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Laser Communication and Coordination Control of Spacecraft SwarmsJan 25 2019Swarms of small spacecraft offer whole new capabilities in Earth observation, global positioning and communications compared to a large monolithic spacecraft. These small spacecrafts can provide bigger apertures that increase gain in communication antennas, ... More

Improved sphere packing lower bounds from Hurwitz latticesMay 19 2011In this paper we prove an asymptotic lower bound for the sphere packing density in dimensions divisible by four. This asymptotic lower bound improves on previous asymptotic bounds by a constant factor and improves not just lower bounds for the sphere ... More

Transpose on vertex symmetric digraphsJul 03 2014We discuss transpose (sometimes called universal exchange or all-to-all) on vertex symmetric networks. We provide a method to compare the efficiency of transpose schemes on two different networks with a cost function based on the number processors and ... More

Linear Hypergraph Edge ColoringMar 16 2016Motivated by the Erdos-Faber Lovasz conjecture (EFL) for hypergraphs, we explore relationships between several conjectures on the edge coloring of linear hypergraphs. In particular, we are able to increase the class of hypergraphs for which EFL is true. ... More

Analysis of first order systems for the solution of Laplace's equationApr 13 2014Kelner, Orecchia, Sidford, and Zhu have given a randomized iterative method for approximating the solution to the discrete Laplace equation that has expected running time nearly linear in the size of the problem. The goal of this note is to explain this ... More

Livelock free routing schemesJan 22 2012We give a livelock free routing algorithm for any allowed network. Unlike some other solutions to this problem: 1) packets entering the network have an absolute upper bound on the time to reach their destination; 2) under light loads, packets are delivered ... More

A Problem of W. R. Scott: Classify the Subgroup of Elements with Many RootsDec 28 2011Let G be an infinite group and let h and g be elements. We say that h is a root of g if some integer power of h is equal to g. We define K(G) to be the subgroup of all elements of G for which the number of elements which are not roots is of smaller cardinality ... More

A Mordell Inequality for Lattices over Maximal OrdersOct 14 2008Jul 30 2010In this paper we prove an analogue of Mordell's inequality for lattices in finite-dimensional complex or quaternionic Hermitian space that are modules over a maximal order in an imaginary quadratic number field or a totally definite rational quaternion ... More

An Autonomous Passive Navigation Method for Nanosatellite Exploration of the Asteroid BeltFeb 08 2019There are more than 750,000 asteroids identified in the main belt. These asteroids are diverse in composition and size. Some of these asteroids can be traced back to the early solar system and can provide insight into the origins of the so-lar system, ... More

Evaluation of Mother-Daughter Architectures for Asteroid Belt ExplorationDec 28 2018This paper examines the effectiveness of an asteroid exploration architecture comprised of multiple nanosatellite sized spacecraft deployed from a single mother ship into a heliocentric orbit in the main asteroid belt where the mothership is ideally located ... More

Hypergraph VersalsFeb 04 2016Let H be a hypergraph on n vertices with the property that no edge contains another. We prove some results for a special case of the Isolation Lemma when the label set for the edges of H can only take two values. Given any set of vertices S and an edge ... More

Diffractive Dijet Production and Nuclear Shadowing in pA InteractionsJun 11 2001We study the implications of non-universality observed recently in e p and pbar p diffraction for nuclear shadowing and diffractive dijet production in pA collisions.

Anti-Hyperon Enhancement through Baryon Junction LoopsJan 06 1999The baryon junction exchange mechanism recently proposed to explain valence baryon number transport in nuclear collisions is extended to study midrapidity anti-hyperon production. Baryon junction-anti-junction (J anti-J) loops are shown to enhance anti-Lambda, ... More

Color Detection Using Chromophore-Nanotube Hybrid DevicesFeb 12 2009We present a nanoscale color detector based on a single-walled carbon nanotube functionalized with azobenzene chromophores, where the chromophores serve as photoabsorbers and the nanotube as the electronic read-out. By synthesizing chromophores with specific ... More

Addendum to Computational Complexity and Black Hole HorizonsMar 22 2014In this addendum to [arXiv:1402.5674] two points are discussed. In the first additional evidence is provided for a dual connection between the geometric length of an Einstein-Rosen bridge and the computational complexity of the quantum state of the dual ... More

Fractal-Flows and Time's ArrowMar 29 2012Apr 07 2012This is the written version of a lecture at the KITP workshop on Bits, Branes, and Black Holes. In it I describe work with D. Harlow, S. Shenker, D. Stanford which explains how the tree-like structure of eternal inflation, together with the existence ... More

Another Conjecture about M(atrix) TheoryApr 10 1997The current understanding of M(atrix) theory is that in the large N limit certain supersymmetric Yang Mills theories become equivalent to M-theory in the infinite momentum frame. In this paper the conjecture is put forward that the equivalence between ... More

Electromagnetic MemoryJul 09 2015An elementary derivation of the electromagnetic memory effect is given. An experimental setup to detect it is suggested.

The Transfer of Entanglement: The Case for FirewallsOct 07 2012Black hole complementarity requires that the interior of a black hole be represented by the same degrees of freedom that describe its exterior. Entanglement plays a crucial role in the reconstruction of the interior degrees of freedom. This connection ... More

Amplitude of Perturbations from InflationFeb 27 2007Mar 22 2007The observed power spectrum of the cosmic microwave background (CMB) is consistent with inflationary cosmology, which predicts a nearly scale-invariant power spectrum of quantum fluctuations of the inflaton field as they exit the Hubble horizon during ... More

Generalized Fixed-Point Algebras and Square-Integrable Representations of Twisted C*-Dynamical SystemsApr 07 2015This paper shows that Ralf Meyer's theory of square-integrable group representations of C*-dynamical systems can be generalized quite naturally to the case of twisted C*-dynamical systems. An outcome of this is a generalized fixed-point algebra that is ... More

A Network Filtration Protocol for Elucidating Relationships between Families in a Protein Similarity NetworkAug 11 2014Motivation: The study of diverse enzyme superfamilies can provide important insight into the relationships between protein sequence, structure and function. It is often challenging, however, to discover these relationships across a large and diverse superfamily. ... More

Singularities, Firewalls, and ComplementarityAug 16 2012Almheiri, Marolf, Polchinski, and Sully, recently claimed that once a black hole has radiated more than half its initial entropy (the Page time), the horizon is replaced by a "firewall" at which infalling observers burn up, in apparent violation of the ... More

Was There a Beginning?Apr 24 2012In this note I respond to Vilenkin's claim that there must have been a beginning.

Some Speculations about Black Hole Entropy in String TheorySep 27 1993Sep 30 1993The classical Bekenstein entropy of a black hole is argued to arise from configurations of strings with ends which are frozen on the horizon. Quantum corrections to this entropy are probably finite unlike the case in quantum field theory. Finally it is ... More

Entanglement is not EnoughNov 03 2014This is the written version of a lecture given at KITP in Oct 2014 on Black Holes and quantum complexity. I've included (in boldface) various questions that came up during the lecture and discussions the following day, as well as the quantitative calculations ... More

Butterflies on the Stretched HorizonNov 28 2013Dec 07 2013In this paper I return to the question of what kind of perturbations on Alice's side of an Einstein-Rosen bridge can send messages to Bob as he enters the horizon at the other end. By definition "easy" operators do not activate messages and "hard" operators ... More

Addendum to Fast ScramblersJan 31 2011This paper is an addendum to [arXiv:0808.2096] in which I point out that both de Sitter space and Rindler space are fast scramblers. This fact naturally suggests that the holographic description of a causal patch of de Sitter space may be a matrix quantum ... More

Cosmic Natural SelectionJul 29 2004I make a number of comments about Smolin's theory of Cosmic Natural Selection.

Testable Consequences of Curved-Spacetime RenormalizationApr 01 1998Apr 08 1998I consider certain renormalization effects in curved spacetime quantum field theory. In the very early universe these effects resemble those of a cosmological constant, while in the present universe they give rise to a significant finite renormalization ... More

Estimating a bivariate linear relationshipFeb 05 2012Solutions of the bivariate, linear errors-in-variables estimation problem with unspecified errors are expected to be invariant under interchange and scaling of the coordinates. The appealing model of normally distributed true values and errors is unidentified ... More

Complementarity And FirewallsJul 17 2012Aug 03 2012This paper has been withdrawn because the author no longer believes the firewall argument is correct.

Holography in the Flat Space LimitJan 19 1999Matrix theory and the AdS/CFT correspondence provide nonperturbative holographic formulations of string theory. In both cases the finite N theories can be thought of as infrared regulated versions of flat space string theory in which removing the cutoff ... More

ER=EPR, GHZ, and the Consistency of Quantum MeasurementsDec 29 2014This paper illustrates various aspects of the ER=EPR conjecture.It begins with a brief heuristic argument, using the Ryu-Takayanagi correspondence, for why entanglement between black holes implies the existence of Einstein-Rosen bridges. The main part ... More

Is Eternal Inflation Past-Eternal? And What if It Is?May 03 2012As a result of discussions with Bousso and Vilenkin I want to return to the question of whether the multiverse is past-eternal or if there was a beginning. Not surprisingly, given three people, there were three answers. However, the discussions have led ... More

Supersymmetry Breaking in the Anthropic LandscapeMay 21 2004Jun 11 2004In this paper I attempt to address a serious criticism of the ``Anthropic Landscape" and "Discretuum" approach to cosmology, leveled by Banks, Dine and Gorbatov. I argue that in this new and unfamiliar setting, the gauge Hierarchy may not favor low energy ... More

Relative regular modules. Applications to von Neumann regular ringsMar 09 2008We use the concept of a regular object with respect to another object in an arbitrary category, defined in \cite{dntd}, in order to obtain the transfer of regularity in the sense of Zelmanowitz between the categories $R-$mod and $S-$mod, when $S$ is an ... More

Metrized Quantum Vector Bundles over Quantum Tori Built from Riemannian Metrics and Rosenberg's Levi-Civita ConnectionsMar 11 2018Jul 29 2018We build metrized quantum vector bundles, over a generically transcendental quantum torus, from Riemannian metrics, using Rosenberg's Levi-Civita connections for these metrics. We also prove that two metrized quantum vector bundles, corresponding to positive ... More

The Yang-Mills heat equation with finite actionJun 13 2016Sep 29 2017The existence and uniqueness of solutions to the Yang-Mills heat equation is proven over three dimensional Euclidean space and over a bounded open convex set therein. The initial data is taken to lie in the Sobolev space of order one half, which is the ... More

Infrared Behaviour of Landau Gauge Yang-Mills Theory with a Fundamentally Charged Scalar FieldFeb 08 2010The infrared behaviour of the n-point functions of a Yang-Mills theory with a charged scalar field in the fundamental representation of SU(N) is studied in the formalism of Dyson-Schwinger equations. Assuming a stable skeleton expansion solutions in form ... More

Hospital Acquired Infections: Advantages of a Computerized SurveillanceMar 05 2009To asses the advantages of a computerized surveillance system to detect Healthcare-Associated Infections (HAI). All HAI reported to the Timis County branch of the Romanian National Health Insurance and the Public Health Authority during the year 2007 ... More

A CryptoCubic Protocol for Hacker-Proof Off-Chain Bitcoin TransactionsAug 11 2014Off-Chain transactions allow for the immediate transfer of Cryptocurrency between two parties, without delays or unavoidable transaction fees. Such capabilities are critical for mainstream Cryptocurrency adaption. They allow for the "Coffee-Coin Criteria"; ... More

New Concepts for Old Black HolesNov 13 2013Dec 07 2013It has been argued that the AMPS paradox implies catastrophic breakdown of the equivalence principle in the neighborhood of a black hole horizon, or even the non-existence of any spacetime at all behind the horizon. Maldacena and the author suggested ... More

Rebuttal to a Paper on WormholesApr 08 2005In a recent paper on wormholes (gr-qc/0503097), the author of that paper demonstrated that he didn't know what he was talking about. In this paper I correct the author's naive erroneous misconceptions.

Twenty Years of Debate with StephenApr 03 2002This is my contribution to Stephen Hawking's 60th birthday party. Happy Birthday Stephen!

T Duality in M(atrix) Theory and S Duality in Field TheoryNov 21 1996The matrix model formulation of M theory can be generalized to compact transverse backgrounds such as tori. If the number of compact directions is K then the matrix model must be generalized to K+1 dimensional super Yang Mills theory on a compact space. ... More

The Typical-State Paradox: Diagnosing Horizons with ComplexityJul 08 2015The concept of transparent and opaque horizons is defined. One example of opaqueness is the presence of a firewall. Two apparently contradictory statements are reconciled: The overwhelming number of black hole states have opaque horizons; and: All black ... More

Black Hole Complementarity and the Harlow-Hayden ConjectureJan 18 2013Jun 06 2013Black hole complementarity, as originally formulated in the 1990's by Preskill, 't Hooft, and myself is now being challenged by the Almheiri-Marolf-Polchinski-Sully firewall argument. The AMPS argument relies on an implicit assumption---the ``proximity ... More

The Census Taker's HatOct 05 2007If the observable universe really is a hologram, then of what sort? Is it rich enough to keep track of an eternally inflating multiverse? What physical and mathematical principles underlie it? Is the hologram a lower dimensional quantum field theory, ... More

Trouble For RemnantsJan 23 1995An argument is presented for the inconsistency of black hole remnants which store the information which falls into black holes. Unlike previous arguments it is not concerned with a possible divergence in the rate of pair production. It is argued that ... More

Comment On A Proposal By StromingerMay 17 1994Strominger has proposed an interesting concrete realization of Hawking's idea that information is lost in black hole evaporation. In this note we demonstrate that a straightforward interpretation of Strominger's model leads to a complete breakdown of ... More

Creation of quantized particles, gravitons and scalar perturbations by the expanding universeMar 01 2015Quantum creation processes during the very rapid early expansion of the universe are believed to give rise to temperature anisotropies and polarization patterns in the CMB radiation. These have been observed by satellites such as COBE, WMAP, and PLANCK, ... More

Particle creation and particle number in an expanding universeMay 25 2012I describe the logical basis of the method that I developed in 1962 and 1963 to define a quantum operator corresponding to the observable particle number of a quantized free scalar field in a spatially-flat isotropically expanding (and/or contracting) ... More

Dalitz plot studies in hadronic charm decaysNov 06 2014Recent studies of hadronic -meson decays are reported. Some experimental searches of CP-symmetry violation using model independent methods are presented. An importance of unitarity constraints in construction of phenomenological models of the D-meson ... More

The Yang-Mills heat equation with finite actionJun 13 2016The existence and uniqueness of solutions to the Yang-Mills heat equation is proven over three dimensional Euclidean space and over a bounded open convex set therein. The initial data is taken to lie in the Sobolev space of order one half, which is the ... More

A homogenization result for weak membrane energiesJan 09 2018We prove a $\Gamma$-convergence result for space dependent weak membrane energies, that is for 'truncated quadratic potentials', that are quadratic below some threshold (depending on the pair of points that we are considering) and constant above. We prove ... More

Axiomatization of Boolean algebras via weak dicomplementationsJul 07 2009In this note we give an axiomatization of Boolean algebras based on weakly dicomplemented lattices: an algebra $(L,\wedge,\vee,\tu)$ of type $(2,2,1)$ is a Boolean algebra iff $(L,\wedge,\vee)$ is a non empty lattice and $(x\wedge y)\vee(x\wedge y\tu)=(x\vee ... More

Crosstalk between nanotube devices: contact and channel effectsJan 31 2006At reduced dimensionality, Coulomb interactions play a crucial role in determining device properties. While such interactions within the same carbon nanotube have been shown to have unexpected properties, device integration and multi-nanotube devices ... More

Copenhagen vs Everett, Teleportation, and ER=EPRApr 09 2016Apr 23 2016Quantum gravity may have as much to tell us about the foundations and interpretation of quantum mechanics as it does about gravity. The Copenhagen interpretation of quantum mechanics and Everett's Relative State Formulation are complementary descriptions ... More

Computational Complexity and Black Hole HorizonsFeb 23 2014Feb 25 2014Computational complexity is essential to understanding the properties of black hole horizons. The problem of Alice creating a firewall behind the horizon of Bob's black hole is a problem of computational complexity. In general we find that while creating ... More

Wormholes and Time Travel? Not LikelyMar 23 2005Apr 08 2005Wormholes have been advanced as both a method for circumventing the limitations of the speed of light as well as a means for building a time machine (to travel to the past). Thus it is argued that General Relativity may allow both of these possibilities. ... More

The Anthropic Landscape of String TheoryFeb 27 2003In this lecture I make some educated guesses, about the landscape of string theory vacua. Based on the recent work of a number of authors, it seems plausible that the lanscape is unimaginably large and diverse. Whether we like it or not, this is the kind ... More

Particle Growth and BPS Saturated StatesNov 17 1995Nov 21 1995Consistency of the Bekenstein bound on entropy requires the physical dimensions of particles to grow with momentum as the particle is boosted to transplanckian energies. In this paper the problem of particle growth in heterotic string theory is mapped ... More

Strings, Black Holes and Lorentz ContractionAug 27 1993Consistency of quantum mechanics in black hole physics requires unusual Lorentz transformation properties of the size and shape of physical systems with momentum beyond the Planck scale. A simple parton model illustrates the kind of behavior which is ... More

Mean-value property on manifolds with minimal horospheresOct 24 2007Let (M,g) be a non-compact and complete Riemannian manifold with minimal horospheres and infinite injectivity radius. We prove that bounded functions on (M,g) satisfying the mean-value property are constant. We extend thus a result of A. Ranjan and H. ... More

An algorithm for one-dimensional Generalized Porous Medium Equations: interface tracking and the hole filling problemOct 06 2014Based on results of E. DiBenedetto and D. Hoff we propose an explicit finite difference scheme for the one dimensional Generalized Porous Medium Equation $\partial_t u=\partial_{xx}^2 \Phi(u)$. The scheme allows to track the moving free boundaries and ... More

Stability of the Yang-Mills heat equation for finite actionOct 31 2017The existence and uniqueness of solutions to the Yang-Mills heat equation over domains in Euclidean three space was proven in a previous paper for initial data lying in the Sobolev space of order one-half, which is the critical Sobolev index for this ... More

Equivalence of helicity and Euclidean self-duality for gauge fieldsNov 18 2018In the canonical formalism for the free electromagnetic field a solution to Maxwell's equations is customarily identified with its initial gauge potential (in Coulomb gauge) and initial electric field, which together determine a point in phase space. ... More

Fine Entanglement and State Manipulation of Two Spin Coupled Qubits: A Lie Theoretic OverviewFeb 18 2015By building on the work in Kuzmak & Tkachuk, "Preparation of quantum states of two spin-$\frac{1}{2}$ particles in the form of the Schmidt decomposition", Physics Letters A, {\bf 378}, pp1469-1474, which outlined the control of the degree of entanglement ... More

Restricted routing and wide diameter of the cycle prefix networkSep 16 1994The cycle prefix network is a Cayley coset digraph based on sequences over an alphabet which has been proposed as a vertex symmetric communication network. This network has been shown to have many remarkable communication properties such as a large number ... More

Global communication algorithms for Cayley graphsMay 28 2013Sep 12 2013We discuss several combinatorial problems that arise when one looks at computational algorithms for highly symmetric networks of processors. More specifically, we are interested in minimal times associated with four communication tasks (defined more precisely ... More

Baryon Number Transport in High Energy Nuclear CollisionsJun 18 1997Recent SPS data on the rapidity distribution of protons in p+S, p+Au and S+S collisions at 200 AGeV and preliminary Pb+Pb collisions at 160 AGeV are compared to HIJING and VENUS calculations as well as to predictions based on the Multi-Chain Model (MCM). ... More

Baryon Number Transport via Gluonic JunctionsJun 03 1998Oct 13 1998A novel non-perturbative gluon junction mechanism is introduced within the HIJING/B nuclear collision event generator to calculate baryon number transport and hyperon production in pA and AA collisions. This gluonic mechanism can account for the observed ... More

Global sum on symmetric networksJan 19 2012We are interested in the following problem we call global sum. Each processor starts with a single real value. At each time step, every directed edge in the graph can simultaneously be used to transmit a single (bounded) number between the processors ... More

Baryon Junction Stopping at the SPS and RHIC via HIJING/BFeb 11 1998Baryon stopping at the SPS and RHIC energies is calculated by introducing a new baryon junction mechanism into HIJING. The exchange of a baryon junction, according to Regge phenomenology, leads to a cosh(y/2) rapidity dependence and an s^(-1/4) energy ... More

Worm-like instability of a vibrated sessile dropNov 23 2016We study the effects of vertical sinusoidal vibrations on a liquid droplet with a low surface tension (ethanol) deposited on a solid substrate. In a precise range of amplitudes and frequencies, the drop exhibits a dramatic worm-like shape instability ... More

biobambam: tools for read pair collation based algorithms on BAM filesJun 04 2013Sequence alignment data is often ordered by coordinate (id of the reference sequence plus position on the sequence where the fragment was mapped) when stored in BAM files, as this simplifies the extraction of variants between the mapped data and the reference ... More

Final State Interactions, T-odd PDFs & the Lensing FunctionJul 17 2009Aug 10 2009It has been suggested that under certain approximations the Sivers effect can be described in terms of factorization of final state interactions and a spatial distortion of impact parameter space parton distribution; that is a convolution of the so-called ... More

Hadron Structure Functions in a Chiral Quark ModelOct 27 1999We present a consistent regularization procedure for calculating hadron structure functions in a bosonized chiral quark model. We find that the Pauli-Villars regularization scheme is most suitable. We also summarize the phenomenology of structure functions ... More

Negative differential resistance in nanotube devicesOct 27 2000Carbon nanotube junctions are predicted to exhibit negative differential resistance, with very high peak-to-valley current ratios even at room temperature. We treat both nanotube p-n junctions and undoped metal-nanotube-metal junctions, calculating quantum ... More

Completion of a Rational Function Sequence of CarlitzJun 14 2000The exponential generating functions of {n^(n+m)} for arbitrary integer m are expressed as rational functions of the e.g.f. of {n^(n-1)} [the tree function] and then of the e.g.f. of {n^n} [the endofunction function]. The coefficients in these rational ... More

The Qth-power algorithm in characteristic 0Jan 25 2013The Qth-power algorithm produces a useful canonical P-module presentation for the integral closures of certain integral extensions of $P:=\mathbf{F}[x_n,...,x_1]$, a polyonomial ring over the finite field $\mathbf{F}:=\mathbf{Z}_q$ of $q$ elements. Here ... More

Seeking Core-Collapse Supernova Progenitors in Pre-Explosion ImagesAug 13 2009I summarize what we have learned about the nature of stars that ultimately explode as core-collapse supernovae from the examination of images taken prior to the explosion. By registering pre-supernova and post-supernova images, usually taken at high resolution ... More

New quantum aspects of a vacuum-dominated universeMar 28 2000In a new model that we proposed, nonperturbative vacuum contributions to the effective action of a free quantized massive scalar field lead to a cosmological solution in which the scalar curvature becomes constant after a time $t_j$ (when the redshift ... More

The Tinsley Diagram RevisitedJan 09 1995Motivated by the recent determinations of the Hubble constant $(H_0)$ from observations of Cepheid variables in NGC4571 and M100, we plot the Tinsley diagram with level curves of the cosmological constant $(\Lambda)$. Based on current estimates of the ... More

On Painleve Related Functions Arising in Random Matrix TheoryJan 27 2011In deriving large n probability distribution function of the rightmost eigenvalue from the classical Random Matrix Theory Ensembles, one is faced with que question of ?finding large n asymptotic of certain coupled set of functions. This paper presents ... More

Edgeworth Expansion of the Largest Eigenvalue Distribution Function of GUE RevisitedNov 27 2007We derive expansions of the resolvent Rn(x;y;t)=(Qn(x;t)Pn(y;t)-Qn(y;t)Pn(x;t))/(x-y) of the Hermite kernel Kn at the edge of the spectrum of the finite n Gaussian Unitary Ensemble (GUEn) and the finite n expansion of Qn(x;t) and Pn(x;t). Using these ... More

Upsilon Production In p-p Collisions at LHCJan 04 2012Feb 17 2012This is a continuation of recent studies of $\Upsilon(nS)$ production at the LHC in p-p collisions. Our previous studies were for 2.76 TeV, while the present predictions are for 7.0 TeV collisions.

Estimate of CP Violation for the LBNE Project and $δ_{CP}Aug 19 2011Jun 27 2012Measurements of CP violation (CPV) and the basic $\delta_{CP}$ parameter are the goals of the LBNE Project, which is being planned. Using the expected energy and baseline parameters for the LBNE Project, CPV and the dependence of CPV on $\delta_{CP}$ ... More

Instanton Model of QCD Phase Transition Bubble WallsFeb 15 2002Mar 21 2003Using the liquid instanton model continued into Minkowski space and modified for finite temperature, the energy momentum tensor and the surface tension for buble walls during the QCD phase transition are derived. The resulting surface tension is in agreement ... More

Temperature diagnostics of the solar atmosphere using SunPyDec 19 2014The solar atmosphere is a hot (about 1MK), magnetised plasma of great interest to physicists. There have been many previous studies of the temperature of the Sun's atmosphere (Plowman2012, Wit2012, Hannah2012, Aschwanden2013, etc.). Almost all of these ... More

Crunches, Hats, and a ConjectureDec 23 2010Our purpose in this paper is to discuss criteria for the existence of a precise dual description of a cosmology. A number of exact descriptions exist for flat and anti de Sitter backgrounds and possibly for open FRW universes that nucleate in an eternally ... More

Cohomological growth rates and Kazhdan-Lusztig polynomialsApr 22 2010Aug 13 2010In previous work, the authors established various bounds for the dimensions of degree $n$ cohomology and $\Ext$-groups, for irreducible modules of semisimple algebraic groups $G$ (in positive characteristic $p$) and (Lusztig) quantum groups $U_\zeta$ ... More

Some Non-Trivial Kazhdan-Lusztig Coefficients of an Affine Weyl Group of Type $\tilde A_n$Sep 18 2009Jun 04 2010In this paper we show that the leading coefficient $\mu(y,w)$ of some Kazhdan-Lusztig polynomials $P_{y,w}$ with $y,w$ in an affine Weyl group of type $\tilde A_n $ is $n+2$. This fact has some consequences on the dimension of first extension groups of ... More

Q-Koszul Algebras and Three ConjecturesMay 17 2014Jun 20 2014In previous work, the authors introduced the notion of Q-Koszul algebras, as a tool to "model" module categories for semisimple algebraic groups over fields of large characteristics. Here we suggest the model extends to small characteristics as well. ... More

Optimal design of mixtures of ferromagnetic interactionsOct 20 2016We provide a general framework for the optimal design of surface energies on networks. We prove sharp bounds for the homogenization of discrete systems describing mixtures of ferromagnetic interactions by constructing optimal microgeometries, and we prove ... More

Forced gradings in integral quasi-hereditary algebras with applications to quantum groupsMar 07 2012Aug 15 2012Let $\sO$ be a discrete valuation ring with fraction field $K$ and residue field $k$. A quasi-hereditary algebra $\wA$ over $\sO$ provides a bridge between the representation theory of the quasi-hereditary algebra $\wA_K:=K\otimes \wA$ over the field ... More

Fields with Analytic StructureAug 17 2009We present a unifying theory of fields with certain classes of analytic functions, called fields with analytic structure. Both real closed fields and Henselian valued fields are considered. For real closed fields with analytic structure, o-minimality ... More

Black Holes: The Legacy of Hilbert's ErrorFeb 13 2001The historical postulates for the point mass are shown to be satisfied by an infinity of space-times, differing as to the limiting acceleration of a radially approaching test particle. Taking this limit to be infinite gives Schwarzschild's result, which ... More