Results for "Mateusz Koren"

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Volume reduction in large-N lattice gauge theories [with adjoint fermions]Dec 18 2013This work covers volume reduction in quantum field theories on a lattice at large $N$ (number of colors), as first described by Eguchi and Kawai in 1982. The volume reduction (or volume independence) means that the theory defined on an arbitrarily small ... More
Screening in two-dimensional gauge theoriesDec 03 2012We analyze the problem of screening in 1+1 dimensional gauge theories. Using QED2 as a warm-up for the non-abelian models we show the mechanism of the string breaking, in particular the vanishing overlap of the Wilson loops to the broken-string ground ... More
Preliminary study of two-dimensional SU(N) Yang-Mills theory with adjoint matter by Hybrid Monte Carlo approachNov 20 2011Two-dimensional non-abelian quantum field models provide a useful laboratory for analytic and numerical investigations of quantum theories with gauge symmetry. They can exhibit various features, such as charge confinement, which are known from D=4 theories ... More
Wilson loops with arbitrary chargesNov 24 2014We discuss how to implement, in lattice gauge theories, external charges which are not commensurate with an elementary gauge coupling. It is shown that an arbitrary, real power of a standard Wilson loop (or Polyakov line) can be defined and consistently ... More
Large-N reduction with two adjoint Dirac fermionsNov 04 2011We study the single site SU(N) lattice gauge theory with N_f=2 adjoint Wilson fermions for values of N up to 53. We determine the phase diagram of the theory as a function of the hopping parameter kappa and the inverse 't Hooft coupling b, searching for ... More
Large-N reduction in QCD with two adjoint Dirac fermionsJun 27 2011May 01 2012We use lattice simulations to study the single-site version of SU(N) lattice gauge theory with two flavors of Wilson-Dirac fermions in the adjoint representation, a theory whose large volume correspondent is expected to be conformal or nearly conformal. ... More
On non-trivial spectra of trivial gauge theoriesOct 24 2012Apr 10 2013In this Letter we point out that the analytic solution of the two dimensional U(1) gauge theory, on a finite lattice, reveals in the continuum limit the renowned Manton's spectrum of topological electric fluxes together with their effective hamiltonian ... More
HQET form factors for $B_s\to K\ellν$ decays beyond leading orderNov 03 2017Nov 25 2017We compute semi-leptonic $B_s$ decay form factors using Heavy Quark Effective Theory on the lattice. To obtain good control of the $1/m_b$ expansion, one has to take into account not only the leading static order but also the terms arising at $O(1/m_b)$: ... More
Glueball masses in 2+1 dimensional SU(N) gauge theories with twisted boundary conditionsNov 19 2014Nov 26 2014We analyze 2+1 dimensional Yang-Mills theory regularized on a lattice with twisted boundary conditions in the spatial directions. In previous work it was shown that the observables in the non-zero electric flux sectors obey the so-called $x$-scaling, ... More
SU(3) Yang Mills theory at small distances and fine latticesNov 06 2017We investigate the SU(3) Yang Mills theory at small gradient flow time and at short distances. Lattice spacings down to $a=0.015$ fm are simulated with open boundary conditions to allow topology to flow in and out. We study the behaviour of the action ... More
Continuum limit of the leading order HQET form factor in $B_s \to K\ellν$ decaysJan 17 2016Jun 02 2016We discuss the computation of form factors for semi-leptonic decays of $\rm B$-, $\rm B_s$- mesons in lattice QCD. Considering in particular the example of the static $\rm B_s$ form factors we demonstrate that after non-perturbative renormalization the ... More
Magnetoresistance and gating effects in ultrathin NbN-$\rm Bi_2Se_3$ bilayersJun 29 2015Ultrathin $\rm Bi_2Se_3$-NbN bilayers comprise a simple proximity system of a topological insulator and an s-wave superconductor for studying gating effects on topological superconductors. Here we report on 3 nm thick NbN layers of weakly connected superconducting ... More
Proximity effects at the interface of a superconductor and a topological insulator in NbN - Bi_2Se_3 thin film bilayersSep 10 2014In a search for a simple proximity system of a topological insulator and a superconductor for studying the role of surface versus bulk effects by gating, we report here on a first step toward this goal, namely the choice of such a system and its characterization. ... More
Large-N reduction with adjoint Wilson fermionsDec 03 2012We analyze the large-N behavior of SU(N) lattice gauge theories with adjoint fermions by studying volume-reduced models, as pioneered by Eguchi and Kawai. We perform simulations on a single-site lattice for Nf = 1 and Nf = 2 Wilson Dirac fermions with ... More
Proximity effects and pair currents in cuprate junctionsNov 16 2016Proximity effects and pair currents were measured in epitaxial trilayer \textit{c-axis} junctions comprise of a $PrBa_2Cu_3O_{7-\delta}$ barrier sandwiched in between an overdoped $Y_{0.94}Ca_{0.06}Ba_2Cu_3O_{7-\delta}$ and underdoped $YBa_2Cu_{2.7}Co_{0.3}O_y$ ... More
The spectrum of 2+1 dimensional Yang-Mills theory on a twisted spatial torusJul 10 2018Aug 07 2018We compute and analyse the low-lying spectrum of 2+1 dimensional $SU(N)$ Yang-Mills theory on a spatial torus of size $l\times l$ with twisted boundary conditions. This paper extends our previous work \cite{Perez:2013dra}. In that paper we studied the ... More
Interface effects in d-wave superconductor-ferromagnet junctionsJun 01 2010Oct 07 2010Measurements of the differential conductance spectra of YBa2Cu3O7-SrRuO3 and YBa2Cu3O7-La0.67Ca_0.33MnO3 ramp-type junctions along the node and anti-node directions are reported. The results are consistent with a crossed Andreev reflection effect only ... More
Zero energy bound states in tunneling conductance spectra at the interface of an s-wave superconductor and a topological insulator in NbN-$Bi_2Se_3$-Au thin film junctionsJul 23 2012Oct 11 2012Measurements of conductance spectra in a superconductor - topological insulator - normal metal thin film junctions of NbN-$\rm Bi_2Se_3$-Au are reported. Junctions with ex-situ and in-situ prepared $\rm NbN-Bi_2Se_3$ interfaces were studied. At low temperatures, ... More
Observation of two Andreev-like energy scales in $La_{2-x}Sr_{x}CuO_4$ superconductor/normal-metal/superconductor junctionsJan 06 2011Conductance spectra measurements of highly transparent ramp-type junctions made of superconducting $La_{2-x}Sr_{x}CuO_4$ electrodes and non superconducting $La_{1.65}Sr_{0.35}CuO_4$ barrier are reported. At low temperatures below $T_c$, these junctions ... More
The Computational Power of Optimization in Online LearningApr 08 2015Jan 27 2016We consider the fundamental problem of prediction with expert advice where the experts are "optimizable": there is a black-box optimization oracle that can be used to compute, in constant time, the leading expert in retrospect at any point in time. In ... More
Optimal Algorithms for Ridge and Lasso Regression with Partially Observed AttributesAug 23 2011Nov 27 2012We consider the most common variants of linear regression, including Ridge, Lasso and Support-vector regression, in a setting where the learner is allowed to observe only a fixed number of attributes of each example at training time. We present simple ... More
Transport and spectroscopic properties of superconductor - ferromagnet - superconductor junctions of $La_{1.9}Sr_{0.1}CuO_4$ - $La_{0.67}Ca_{0.33}MnO_3$ - $La_{1.9}Sr_{0.1}CuO_4$Jul 05 2011Transport and Conductance spectra measurements of ramp-type junctions made of cuprate superconducting $La_{1.9}Sr_{0.1}CuO_4$ electrodes and a manganite ferromagnetic $La_{0.67}Ca_{0.33}MnO_3$ barrier are reported. At low temperatures below $T_c$, the ... More
Signature of a crossed Andreev reflection effect (CARE) in the magnetic response of YBCO junctions with the itinerant ferromagnet SrRuO_3Aug 31 2005Magnetic properties of SFS and SF ramp-type junctions with $YBa_2Cu_3O_{7-\delta}$ (YBCO) electrodes (S), and the itinerant ferromagnet $SrRuO_3$ (SRO - F), were investigated. We looked for a crossed Andreev reflection effect (CARE) in which an electron ... More
Linear Regression with Limited ObservationJun 18 2012We consider the most common variants of linear regression, including Ridge, Lasso and Support-vector regression, in a setting where the learner is allowed to observe only a fixed number of attributes of each example at training time. We present simple ... More
On the Empirical Importance of the Conditional Skewness Assumption in Modelling the Relationship Between Risk and ReturnDec 26 2007May 06 2008The main goal of this paper is an application of Bayesian inference in testing the relation between risk and return on the financial instruments. On the basis of the Intertemporal CAPM model we built a general sampling model suitable in analysing such ... More
Toric geometry of the 3-Kimura model for any treeFeb 23 2011Apr 06 2011In this paper we present geometric features of group based models. We focus on the 3-Kimura model. We present a precise geometric description of the variety associated to any tree on a Zariski open set. In particular this set contains all biologically ... More
Spectral analysis of subordinate Brownian motions in half-lineJun 02 2010Oct 22 2011We study one-dimensional Levy processes with Levy-Khintchine exponent psi(xi^2), where psi is a complete Bernstein function. These processes are subordinate Brownian motions corresponding to subordinators, whose Levy measure has completely monotone density; ... More
Eigenvalues of the fractional Laplace operator in the intervalDec 06 2010Two-term Weyl-type asymptotic law for the eigenvalues of one-dimensional fractional Laplace operator (-d^2/dx^2)^(alpha/2) (0 < alpha < 2) in the interval (-1,1) is given: the n-th eigenvalue is equal to (n pi/2 - (2 - alpha) pi/8)^alpha + O(1/n). Simplicity ... More
A Linear-Time Algorithm for Trust Region ProblemsJan 27 2014We consider the fundamental problem of maximizing a general quadratic function over an ellipsoidal domain, also known as the trust region problem. We give the first provable linear-time (in the number of non-zero entries of the input) algorithm for approximately ... More
Pairing and the phase diagram of the normal coherence length $ξ_N(T,x)$ above $T_c$ of $La_{2-x}Sr_xCuO_4$ thin films probed by the Josephson effectNov 10 2013Apr 30 2014Critical currents $I_c$ were measured in Superconducting - normal - superconducting SNS c-axis junctions, where S was optimally doped $YBa_2Cu_3O_{7-\delta}$ below $T_c$ (90 K) and N was $La_{2-x}Sr_xCuO_4$ above its $T_c$ ($<$25 K) but in the pseudogap ... More
Conventional proximity effect in bilayers of superconducting underdoped $La_{1.88}Sr_{0.12}CuO_4$ islands coated with non superconducting overdoped $La_{1.65}Sr_{0.35}CuO_4$Apr 13 2009Following a recent study by our group in which a large $T_c$ enhancement was reported in bilayers of the non-superconducting $La_{1.65}Sr_{0.35}CuO_4$ and superconducting $La_{1.88}Sr_{0.12}CuO_4$ films [Phys. Rev. Lett. \textbf{101}, 057005 (2008)], ... More
Short note on Smithson's paper concerning Arzelà-Ascoli theorem for multifunctionsAug 15 2016As indicated in the title, this paper was inspired by Smithson's work on Arzel\`a-Ascoli theorem. Up to this point, the author's interest in the topic has led him to generalize Arzel\`a-Ascoli theorem in the context of uniform spaces. This approach was ... More
Arzelà-Ascoli theorem via Wallman compactificationFeb 18 2016May 08 2016In the paper, we recall the Wallman compactification of a Tychonoff space $T$ (denoted by $\text{Wall}(T)$) and the contribution made by Gillman and Jerison. Motivated by the Gelfand-Naimark theorem, we investigate the homeomorphism between $BC(T,\mathbb{R})$ ... More
Rogers functions and fluctuation theoryDec 06 2013Extending earlier work by Rogers, Wiener-Hopf factorisation is studied for a class of functions closely related to Nevanlinna-Pick functions and complete Bernstein functions. The name 'Rogers functions' is proposed for this class. Under mild additional ... More
Ten equivalent definitions of the fractional Laplace operatorJul 27 2015Sep 14 2015This article reviews several definitions of the fractional Laplace operator (-Delta)^{alpha/2} (0 < alpha < 2) in R^d, also known as the Riesz fractional derivative operator, as an operator on Lebesgue spaces L^p, on the space C_0 of continuous functions ... More
Amalgamated direct sums of operator spacesOct 05 2014We consider amalgamated direct sums (and their dual counterparts -- fibre products) of operator spaces and study their behaviour with respect to different quantisations (minimal and maximal). We show examples of amalgamated direct sums of two $L^{\infty}$-spaces ... More
Definable functions in the simply typed lambda-calculusJan 04 2007It is a common knowledge that the integer functions definable in simply typed lambda-calculus are exactly the extended polynomials. This is indeed the case when one interprets integers over the type (p->p)->p->p where p is a base type and/or equality ... More
Bayesian Comparison of GARCH Processes with Skewnes Mechanism in Conditional DistributionsJun 29 2006Jul 04 2006The main goal of this paper is an application of Bayesian model comparison, based on the posterior probabilities and posterior odds ratios, in testing the explanatory power of the set of competing GARCH (ang. Generalised Autoregressive Conditionally Heteroscedastic) ... More
Quantum holonomies with Josephson-junction devicesJan 07 2004Apr 22 2004We examined properties of a Josephson-junction system composed of two coupled Cooper-pair boxes (charge qubits) as a candidate for observation of quantum holonomies. We construct a universal set of transformations in a two-fold degenerate ground state, ... More
Linear and Circular Polarization Properties of JetsOct 03 2002I discuss the transfer of polarized synchrotron radiation in relativistic jets. I argue that the main mechanism responsible for the circular polarization properties of compact synchrotron sources is likely to be Faraday conversion and that, contrary to ... More
Coupling and exponential ergodicity for stochastic differential equations driven by Lévy processesSep 29 2015Oct 28 2015We present a novel idea for a coupling of solutions of stochastic differential equations driven by L\'{e}vy noise, inspired by some results from the optimal transportation theory. Then we use this coupling to obtain exponential contractivity of the semigroups ... More
Appearance of Topological Phases in Superconducting NanocircuitsAug 02 2004Feb 16 2005We construct non-Abelian geometric transformations in superconducting nanocircuits, which resemble in properties the Aharonov-Bohm phase for an electron transported around a magnetic flux line. The effective magnetic fields can be strongly localized, ... More
Darbo-type theorem for quasimeasure of noncompactnessMay 17 2016The paper introduces the concept of quasimeasure of noncompactness. Motivated by the Arzel\`a-Ascoli theorem for $C^b(X,E)$, where $X$ is an Euclidean space and $E$ an arbitrary Banach space, we construct a quasimeasure for this space and study its properties. ... More
Arzelà-Ascoli theorem in uniform spacesFeb 18 2016In the paper, we generalize the Arzel\`a-Ascoli theorem in the setting of uniform spaces. At first, we recall well-known facts and theorems coming from monographs of Kelley and Willard. The main part of the paper introduces the notion of extension property ... More
$q$-Araki-Woods algebras: extension of second quantisation and Haagerup approximation propertyMay 19 2016Oct 06 2016We extend the class of contractions for which the second quantisation on $q$-Araki-Woods algebras can be defined. As a corollary, we prove that all $q$-Araki-Woods algebras possess the Haagerup approximation property.
Algebraic varieties representing group-based Markov processes on treesApr 18 2010In this paper we complete the results of Sullivant and Sturmfels proving that many of the algebraic group-based models for Markov processes on trees are pseudo-toric. We also show in which cases these varieties are normal. This is done by the generalization ... More
Birational maps between Calabi-Yau manifolds associated to webs of quadricsApr 28 2009Aug 12 2009We consider two varieties associated to a web of quadrics W in the projective space of dimension 7. One is the base locus and the second one is the double cover of the three dimensional projective space branched along the determinant surface of W. We ... More
Investigating Bimodal Clustering in Human MobilityNov 03 2009We apply a simple clustering algorithm to a large dataset of cellular telecommunication records, reducing the complexity of mobile phone users' full trajectories and allowing for simple statistics to characterize their properties. For the case of two ... More
Effects of supersymmetric threshold corrections on the Yukawa matrix unificationAug 09 2014Feb 11 2015We present an updated analysis of the Yukawa matrix unification within the renormalizable Minimal Supersymmetric Standard Model. It is assumed that the soft terms are non-universal but flavour-diagonal in the super-CKM basis at the GUT scale. Trilinear ... More
X-ray iron line variability for the model of an orbiting flare above a black hole accretion discJun 24 1999The broad X-ray iron line, detected in many active galactic nuclei, is likely to be produced by fluorescence from the X-ray illuminated central parts of an accretion disc close to a supermassive black hole. The time-averaged shape of the line can be explained ... More
Yukawa matrix unification in the Minimal Supersymmetric Standard ModelNov 27 2015In this dissertation, the Minimal Supersymmetric Standard Model (MSSM) is studied as a low-energy theory stemming from the $SU(5)$ Grand Unified Theory (GUT). We investigate the possibility of satisfying the minimal $SU(5)$ boundary condition $\mathbf{Y}^d=\mathbf{Y}^{e\,T}$ ... More
Effective Operators for Dark Matter InteractionsOct 16 2014The aim of this thesis is to determine possible interactions between the Standard Model with right-chiral neutrinos and a sector of dark matter composed of a real scalar, left- and right-chiral fermion and a vector particle, which are singlets of the ... More
Spectral theory for one-dimensional symmetric Levy processes killed upon hitting the originOct 26 2011Feb 29 2012Spectral theory for the transition semigroup of one-dimensional symmetric Levy process killed upon hitting the origin is studied. Under very mild assumptions, an integral-type formula for eigenfunctions is obtained, and eigenfunction expansion of transition ... More
Two particle azimuthal correlations at high transverse momentum in Pb-Au at 158 AGeV/cJan 16 2007Jan 21 2007The analysis of two-particle azimuthal angular correlations at high transverse momentum from Pb+Au collisions at 158 AGeV/c at SPS reveals substantial modifications of the away-side peak as compared to the distributions from p+p reactions. The data recorded ... More
A short proof of Combinatorial NullstellensatzApr 29 2009In this note we give a short, direct proof of the well known Combinatorial Nullstellensatz.
Exact Pollard-like internal water wavesDec 01 2018In this paper we construct a new solution which represents Pollard-like three-dimensional nonlinear geophysical internal water waves. The Pollard-like solution includes the effects of the rotation of Earth and describes the internal water wave which exists ... More
Reflected BSDEs with general filtration and two completely separated barriersNov 21 2016Oct 31 2018We consider reflected backward stochastic differential equations, with two barriers, defined on probability spaces equipped with filtration satisfying only the usual assumptions of right continuity and completeness. As for barriers we assume that there ... More
Two-particle azimuthal correlations at high transverse momentum in Pb-Au at 158 AGeV/cNov 22 2005Jan 31 2006The study of two-particle azimuthal correlations at high transverse momentum has become an important tool to investigate the interaction of hard partons with the medium formed in high-energy nucleus-nucleus collisions. At SPS energies, pioneering studies ... More
Geometry of an adiabatic passage at a level crossingFeb 21 2005Jun 23 2005We discuss adiabatic quantum phenomena at a level crossing. Given a path in the parameter space which passes through a degeneracy point, we find a criterion which determines whether the adiabaticity condition can be satisfied. For paths that can be traversed ... More
Family of counterexamples to King's conjectureSep 04 2010Oct 18 2010In this short note we present a family of counterexamples to the King's conjecture.
Reflected BSDEs with general filtration and two completely separated barriersNov 21 2016We consider reflected backward stochastic differential equations, with two barriers, defined on probability spaces equipped with filtration satisfying only the usual assumptions of right continuity and completeness. As for barriers we assume that there ... More
Selected topics on Toric VarietiesFeb 10 2017This article is based on a series of lectures on toric varieties given at RIMS, Kyoto. We start by introducing toric varieties, their basic properties and later pass to more advanced topics relating mostly to combinatorics.
Constructive degree bounds for group-based modelsJul 04 2012Jun 04 2013Group-based models arise in algebraic statistics while studying evolution processes. They are represented by embedded toric algebraic varieties. Both from the theoretical and applied point of view one is interested in determining the ideals defining the ... More
Systems of BSDEs with oblique reflection and related optimal switching problemsDec 14 2017Oct 03 2018We consider systems of backward stochastic differential equations with c\`adl\`ag upper barrier $U$ and oblique reflection from below driven by an increasing continuous function $H$. Our equations are defined on general probability spaces with a filtration ... More
Extraction of bare Form Factors for $\mathrm B_\mathrm s \to \mathrm K \ell ν$ Decays in non-perturbative HQETMar 14 2019We discuss the extraction of the ground state $\langle \mathrm{K} ({\bf p})|V_\mu(0)|\mathrm{B} ({\bf 0})\rangle$ matrix elements from Euclidean lattice correlation functions. The emphasis is on the elimination of excited state contributions. Two typical ... More
Logistic Regression: Tight Bounds for Stochastic and Online OptimizationMay 15 2014The logistic loss function is often advocated in machine learning and statistics as a smooth and strictly convex surrogate for the 0-1 loss. In this paper we investigate the question of whether these smoothness and convexity properties make the logistic ... More
A mimetic spectral element solver for the Grad-Shafranov equationDec 18 2015Apr 07 2016In this work we present a robust and accurate arbitrary order solver for the fixed-boundary plasma equilibria in toroidally axisymmetric geometries. To achieve this we apply the mimetic spectral element formulation presented in [56] to the solution of ... More
On high spots of the fundamental sloshing eigenfunctions in axially symmetric domainsMar 03 2011We investigate the classical eigenvalue problem that arises in hydrodynamics and is referred to as the sloshing problem. It describes free liquid oscillations in a liquid container W in R^3. We study the case when W is an axially symmetric, convex, bounded ... More
Efficiency of pair formation in a model societyMay 08 2006Aug 10 2006In a recent paper a set of differential equations was proposed to describe a social process, where pairs of partners emerge in a community. The choice was performed on a basis of attractive resources and of random initial preferences. An efficiency of ... More
Laser-Driven Localization of Collective CO Vibrations in Metal-Carbonyl ComplexesSep 09 2014Nov 06 2014Using the example of a cobalt dicarbonyl complex it is shown that two perpendicularly polarized IR laser pulses can be used to trigger an excitation of the delocalized CO stretching modes, which corresponds to an alternating localization of the vibration ... More
The role of dry mergers for the formation and evolution of brightest cluster galaxiesFeb 02 2009Using a resimulation technique, we perform high-resolution cosmological simulations of dry mergers in a massive galaxy cluster identified in the Millennium Run. Our initial conditions include well resolved compound galaxy models consisting of dark matter ... More
Examples of $k$-regular maps and interpolation spacesDec 02 2015A continous map $f: \mathbb{C}^n \rightarrow \mathbb{C}^N$ is $k$-regular if the image of any $k$ points spans a $k$-dimensional subspace. It is an important problem in topology and interpolation theory, going back to Borsuk and Chebyshev, to construct ... More
The role of finite-size effects on the spectrum of equivalent photons in proton-proton collisions at the LHCOct 11 2014Dec 09 2014Photon-photon interactions represent an important class of physics processes at the LHC, where quasi-real photons are emitted by both colliding protons. These reactions can result in the exclusive production of a final state $X$, $p+p \rightarrow p+p+X$. ... More
A Multi-World Approach to Question Answering about Real-World Scenes based on Uncertain InputOct 01 2014May 05 2015We propose a method for automatically answering questions about images by bringing together recent advances from natural language processing and computer vision. We combine discrete reasoning with uncertain predictions by a multi-world approach that represents ... More
Fast dynamics for atoms in optical latticesOct 30 2012Jan 09 2013Cold atoms in optical lattices allow for accurate studies of many body dynamics. Rapid time-dependent modifications of optical lattice potentials may result in significant excitations in atomic systems. The dynamics in such a case is frequently quite ... More
Boundary Harnack Inequality for alpha-harmonic functions on the Sierpiński triangleJul 04 2009We prove an uniform boundary Harnack inequality for nonnegative functions harmonic with respect to $\alpha$-stable process on the Sierpi{\'n}ski triangle, where $\alpha \in (0, 1)$. Our result requires no regularity assumptions on the domain of harmonicity. ... More
Critical current measurements in superconductor - ferromagnet - superconductor junctions of $YBa_2Cu_3O_y$-$SrRuO_3$-$YBa_2Cu_3O_y$: No evidence for a dominant proximity induced triplet superconductivity in the ferromagnetic barrierJul 05 2011Transport measurements in ramp-type junctions of $YBa_2Cu_3O_y-SrRuO_3-YBa_2Cu_3O_y$ with $T_c$ values of either 80-90 K or 60-70 K are reported. In both type of junctions but without a barrier ("shorts"), the supercurrent densities at 4.2 K reached 7.5 ... More
Recommender Systems for the Conference Paper Assignment ProblemJun 22 2009Conference paper assignment, i.e., the task of assigning paper submissions to reviewers, presents multi-faceted issues for recommender systems research. Besides the traditional goal of predicting `who likes what?', a conference management system must ... More
A study of the ferromagnetic transition of $SrRuO_3$ in nanometer thick bilayers with $YBa_2Cu_3O_y$, $La_{1.88}Sr_{0.12}CuO_{4-y}$, Au and Cr: Signature of injected carriers in the pseudogap regimeJul 17 2007The hypothesis regarding the existence of uncorrelated pre-formed pairs in the pseudogap regime of superconducting $YBa_2Cu_3O_y$ is tested experimentally using bilayers of $YBa_2Cu_3O_y$ and the itinerant ferromagnet $SrRuO_3$. In our study, we monitor ... More
Aerosol Effect on the Mobility of Cloud DropletsJul 02 2015Oct 19 2015Cloud droplet mobility is referred to here as a measure of the droplets ability to move with ambient air. We claim that an important part of the aerosol effect on convective clouds is driven by changes in droplet mobility. We show that the mass-weighted ... More
Constructing $\mathcal{N}=4$ Coulomb Branch SuperamplitudesFeb 19 2019We study scattering amplitudes of massive BPS states on the Coulomb branch of $4d$ $\mathcal{N}=4$ super-Yang-Mills, utilising a little group covariant on-shell superspace for massive particles. Super-BCFW recursion for massive amplitudes is constructed ... More
The poset of rational conesJun 07 2016Jun 14 2016We introduce a natural partial order on the set Cones(d) of rational cones in R^d. The poset NPol(d-1) of normal polytopes in R^{d-1} embeds into Cones(d) via the homogenization map. Informally Cones(d) can be thought of as a minimal smooth extension ... More
Tutorial on Answering Questions about Images with Deep LearningOct 04 2016Together with the development of more accurate methods in Computer Vision and Natural Language Understanding, holistic architectures that answer on questions about the content of real-world images have emerged. In this tutorial, we build a neural-based ... More
Dynamical quantum phase transitions in collapse and revival oscillations of a quenched superfluidDec 05 2018In this work we revisit collapse and revival oscillations in superfluids suddenly quenched by strong local interactions for the case of a one-dimensional Bose-Hubbard model. As the main result we identify the inherent nonequilibrium quantum many-body ... More
Potential kernels, probabilities of hitting a ball, harmonic functions and the boundary Harnack inequality for unimodal Lévy processesNov 30 2016In the first part of this article, we prove two-sided estimates of hitting probabilities of balls, the potential kernel and the Green function for a ball for general isotropic unimodal L\'evy processes. Our bounds are sharp under the absence of the Gaussian ... More
Parametric critical point theorems and their applications to boundary value problems on the Sierpiński GasketNov 30 2017In this note we consider the classical variational tools like: Ekelenad's Variational Principle, Mountain Pass Lemma and some of their corollaries subject to a parameter. Next, we investigate the behaviour of critical points obtained once a sequence of ... More
Cotranslational folding of deeply knotted proteinsSep 03 2015Proper folding of deeply knotted proteins has a very low success rate even in structure-based models which favor formation of the native contacts but have no topological bias. By employing a structure-based model, we demonstrate that cotranslational folding ... More
Spin-orbit coupling and spin relaxation of hole states in [001]- and [111]-orientedquantum dots of various geometrySep 24 2018Feb 20 2019We study the influence of spin-orbit coupling on the hole states in InAs/GaAs quantum dots grown on [001]- and [111]-oriented substrates belonging to symmetry point groups: C2v, C3v and D2d. We investigate the impact of various spin-orbit mechanisms on ... More
Plethysm and lattice point countingAug 25 2014Aug 12 2015We apply lattice point counting methods to compute the multiplicities in the plethysm of $GL(n)$. Our approach gives insight into the asymptotic growth of the plethysm and makes the problem amenable to computer algebra. We prove an old conjecture of Howe ... More
On the toric ideal of a matroidFeb 21 2013Mar 30 2014Describing minimal generating set of a toric ideal is a well-studied and difficult problem. In 1980 White conjectured that the toric ideal associated to a matroid is equal to the ideal generated by quadratic binomials corresponding to symmetric exchanges. ... More
Extension technique for complete Bernstein functions of the Laplace operatorJul 08 2017We discuss representation of certain functions of the Laplace operator $\Delta$ as Dirichlet-to-Neumann maps for appropriate elliptic operators in half-space. A classical result identifies $(-\Delta)^{1/2}$, the square root of the $d$-dimensional Laplace ... More
Spectral analysis of stable processes on the positive half-lineSep 22 2015We study the spectral expansion of the semigroup of a general stable process killed on the first exit from the positive half-line. Starting with the Wiener-Hopf factorization we obtain the q-resolvent density for the killed process, from which we derive ... More
Transportation inequalities for non-globally dissipative SDEs with jumps via Malliavin calculus and couplingOct 21 2016Nov 24 2016By using the mirror coupling for solutions of SDEs driven by pure jump L\'evy processes, we extend some transportation and concentration inequalities, which were previously known only in the case where the coefficients in the equation satisfy a global ... More
Obstructions to combinatorial formulas for plethysmJul 25 2015Feb 26 2016Motivated by questions of Mulmuley and Stanley we investigate quasi-polynomials arising in formulas for plethysm. We demonstrate, on the examples of $S^3(S^k)$ and $S^k(S^3)$, that these need not be counting functions of inhomogeneous polytopes of dimension ... More
Notes on bounded induction for the compositional truth predicateDec 01 2017We prove that the theory of the extensional compositional truth predicate for the language of arithmetic with $\Delta_0$-induction scheme for the truth predicate and the full arithmetical induction scheme is not conservative over Peano Arithmetic. In ... More
Hitting times of points for symmetric Lévy processes with completely monotone jumpsMar 14 2014Apr 17 2015Small-space and large-time estimates and asymptotic expansion of the distribution function and (the derivatives of) the density function of hitting times of points for symmetric L\'evy processes are studied. The L\'evy measure is assumed to have completely ... More
Martin kernels for Markov processes with jumpsSep 18 2015We prove existence of boundary limits of ratios of positive harmonic functions for a wide class of Markov processes with jumps and irregular domains, in the context of general metric measure spaces. As a corollary, we prove uniqueness of the Martin kernel ... More
Structural and electrical properties of electrodeposited single junction of cuprous (I) oxide copperNov 03 2016Cuprous (I) oxide (Cu_{2}O) based solar cells were fabricated with the use of the electrodeposition technique at nanometre scale, and the structural, morphological and electrical properties were investigated. The Cu_{2}O layers were electrodeposited on ... More
Formation of Cystine Slipknots in Dimeric ProteinsMar 26 2013We consider mechanical stability of dimeric and monomeric proteins with the cystine knot motif. A structure based dynamical model is used to demonstrate that all dimeric and some monomeric proteins of this kind should have considerable resistance to stretching ... More
Hard to Cheat: A Turing Test based on Answering Questions about ImagesJan 14 2015Jan 15 2015Progress in language and image understanding by machines has sparkled the interest of the research community in more open-ended, holistic tasks, and refueled an old AI dream of building intelligent machines. We discuss a few prominent challenges that ... More