Results for "Charlotte Christensen"

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The Role of Baryons in Creating Statistically Significant Planes of Satellites around Milky Way-Mass GalaxiesOct 10 2016We investigate whether the inclusion of baryonic physics influences the formation of thin, coherently rotating planes of satellites such as those seen around the Milky Way and Andromeda. For four Milky Way-mass simulations, each run both as dark matter-only ... More
Justifying Typicality Measures of Boltzmannian Statistical Mechanics and Dynamical SystemsOct 06 2013A popular view in contemporary Boltzmannian statistical mechanics is to interpret the measures as typicality measures. In measure-theoretic dynamical systems theory measures can similarly be interpreted as typicality measures. However, a justification ... More
Bulge Formation via Mergers in Cosmological SimulationsNov 12 2015The latest generation of cosmological simulations are on the verge of being able to resolve the structure of bulges for the first time. Hence, we review the current state of bulge formation in cosmological simulations, and discuss open questions that ... More
On the Observational Equivalence of Continuous-Time Deterministic and Indeterministic DescriptionsOct 06 2013This paper presents and philosophically assesses three types of results on the observational equivalence of continuous-time measure-theoretic deterministic and indeterministic descriptions. The first results establish observational equivalence to abstract ... More
Ashkin-Teller universality in a quantum double model of Ising anyonsFeb 01 2009Jul 09 2009We study a quantum double model whose degrees of freedom are Ising anyons. The terms of the Hamiltonian of this system give rise to a competition between single and double topologies. By studying the energy spectra of the Hamiltonian at different values ... More
Computation of the Galois groups occuring in M. Papanikolas's study of Carlitz logarithmsJun 24 2009In this note, we state a theorem of compution of the unipotent radical of the Galois group of an object $U$ of a tannakian category defined over a field of positive characteristic, extension of the unit object by a semi-simple one. We then give a criteria ... More
Pressure Dependent Viscosity Model for Granular Media Obtained from Compressible Navier-Stokes EquationsJun 12 2015Aug 20 2015The aim of this article is to justify mathematically, in the two-dimensional periodic setting, a generalization of a two-phase model with pressure dependent viscosity first proposed by A. Lefebvre-Lepot and B. Maury to describe a system in one dimension ... More
Are Deterministic Descriptions And Indeterministic Descriptions Observationally Equivalent?Oct 06 2013The central question of this paper is: are deterministic and indeterministic descriptions observationally equivalent in the sense that they give the same predictions? I tackle this question for measure-theoretic deterministic systems and stochastic processes, ... More
What Are the New Implications of Chaos for Unpredictability?Oct 06 2013From the beginning of chaos research until today, the unpredictability of chaos has been a central theme. It is widely believed and claimed by philosophers, mathematicians and physicists alike that chaos has a new implication for unpredictability, meaning ... More
Homological index formulas for elliptic operators over C*-algebrasMar 30 2006Jan 03 2009We prove index formulas for elliptic operators acting between sections of C*-vector bundles on a closed manifold. The formulas involve Karoubi's Chern character from K-theory of a C*-algebra to de Rham homology of smooth subalgebras. We show how they ... More
Deligne--Lusztig constructions for division algebras and the local Langlands correspondence, IIMay 27 2015Jul 24 2015In 1979, Lusztig proposed a cohomological construction of supercuspidal representations of reductive $p$-adic groups, analogous to Deligne-Lusztig theory for finite reductive groups. In this paper we establish a new instance of Lusztig's program. Precisely, ... More
Product formula for Atiyah-Patodi-Singer index classes and higher signaturesNov 01 2008Apr 14 2009We define generalized Atiyah-Patodi-Singer boundary conditions of product type for Dirac operators associated to C*-vector bundles on the product of a compact manifold with boundary and a closed manifold. We prove a product formula for the K-theoretic ... More
Implementing Dust Shielding as a Criteria for Star FormationJan 03 2019Star formation is observed to be strongly correlated to dense regions of molecular gas. Although the exact nature of the link between star formation and molecular hydrogen is still unclear, some have suggested that shielding of dense gas by dust grains ... More
Star Formation and Feedback in Smoothed Particle Hydrodynamic Simulations II: Resolution EffectsMay 10 2010We examine the effect of mass and force resolution on a specific star formation (SF) recipe using a set of N-body/Smooth Particle Hydrodynamic simulations of isolated galaxies. Our simulations span halo masses from 10^9 to 10^13 solar masses, more than ... More
Discovering the laws of urbanisationDec 11 2015In 2012 the world's population exceeded 7 billion, and since 2008 the number of individuals living in urban areas has surpassed that of rural areas. This is the result of an overall increase of life expectancy in many countries that has caused an unprecedented ... More
Is there an order-barrier $p\leq2$ for time integration in computational elasto-plasticity?Dec 21 2015This paper is devoted to the question, whether there is an order barrier $p\leq2$ for time integration in computational elasto-plasticity. In the analysis we use an implicit Runge-Kutta (RK) method of order $p=3$ for integrating the evolution equations ... More
More about One-Loop Effective Action of Open Superstring in $AdS_5\times S^5$Jun 25 2012Sep 13 2012We reconsider the calculation of the one-loop effective action for an open Green-Schwarz superstring in the $AdS_5\times S^5$ background for a circular boundary loop. By an explicit computation of the ratio of relevant determinants, describing semi-classical ... More
Modelling Inflation with a Power-law Approach to the Inflationary PlateauJul 08 2016Sep 18 2016A new family of inflationary models is introduced and analysed. The behaviour of the parameters characterising the models suggest preferred values, which generate the most interesting testable predictions. Results are further improved if late reheating ... More
Nonparametric drift estimation for diffusions with jumps driven by a Hawkes processApr 17 2019We consider a 1-dimensional diffusion process X with jumps. The particularity of this model relies in the jumps which are driven by a multidimensional Hawkes process denoted N. This article is dedicated to the study of a nonparametric estimator of the ... More
Non-Gaussian sampling effects on the CMB power spectrum estimationJul 24 1997We introduce a non-Gaussian model of structure formation, and show how it produces surprising sampling effects on the estimation of the CMB power spectrum. Estimates of the average power spectrum based on small sky patches produce qualitatively different ... More
Higher-Spin Algebras, Holography and Flat SpaceSep 04 2016In this article we study the algebra generated by the holographically reconstructed cubic couplings for the type A minimal bosonic higher-spin theory on AdS$_{d+1}$, which were recently extracted from the free scalar $O(N)$ model. We demonstrate that ... More
Boltzmannian Equilibrium in Stochastic SystemsJul 22 2016Equilibrium is a central concept of statistical mechanics. In previous work we introduced the notions of a Boltzmannian alpha-epsilon-equilibrium and a Boltzmannian gamma-varepsilon-equilibrium (Werndl and Frigg 2015a, 2015b). This was done in a deterministic ... More
Towards a Low-Complexity Dynamic Decode-and-Forward Relay ProtocolDec 02 2010The dynamic decode-and-forward (DDF) relaying protocol is a relatively new cooperative scheme which has been shown to achieve promising theoretical results in terms of diversity-multiplexing gain tradeoff and error rates. The case of a single relay has ... More
Separable Representation of Energy-Dependent Optical PotentialsDec 22 2015Background. One important ingredient for many applications of nuclear physics to astrophysics, nuclear energy, and stockpile stewardship are cross sections for reactions of neutrons with rare isotopes. Since direct measurements are often not feasible, ... More
The definable (p,q)-theorem for distal theoriesFeb 03 2016Jan 20 2017Answering a special case of a question of Chernikov and Simon, we show that any non-dividing formula over a model M in a distal NIP theory is a member of a consistent definable family, definable over M.
Tensor Products of Cyclic Algebras of Degree 4 and their Kummer SubspacesFeb 16 2015Jul 08 2016We prove that the maximal dimension of a Kummer space in the generic tensor product of $n$ cyclic algebras of degree 4 is $4 n+1$.
Explaining Thermodynamic-Like Behaviour In Terms of Epsilon-ErgodicityOct 07 2013Why do gases reach equilibrium when left to themselves? The canonical answer, originally proffered by Boltzmann, is that the systems have to be ergodic. This answer is now widely regarded as flawed. We argue that some of the main objections, in particular, ... More
Using Distributed Rotations for a Low-Complexity Dynamic Decode-and-Forward Relay ProtocolFeb 21 2011In this paper, we propose to implement the dynamic decode-and-forward (DDF) protocol with distributed rotations. In addition to being the first minimum-delay implementation of the DDF protocol proposed for any number of relays, this technique allows to ... More
Higher-Spin Algebras, Holography and Flat SpaceSep 04 2016Oct 24 2016In this article we study the algebra generated by the holographically reconstructed cubic couplings for the type A minimal bosonic higher-spin theory on AdS$_{d+1}$, which were recently extracted from the free scalar $O(N)$ model. We demonstrate that ... More
When Does a Boltzmannian Equilibrium Exist?Jun 03 2016The received wisdom in statistical mechanics is that isolated systems, when left to themselves, approach equilibrium. But under what circumstances does an equilibrium state exist and an approach to equilibrium take place? In this paper we address these ... More
Higher-spin Interactions from CFT: The Complete Cubic CouplingsFeb 29 2016Mar 28 2016In this letter we provide a complete holographic reconstruction of the cubic couplings in the minimal bosonic higher-spin theory in AdS$_{d+1}$. For this purpose we also determine the OPE coefficients of all single-trace conserved currents in the $d$-dimensional ... More
Rethinking Boltzmannian EquilibriumOct 08 2015Boltzmannian statistical mechanics partitions the phase space of a system into macro-regions, and the largest of these is identified with equilibrium. What justifies this identification? Common answers focus on Boltzmann's combinatorial argument, the ... More
Free/Congested Two-Phase Model from Weak Solutions to Multi-Dimensional Compressible Navier-Stokes EquationsOct 02 2014We approximate a two--phase model by the compressible Navier-Stokes equations with a singular pressure term. Up to a subsequence, these solutions are shown to converge to a global weak solution of the compressible system with the congestion constraint ... More
Diagonalizing the Hamiltonian of $λφ^4$ Theory in 2 Space-Time DimensionsMar 03 2016We propose a new non-perturbative technique for calculating the field-theory S-matrix directly from the eigenstates of the Hamiltonian. Our method involves a discretized momentum space and a momentum cutoff, thereby truncating the Hilbert space and making ... More
A decomposition of the Schur block product on matrices of operatorsNov 08 2018Given two $m \times n $ matrices $A = (a_{ij})$ and $B=(b_{ij}) $ with entries in $B(H)$ for some Hilbert space $H,$ the Schur block product is the $m \times n$ matrix $ A\square B := (a_{ij}b_{ij}).$ There exists an $m \times n$ matrix $S = (s_{ij})$ ... More
Stochastic Gravitational Wave BackgroundsNov 21 2018A stochastic background of gravitational waves can be created by the superposition of a large number of independent sources. The physical processes occurring at the earliest moments of the universe certainly created a stochastic background that exists, ... More
KMS states on the Toeplitz algebras of higher-rank graphsMay 23 2018The Toeplitz algebra $\mathcal{T}C^{*}(\Lambda)$ for a finite $k$-graph $\Lambda$ is equipped with a continuous one-parameter group $\alpha^{r}$ for each $ r\in \mathbb{R}^{k}$, obtained by composing the map $\mathbb{R} \ni t \to (e^{itr_{1}}, \dots , ... More
Higher Weak Derivatives and Reflexive Algebras of OperatorsApr 14 2015Jul 09 2015Let D be a self-adjoint operator on a Hilbert space H and x a bounded operator on H. We say that x is n-times weakly D-differentiable, if for any pair of vectors a, b from H the function < exp(itD)x exp(-itD) a, b> is n-times differentiable. We give several ... More
Giant D5 Brane Holographic Hall StateDec 21 2012May 16 2013We find a new holographic description of strongly coupled defect field theories using probe D5 branes. We consider a system where a large number of probe branes, which are asymptotically D5 branes, blow up into a D7 brane suspended in the bulk of anti-de ... More
Six problems in frame theoryAug 23 2013We discuss various problems in frame theory that have been open for some years. A short discussion of frame theory is also provided, but it only contains the information that is necessary in order to understand the open problems and their role.
Pattern Avoidance in Set PartitionsJul 25 2018A set partition avoids a pattern if no subdivision of that partition standardizes to the pattern. There exists a bijection between set partitions and restricted growth functions (RGFs) on which Wachs and White defined four statistics of interest to this ... More
A method for pricing American options using semi-infinite linear programmingMar 23 2011Jun 09 2011We introduce a new approach for the numerical pricing of American options. The main idea is to choose a finite number of suitable excessive functions (randomly) and to find the smallest majorant of the gain function in the span of these functions. The ... More
The Hadamard product in a crossed product C*-algebraMay 14 2019We show that for a C*-algebra A and a discrete group G with an action of G on A, the reduced crossed product C*-algebra possesses a natural generalization of the convolution product, which we suggest should be named the Hadamard product. We show that ... More
Roll of the Dice: A Stochastically Sampled IMF Alters the StellarContent of Simulated Dwarf GalaxiesOct 31 2018Cosmological simulations are reaching the resolution necessary to study ultra-faint dwarf galaxies. Observations indicate that in small populations, the stellar initial mass function (IMF) is not fully populated; rather, stars are sampled in a way that ... More
Not So Heavy Metals: Black Hole Feedback Enriches The Circumgalactic MediumOct 29 2018We examine the effects of SMBH feedback on the CGM using a cosmological hydrodynamic simulation \citep[{\sc Romulus25};][]{Tremmel2017} and a set of four zoom-in `genetically modified' Milky Way-mass galaxies sampling different evolutionary paths. By ... More
Multimessenger Signatures of Massive Black Holes in Dwarf GalaxiesJun 01 2018Oct 19 2018Recent discoveries of massive black holes (MBHs) in dwarf galaxies suggest that they may have a more common presence than once thought. Systematic searches are revealing more candidates, but this process could be accelerated by predictions from simulations. ... More
Sowing black hole seeds: Direct collapse black hole formation with realistic Lyman-Werner radiation in cosmological simulationsMar 02 2018Jun 11 2018We study the birth of supermassive black holes from the direct collapse process and characterize the sites where these black hole seeds form. In the pre-reionization epoch, molecular hydrogen (H$_2$) is an efficient coolant, causing gas to fragment and ... More
The D3-probe-D7 brane holographic fractional topological insulatorApr 28 2016Oct 22 2016The D3-probe-D7 brane system, oriented so as to have 2+1-dimensional Poincare symmetry, is argued to be the holographic representation of a strongly correlated fractional topological insulator which exhibits a zero-field quantized Hall effect with half-units ... More
Optimal decision under ambiguity for diffusion processesOct 18 2011Oct 18 2012In this paper we consider stochastic optimization problems for an ambiguity averse decision maker who is uncertain about the parameters of the underlying process. In a first part we consider problems of optimal stopping under drift ambiguity for one-dimensional ... More
Commutator inequalities via Schur productsDec 15 2015For a self-adjoint unbounded operator D on a Hilbert space H, a bounded operator y on H and some complex Borel functions g(t) we establish inequalities of the type ||[g(D),y]|| \leq A|||y|| + B||[D,y]|| + ...+ X|[D, [D,...[D, y]...]]||. The proofs take ... More
On invertibility preserving linear maps, simultaneous triangularization and Property LFeb 18 1997Let F be a linear unital map of a unital matrix algebra A over the complex numbers into the complex n by n matrices. Then F induces a linear unital map Fk of the k by k matrices over A into the complex nk by nk matrices by the action of F on each entry ... More
Finite von Neumann algebra factors with property GammaOct 13 2000Oct 14 2000Techniques introduced by G. Pisier in his proof that finite von Neumann factors with property gamma have length at most 5 are modified to prove that the length is 3. It is proved that if such a factor is a complemented subspace of some larger C*-algebra ... More
Comment: Fisher Lecture: Dimension Reduction in RegressionAug 28 2007Comment: Fisher Lecture: Dimension Reduction in Regression [arXiv:0708.3774]
On weakly D-differentiable operatorsMar 29 2013Mar 11 2015For an unbounded self-adjoint operator D on a Hilbert space H and a bounded operator a on H we say that a is weakly D-differentiable if for any pair of vectors x, y in H the function <exp(itD) a exp(-itD)x, y> is differentiable at t =0. We find several ... More
Reignition of Star Formation in Dwarf GalaxiesFeb 08 2018Oct 12 2018The Local Group hosts a number of star-forming dwarf galaxies that show evidence of periods of little to no star formation. We use a suite of cosmological simulations to study how star formation is reignited in such galaxies. We focus on isolated galaxies ... More
Implementing Molecular Hydrogen in Hydrodynamic Simulations of Galaxy FormationMay 24 2012Motivated by the observed connection between molecular hydrogen (H2) and star formation, we present a method for tracking the non-equilibrium abundance and cooling processes of H2 and H2-based star formation in Smoothed Particle Hydrodynamic simulations. ... More
The effects of host galaxy properties on merging compact binaries detectable by LIGOSep 21 2016Cosmological simulations of galaxy formation can produce present-day galaxies with a large range of assembly and star formation histories. A detailed study of the metallicity evolution and star formation history of such simulations can assist in predicting ... More
The ACS Nearby Galaxy Survey TreasuryMay 22 2009May 25 2009The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D<4 Mpc). The survey volume encompasses 69 galaxies in diverse ... More
The Pressure of the Star Forming ISM in Cosmological SimulationsDec 05 2013We examine the pressure of the star-forming interstellar medium (ISM) of Milky-Way sized disk galaxies using fully cosmological SPH+N-body, high resolution simulations. These simulations include explicit treatment of metal-line cooling in addition to ... More
Tracing Outflowing Metals in Simulations of Dwarf and Spiral GalaxiesAug 23 2018We analyze the metal accumulation in dwarf and spiral galaxies by following the history of metal enrichment and outflows in a suite of twenty high-resolution simulated galaxies. These simulations agree with the observed stellar and gas-phase mass-metallicity ... More
Nonparametric Stochastic Discount Factor DecompositionDec 15 2014Aug 19 2016Stochastic discount factor (SDF) processes in dynamic economies admit a permanent-transitory decomposition in which the permanent component characterizes pricing over long investment horizons. This paper introduces econometric methods to extract the permanent ... More
Specialization of Néron-Severi groups in characteristic $p$Oct 15 2018Oct 16 2018Andr\'{e} and Maulik--Poonen proved that for any smooth proper family $X\to B$ of varieties over an algebraically closed field of characteristic $0$, there is a closed fiber whose N\'{e}ron-Severi group has the same rank as that of the N\'{e}ron-Severi ... More
Decompositions of Schur block productsNov 08 2018Feb 17 2019Given two m x n matrices A = (a_{ij}) and B=(b_{ij}) with entries in B(H), the Schur block product is the m x n matrix A \square B := (a_{ij}b_{ij}). There exists an m x n contraction matrix S = (s_{ij}), such that A \square B = diag(AA*)^(1/2) S diag(B*B)^(1/2). ... More
On the complete boundedness of the Schur block productDec 14 2017Nov 08 2018We give a Stinespring representation of the Schur block product, say (*), on pairs of square matrices with entries in a C*-algebra as a completely bounded bilinear operator of the form: A:=(a_{ij}), B:= (b_{ij}): A (*) B := (a_{ij}b_{ij}) = V* pi(A) F ... More
Phasetype distributions, autoregressive processes and overshootAug 04 2010Autoregressive processes are intensively studied in statistics and other fields of applied stochastics. For many applications the overshoot and the threshold-time are of special interest. When the upward innovations are in the class of phasetype distributions ... More
Likelihood ratio test for variance components in nonlinear mixed effects modelsDec 22 2017Mixed effects models are widely used to describe heterogeneity in a population. A crucial issue when adjusting such a model to data consists in identifying fixed and random effects. From a statistical point of view, it remains to test the nullity of the ... More
Prediction of Parallel Speed-ups for Las Vegas AlgorithmsDec 18 2012We propose a probabilistic model for the parallel execution of Las Vegas algorithms, i.e., randomized algorithms whose runtime might vary from one execution to another, even with the same input. This model aims at predicting the parallel performances ... More
Sonet Network Design ProblemsOct 07 2009This paper presents a new method and a constraint-based objective function to solve two problems related to the design of optical telecommunication networks, namely the Synchronous Optical Network Ring Assignment Problem (SRAP) and the Intra-ring Synchronous ... More
AdS/dCFT one-point functions of the SU(3) sectorJul 11 2016We propose a closed formula for the tree-level one-point functions of non-protected operators belonging to an SU(3) sub-sector of the defect CFT dual to the D3-D5 probe brane system with background gauge field flux, k, valid for k=2. The formula passes ... More
One-Point Functions of Non-protected Operators in the SO(5) symmetric D3-D7 dCFTDec 19 2016Jun 05 2018We study tree level one-point functions of non-protected scalar operators in the defect CFT, based on N=4 SYM, which is dual to the SO(5) symmetric D3-D7 probe brane system with non-vanishing instanton number. Whereas symmetries prevent operators from ... More
Calculating differential Galois groups of parametrized differential equations, with applications to hypertranscendenceMay 26 2015Jun 17 2016The main motivation of our work is to create an efficient algorithm that decides hypertranscendence of solutions of linear differential equations, via the parameterized differential and Galois theories. To achieve this, we expand the representation theory ... More
On the spectral problem of N=4 SYM with orthogonal or symplectic gauge groupMay 14 2010Aug 24 2010We study the spectral problem of N=4 SYM with gauge group SO(N) and Sp(N). At the planar level, the difference to the case of gauge group SU(N) is only due to certain states being projected out, however at the non-planar level novel effects appear: While ... More
Non-planar ABJ Theory and ParityMar 19 2009Apr 14 2009While the ABJ Chern-Simons-matter theory and its string theory dual manifestly lack parity invariance, no sign of parity violation has so far been observed on the weak coupling spin chain side. In particular, the planar two-loop dilatation generator of ... More
In-N-Out: the gas cycle from dwarfs to spiral galaxiesJul 31 2015We examine the scalings of galactic outflows with halo mass across a suite of twenty high-resolution cosmological zoom galaxy simulations covering halo masses from 10^9.5 - 10^12 M_sun. These simulations self-consistently generate outflows from the available ... More
Constraints on the Shape of the Milky Way Dark Matter Halo from Jeans Equations Applied to SDSS DataSep 12 2012We search for evidence of dark matter in the Milky Way by utilizing the stellar number density distribution and kinematics measured by the Sloan Digital Sky Survey (SDSS) to heliocentric distances exceeding ~10 kpc. We employ the cylindrically symmetric ... More
High Velocity Dispersion in A Rare Grand Design Spiral Galaxy at Redshift z=2.18Jul 17 2012Although relatively common in the local Universe, only one grand-design spiral galaxy has been spectroscopically confirmed to lie at z>2 (HDFX 28; z=2.011), and may prove to be a major merger that simply resembles a spiral in projection. The rarity of ... More
Consequences of bursty star formation on galaxy observables at high redshiftsAug 25 2014May 15 2015The star formation histories (SFHs) of dwarf galaxies are thought to be \emph{bursty}, with large -- order of magnitude -- changes in the star formation rate on timescales similar to O-star lifetimes. As a result, the standard interpretations of many ... More
Dancing in the Dark: Uncertainty in ultra-faint dwarf galaxy predictions from cosmological simulationsOct 29 2018Feb 08 2019The existence of ultra-faint dwarf (UFD) galaxies highlights the need to push our theoretical understanding of galaxies to extremely low mass. We examine the formation of UFDs by twice running a fully cosmological simulations of dwarf galaxies, but varying ... More
Effects of Inclination on Measuring Velocity Dispersion and Implications for Black HolesMay 01 2014Sep 23 2014The relation of central black hole mass and stellar spheroid velocity dispersion (the M-$\sigma$ relation) is one of the best-known and tightest correlations linking black holes and their host galaxies. There has been much scrutiny concerning the difficulty ... More
The effect of models of the interstellar media on the central mass distribution of galaxiesNov 01 2012Jan 24 2014We compare the central mass distribution of galaxies simulated with three different models of the interstellar medium (ISM) with increasing complexity: primordial (H+He) cooling down to 10^4K, additional cooling via metal lines and to lower temperatures, ... More
Increasing the Number of Underrepresented Minorities in Astronomy: Executive SummaryMar 26 2009Promoting racial and ethnic diversity is critically important to the future success and growth of the field of astronomy. The raw ability, drive and interest required to excel in the field is distributed without regard to race, gender, or socioeconomic ... More
Natural lifts of Dorfman bracketsOct 19 2016In this note we prove that, for a vector bundle $E$ over a manifold $M$, Dorfman brackets on $TM\oplus E^*$ anchored by the projection to $TM$ and with $E$ a vector bundle over $M$, are equivalent to lifts from $\Gamma(TM\oplus E^*)$ to linear sections ... More
Interferometer responses to gravitational waves: Comparing FINESSE simulations and analytical solutionsJun 28 2013A comparison of analytic calculations and FINESSE simulations of interferometer responses to gravitational wave strain. The response to a gravitational wave is gradually built up from the effect of modulating a space by a gravitational wave to Sagnac ... More
Wrapping interactions and a new source of corrections to the spin-chain/string dualityOct 20 2005Oct 17 2006Assuming that the world-sheet sigma-model in the AdS/CFT correspondence is an integrable {\em quantum} field theory, we deduce that there might be new corrections to the spin-chain/string Bethe ansatz paradigm. These come from virtual particles propagating ... More
Non-planar ABJM Theory and IntegrabilityNov 13 2008Mar 31 2009Using an effective vertex method we explicitly derive the two-loop dilatation generator of ABJM theory in its SU(2)xSU(2) sector, including all non-planar corrections. Subsequently, we apply this generator to a series of finite length operators as well ... More
MorphIC: A 65-nm 738k-Synapse/mm$^2$ Quad-Core Binary-Weight Digital Neuromorphic Processor with Stochastic Spike-Driven Online LearningApr 17 2019Recent trends in the field of artificial neural networks (ANNs) and convolutional neural networks (CNNs) investigate weight quantization as a means to increase the resource- and power-efficiency of hardware devices. As full on-chip weight storage is necessary ... More
The Brightest Galaxies at Cosmic Dawn from Scatter in the Galaxy Luminosity versus Halo Mass RelationMay 13 2019The Ultraviolet Luminosity Function (UVLF) is a key observable for understanding galaxy formation from cosmic dawn. There has been considerable debate on whether Schechter-like LFs (characterized by an exponential drop-off at the bright end) that well ... More
ASTEC -- the Aarhus STellar Evolution CodeOct 16 2007The Aarhus code is the result of a long development, starting in 1974, and still ongoing. A novel feature is the integration of the computation of adiabatic oscillations for specified models as part of the code. It offers substantial flexibility in terms ... More
Resolvent-Techniques For Multiple Exercise ProblemsSep 27 2013We study optimal multiple stopping of strong Markov processes with random refraction periods. The refraction periods are assumed to be exponentially distributed with a common rate and independent of the underlying dynamics. Our main tool is using the ... More
A Conversation with Seymour GeisserApr 21 2008Seymour Geisser received his bachelor's degree in Mathematics from the City College of New York in 1950, and his M.A. and Ph.D. degrees in Mathematical Statistics at the University of North Carolina in 1952 and 1955, respectively. He then held positions ... More
On time-inconsistent stopping problems and mixed strategy stopping timesApr 19 2018May 07 2018A game-theoretic framework for time-inconsistent stopping problems where the time-inconsistency is due to the consideration of a non-linear function of an expected reward is developed. A class of mixed strategy stopping times that allows the agents in ... More
On Finding Equilibrium Stopping Times for Time-Inconsistent Markovian ProblemsSep 15 2017Dec 04 2018Standard Markovian optimal stopping problems are consistent in the sense that the first entrance time into the stopping set is optimal for each initial state of the process. Clearly, the usual concept of optimality cannot in a straightforward way be applied ... More
Derived Categories and Projective ClassesDec 20 1999Sep 20 2001An important example of a model category is the category of unbounded chain complexes of R-modules, which has as its homotopy category the derived category of the ring R. This example shows that traditional homological algebra is encompassed by Quillen's ... More
Stellar model fits and inversionsNov 12 2012The recent asteroseismic data from the CoRoT and Kepler missions have provided an entirely new basis for investigating stellar properties. This has led to a rapid development in techniques for analysing such data, although it is probably fair to say that ... More
Asteroseismology with solar-like oscillationsFeb 22 2016Almost 100 years ago Sir Arthur Eddington noted that the interiors of stars were inaccessible to observations. The advent of helio- and asteroseismology has completely changed this assessment. Helioseismology has provided very detailed information about ... More
CyberCampaigns and Canadian Politics: Still Waiting?Sep 24 2001The early election call in the fall of 2000 provided the perfect opportunity to study the impact the Internet has had on election campaigning in Canada. With the explosion of use the Net has seen since the 1997 general election, Canadian federal parties ... More
Universality Class of One-Dimensional Directed Sandpile ModelsJun 29 2005A general n-state directed `sandpile' model is introduced. The stationary properties of the n-state model are derived for n < infty, and analytical arguments based on a central limit theorem show that the model belongs to the universality class of the ... More
A break in the high-redshift stellar mass Tully-Fisher relationJun 08 2017We investigate the stellar-mass Tully-Fisher relation (TFR) between the stellar mass and the integrated gas velocity dispersion, quantified by the kinematic estimator S_0.5 measured from strong emission lines in spectra of galaxies at 0<z<5. We combine ... More
Regularity of Villadsen algebras and characters on their central sequence algebrasMar 03 2016We show that if A is a simple Villadsen algebra of either the first type with seed space a finite dimensional CW complex, or of the second type, then A absorbs the Jiang-Su algebra tensorially if and only if the central sequence algebra of A does not ... More
On the red-giant luminosity bumpJul 20 2015The increase in luminosity as a star evolves on the red-giant branch is interrupted briefly when the hydrogen-burning shell reaches the vicinity of the composition discontinuity left behind from the first convective dredge-up. The non-monotonic variation ... More