Results for "Prachi Telang"

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Dilute stuffing in the pyrochlore iridate $Eu_2Ir_2O_7$May 04 2018The pyrochlore Eu$_2$Ir$_2$O$_7$ has recently attracted significant attention as a candidate Weyl semimetal. The previous reports on this compound unanimously show a thermally induced metal to insulator (MI) transition, concomitant with antiferromagnetic ... More
Anomalous lattice contraction and emergent electronic phases in Bi-doped Eu$_2$Ir$_2$O$_7$Feb 08 2019We study the pyrochlore series (Eu$_{1-x}$Bi$_x$)$_2$Ir$_2$O$_7$ for $ 0 \leq x \leq 1$. We show that for small $x$, the lattice undergoes an anomalous contraction but the all-in/all-out and metal-to-insulator transitions remain robust, and the resistivity ... More
On isometries of the Kobayashi and Carathéodory metricsSep 13 2010Sep 15 2010This article considers isometries of the Kobayashi and Carath\'{e}od-ory metrics on domains in $ \mathbf{C}^n $ and the extent to which they behave like holomorphic mappings. First we prove a metric version of Poincar\'{e}'s theorem about biholomorphic ... More
Improving Efficiency of Hospitals and Healthcare CentresNov 10 2015The Project aims at improving the efficiency of hospitals and healthcare centres using Big Data Analytics to evaluate identified KPIs (Key Performance Indicators) of its various functions. The Dashboards designed using computer technology serves as an ... More
A Hybrid Density Functional Study of Armchair Si and Ge NanotubesJul 28 2005First principles calculations based on hybrid density functional theory have been used to study the electronic and geometric properties of armchair silicon and germanium nanotubes ranging from A (3, 3) through A (9, 9). The approach used is the finite ... More
Call Me MayBe: Understanding Nature and Risks of Sharing Mobile Numbers on Online Social NetworksDec 12 2013There is a great concern about the potential for people to leak private information on OSNs, but few quantitative studies on this. This research explores the activity of sharing mobile numbers on OSNs, via public profiles and posts. We attempt to understand ... More
Some aspects of the Kobayashi and Carathéodory metrics on pseudoconvex domainsOct 28 2009The purpose of this article is to consider two themes both of which emanate from and involve the Kobayashi and the Carath\'eodory metric. First we study the biholomorphic invariant introduced by B. Fridman on strongly pseudoconvex domains, on weakly pseudoconvex ... More
Analyzing the Wu metric on a class of eggs in $\mathbb{C}^n$ -- IIMar 10 2015We study the Wu metric for the non-convex domains of the form \[ E_{2m} = \big\{ z \in \mathbb{C}^n : \vert z_1 \vert^{2m} + \vert z_2 \vert^2 + \ldots + \vert z_{n-1} \vert^2 + \vert z_n \vert^{2} <1 \big \}, \] where $ 0 < m < 1/2$. Explicit expressions ... More
A Density Functional Study of the Structure and Energetics of Small Hetero-Atomic Silicon-Carbon NanoclustersAug 03 2004Nov 17 2004The theoretical formalism of the local density approximation (LDA) to density functional theory (DFT) has been used to study the electronic and geometric structures of SimCn (1<=m, n<=4;n<=m) clusters. An all electron 6-311++G** basis set has been used ... More
Analyzing the Wu metric on a class of eggs in $\mathbb{C}^n$ -- IMar 10 2015We study the Wu metric on convex egg domains of the form \[ E_{2m} = \big\{ z \in \mathbb{C}^n : \vert z_1 \vert^{2m} + \vert z_2 \vert^2 + \ldots + \vert z_{n-1} \vert^2 + \vert z_n \vert^{2} <1 \big\} \] where $m \geq 1/2, m \neq 1$. The Wu metric is ... More
Computing Teichmüller Maps between PolygonsJan 24 2014By the Riemann-mapping theorem, one can bijectively map the interior of an $n$-gon $P$ to that of another $n$-gon $Q$ conformally. However, (the boundary extension of) this mapping need not necessarily map the vertices of $P$ to those $Q$. In this case, ... More
The Non-Uniform k-Center ProblemMay 12 2016May 13 2016In this paper, we introduce and study the Non-Uniform k-Center problem (NUkC). Given a finite metric space $(X,d)$ and a collection of balls of radii $\{r_1\geq \cdots \ge r_k\}$, the NUkC problem is to find a placement of their centers on the metric ... More
Casimir torque in weak couplingAug 31 2013In this paper, dedicated to Johan H{\o}ye on the occasion of his 70th birthday, we examine manifestations of Casimir torque in the weak-coupling approximation, which allows exact calculations so that comparison with the universally applicable, but generally ... More
On the Parameterized Complexity of the Maximum Edge Coloring ProblemJun 12 2013We investigate the parameterized complexity of the following edge coloring problem motivated by the problem of channel assignment in wireless networks. For an integer q>1 and a graph G, the goal is to find a coloring of the edges of G with the maximum ... More
A bad 2-dimensional instance for k-means++Jun 18 2013The k-means++ seeding algorithm is one of the most popular algorithms that is used for finding the initial $k$ centers when using the k-means heuristic. The algorithm is a simple sampling procedure and can be described as follows: {quote} Pick the first ... More
Augmenting transcriptome assembly combinatoriallyMay 27 2013May 31 2013RNA-seq allows detection and precise quantification of transcripts, provides comprehensive understanding of exon/intron boundaries, aids discovery of alternatively spliced isoforms and fusion transcripts along with measurement of allele-specific expression. ... More
Bounds for Invariant Distances on Pseudoconvex Levi Corank One Domains and ApplicationsMar 14 2013Mar 29 2013Let $D \subset \mathbb{C}^n$ be a smoothly bounded pseudoconvex Levi corank one domain with defining function $r$, i.e., the Levi form $\partial \bar {\partial} r$ of the boundary $\partial D$ has at least $(n - 2)$ positive eigenvalues everywhere on ... More
BCS theory of nodal superconductorsJan 19 2005This course has a dual purpose. First we review the successes of the weak-coupling BCS theory in describing new classes of superconductors discovered since 1979. They include the heavy-fermion superconductors, high-Tc cuprate superconductors, organic ... More
Trajectory Aware Macro-cell Planning for Mobile UsersJan 13 2015Jan 14 2015We design and evaluate algorithms for efficient user-mobility driven macro-cell planning in cellular networks. As cellular networks embrace heterogeneous technologies (including long range 3G/4G and short range WiFi, Femto-cells, etc.), most traffic generated ... More
Multiple Scattering Casimir Force Calculations: Layered and Corrugated Materials, Wedges, and Casimir-Polder ForcesOct 16 2009Various applications of the multiple scattering technique to calculating Casimir energy are described. These include the interaction between dilute bodies of various sizes and shapes, temperature dependence, interactions with multilayered and corrugated ... More
Exact results for Casimir interactions between dielectric bodies: The weak-coupling or van der Waals LimitJun 17 2008In earlier papers we have applied multiple scattering techniques to calculate Casimir forces due to scalar fields between different bodies described by delta function potentials. When the coupling to the potentials became weak, closed-form results were ... More
Weak Coupling Casimir Energies for Finite Plate ConfigurationsNov 14 2008We derive and use an extremely simplified formula for the interaction Casimir energy for two separate bodies in the weak coupling regime for massless scalar fields. We derive closed form solutions for a general arrangement of two $\delta$-function plates ... More
From multiple scattering to van der Waals interactions: exact results for eccentric cylindersNov 02 2008Dec 10 2008In this paper, dedicated to the career of Iver Brevik, we review the derivation of the retarded van der Waals or Casimir-Polder interaction between polarizable molecules from the general multiple scattering formulation of Casimir interactions between ... More
Casimir Self-Entropy of an Electromagnetic Thin SheetJul 26 2016Casimir entropies due to quantum fluctuations in the interaction between electrical bodies can often be negative, either caused by dissipation or by geometry. Although generally such entropies vanish at zero temperature, consistent with the third law ... More
Exact Casimir energies at nonzero temperature: Validity of proximity force approximation and interaction of semitransparent spheresSep 04 2009Mar 17 2010In this paper, dedicated to the career of Tom Erber, we consider the Casimir interaction between weakly coupled bodies at nonzero temperature. For the case of semitransparent bodies, that is, ones described by delta-function potentials, we first examine ... More
Casimir energies of self-similar plate configurationsJul 01 2016Sep 13 2016We construct various self-similar configurations using parallel $\delta$-function plates and show that it is possible to evaluate the Casimir interaction energy of these configurations using the idea of self-similarity alone. We restrict our analysis ... More
How does Casimir energy fall? II. Gravitational acceleration of quantum vacuum energyMay 17 2007Jul 07 2007It has been demonstrated that quantum vacuum energy gravitates according to the equivalence principle, at least for the finite Casimir energies associated with perfectly conducting parallel plates. We here add further support to this conclusion by considering ... More
Three-body Casimir-Polder interactionsJan 11 2013As part of our program to develop the description of three-body effects in quantum vacuum phenomena, we study the three-body interaction of two anisotropically polarizable atoms with a perfect electrically conducting plate, a generalization of earlier ... More
Casimir energy, dispersion, and the Lifshitz formulaJan 23 2010Despite suggestions to the contrary, we show in this paper that the usual dispersive form of the electromagnetic energy must be used to derive the Lifshitz force between parallel dielectric media. This conclusion follows from the general form of the quantum ... More
A generalized topological recursion for arbitrary ramificationAug 29 2012The Eynard-Orantin topological recursion relies on the geometry of a Riemann surface S and two meromorphic functions x and y on S. To formulate the recursion, one must assume that x has only simple ramification points. In this paper we propose a generalized ... More
Further remarks on the higher dimensional Suita conjectureDec 07 2018For a domain $D \subset \mathbb C^n$, $n \ge 2$, let $F^k_D(z)=K_D(z)\lambda\big(I^k_D(z)\big)$, where $K_D(z)$ is the Bergman kernel of $D$ along the diagonal and $\lambda\big(I^k_D(z)\big)$ is the Lebesgue measure of the Kobayashi indicatrix at the ... More
From graphene to graphane : A density functional investigation of metal insulator transitionNov 08 2009While graphene is a semi-metal, recently synthesized hydrogenated graphene called graphane, turns out to be an insulator. We have probed the metal insulator Transition in graphene-graphane system within the framework of density functional theory. By analysing ... More
Casimir interaction energies for magneto-electric δ-function platesFeb 01 2013We present boundary conditions for the electromagnetic fields on a \delta-function plate, having both electric and magnetic properties, sandwiched between two magneto-electric semi-infinite half spaces. The optical properties for an isolated \delta-function ... More
Casimir-Polder repulsion: Polarizable atoms, cylinders, spheres, and ellipsoidsNov 17 2011Jan 24 2012Recently, the topic of Casimir repulsion has received a great deal of attention, largely because of the possibility of technological application. The general subject has a long history, going back to the self-repulsion of a conducting spherical shell ... More
Electromagnetic semitransparent $δ$-function plate: Casimir interaction energy between parallel infinitesimally thin platesJun 01 2012Sep 12 2012We derive boundary conditions for electromagnetic fields on a $\delta$-function plate. The optical properties of such a plate are shown to necessarily be anisotropic in that they only depend on the transverse properties of the plate. We unambiguously ... More
Finding Even Subgraphs Even FasterSep 17 2014Problems of the following kind have been the focus of much recent research in the realm of parameterized complexity: Given an input graph (digraph) on $n$ vertices and a positive integer parameter $k$, find if there exist $k$ edges (arcs) whose deletion ... More
Experimental Study of A Novel Variant of Fiduccia Mattheyses(FM) Partitioning AlgorithmMar 02 2014Partitioning is a well studied research problem in the area of VLSI physical design automation. In this problem, input is an integrated circuit and output is a set of almost equal disjoint blocks. The main objective of partitioning is to assign the components ... More
Electromagnetic Non-contact Gears: PreludeJan 22 2010We calculate the lateral Lifshitz force between corrugated dielectric slabs of finite thickness. Taking the thickness of the plates to infinity leads us to the lateral Lifshitz force between corrugated dielectric surfaces of infinite extent. Taking the ... More
Non-contact gears: I. Next-to-leading order contribution to lateral Casimir force between corrugated parallel platesMay 19 2008Jul 03 2008We calculate the lateral Casimir force between corrugated parallel plates, described by $\delta$-function potentials, interacting through a scalar field, using the multiple scattering formalism. The contributions to the Casimir energy due to uncorrugated ... More
Low energy theorems and the unitarity bounds in the extra U(1) superstring inspired E6 modelsJan 15 2008The conventional method using low energy theorems [3] does not seem to lead to an explicit unitarity limit in the scattering processes of longitudinally polarized gauge bosons for the high energy case in the extra U(1) superstring inspired models, commonly ... More
Multiple Scattering: Dispersion, Temperature Dependence, and Annular PistonsJul 20 2010We review various applications of the multiple scattering approach to the calculation of Casimir forces between separate bodies, including dispersion, wedge geometries, annular pistons, and temperature dependence. Exact results are obtained in many cases. ... More
Density Matrix Renormalization Group Pair-Density Functional Theory (DMRG-PDFT): Singlet-Triplet Gaps in Polyacenes and PolyacetylenesAug 20 2018The density matrix renormalization group (DMRG) is a powerful method to treat static correlation. Here we present an inexpensive way to add additional dynamic correlation energy to a DMRG self-consistent field (DMRG) wave function using pair-density functional ... More
Repulsive Casimir and Casimir-Polder ForcesFeb 29 2012Apr 25 2012Casimir and Casimir-Polder repulsion have been known for more than 50 years. The general "Lifshitz" configuration of parallel semi-infinite dielectric slabs permits repulsion if they are separated by a dielectric fluid that has a value of permittivity ... More
PT-Symmetry Quantum Electrodynamics--PTQEDDec 01 2007The construction of $\mathcal{PT}$-symmetric quantum electrodynamics is reviewed. In particular, the massless version of the theory in 1+1 dimensions (the Schwinger model) is solved. Difficulties with unitarity of the $S$-matrix are discussed.
A Systematic Study of Electronic Structure from Graphene to GraphaneOct 20 2010While graphene is a semi-metal, a recently synthesized hydrogenated graphene called graphane, is an insulator. We have probed the transformation of graphene upon hydrogenation to graphane within the framework of density functional theory. By analyzing ... More
Signatures of Heavy Z-prime in the Extra U(1) Superstring Inspired Model: RGEs AnalysisMay 17 2007May 21 2007In the extra U(1) superstring inspired model, we examine the electroweak and U(1)-prime symmetry breaking with the singlet and exotic quark D, D+{\c}along with the study of heavy Z-prime boson in accordance with the top quark mass region. For this, we ... More
PT-Symmetric Quantum Electrodynamics and UnitarityApr 23 2012Jun 07 2012More than 15 years ago, a new approach to quantum mechanics was suggested, in which Hermiticity of the Hamiltonian was to be replaced by invariance under a discrete symmetry, the product of parity and time-reversal symmetry, $\mathcal{PT}$. It was shown ... More
How does Casimir energy fall? III. Inertial forces on vacuum energyNov 08 2007We have recently demonstrated that Casimir energy due to parallel plates, including its divergent parts, falls like conventional mass in a weak gravitational field. The divergent parts were suitably interpreted as renormalizing the bare masses of the ... More
Casimir-Polder repulsion near edges: wedge apex and a screen with an apertureMar 22 2011May 09 2011Although repulsive effects have been predicted for quantum vacuum forces between bodies with nontrivial electromagnetic properties, such as between a perfect electric conductor and a perfect magnetic conductor, realistic repulsion seems difficult to achieve. ... More
Lateral Casimir forces on parallel plates and concentric cylinders with corugationsOct 10 2008In this paper we are giving a quantitative description of two different configurations for noncontact gears. We consider the solutions from a perturbative calculation for two semitransparent parallel plates and concentric cylinders both with corrugations ... More
Non-contact gears: II. Casimir torque between concentric corrugated cylinders for the scalar caseMay 19 2008Jul 03 2008The Casimir interaction between two concentric corrugated cylinders provides the mechanism for non-contact gears. To this end, we calculate the Casimir torque between two such cylinders, described by $\delta$-potentials, which interact through a scalar ... More
Negative Entropies in Casimir and Casimir-Polder InteractionsMay 03 2016It has been increasingly becoming clear that Casimir and Casimir-Polder entropies may be negative in certain regions of temperature and separation. In fact, the occurrence of negative entropy seems to be a nearly ubiquitous phenomenon. This is most highlighted ... More
Casimir-Polder repulsion: Three-body effectsFeb 21 2015In this paper we study an archetypical scenario in which repulsive Casimir-Polder forces between an atom or molecule and two macroscopic bodies can be achieved. This is an extension of previous studies of the interaction between a polarizable atom and ... More
Stress tensor for a scalar field in a spatially varying background potential: Divergences, "renormalization," anomalies, and Casimir forcesFeb 02 2016Motivated by a desire to understand quantum fluctuation energy densities and stress within a spatially varying dielectric medium, we examine the vacuum expectation value for the stress tensor of a scalar field with arbitrary conformal parameter, in the ... More
How does Casimir energy fall? IV. Gravitational interaction of regularized quantum vacuum energyJan 04 2014Several years ago we demonstrated that the Casimir energy for perfectly reflecting and imperfectly reflecting parallel plates gravitated normally, that is, obeyed the equivalence principle. At that time the divergences in the theory were treated only ... More
Investigations of the torque anomaly in an annular sector. II. Global calculations, electromagnetic caseJul 09 2013Recently, it was suggested that there was some sort of breakdown of quantum field theory in the presence of boundaries, manifesting itself as a torque anomaly. In particular, Fulling et al. used the finite energy-momentum-stress tensor in the presence ... More
Repulsive Casimir EffectsNov 22 2011Like Casimir's original force between conducting plates in vacuum, Casimir forces are usually attractive. But repulsive Casimir forces can be achieved in special circumstances. These might prove useful in nanotechnology. We give examples of when repulsive ... More
Leading- and next-to-leading-order lateral Casimir force on corrugated surfacesOct 10 2008We derive explicit analytic expressions for the lateral force for two different configurations with corrugations, parallel plates and concentric cylinders. By making use of the multiple scattering formalism, we calculate the force for a scalar field under ... More
Bounds on the W-Boson Electric Dipole Moment -RevisitedApr 02 2002Keeping in view the suggestion of Barr and Marciano [7] that the cut of procedure involves a good deal of uncertainity in the prediction of E.D.M. of W - boson, we have re-examined the earlier calculation by Marciano and Queijeiro [2] by replacing the ... More
Limited Attention and Centrality in Social NetworksMar 18 2013How does one find important or influential people in an online social network? Researchers have proposed a variety of centrality measures to identify individuals that are, for example, often visited by a random walk, infected in an epidemic, or receive ... More
Gravitational and Inertial Mass of Casimir EnergyOct 20 2007It has been demonstrated, using variational methods, that quantum vacuum energy gravitates according to the equivalence principle, at least for the finite Casimir energies associated with perfectly conducting parallel plates. This conclusion holds independently ... More
How Does Casimir Energy Fall?Feb 12 2007Mar 22 2007Doubt continues to linger over the reality of quantum vacuum energy. There is some question whether fluctuating fields gravitate at all, or do so anomalously. Here we show that for the simple case of parallel conducting plates, the associated Casimir ... More
Investigations of the torque anomaly in an annular sector. I. Global calculations, scalar caseJun 04 2013In an attempt to understand a recently discovered torque anomaly in quantum field theory with boundaries, we calculate the Casimir energy and torque of a scalar field subject to Dirichlet boundary conditions on an annular sector defined by two coaxial ... More
Distance-dependent sign-reversal in the Casimir-Lifshitz torqueJan 03 2018The Casimir-Lifshitz torque between two biaxially polarizable anisotropic planar slabs is shown to exhibit a non-trivial sign-reversal in its rotational sense. The critical distance $a_c$ between the slabs that marks this reversal is characterized by ... More
Anisotropic contribution to the van der Waals and the Casimir-Polder energies for CO$_2$ and CH$_4$ molecules near surfaces and thin filmsJun 04 2015In order to understand why carbon dioxide (CO$_2$) and methane (CH$_4$) molecules interact differently with surfaces, we investigate the Casimir-Polder energy of a linearly polarizable CO$_2$ molecule and an isotropically polarizable CH$_4$ molecule in ... More
Lifshitz interaction can promote ice growth at water-silica interfacesApr 05 2017At air-water interfaces, the Lifshitz interaction by itself does not promote ice growth. On the contrary, we find that the Lifshitz force promotes the growth of an ice film, up to 1-8 nm thickness, near silica-water interfaces at the triple point of water. ... More
The Keck Cosmic Web Imager Integral Field SpectrographJul 26 2018We report on the design and performance of the Keck Cosmic Web Imager (KCWI), a general purpose optical integral field spectrograph that has been installed at the Nasmyth port of the 10 m Keck II telescope on Mauna Kea, HI. The novel design provides blue-optimized ... More
The Ninth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-III Baryon Oscillation Spectroscopic SurveyJul 30 2012The Sloan Digital Sky Survey III (SDSS-III) presents the first spectroscopic data from the Baryon Oscillation Spectroscopic Survey (BOSS). This ninth data release (DR9) of the SDSS project includes 535,995 new galaxy spectra (median z=0.52), 102,100 new ... More