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Reflections and Thoughts on Tired LightJul 23 2007The position of the various tired light theories is reviewed briefly and it is noted that one of the biggest objections to them concerns the mechanism by which light might lose energy as it travels through space. Here some new work relating to the constancy ... More

The Complexity of Vector Spin GlassesApr 07 2004We study the annealed complexity of the m-vector spin glasses in the Sherrington-Kirkpatrick limit. The eigenvalue spectrum of the Hessian matrix of the Thouless-Anderson-Palmer (TAP) free energy is found to consist of a continuous band of positive eigenvalues ... More

The Thermodynamic Glass Transition in Finite DimensionsOct 14 2005Mar 09 2006Using an effective potential method, a replica formulism is set up for describing supercooled liquids near their glass transition. The resulting potential is equivalent to that for an Ising spin glass in a magnetic field. Results taken from the droplet ... More

Static and dynamical properties of a hard-disk fluid confined to a narrow channelDec 20 2013Mar 14 2014The thermodynamic properties of disks moving in a channel sufficiently narrow that they can collide only with their nearest neighbors can be solved exactly by determining the eigenvalues and eigenfunctions of an integral equation. Using it we have determined ... More

Understanding the ideal glass transition: Lessons from an equilibrium study of hard disks in a channelNov 18 2014Feb 18 2015We use an exact transfer-matrix approach to compute the equilibrium properties of a system of hard disks of diameter $\sigma$ confined to a two-dimensional channel of width $1.95\,\sigma$ at constant longitudinal applied force. At this channel width, ... More

Topological Defects in the Abrikosov Lattice of Vortices in Type-II SuperconductorsNov 29 1994The free energy costs for various defects within an Abrikosov lattice of vortices are calculated using the lowest Landau level approximation (LLL). Defect solutions with boundary conditions for lines to meet at a point (crossing defect) and for lines ... More

Vortices in a Thin Film Superconductor with a Spherical GeometryDec 15 1995Jun 10 1996We report results from Monte Carlo simulations of a thin film superconductor in a spherical geometry within the lowest Landau level approximation. We observe the absence of a phase transition to a low temperature vortex solid phase with these boundary ... More

Lopsided galaxies: the case of NGC 891May 08 2008It has been known for a long time that a large fraction of disc galaxies are lopsided. We simulate three different mechanisms that can induce lopsidedness: flyby interactions, gas accretion from cosmological filaments and ram pressure from the intergalactic ... More

Edge Excitations of the $ν= 2/3$ Spin-Singlet Quantum Hall StateJun 21 1996The spectrum of edge excitations is derived for the spin-unpolarized $\nu = 2$ and $\nu = 2/3$ FQHE. Numerical diagonalization of a system of six electrons on a disc confirms that the edge $\nu = 2/3$ spin-singlet FQHE state consists of oppositely directed ... More

Critical Fluctuations and Disorder at the Vortex Liquid to Crystal Transition in Type-II SuperconductorsApr 10 1995We present a functional renormalization group (FRG) analysis of a Landau-Ginzburg model of type-II superconductors (generalized to $n/2$ complex fields) in a magnetic field, both for a pure system, and in the presence of quenched random impurities. Our ... More

Exact solution of site and bond percolation on small-world networksJan 26 2000We study percolation on small-world networks, which has been proposed as a simple model of the propagation of disease. The occupation probabilities of sites and bonds correspond to the susceptibility of individuals to the disease and the transmissibility ... More

Exciton condensation and charge fractionalization in a topological insulator filmFeb 06 2009Jul 16 2009An odd number of gapless Dirac fermions is guaranteed to exist at a surface of a strong topological insulator. We show that in a thin-film geometry and under external bias, electron-hole pairs that reside in these surface states can condense to form a ... More

The Growing Correlation Length in GlassesApr 16 2013The growing correlation length observed in supercooled liquids as their temperature is lowered has been studied with the aid of a single occupancy cell model. This model becomes more accurate as the density of the system is increased. One of its advantages ... More

The origin of lopsidedness in galaxiesAug 29 2008It has long been known that a large fraction of disc galaxies are lopsided. We simulate three different mechanisms that can induce lopsidedness: flyby interactions, gas accretion from cosmological filaments and ram pressure from the intergalactic medium. ... More

Glassy dynamics and aging in an exactly solvable spin modelJul 25 1997Aug 24 1999We introduce a simple two-dimensional spin model with short-range interactions which shows glassy behavior despite a Hamiltonian which is completely homogeneous and possesses no randomness. We solve exactly for both the static partition function of the ... More

Nature of perturbation theory in spin glassesJan 18 2005The high-order behavior of the perturbation expansion in the cubic replica field theory of spin glasses in the paramagnetic phase has been investigated. The study starts with the zero-dimensional version of the replica field theory and this is shown to ... More

On The Formation of Disk Galaxies and Massive Central ObjectsJul 01 1998We propose that massive central objects form in the centers of the bars which must develop in young high-surface density galactic disks. Large-scale dynamics shuts off the growth of the central mass before it reaches $\sim 2%$ of the disk mass at the ... More

Height representation, critical exponents, and ergodicity in the four-state triangular Potts antiferromagnetFeb 22 1999We study the four-state antiferromagnetic Potts model on the triangular lattice. We show that the model has six types of defects which diffuse and annihilate according to certain conservation laws consistent with their having a vector-valued topological ... More

Disappearance of the de Almeida-Thouless line in six dimensionsFeb 08 2011May 24 2011We show that the Almeida-Thouless line in Ising spin glasses vanishes when their dimension d -> 6 as h_{AT}^2/T_c^2 = C(d-6)^4(1- T/T_c)^{d/2 - 1}, where C is a constant of order unity. An equivalent result which could be checked by simulations is given ... More

Topological insulators beyond the Brillouin zone via Chern parityMay 02 2007The topological insulator is an electronic phase stabilized by spin-orbit coupling that supports propagating edge states and is not adiabatically connected to the ordinary insulator. In several ways it is a spin-orbit-induced analogue in time-reversal-invariant ... More

Comment on ``On the formal equivalence of the TAP and thermodynamic methods in the SK model''May 27 2003Sep 08 2003This paper has been replaced by cond-mat/0309113

Cavity atom optics and the `free atom laser'Jul 15 1999The trap environment in which Bose-Einstein condensates are generated and/or stored strongly influences the way they interact with light. The situation is analogous to cavity QED in quantum optics, except that in the present case, one tailors the matter-wave ... More

Supersymmetric Electroweak Phase Transition: Baryogenesis versus Experimental ConstraintsJun 12 1998Oct 08 1998We use the two loop effective potential to study the first order electroweak phase transition in the minimial supersymmetric standard model. A global search of the parameter space is made to identify parameters compatible with electroweak baryogenesis. ... More

Epidemics and percolation in small-world networksNov 30 1999Jan 07 2000We study some simple models of disease transmission on small-world networks, in which either the probability of infection by a disease or the probability of its transmission is varied, or both. The resulting models display epidemic behavior when the infection ... More

A boundary-integral framework to simulate viscous erosion of a porous mediumApr 17 2018We develop numerical methods to simulate the fluid-mechanical erosion of many bodies in two-dimensional Stokes flow. The broad aim is to simulate the erosion of a porous medium (e.g. groundwater flow) with grain-scale resolution. Our fluid solver is based ... More

Glass-like behavior of a hard-disk fluid confined to a narrow channelJan 15 2015Mar 08 2016Disks moving in a narrow channel have many features in common with the glassy behavior of hard spheres in three dimensions. In this paper we study the caging behavior of the disks which sets in at characteristic packing fraction $\phi_d$. Four-point overlap ... More

Mean-field solution of the small-world network modelSep 10 1999Sep 21 1999The small-world network model is a simple model of the structure of social networks, which simultaneously possesses characteristics of both regular lattices and random graphs. The model consists of a one-dimensional lattice with a low density of shortcuts ... More

Gravity-induced Wannier-Stark ladder in an optical latticeSep 12 2000We discuss the dynamics of ultracold atoms in an optical potential accelerated by gravity. The positions and widths of the Wannier-Stark ladder of resonances are obtained as metastable states. The metastable Wannier-Bloch states oscillate in a single ... More

Influence of Dislocations in Thomson's ProblemJan 14 1997Jan 29 1997We investigate Thomson's problem of charges on a sphere as an example of a system with complex interactions. Assuming certain symmetries we can work with a larger number of charges than before. We found that, when the number of charges is large enough, ... More

Convection in a coupled fluid-porous media systemJan 09 2019We perform linear and nonlinear stability analysis for thermal convection in a fluid overlying a saturated porous medium. We use a coupled system in which Navier-Stokes governs the free flow and Darcy's equation governs the porous-medium flow. Incorporating ... More

Comment on "General Method to Determine Replica Symmetry Breaking Transitions"Nov 05 1998In a recent letter Marinari et al [Phys. Rev. Lett. 81, 1698 (1998)] introduced a new method to study spin glass transitions and argued that by probing replica symmetry (RS) as opposed to time reversal symmetry (TRS), their method unambiguously shows ... More

Why temperature chaos in spin glasses is hard to observeJul 11 2002The overlap length of a three-dimensional Ising spin glass on a cubic lattice with Gaussian interactions has been estimated numerically by transfer matrix methods and within a Migdal-Kadanoff renormalization group scheme. We find that the overlap length ... More

Community detection in networks with unequal groupsSep 01 2015Sep 10 2015Recently, a phase transition has been discovered in the network community detection problem below which no algorithm can tell which nodes belong to which communities with success any better than a random guess. This result has, however, so far been limited ... More

Exact solutions for models of evolving networks with addition and deletion of nodesApr 04 2006There has been considerable recent interest in the properties of networks, such as citation networks and the worldwide web, that grow by the addition of vertices, and a number of simple solvable models of network growth have been studied. In the real ... More

Electronic-vibrational coupling in single-molecule devicesFeb 12 2003Mar 10 2003Experiments studying vibrational effects on electronic transport through single molecules have observed several seemingly inconsistent behaviors, ranging from up to 30 harmonics of a vibrational frequency in one experiment, to an absence of higher-harmonic ... More

On the Use of Finite-Size Scaling to Measure Spin-Glass ExponentsFeb 11 2003Finite-size scaling (FSS) is a standard technique for measuring scaling exponents in spin glasses. Here we present a critique of this approach, emphasizing the need for all length scales to be large compared to microscopic scales. In particular we show ... More

Instabilities and self-socillations in atomic four-wave mixingMay 26 2000The development of integrated, waveguide-based atom optical devices requires a thorough understanding of nonlinear matter-wave mixing processes in confined geometries. This paper analyzes the stability of counterpropagating two-component Bose-Einstein ... More

Random graph models for dynamic networksJul 26 2016We propose generalizations of a number of standard network models, including the classic random graph, the configuration model, and the stochastic block model, to the case of time-varying networks. We assume that the presence and absence of edges are ... More

Finding community structure in very large networksAug 09 2004Aug 30 2004The discovery and analysis of community structure in networks is a topic of considerable recent interest within the physics community, but most methods proposed so far are unsuitable for very large networks because of their computational cost. Here we ... More

Reply to "Comment on Evidence for the droplet picture of spin glasses"Feb 19 1999Using Monte Carlo simulations (MCS) and the Migdal-Kadanoff approximation (MKA), Marinari et al. study in their comment on our paper the link overlap between two replicas of a three-dimensional Ising spin glass in the presence of a coupling between the ... More

A study of nonlocal conductivity in high-temperature superconductorsOct 08 1997We examine nonlocal conductivity in high-temperature superconductors from a phenomenological point of view. One wants to deduce the properties of the conductivity, especially its inherent length scales, from the transport data. Although this is a challenging ... More

The Link Overlap and Finite Size Effects for the 3D Ising Spin GlassMay 25 1999We study the link overlap between two replicas of an Ising spin glass in three dimensions using the Migdal-Kadanoff approximation and scaling arguments based on the droplet picture. For moderate system sizes, the distribution of the link overlap shows ... More

Excitation of gravity waves by fingering convection, and the formation of compositional staircases in stellar interiorsMay 28 2015Fingering convection (or thermohaline convection) is a weak yet important kind of mixing that occurs in stably-stratified stellar radiation zones in the presence of an inverse mean-molecular-weight gradient. Brown et al. (2013) recently proposed a new ... More

Pointing the SOFIA TelescopeJan 01 2010SOFIA is an airborne, gyroscopically stabilized 2.5m infrared telescope, mounted to a spherical bearing. Unlike its predecessors, SOFIA will work in absolute coordinates, despite its continually changing position and attitude. In order to manage this, ... More

The Complexity of Ising Spin GlassesSep 04 2003Sep 30 2003We compute the complexity (logarithm of the number of TAP states) associated with minima and index-one saddle points of the TAP free energy. Higher-index saddles have smaller complexities. The two leading complexities are equal, consistent with the Morse ... More

Mid-infrared spectroscopy of SVS13: Silicates, quartz and SiC in a protoplanetary discMay 21 2015We present $N$-band (8$-$13 $\mu$m) spectroscopic observations of the low-mass, embedded pre-main-sequence close binary system SVS13. Absorption features are clearly detected which are attributable to amorphous silicates, crystalline forsterite, crystalline ... More

Optimal Determination of the Equilibrium Displacement of a Damped Harmonic Oscillator in the Presence of Thermal NoiseDec 17 2004Using a matched filter technique, we derive the minimum variance, unbiased estimator for the equilibrium displacement of a damped harmonic oscillator in thermal equilibrium when interactions with the thermal bath are the leading source of noise. We compare ... More

Aspect-Ratio Scaling and The Stiffness Exponent $θ$ for Ising Spin GlassesAug 03 2001Nov 19 2001We introduce the technique of aspect-ratio scaling to study the scale-dependence of interfacial energies in Ising spin glasses, and we show how one can use it to determine the stiffness exponent $\theta$ in a clean way, with results that are independent ... More

Hierarchical structure and the prediction of missing links in networksNov 04 2008Networks have in recent years emerged as an invaluable tool for describing and quantifying complex systems in many branches of science. Recent studies suggest that networks often exhibit hierarchical organization, where vertices divide into groups that ... More

Structural Inference of Hierarchies in NetworksOct 09 2006One property of networks that has received comparatively little attention is hierarchy, i.e., the property of having vertices that cluster together in groups, which then join to form groups of groups, and so forth, up through all levels of organization ... More

The physical limits of communicationJul 30 1999It has been well-known since the pioneering work of Claude Shannon in the 1940s that a message transmitted with optimal efficiency over a channel of limited bandwidth is indistinguishable from random noise to a receiver who is unfamiliar with the language ... More

Transport properties of the one-dimensional Hubbard model at finite temperatureAug 08 2014Oct 06 2014We study finite-temperature transport properties of the one-dimensional Hubbard model using the density matrix renormalization group. Our aim is two-fold: First, we compute both the charge and the spin current correlation function of the integrable model ... More

Anomalous wave statistics induced by abrupt depth changeAug 23 2018Laboratory experiments reveal that variations in bottom topography can qualitatively alter the distribution of randomized surface waves. A normally-distributed, unidirectional wave field becomes highly skewed and non-Gaussian upon encountering an abrupt ... More

Efficacy of multimedia learning modules as preparation for lecture-based tutorials in electromagnetismSep 26 2014We have investigated the efficacy of online, multimedia learning modules (MLMs) as preparation for in-class, lecture-based tutorials in electromagnetism in a physics course for natural science majors (biology and marine science). Specifically, we report ... More

A pseudo-potential analog for zero-range photoassociation and Feshbach resonanceJun 15 2005A zero-range approach to atom-molecule coupling is developed in analogy to the Fermi-Huang pseudo-potential treatment of atom-atom interactions. It is shown by explicit comparison to an exactly-solvable finite-range model that replacing the molecular ... More

The Stability of the Replica Symmetric State in Finite Dimensional Spin GlassesAug 03 2005Sep 26 2005According to the droplet picture of spin glasses, the low-temperature phase of spin glasses should be replica symmetric. However, analysis of the stability of this state suggested that it was unstable and this instability lends support to the Parisi replica ... More

Is there a Phase Transition to the Flux Lattice State?Aug 23 1996The sharp drops in the resistance and magnetization which are usually attributed to a phase transition from the vortex liquid state to a crystal state are explained instead as a crossover between three and two dimensional behavior, which occurs when the ... More

Why replica symmetry breaking does not occur below six dimensions in Ising spin glassesFeb 19 2019The leading term for the average height of the barriers which could separate pure states in Ising spin glasses is calculated using instanton methods. It is finite in dimensions $d < 6$. Replica symmetry breaking requires that the barriers between pure ... More

Why replica symmetry breaking does not occur below six dimensions in Ising spin glassesFeb 19 2019Feb 21 2019The leading term for the average height of the barriers which could separate pure states in Ising spin glasses is calculated using instanton methods. It is finite in dimensions $d < 6$. Replica symmetry breaking requires that the barriers between pure ... More

A predictive coding account of OCDApr 25 2015Jun 08 2015This paper presents a predictive coding account of obsessive-compulsive disorder (OCD). We extend the predictive coding model to include the concept of a 'formal narrative', or temporal sequence of cognitive states inferred from sense data. We propose ... More

A hierarchical narrative framework for OCDMar 03 2015This paper gives an explanatory framework for obsessive-compulsive disorder (OCD) based on a generative model of cognition. The framework is constructed using the new concept of a 'formal narrative' which is a sequence of cognitive states inferred from ... More

Stateman: Using Metafunctions to Manage Large Terms Representing Machine StatesSep 21 2015When ACL2 is used to model the operational semantics of computing machines, machine states are typically represented by terms recording the contents of the state components. When models are realistic and are stepped through thousands of machine cycles, ... More

Generalizations of the KPZ equation (minor changes to enable easy latexing)Jul 26 1993Jul 30 1993We generalize the KPZ equation to an O(3) $N=2j+1$ component model. In the limit $N \to \infty$ we show that the mode coupling equations become exact. Solving these approximately we find that the dynamic exponent $z$ increases from $3/2$ for $d=1$ to ... More

The 1/m expansion in spin glasses and the de Almeida-Thouless lineJun 20 2012It is shown by means of a 1/m expansion about the large-m limit of the m-vector spin glass that the lower critical dimension of the de Almeida-Thouless line in spin glasses is equal to the lower critical dimension of the large-m limit of the m-vector ... More

The ordered phase of the one-dimensional Ising spin glass with long-range interactionsMay 04 2010The one-dimensional long-range Ising spin glass provides useful insights into the properties of finite dimensional spin glasses with short-range interactions. The defect energy renormalization group equations derived for it by Kotliar, Anderson and Stein ... More

The sensitivity of pulsar timing arraysAug 04 2014Simple analytic expressions are derived for the sensitivity curve of a pulsar timing array (PTA) to both a monochromatic source of gravitational waves and an isotropic stochastic background of gravitational waves. These derivations are performed in both ... More

Are ring galaxies the ancestors of giant low surface brightness galaxies?Feb 20 2009Giant low surface brightness galaxies (GLSBs), such as Malin 1, have unusually large and flat discs. Their formation is a puzzle for cosmological simulations in the cold dark matter scenario. We suggest that GLSBs might be the final product of the dynamical ... More

Threshhold Corrections in $K3\times T2$ Heterotic String CompactificationsAug 21 1996We consider compactifications of the heterotic string on $K3 \times T2$ so that the resulting theory in $d = 4$ space-time dimensions has $N = 2$ supersymmetry. The gravitational and gauge coupling constants of the low-energy effective theory receive ... More

Corrections to scaling in the droplet picture of spin glassesMar 22 2002The energy of a droplet of linear extent L in the ``droplet theory'' of spin glasses goes as $L^{\theta}$ for large L. It is argued that this formula needs to be modified by the addition of a scaling correction $L^{-\omega}$ in order to accurately describe ... More

Interface free energies in p-spin glass modelsFeb 02 2006The replica method has been used to calculate the interface free energy associated with the change from periodic to anti-periodic boundary conditions in finite-dimensional p-spin glass models in the phase which at mean-field level has one-step replica ... More

Changing the lattice position of a bistable single magnetic dopant in a semiconductor using a scanning tunneling microscopeMay 14 2015We report a reversible and hysteretic change in the topography measured with a scanning tunneling microscope near a single Fe dopant in a GaAs surface when a small positive bias voltage is applied. First-principles calculations of the formation energy ... More

Fossil remnants of reionization in the halo of the Milky WayOct 21 2008Our recently completed one billion particle Via Lactea II simulation of a Milky Way-sized dark matter halo resolves over 50,000 gravitationally bound clumps orbiting today within the virialized region of the main host. About 2,300 of these subhalos have ... More

Clumps and streams in the local dark matter distributionMay 08 2008May 29 2008In cold dark matter cosmological models, structures form and grow by merging of smaller units. Numerical simulations have shown that such merging is incomplete; the inner cores of halos survive and orbit as "subhalos" within their hosts. Here we report ... More

Glassy Solutions of the Kardar-Pasrisi-Zhang EquationJul 18 1994Feb 02 1995It is shown that the mode-coupling equations for the strong-coupling limit of the KPZ equation have a solution for d>4 such that the dynamic exponent z is 2 (with possible logarithmic corrections) and that there is a delta function term in the height ... More

Dark Matter Direct Detection with Non-Maxwellian Velocity StructureDec 12 2009The velocity distribution function of dark matter particles is expected to show significant departures from a Maxwell-Boltzmann distribution. This can have profound effects on the predicted dark matter - nucleon scattering rates in direct detection experiments, ... More

Star formation in Galactic spiral arms and the inter-arm regionsFeb 12 2013The line of sight through the Galactic Plane between longitudes l = 37.83 degr and l = 42.50 degr allows for the separation of Galactic Ring Survey molecular clouds into those that fall within the spiral arms and those located in the inter-arm regions. ... More

Transition state theory and the dynamics of hard disksNov 08 2012Sep 18 2013The dynamics of two and five disk systems confined in a square has been studied using molecular dynamics simulations and compared with the predictions of transition state theory. We determine the partition functions Z and Z^\ddagger of transition state ... More

Confinement-induced Berry phase and helicity-dependent photocurrentsNov 18 2009The photocurrent in an optically active metal is known to contain a component that switches sign with the helicity of the incident radiation. At low frequencies, this current depends on the orbital Berry phase of the Bloch electrons via the "anomalous ... More

Glass Phenomenology from the Connection to Spin GlassesSep 06 2006Jan 17 2007Typical features of glass phenomenology such as the Vogel-Fulcher law, the Kauzmann paradox and the Adam-Gibbs relationship are shown to follow from the recently discovered mapping of glasses to Ising spin glasses in a magnetic field. There seems to be ... More

Quantifying How Density Gradients and Front Curvature Affect Carbon Detonation Strength During Type Ia SupernovaeJun 20 2018Accurately reproducing the physics behind the detonations of Type Ia supernovae and the resultant nucleosynthetic yields is important for interpreting observations of spectra and remnants. The scales of the processes involved span orders of magnitudes, ... More

Quasi Many-body Localization in Translation Invariant SystemsOct 27 2014It is typically assumed that disorder is essential to realize Anderson localization. Recently, a number of proposals have suggested that an interacting, translation invariant system can also exhibit localization. We examine these claims in the context ... More

Blue straggler stars in dwarf spheroidal galaxies II: Sculptor and FornaxApr 03 2009The existence of blue straggler stars (BSSs) in dwarf spheroidal galaxies (dSphs) is still an open question. In fact, many BSS candidates have been observed in the Local Group dSphs, but it is unclear whether they are real BSSs or young stars. Shedding ... More

Mixed phases in U(N) superconductivityJul 29 1997We consider a general class of type-II superconductors which are described by N complex order parameters (OP), with an overall U(N) symmetry for the energy functional. In the lowest energy state, each OP adopts its own particular lattice structure, making ... More

The RMS Survey: A Galaxy-wide Sample of Massive Young Stellar ObjectsNov 29 2007Here we describe the Red MSX Source (RMS) survey which is the largest, systematic, galaxy-wide search for massive young stellar objects (MYSOs) yet undertaken. Mid-IR bright point sources from the MSX satellite survey have been followed-up with ground-based ... More

The statistics of triggered star formation: an overdensity of massive YSOs around Spitzer bubblesNov 03 2011Dec 06 2011We present a detailed statistical study of massive star formation in the environment of 322 Spitzer mid-infrared bubbles by using the RMS survey for massive Young Stellar Objects (YSOs). Using a combination of simple surface density plots and a more sophisticated ... More

The Effect of Spiral Arms on Star Formation in the GalaxyApr 06 2012Jul 20 2012We have examined the ratio between the integrated luminosity of massive young stellar objects detected by the Red MSX Source (RMS) survey and the mass of molecular clouds in the Galactic Ring Survey region, as a function of Galactocentric radius. The ... More

Helium and Hydrogen Line Ratios and The Stellar Content of Compact HII RegionsDec 05 2002We present observations and models of the behaviour of the HI and HeI lines between 1.6 and 2.2um in a small sample of compact HII regions. As in our previous papers on planetary nebulae, we find that the `pure' 1.7007um 4^3D-3^3P and 2.16475um 7^(3,1)G-4^(3,1)F ... More

Study of off-diagonal disorder using the typical medium dynamical cluster approximationJun 04 2014We generalize the typical medium dynamical cluster approximation (TMDCA) and the local Blackman, Esterling, and Berk (BEB) method for systems with off-diagonal disorder. Using our extended formalism we perform a systematic study of the effects of non-local ... More

Tree Codes and a Conjecture on Exponential SumsAug 27 2013Dec 09 2013We propose a new conjecture on some exponential sums. These particular sums have not apparently been considered in the literature. Subject to the conjecture we obtain the first effective construction of asymptotically good tree codes. The available numerical ... More

Enhancements to ACL2 in Versions 5.0, 6.0, and 6.1Apr 30 2013We report on highlights of the ACL2 enhancements introduced in ACL2 releases since the 2011 ACL2 Workshop. Although many enhancements are critical for soundness or robustness, we focus in this paper on those improvements that could benefit users who are ... More

Entanglement entropy of random quantum critical points in one dimensionJun 30 2004For quantum critical spin chains without disorder, it is known that the entanglement of a segment of N>>1 spins with the remainder is logarithmic in N with a prefactor fixed by the central charge of the associated conformal field theory. We show that ... More

Sequence Pairs with Lowest Combined Autocorrelation and CrosscorrelationNov 07 2017For a pair $(f,g)$ of sequences of length $\ell$ whose terms are in $\{-1,1\}$, Pursley and Sarwate established a lower bound on a combined measure of crosscorrelation and autocorrelation for $f$ and $g$. They showed that the sum of the mean square crosscorrelation ... More

Stability of the quantum spin Hall effect: effects of interactions, disorder, and Z_2 topologyAug 11 2005The stability to interactions and disorder of the quantum spin Hall effect (QSHE) proposed for time-reversal-invariant 2D systems is discussed. The QSHE requires an energy gap in the bulk and gapless edge modes that conduct spin-up and spin-down excitations ... More

Geometric criticality between plaquette phases in integer-spin kagome XXZ antiferromagnetsJan 25 2005Jul 25 2005The phase diagram of the uniaxially anisotropic $s=1$ antiferromagnet on the kagom\'e lattice includes a critical line exactly described by the classical three-color model. This line is distinct from the standard geometric classical criticality that appears ... More

The Initiation and Propagation of Helium Detonations in White Dwarf EnvelopesSep 11 2014Oct 16 2014Detonations in helium-rich envelopes surrounding white dwarfs have garnered attention as triggers of faint thermonuclear ".Ia" supernovae and double detonation Type Ia supernovae. However, recent studies have found that the minimum size of a hotspot that ... More

Tidal streams in a MOND potential: constraints from SagittariusJan 14 2005May 26 2005We compare orbits in a thin axisymmetric disc potential in MOND to those in a thin disc plus near-spherical dark matter halo predicted by a $\Lambda$CDM cosmology. Remarkably, the amount of orbital precession in MOND is nearly identical to that which ... More

How Can I Do That with ACL2? Recent Enhancements to ACL2Oct 21 2011The last several years have seen major enhancements to ACL2 functionality, largely driven by requests from its user community, including utilities now in common use such as 'make-event', 'mbe', and trust tags. In this paper we provide user-level summaries ... More

p-spin model in finite dimensions and its relation to structural glassesJan 08 2002The p-spin spin-glass model has been studied extensively at mean-field level because of the insights which it provides into the mode-coupling approach to structural glasses and the nature of the glass transition. We demonstrate explicitly that the finite ... More

Energy barriers in spin glassesMar 10 2004Mar 15 2004For an Ising spin glass on a hierarchical lattice, we show that the energy barrier to be overcome during the flip of a domain of size L scales as L to the power d-1 for all dimensions d. We do this by investigating appropriate lower bounds to the barrier ... More

Reply to "Comment on "Critical Point Scaling of Ising Spin Glasses in a Magnetic Field" "Oct 18 2016In his Comment, Temesv\'{a}ri objects to a remark in our paper [Phys.\ Rev.\ B {\bf 91}, 104432 (2015)] that his result for the form of the Almeida-Thouless (AT) line obtained in an earlier paper with Parisi [Nucl.\ Phys.\ B {\bf 858}, 293 (2012)] in ... More