Results for "Paul Smolen"

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A Model of Late Long-Term Potentiation Simulates Aspects of Memory MaintenanceApr 27 2007Late long-term potentiation (L-LTP) appears essential for the formation of long-term memory, with memories at least partly encoded by patterns of strengthened synapses. How memories are preserved for months or years, despite molecular turnover, is not ... More
Modeling Maintenance of Long-Term Potentiation in Clustered Synapses, Long-Term Memory Without BistabilityApr 08 2015Memories are stored, at least partly, as patterns of strong synapses. Given molecular turnover, how can synapses maintain strong for the years that memories can persist? Some models postulate that biochemical bistability maintains strong synapses. However, ... More
Simulations Suggest Pharmacological Methods for Rescuing Long-Term PotentiationAug 08 2014Congenital cognitive dysfunctions are frequently due to deficits in molecular pathways that underlie synaptic plasticity. For example, Rubinstein-Taybi syndrome (RTS) is due to a mutation in cbp, encoding the histone acetyltransferase CREB-binding protein ... More
Bistable MAP Kinase Activity: A Plausible Mechanism Contributing to Maintenance of Late Long-Term PotentiationFeb 18 2008Bistability of MAP kinase (MAPK) activity has been suggested to contribute to several cellular processes, including differentiation and long-term synaptic potentiation. A recent model (48) predicts bistability due to interactions of the kinases and phosphatases ... More
The right time to learn: mechanisms and optimization of spaced learningJun 27 2016For many types of learning, spaced training that involves repeated long inter-trial intervals (ITIs) leads to more robust memory formation than does massed training that involves short or no intervals. Several cognitive theories have been proposed to ... More
Molecular Constraints on Synaptic Tagging and Maintenance of Long-Term Potentiation: A Predictive ModelJun 16 2012Aug 03 2012Protein synthesis-dependent, late long-term potentiation (LTP) and depression (LTD) at glutamatergic hippocampal synapses are well characterized examples of long-term synaptic plasticity. Persistent increased activity of the enzyme protein kinase M (PKM) ... More
How Can Memories Last for Days, Years, or a Lifetime? Proposed Mechanisms for Maintaining Synaptic Potentiation and MemoryMar 13 2019Apr 16 2019With memory encoding reliant on persistent changes in the properties of synapses, a key question is how can memories be maintained from days to months or a lifetime given molecular turnover? It is likely that positive feedback loops are necessary to persistently ... More
Interlinked Dual-Time Feedback Loops can Enhance Robustness to Stochasticity and Persistence of MemoryAug 29 2012Multiple interlinked positive feedback loops shape the stimulus responses of various biochemical systems, such as the cell cycle or intracellular calcium release. Recent studies with simplified models have identified two advantages of coupling fast and ... More
How Can Memories Last for Days, Years, or a Lifetime? Proposed Mechanisms for Maintaining Synaptic Potentiation and MemoryMar 13 2019With memory encoding reliant on persistent changes in the properties of synapses, a key question is how can memories be maintained from days to months or a lifetime given molecular turnover? It is likely that positive feedback loops are necessary to persistently ... More
Paradoxical LTP maintenance with inhibition of protein synthesis and the proteasome suggests a novel protein synthesis requirement for early LTP reversalAug 20 2018The transition from early long-term potentiation (E-LTP) to late LTP (L-LTP) involves protein synthesis and degradation. L-LTP is blocked by inhibiting either protein synthesis or proteasome-dependent degradation prior to and during a tetanic stimulus, ... More
A Model of the Roles of Essential Kinases in the Induction and Expression of Late Long-Term PotentiationJan 03 2006The induction of late long-term potentiation (L-LTP) involves complex interactions among second messenger cascades. To gain insights into these interactions, a mathematical model was developed for L-LTP induction in the CA1 region of the hippocampus. ... More
How Can Memories Last for Days, Years, or a Lifetime? Proposed Mechanisms for Maintaining Synaptic Potentiation and MemoryMar 13 2019Apr 05 2019With memory encoding reliant on persistent changes in the properties of synapses, a key question is how can memories be maintained from days to months or a lifetime given molecular turnover? It is likely that positive feedback loops are necessary to persistently ... More
Simulation of Drosophila Circadian Oscillations, Mutations, and Light Responses by a Model with VRI, PDP-1, and CLKJan 23 2004A model of Drosophila circadian rhythm generation was developed to represent feedback loops based on transcriptional regulation of per, Clk (dclock), Pdp-1, and vri (vrille). The model postulates that histone acetylation kinetics make transcriptional ... More
The dynamics of domain wall SkyrmionsMay 13 2013It has recently been shown that Skyrmions with a fixed size can exist in theories without a Skyrme term, providing the Skyrmion is located on a domain wall. Here we numerically compute domain wall Skyrmions of this type, in a (2+1)-dimensional O(3) sigma ... More
Automorphisms of $\mathscr{P}(λ)/\mathscr{I}_κ$Jun 10 2015Aug 27 2015We study conditions on automorphisms of Boolean algebras of the form $P(\lambda)/I_\kappa$ (where $\lambda$ is an uncountable cardinal and $I_\kappa$ is the ideal of sets of cardinality less than $\kappa$) which allow one to conclude that a given automorphism ... More
Securing Data in Storage: A Review of Current ResearchSep 17 2004Protecting data from malicious computer users continues to grow in importance. Whether preventing unauthorized access to personal photographs, ensuring compliance with federal regulations, or ensuring the integrity of corporate secrets, all applications ... More
Reduced products of UHF algebras under forcing axiomsMar 20 2013If $A_n$ is a sequence of C*-algebras, then the C*-algebra $\prod A_n / \bigoplus A_n$ is called a reduced product. We prove, assuming Todorcevic's Axiom and Martin's Axiom, that every isomorphism between two reduced products of separable, unital UHF ... More
Transcendence of some Hilbert-Kunz multiplicities (modulo a conjecture)Aug 07 2009Suppose that h in F[x,y,z], char F=2, defines a nodal cubic. In earlier papers we made a precise conjecture as to the Hilbert-Kunz functions attached to the powers of h. Assuming this conjecture we showed that a class of characteristic 2 hypersurfaces ... More
Arithmetic Algorithms for Hereditarily Binary Natural NumbersJun 05 2013We study some essential arithmetic properties of a new tree-based number representation, {\em hereditarily binary numbers}, defined by applying recursively run-length encoding of bijective base-2 digits. Our representation expresses giant numbers like ... More
A Unified Formal Description of Arithmetic and Set Theoretical Data TypesJun 30 2010We provide a "shared axiomatization" of natural numbers and hereditarily finite sets built around a polymorphic abstraction of bijective base-2 arithmetics. The "axiomatization" is described as a progressive refinement of Haskell type classes with examples ... More
Towards a model of large scale dynamics in transitional wall-bounded flowsApr 02 2015A system of simplified equations is proposed to govern the feedback interactions of large-scale flows present in laminar-turbulent patterns of transitional wall-bounded flows, with small-scale Reynolds stresses generated by the self-sustainment process ... More
Various notions of best approximation property in spaces of Bochner integrable functionsOct 11 2016Oct 12 2016We derive that for a separable proximinal subspace $Y$ of $X$, $Y$ is strongly proximinal (strongly ball proximinal) if and only if for $1\leq p< \infty$, $L_p(I,Y)$ is strongly proximinal (strongly ball proximinal) in $L_p(I,X)$. Case for $p=\infty$ ... More
A Discipline of Evolutionary ProgrammingFeb 02 1999Genetic fitness optimization using small populations or small population updates across generations generally suffers from randomly diverging evolutions. We propose a notion of highly probable fitness optimization through feasible evolutionary computing ... More
Various notions of best approximation property in spaces of Bochner integrable functionsOct 11 2016Oct 15 2016We derive that for a separable proximinal subspace $Y$ of $X$, $Y$ is strongly proximinal (strongly ball proximinal) if and only if for $1\leq p< \infty$, $L_p(I,Y)$ is strongly proximinal (strongly ball proximinal) in $L_p(I,X)$. Case for $p=\infty$ ... More
Inversions of Semistandard Young TableauxAug 05 2015A tableau inversion is a pair of entries from the same column of a row-standard tableau that lack the relative ordering necessary to make the tableau column-standard. An $i$-inverted Young tableau is a row-standard tableau with precisely $i$ inversion ... More
Di-jet Shape Modification in Heavy Ion CollisionsOct 28 2005Jan 31 2006We present preliminary results from intermediate $p_T$ (1-5 GeV/c) di-hadron azimuthal correlations induced by hadronic di-jets produced in $AuAu$ collisions at $\sqrt{s_{NN}} = 200 GeV$. The near side ($\Delta\phi\sim 0$) has a typical single-peaked ... More
Sur une classe de groupoides riemanniensMay 27 2013In this work we show that there is a Riemannian groupoid whose orbits are the closures of the leaves of a regular Riemannian foliation on a compact manifold. This groupoid is equivalent (in a generalized sense of Haefliger) with a transformational groupoid ... More
Ways of Listening and Modes of Being: Electroacoustic Auditory DisplayNov 21 2013Auditory display is concerned with the use of non-speech sound to communicate information. If the term seems at first oxymoronic, then consider auditory display as an activity of perceptualization, that is, the process of making perceptible to humans ... More
The Nature of Ionized Gas in Giant Elliptical GalaxiesSep 04 1998I review the current understanding of the origin and nature of ``warm'' ionized gas in giant elliptical galaxies in the light of results of recent imaging and spectroscopic surveys. CCD imaging surveys have revealed that emission-line disks or filaments ... More
Symmetries of the Black-Scholes equationOct 27 2011Oct 31 2011We determine the algebra of isovectors for the Black--Scholes equation. As a consequence, we obtain some previously unknown families of transformations on the solutions.
The rapid points of a complex oscillationFeb 17 2012Mar 08 2012By considering a counting-type argument on Brownian sample paths, we prove a result similar to that of Orey and Taylor on the exact Hausdorff dimension of the rapid points of Brownian motion. Because of the nature of the proof we can then apply the concepts ... More
Principal fiber bundle description of number scaling for scalars and vectors: Application to gauge theoryMar 18 2015The purpose of this paper is to put the description of number scaling and its effects on physics and geometry on a firmer foundation, and to make it more understandable. A main point is that two different concepts, number and number value are combined ... More
Space of Quantum Theory Representations of Natural Numbers, Integers, and Rational NumbersApr 26 2007This paper extends earlier work on quantum theory representations of natural numbers N, integers I, and rational numbers Ra to describe a space of these representations and transformations on the space. The space is parameterized by 4-tuple points in ... More
Complex Rational Numbers in Quantum MechanicsAug 03 2005A binary representation of complex rational numbers and their arithmetic is described that is not based on qubits. It takes account of the fact that $0s$ in a qubit string do not contribute to the value of a number. They serve only as place holders. The ... More
Towards a Coherent Theory of Physics and MathematicsJan 21 2002May 02 2002As an approach to a Theory of Everything a framework for developing a coherent theory of mathematics and physics together is described. The main characteristic of such a theory is discussed: the theory must be valid and and sufficiently strong, and it ... More
Space Searches with a Quantum RobotMar 01 2000Jun 26 2001Quantum robots are described as mobile quantum computers and ancillary systems that move in and interact with arbitrary environments. Their dynamics is given as tasks which consist of sequences of alternating computation and action phases. A task example ... More
Local Availability of mathematics and number scaling: Effects on quantum physicsMay 01 2012Local availability of mathematics and number scaling provide an approach to a coherent theory of physics and mathematics. Local availability of mathematics assigns separate mathematical universes, U_{x}, to each space time point, x. The mathematics available ... More
New Gauge Fields from Extension of Parallel Transport of Vector Spaces to Underlying Scalar FieldsMay 03 2011Gauge theories can be described by assigning a vector space V(x) to each space time point x. A common set of complex numbers, C, is usually assumed to be the set of scalars for all the V{x}. This is expanded here to assign a separate set of scalars, C{x}, ... More
Efficient Implementation and the Product State Representation of NumbersApr 11 2001Sep 24 2001The relation between the requirement of efficient implementability and the product state representation of numbers is examined. Numbers are defined to be any model of the axioms of number theory or arithmetic. Efficient implementability (EI) means that ... More
Connectedness of spaces of symplectic embeddingsMar 19 1996We prove that the space of symplectic packings of ${\Bbb C}P^2$ by $k$ equal balls is connected for $3\leq k\leq 6$. The proof is based on Gromov-Witten invariants and on the inflation technique due to Lalonde and McDuff.
The Einstein-Hilbert Action Horizons and Connections with ThermodynamicsNov 22 2011It is shown that the Einstein-Hilbert action can be constructed by minimizing free energy. The entropy used to determine the free energy is determined on the horizon of a black hole. Some further considerations with regard to generalizations of these ... More
A Chiral Schwinger model, its Constraint Structure and Applications to its QuantizationOct 12 2007Dec 06 2007The Jackiw-Rajaraman version of the chiral Schwinger model is studied as a function of the renormalization parameter. The constraints are obtained and they are used to carry out canonical quantization of the model by means of Dirac brackets. By introducing ... More
Determination of the Electromagnetic Lagrangian from a System of Poisson BracketsJul 30 2006The Lagrangian and Hamiltonian formulations of electromagnetism are reviewed and the Maxwell equations are obtained from the Hamiltonian for a system of many electric charges. It is shown that three of the equations which were obtained from the Hamiltonian, ... More
Motion on Constant Curvature Spaces and Quantization Using Noether SymmetriesJun 11 2014Jul 02 2014A general approach is presented for quantizing a metric nonlinear system on a manifold of constant curvature. It makes use of a curvature dependent procedure which relies on determining Noether symmetries from the metric. The curvature of the space functions ... More
Asteroid Evolution: Role of Geotechnical PropertiesNov 26 2015This paper presents a brief review and latest results of the work that has been carried out by the Planetary Science community in order to understand that role of the geotechnical properties of granular asteroids (commonly known as "rubble-pile" asteroids) ... More
On the number of geodesic segments connecting two points on manifolds of non-positive curvatureFeb 28 1995In this paper we show that on a complete Riemannian manifold of negative curvature and dimension $n>1$ every two points which realize a local maximum for the distance function are connected by at least $2n+1$ geometrically distinct geodesic segments (i.e. ... More
Deep Inelastic Scattering at the TeV Energy Scale and the LHeC ProjectFeb 13 2009Feb 15 2009The prospect of an ep collider involving an LHC proton beam and a new electron accelerator is discussed. Configurations reaching centre of mass energies a factor of 5 beyond HERA are possible with luminosities of the order of 10^33 cm^-2 s^-1. The physics ... More
Measurements of the Diffractive Structure Function F2D at HERADec 21 2001Recent measurements of the diffractive cross section in deep-inelastic scattering at HERA are presented. The data are used to investigate the factorisation properties of diffractive DIS and to examine its quantum chromodynamic structure. Models based ... More
The Critical Value of the Contact Process with Added and Removed EdgesMay 04 2004Nov 19 2004We show that the critical value for the contact process on a vertex-transitive graph G with finitely many edges added and/or removed is the same as the critical value for the contact process on G.
The noisy voter-exclusion processOct 31 2003The symmetric exclusion process and the voter model are two interacting particle systems for which a dual finite particle system allows one to characterize its invariant measures. Adding spontaneous births and deaths to the two processes still allows ... More
Relativistic bound states at Born levelOct 30 2012Theoretical and phenomenological studies indicate that the QCD coupling \alpha_s(Q^2) freezes in the infrared. Hadrons may then be described by a perturbative expansion around "Born" states bound only by a confining potential. A linear potential results ... More
Bound states at lowest order in hbarSep 16 2009Jan 19 2010Bound states poles in scattering amplitudes are generated by the divergence of the perturbative series due to enhanced Coulomb scattering near thresholds. This suggests to organize bound state calculations according to an expansion in hbar, i.e., in the ... More
ELFE PhysicsNov 25 1999This is an introductory review of central topics in hadron physics that are addressed by high intensity, continuous electron beam facilities in the multi-GeV range. Exclusive processes are a crucial tool for increasing our knowledge of hadron wave functions ... More
Physics Opportunities at ELFENov 26 1996Dec 19 1996I review some central physics opportunities at the 15 ... 30 GeV continuous beam electron accelerator ELFE, proposed to be built in conjunction with the DESY linear collider. Our present detailed knowledge of single parton distributions in hadrons and ... More
Bound states -- from QED to QCDFeb 20 2014These lectures are divided into two parts. In Part 1 I discuss bound state topics at the level of a basic course in field theory: The derivation of the Schr\"odinger and Dirac equations from the QED Lagrangian, by summing Feynman diagrams and in a Hamiltonian ... More
Inclusive PerspectivesAug 21 2007I discuss the relation between inclusive and exclusive dynamics suggested by Bloom-Gilman duality. Duality implies the simultaneous applicability of two distinct limits, the standard DIS limit of hard inclusive processes taken at fixed xB and a limit ... More
Filling Perturbative Ground StatesApr 02 2003I discuss a degree of freedom in formulating perturbation theory that is often neglected: the in- and out-states need not be empty. The inclusion of (free) particles in the asymptotic states modifies the on-shell prescription of the free propagator. This ... More
Perturbative QCD with Quark and Gluon CondensatesMar 25 2002QCD perturbation theory using quark and gluon propagators that have an extra term at zero four-momentum is equivalent to standard PQCD in the presence of massless quark and gluon pairs in the perturbative vacuum. We verify at low orders in perturbation ... More
Charmonium Production at ELFE EnergiesFeb 21 1997I discuss issues related to charmonium production, in view of physics possibilities at a 15 ... 30 GeV continuous beam electron facility. High energy photo- and hadroproduction of heavy quarkonia presents several challenges to QCD models concerning cross ... More
Interactions on NucleiOct 24 1995I review hard photon initiated processes on nuclei. The space-time development of the DIS reaction as viewed in the target rest frame qualitatively describes the nuclear shadowing of quark and gluon distributions, although it may be difficult to understand ... More
Some geometry of de Sitter spaceMay 22 2015In this expository note, I present some basic geometric and twistor theoretic facts about de Sitter space leading up to a discussion of Penrose's quasi-local mass construction for linear gravity theory in the de Sitter background. The corresponding results ... More
Ionospheric dispersion compensation using a novel microwave de-dispersion filterMay 02 2013Free electrons in the ionosphere lead to significant group delay dispersion for signals in the megahertz and low gigahertz range. A novel microwave filter is presented that is capable of compensating for the non-linear ionospheric dispersion over a 600 ... More
Efficient Tabling Mechanisms for Transaction Logic ProgramsSep 11 2007In this paper we present efficient evaluation algorithms for the Horn Transaction Logic (a generalization of the regular Horn logic programs with state updates). We present two complementary methods for optimizing the implementation of Transaction Logic. ... More
The Moduli Space of N = 2 Superconformal Field TheoriesDec 12 1994We review the structure of the moduli space of particular N = (2,2) superconformal field theories. We restrict attention to those of particular use in superstring compactification, namely those with central charge c = 3d for some integer d and whose NS ... More
Precision Electroweak Data: Phenomenological AnalysisOct 09 2001The precision electroweak program, including weak neutral current (WNC), $Z$-pole, and high energy collider experiments, has been the primary prediction and test of electroweak unification. It has established that the standard model (SM) is correct and ... More
Physics Implications of Precision Electroweak ExperimentsFeb 07 2001A brief review is given of precision electroweak physics, and its implications for establishing the standard model and constraining the possibilities for new physics at the TeV scale and beyond.
Implications of Solar and Atmospheric NeutrinosNov 24 1998The importance of non-zero neutrino mass as a probe of particle physics, astrophysics, and cosmology is emphasized. The present status and future prospects for the solar and atmospheric neutrinos are reviewed, and the implications for neutrino mass and ... More
Precision Experiments, Grand Unification, and CompositenessNov 02 1995Precision electroweak data allow one to test the standard model, constrain its parameters, and search for the effects of some kinds of new physics. The results of the most recent data from LEP, SLC, and elsewhere are described, as are their predictions ... More
Z' Physics at the LHCNov 23 2009Nov 30 2009The existing limits on Z' gauge bosons and prospects for discovery and diagnostic studies at the LHC are briefly reviewed.
The Physics of Heavy Z' Gauge BosonsJan 09 2008Nov 30 2009The U(1)' symmetry associated with a possible heavy Z' would have profound implications for particle physics and cosmology. The motivations for such particles in various extensions of the standard model, possible ranges for their masses and couplings, ... More
Electroweak PhysicsAug 13 2003The results of high precision weak neutral current (WNC), Z-pole, and high energy collider electroweak experiments have been the primary prediction and test of electroweak unification. The electroweak program is briefly reviewed from a historical perspective. ... More
Tests of the Standard Model and Searches for New PhysicsDec 22 1994The implications of precision $Z$ and $W$-pole and neutral current data for testing the standard electroweak model, determining its parameters, and searching for new physics, are described.
Direct Evidence for Dynamical Evolution of Luminosity Functions of Globular Cluster Systems: HST/ACS observations of the 3-Gyr-old merger remnant NGC 1316Apr 08 2004Recent observations of globular clusters (GCs) in intermediate-age (2-4 Gyr old), early-type merger remnants have provided the hitherto `missing link' between young merger remnants and `normal' elliptical galaxies in the form of a GC subsystem with colors ... More
RHIC Critical Point Search: Assessing STAR's CapabilitiesJan 19 2007In this report we discuss the capabilities and limitations of the STAR detector to search for signatures of the QCD critical point in a low energy scan at RHIC. We find that a RHIC low energy scan will cover a broad region of interest in the nuclear matter ... More
Isoscalar-isovector mass splittings in excited mesonsNov 10 1993Mass splittings between the isovector and isoscalar members of meson nonets arise in part from hadronic loop diagrams which violate the Okubo-Zweig-Iizuka rule. Using a model for these loop processes which works qualitatively well in the established nonets, ... More
Calculating Bar-Natan's characteristic two Khovanov homologyNov 10 2004Aug 29 2005We investigate Bar-Natan's characteristic two Khovanov link homology theory studying both the filtered and bi-graded theories. The filtered theory is computed explicitly and the bi-graded theory analysed by setting up a family of spectral sequences. The ... More
Five Lectures on Khovanov HomologyJun 19 2006These lecture notes, which were designed for the Summer School "Heegaard-Floer Homology and Khovanov Homology" in Marseilles, 29th May - 2nd June, 2006, provide an elementary introduction to Khovanov homology. The intended audience is graduate students ... More
How not to Rényi generalize the Quantum Conditional Mutual InformationApr 14 2014Jun 22 2015We study the relation between the quantum conditional mutual information and the quantum $\alpha$-R\'enyi divergences. Considering the totally antisymmetric state we show that it is not possible to attain a proper generalization of the quantum conditional ... More
Rank 4 Premodular CategoriesApr 21 2012Jul 17 2015We consider the classification problem for rank 4 premodular categories. We uncover a formula for the 2nd Frobenius-Schur indicator of a premodular category, and complete the classification of rank 4 premodular categories (up to Grothendieck equivalence). ... More
On complex singularities of the 2D Euler equation at short timesMar 18 2009We present a study of complex singularities of a two-parameter family of solutions for the two-dimensional Euler equation with periodic boundary conditions and initial conditions F(p) cos p z + F(q) cos q z in the short-time asymptotic regime. As has ... More
Hawking radiation for Dirac spinors on the RP^3 geonMar 02 2004Nov 19 2004We analyse the Hawking(-Unruh) effect for a massive Dirac spinor on the Z_2 quotient of Kruskal spacetime known as the RP^3 geon. There are two distinct Hartle-Hawking-like vacua, depending on the choice of the spin structure, and suitable measurements ... More
Causal particle detectors and topologyOct 10 2005We investigate particle detector responses in some topologically non-trivial spacetimes. We extend a recently proposed regularization of the massless scalar field Wightman function in 4-dimensional Minkowski space to arbitrary dimension, to the massive ... More
Rossby waves trapped by quantum mechanicsMar 11 2013Extended abstract for the workshop "Geophysical Fluid Dynamics " held in Oberwolfach, 17 February - 23 February 2013, to be published by the Mathematisches Forschungsinstitut Oberwolfach in the "Oberwolfach Reports" series.
Strong zero modes and eigenstate phase transitions in the XYZ/interacting Majorana chainDec 10 2015I explicitly construct a strong zero mode in the XYZ chain or, equivalently, Majorana wires coupled via a four-fermion interaction. The strong zero mode is an operator that pairs states in different symmetry sectors, resulting in identical spectra up ... More
Free parafermionsOct 22 2013Nov 18 2013The spectrum of the quantum Ising chain can be found by expressing the spins in terms of free fermions. An analogous transformation exists for clock chains with $Z_n$ symmetry, but is of less use because the resulting parafermionic operators remain interacting. ... More
Parafermionic edge zero modes in Z_n-invariant spin chainsSep 03 2012Oct 02 2012A sign of topological order in a gapped one-dimensional quantum chain is the existence of edge zero modes. These occur in the Z_2-invariant Ising/Majorana chain, where they can be understood using free-fermion techniques. Here I discuss their presence ... More
Topological order from quantum loops and netsApr 03 2008Apr 15 2008I define models of quantum loops and nets which have ground states with topological order. These make possible excited states comprised of deconfined anyons with non-abelian braiding. With the appropriate inner product, these quantum loop models are equivalent ... More
Integrable sigma models with theta=piAug 24 2000May 15 2001A fundamental result relevant to spin chains and two-dimensional disordered systems is that the sphere sigma model with instanton coupling theta=pi has a non-trivial low-energy fixed point and a gapless spectrum. This result is extended to two series ... More
Negative local feedbacks in Boolean networksDec 04 2015Oct 16 2016We study the asymptotic dynamical properties of Boolean networks without local negative cycle. While the properties of Boolean networks without local cycle or without local positive cycle are rather well understood, recent literature raises the following ... More
Exotic iterated Dehn twistsMay 20 2013Apr 14 2014Consider cotangent bundles of exotic spheres, with their canonical symplectic structure. They admit automorphisms which preserve the part at infinity of one fibre, and which are analogous to the square of a Dehn twist. Pursuing that analogy, we show that ... More
Suspending Lefschetz fibrations, with an application to Local Mirror SymmetryJul 12 2009Aug 05 2009We consider the suspension operation on Lefschetz fibrations, which takes p(x) to p(x)-y^2. This leaves the Fukaya category of the fibration invariant, and changes the category of the fibre (or more precisely, the subcategory consisting of a basis of ... More
A long exact sequence for symplectic Floer cohomologyMay 23 2001Jul 20 2002The long exact sequence describes how the Floer cohomology of two Lagrangian submanifolds changes if one of them is modified by applying a Dehn twist. We give a proof in the simplest case (no bubbling). The paper contains a certain amount of material ... More
Fukaya A_\infty structures associated to Lefschetz fibrations. IDec 19 2009Feb 06 2016This (partially expository) paper discusses Lagrangian Floer cohomology in the context of Lefschetz fibrations, with emphasis on the algebraic structures encountered there. In addition to the well-known directed A_infinity algebras which appear in this ... More
A_\infty-subalgebras and natural transformationsJan 26 2007Apr 24 2008The paper explores some algebraic constructions arising in the theory of Lefschetz fibrations. Specifically, it covers in a fair amount of detail the algebraic issues outlined in ``Symplectic homology as Hochschild homology'' (math.SG/0609037). We also ... More
Geometric renormalization below the ground stateSep 30 2010Dec 06 2011The caloric gauge was introduced by Tao with studying large data energy critical wave maps mapping from $\mathbf{R}^{2+1}$ to hyperbolic space $\mathbf{H}^m$ in view. In \cite{BIKT} Bejenaru, Ionescu, Kenig, and Tataru adapted the caloric gauge to the ... More
Retarded Correlators in Kinetic Theory: Branch Cuts, Poles and Hydrodynamic Onset TransitionsDec 08 2015Jul 25 2016In this work the collective modes of an effective kinetic theory description based on the Boltzmann equation in relaxation time approximation applicable to gauge theories at weak but finite coupling and low frequencies are studied. Real time retarded ... More
The Consistency of Topological Expansions in Field Theory: `BRST Anomalies' in Strings and Yang-MillsAug 25 1993Sep 04 1993Many field theories of physical interest have configuration spaces consisting of disconnected components. Quantum mechanical amplitudes are then expressed as sums over these components. We use the Faddeev-Popov approach to write the terms in this topological ... More
A Large Distance Expansion for Quantum Field TheoryAug 15 1996Using analyticity of the vacuum wave-functional under complex scalings, the vacuum of a quantum field theory may be reconstructed from a derivative expansion valid for slowly varying fields. This enables the eigenvalue problem for the Hamiltonian to be ... More
Do nuclear collisions create a locally equilibrated quark-gluon plasma?Sep 09 2016Oct 03 2016Experimental results on azimuthal correlations in high energy nuclear collisions (nucleus-nucleus, proton-nucleus and proton-proton) seem to be well described by viscous hydrodynamics. It is often argued that this agreement implies either local thermal ... More
Fukaya A_\infty-structures associated to Lefschetz fibrations. IIIAug 13 2016Floer cohomology groups are usually defined over a field of formal functions (a Novikov field). Under certain assumptions, one can equip them with connections, which means operations of differentiation with respect to the Novikov variable. This allows ... More