Feynman classical electromagnetic theory. An alternative way of understanding this distinction is proposed, ... More
The Three-Box "Paradox" and Other Reasons to Reject the Counterfactual Usage of the ABL RuleJul 14 1998Feb 10 1999An apparent paradox proposed by Aharonov and Vaidman in which a single particle can be found with certainty in two (or more) boxes is analyzed by way of a simple thought experiment. It is found that the apparent paradox arises from an invalid counterfactual ... More
Time-Symmetrized Quantum Theory, Counterfactuals, and `Advanced Action'Jun 01 1998Sep 22 1998Recent authors have raised objections to the counterfactual interpretation of the Aharonov-Bergmann-Lebowitz (ABL) rule of time symmetrized quantum theory (TSQT). I distinguish between two different readings of the ABL rule, counterfactual and non-counterfactual, ... More
The Relativistic Transactional Interpretation: Immune to the Maudlin ChallengeOct 14 2016The Transactional Interpretation has been subject at various times to a challenge based on a type of thought experiment first proposed by Maudlin. It has been argued by several authors that such experiments do not in fact constitute a significant problem ... More
Strain-controlled correlation effects in self-assembled quantum dot stacksJul 01 2006We show that elastic interactions of an array of self-assembled quantum dots in a parent material matrix are markedly distinct from the elastic field created by a single point defect, and can explain the observed abrupt correlation--anticorrelation transition ... More
Diffeomorphic flows driven by Levy processesJan 04 2000We prove that the stochastic differential equation $$ Y_{s,t}(x) = Y_{s,s}(x) + \int_0^{t-s} f(Y_{s,s+u}(x)) dX_{s+u}, Y_{s,s}(x)=x\in\R^d. $$ driven by a L\'evy process whose paths have finite p-variation almost surely for some $p\in[1,2)$ defines a ... More
Thermally-Diven Atmospheric EscapeJan 06 2010Feb 07 2010Accurately determining escape rates from a planet's atmosphere is critical for determining its evolution. Escape can be driven by upward thermal conduction of energy deposited well below the exobase, as well as by non-thermal processes produced by energy ... More
Screening in three-dimensional QEDApr 24 1997Nov 12 1997We compute the quark-antiquark potential in three dimensional massive Quantum Electrodynamics. The result indicates that screening prevails for large quark masses, contrary to the classical expectations. The classical result is reproduced for small separation ... More
Virasoro constraints and the Chern classes of the Hodge bundleMay 25 1998We analyse the consequences of the Virasoro conjecture of Eguchi, Hori and Xiong for Gromov-Witten invariants, in the case of zero degree maps to the manifolds CP^1 and CP^2 (or more generally, smooth projective curves and smooth simply-connected projective ... More
Flowlines transverse to fibred knots and linksJan 22 2003We consider vector fields on knot/link complements in $S^3$ which are transverse to the fibres of a fibration of the complement over a circle. We prove that a large class of fibred knots/links, including all non-torus fibred 2-bridge knots, has the following ... More
Ad~$(G)$ is of type $R$ implies $G$ is of type $R$ for certain $p$-adic Lie groupsJul 09 2014We provide a sufficient condition for a $p$-adic Lie group to be of type $R$ when its adjoint image is of type $R$.
Periodic Slab LAPW Computations for Ferroelectric BaTiO$_3$May 12 1995Linearized augmented plane wave (LAPW) calculations are performed for periodic (001) and (111) slabs of BaTiO$_3$ to understand the effects of surfaces on ferroelectric BaTiO$_3$. The (111) slab is found to be much less stable than the (001) slab. The ... More
Strong relative property $(T)$ and spectral gap of random walksNov 22 2011We consider strong relative property $(T)$ for pairs $(\Ga, G)$ where $\Ga$ acts on $G$. If $N$ is a connected Lie group and $\Ga$ is a group of automorphisms of $N$, we choose a finite index subgroup $\Ga ^0$ of $\Ga$ and obtain that $(\Ga, [\Ga ^0, ... More
No representation of Moore groups and affine groups has any rate of random mixingFeb 16 2005A sequence $a_n\da 0$ forms a rate of random mixing for a unitary system $(G,\mu, \pi, {\cal H})$ if for any $u, v\in {\cal H}$ $$\limsup {|<\pi (g_n^\omega)u, v>|\over a_n} < \infty$$ a.e. $\omega$ in the probability space $(G^{\mathbb N}, \mu ^{\mathbb ... More
Chemical abundance analysis of the Open Clusters Berkeley 32, NGC 752, Hyades and PraesepeJul 12 2011Sep 11 2011Context. Open clusters are ideal test particles to study the chemical evolution of the Galactic disc. However the existing high-resolution abundance determinations, not only of [Fe/H], but also of other key elements, is largely insufficient at the moment. ... More
An Experimental Review of CharmoniumOct 17 2008This review briefly outlines recent experimental results from the charmonium system. These include new measurements of the M1 radiative transition rates $B(\psi(1S,2S)\to\gamma\eta_c(1S))$; new insights into the mass of the $\eta_c(1S)$; the observation ... More
Atom-molecule coherence in a one-dimensional systemMay 30 2005Oct 02 2005We study a model of one-dimensional fermionic atoms that can bind in pairs to form bosonic molecules. We show that at low energy, a coherence develops between the molecule and fermion Luttinger liquids. At the same time, a gap opens in the spin excitation ... More
Quantum Computation and Quadratically Signed Weight EnumeratorsSep 30 1999We prove that quantum computation is polynomially equivalent to classical probabilistic computation with an oracle for estimating the value of simple sums, quadratically signed weight enumerators. The problem of estimating these sums can be cast in terms ... More
DC Conductance of Molecular WiresFeb 08 2007Inspired by the work of Kamenev and Kohn, we present a general discussion of the two-terminal dc conductance of molecular devices within the framework of Time Dependent Current-Density Functional Theory. We derive a formally exact expression for the adiabatic ... More
Scattering of X-ray emission lines by the neutral and molecular hydrogen in the Sun's atmosphere and in the vicinity of active galactic nuclei and compact sourcesAug 19 1996In many astrophysical objects an account for scattering of the X-ray fluorescent and resonance lines of iron ions by the electrons, bound in atomic and molecular hydrogen is important. Specific distortions of the scattered line profile spectrum appear ... More
Resolvendo a equação de Schrödinger através da substituição direta da série de potênciasAug 25 2014Sep 24 2014This work presents a direct and highly accurate method to solve ordinary differential equations, in particular the Schr\"odinger equation in one dimension, through the direct substitution of a power series solution to obtain a purely algebraical system ... More
High redshift radio galaxiesMay 12 2000There is considerable evidence that powerful radio quasars and radio galaxies are orientation-dependent manifestations of the same parent population: massive spheroids containing correspondingly massive black holes. Following the recognition of this unification, ... More
Scattering of He-3 Atoms from He-4 SurfacesFeb 21 1998We develop a first principles, microscopic theory of impurity atom scattering from inhomogeneous quantum liquids such as adsorbed films, slabs, or clusters of He-4. The theory is built upon a quantitative, microscopic description of the ground state of ... More
Connection Between Magnetism and Structure in Fe Double Chains on the Ir(100) SurfaceMar 13 2009The magnetic ground state of nanosized systems such as Fe double chains, recently shown to form in the early stages of Fe deposition on Ir(100), is generally nontrivial. Using ab initio density functional theory we find that the straight ferromagnetic ... More
An approach to effective temperature and surface gravity in post-AGB and RV Tauri stars at the near-IR regionJan 13 2012A number of empirical correlations that allows us to calculate the effective temperature and surface gravity for a set evolved post-AGB and RV Tauri stars are determined using as calibrators the intrinsic colours of 2MASS (Two Micron All Sky Survey) photometry. ... More
Global simulations of magnetorotational turbulence II: turbulent energeticsDec 11 2013Magnetorotational turbulence draws its energy from gravity and ultimately releases it via dissipation. However, the quantitative details of this energy flow have not been assessed for global disk models. In this work we examine the energetics of a well-resolved, ... More
Adaptive image ray-tracing for astrophysical simulationsOct 26 2010A technique is presented for producing synthetic images from numerical simulations whereby the image resolution is adapted around prominent features. In so doing, adaptive image ray-tracing (AIR) improves the efficiency of a calculation by focusing computational ... More
Abundance variations and first ionization potential trends during large stellar flaresDec 04 2007The Solar First Ionization Potential (FIP) effect, where low-FIP elements are enriched in the corona relative to the photosphere, while high-FIP abundances remain unchanged, has been known for a long while. High resolution X-ray spectroscopy has revealed ... More
GLSM's for partial flag manifoldsApr 13 2007Aug 30 2007In this paper we outline some aspects of nonabelian gauged linear sigma models. First, we review how partial flag manifolds (generalizing Grassmannians) are described physically by nonabelian gauged linear sigma models, paying attention to realizations ... More
The chemistry of compact planetary nebulaeOct 31 2002We report high-sensitivity millimetre observations of several molecular species (13CO, HCN, HNC, CN, HCO+ and N2H+) in a sample of compact planetary nebulae. Some species such as HCO+ and CN are particularly abundant compared to envelopes around AGB stars ... More
Chiral boundary conditions for Quantum Hall systemsSep 29 1997A quantum mesoscopic billiard can be viewed as a bounded electronic system due to some external confining potential. Since, in general, we do not have access to the exact expression of this potential, it is usually replaced by a set of boundary conditions. ... More
Third order dielectric susceptibility in a model quantum paraelectricFeb 15 1996In the context of perovskite quantum paraelectrics, we study the effects of a quadrupolar interaction $J_q$, in addition to the standard dipolar one $J_d$. We concentrate here on the nonlinear dielectric response $\chi_{P}^{(3)}$, as the main response ... More
On the origin of facular brightnessFeb 10 2016This paper studies the dependence of the CaIIH line core brightness on the strength and inclination of photospheric magnetic field, and on the parameters of convective and wave motions in a facular region at the solar disc center. We use three simultaneous ... More
Quark-Resonance modelJan 21 1994Feb 03 1994We construct an effective Lagrangian for low energy hadronic interactions through an infinite expansion in inverse powers of the low energy cutoff $\Lambda_\chi$ of all possible chiral invariant non-renormalizable interactions between quarks and mesons ... More
Gravity's smoking gun?Jul 20 2001Aug 21 2001We present a new constraint on the biased galaxy formation picture. Gravitational instability theory predicts that the two-point mass density correlation function, \xi(r), has an inflection point at the separation r=r_0, corresponding to the boundary ... More
Is There Really "Retrocausation" in Time-Symmetric Approaches to Quantum Mechanics?Jul 12 2016Aug 08 2016Time-symmetric interpretations of quantum theory are often presented as featuring "retrocausal" effects in addition to the usual forward notion of causation. This paper examines the ontological implications of certain timesymmetric theories, and finds ... More
The Emergence of Spacetime: Transactions and Causal SetsNov 08 2014This paper discusses how the transactional interpretation of quantum mechanics can provide for a natural account of the emergence of spacetime events from a quantum substratum. In this account, spacetime is not a substantive manifold that becomes occupied ... More
Violation of the Born Rule: Implications for the Classical Electromagnetic FieldMar 16 2016Jun 25 2016It is shown that violation of the Born Rule leads to a breakdown of the correspondence between the quantum electromagnetic field and its classical counterpart. Specifically, the relationship of the quantum coherent state to the classical electromagnetic ... More
TSQT `Elements of Possibility'?Dec 12 1998I defend my arguments in quant-ph/9806002, which have recently been criticized by L. Vaidman (quant-ph/9811092). I emphasize that the correct usage of the ABL rule applies not to a genuine counterfactual statement but rather to a conjunction of material ... More
The role of references in the astronomical discourseDec 23 1996Jan 09 1997We have counted the number of references in 1179 papers published in Astronomy and Astrophysics over twenty years. The number of references has increased by 60% between 1975 and 1995, reflecting the increase (by the same amount) of the literature which ... More
One Loop Beta Functions in Topologically Massive GravityFeb 15 2010We calculate the running of the three coupling constants in cosmological, topologically massive 3d gravity. We find that \nu, the dimensionless coefficient of the Chern-Simons term, has vanishing beta function. The flow of the cosmological constant and ... More
Stringy Robinson-Trautman SolutionsSep 10 1996A class of solutions of the low energy string theory in four dimensions is studied. This class admits a geodesic, shear-free null congruence which is non-twisting but in general diverging and the corresponding solutions in Einstein's theory form the Robinson-Trautman ... More
Possibilities of MgB2/Cu Wires Fabricated by the in-situ Reaction TechniqueJun 04 2003The superconducting properties of copper-sheathed MgB2 wires fabricated by conventional powder-in-tube techniques and the in-situ reaction procedure are analysed. The influence of the processing conditions and initial (1+x)Mg + 2B (x = 0, 0.1, 0.2) proportions ... More
First Principles Theories of Piezoelectric MaterialsFeb 28 2007Piezoelectrics have long been studied using parameterized models fit to experimental data, starting with the work of Devonshire in 1954. Much has been learned using such approaches, but they can also miss major phenomena if the materials properties are ... More
Renormalization and quantum field theoryJul 31 2010Mar 09 2011The aim of this paper is to describe how to use regularization and renormalization to construct a perturbative quantum field theory from a Lagrangian. We first define renormalizations and Feynman measures, and show that although there need not exist a ... More
Coexistence of phases in asymmetric nuclear matter under strong magnetic fieldsNov 07 2014Oct 01 2015The equation of state of nuclear matter is strongly affected by the presence of a magnetic field. Here we study the equilibrium configuration of asymmetric nuclear matter for a wide range of densities, isospin composition, temperatures and magnetic fields. ... More
Liouville property on $G$-spacesDec 30 2013Let $G$ be a locally compact group and $E$ be a $G$-space. An irreducible probability measure $\mu$ on $G$ is said to have Liouville property on $E$ if $G$-invariant functions on $E$ are the only continuous bounded functions on $E$ that satisfy the mean ... More
On absolute convergence of Fourier integralsMay 29 2009New sufficient conditions for representation of a function via the absolutely convergent Fourier integral are obtained in the paper. In the main result, Theorem 1.1, this is controlled by the behavior near infinity of both the function and its derivative. ... More
A stochastic difference equation with stationary noise on groupsAug 05 2010We consider the stochastic difference equation $$\eta _k = \xi _k \phi (\eta _{k-1}), ~~~~ k \in \Z $$ on a locally compact group $G$ where $\xi _k$ are given $G$-valued random variables, $\eta _k$ are unknown $G$-valued random variables and $\phi$ is ... More
New blazar candidates from the 9Y-MST catalogue detected at energies higher than 10 GeVJul 03 2019We present a list of 24 new blazar candidates selected in a search for possible counterparts of spatial clusters of gamma-ray photons in the recent 9Y-MST catalogue, at energies higher than 10 GeV and at Galactic latitudes higher than 20 degrees. 13 of ... More
Investigating the X-ray emission from the massive WR+O binary WR 22 using 3D hydrodynamical modelsApr 13 2011We examine the dependence of the wind-wind collision and subsequent X-ray emission from the massive WR+O star binary WR~22 on the acceleration of the stellar winds, radiative cooling, and orbital motion. Simulations were performed with instantaneously ... More
Maximum GCD Among Pairs of Random IntegersNov 13 2009Fix $\alpha >0$, and sample $N$ integers uniformly at random from $\{1,2,\ldots ,\lfloor e^{\alpha N}\rfloor \}$. Given $\eta >0$, the probability that the maximum of the pairwise GCDs lies between $N^{2-\eta }$ and $N^{2+\eta}$ converges to 1 as $N\to ... More
Spallogenic Light Elements and Cosmic-Ray OriginMar 12 1999Using a Monte Carlo code which incorporates the delayed mixing into the ISM of supernovae nucleosynthetic yields and ejecta kinetic energies (including events with very large energies, e.g. collapsars/hypernovae), we tested three evolutionary models of ... More
Astrophysical Gamma Ray Emission LinesMar 10 1995We review the wide range of astrophysical observations of gamma ray emission lines and we discuss their implications. We consider line emission from solar flares, the Orion molecular cloud complex, supernovae 1987A and 1991T, the supernova remnants Cas ... More
Theory of Single File Diffusion in a Force FieldNov 20 2008The dynamics of hard-core interacting Brownian particles in an external potential field is studied in one dimension. Using the Jepsen line we find a very general and simple formula relating the motion of the tagged center particle, with the classical, ... More
The Quantum Liar Experiment in Cramer's Transactional InterpretationJun 09 2009Dec 28 2010Cramer's Transactional Interpretation (TI) is applied to the "Quantum Liar Experiment" (QLE). It is shown how some apparently paradoxical features can be explained naturally, albeit nonlocally (since TI is an explicitly nonlocal interpretation, at least ... More
Bound States as Emergent Quantum StructuresJan 26 2016Bound states arise in many interactions among elementary field states, and are represented by poles in the scattering matrix. The emergent nature of bound states suggests that they play a perhaps under-appreciated role in specifying the ontologically ... More
Antimatter in the Direct-Action Theory of FieldsSep 20 2015One of Feynman's greatest contributions to physics was the interpretation of negative energies as antimatter in quantum field theory. A key component of this interpretation is the Feynman propagator, which seeks to describe the behavior of antimatter ... More
Comment on "Quantum Darwinism, Decoherence, and the Randomness of Quantum Jumps," arXiv:1412.5206Dec 19 2014Mar 11 2015This brief note in response to Wojciech Zurek's article "Quantum Darwinism, classical reality, and the randomness of quantum jumps" (Physics Today, October 2014, page 44) points out extant rebuttals in the literature to some of the author's key claims. ... More
de Broglie waves as the "Bridge of Becoming" between quantum theory and relativityJul 08 2011Jul 14 2011It is hypothesized that de Broglie's 'matter waves' provide a dynamical basis for Minkowski spacetime in an antisubstantivalist or relational account. The relativity of simultaneity is seen as an effect of the de Broglie oscillation together with a basic ... More
Quantum Nonlocality: Not Eliminated by the Heisenberg PictureNov 13 2010Jan 07 2011It is argued that the Heisenberg picture of standard quantum mechanics does not save Einstein locality as claimed in Deutsch and Hayden (2000). In particular, the EPR-type correlations that DH obtain by comparing two qubits in a local manner are shown ... More
The Hardy Experiment in the Transactional InterpretationJun 25 2010Sep 10 2010The Hardy experiment is analyzed from the standpoint of the Transactional Interpretation (TI) in its possibilist variant, PTI. It is argued that PTI provides a natural and illuminating account of the associated phenomena, resolving the apparent paradox ... More
Comment on Mohrhoff's "What quantum mechanics is trying to tell us"Mar 21 2000May 23 2001Mohrhoff proposes using the Aharonov-Bergmann-Lebowitz (ABL) rule for time-symmetric ``objective'' (meaning non-epistemic) probabilities corresponding to the possible outcomes of not-actually-performed measurements between specified pre- and post-selection ... More