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Dephasing-assisted Gain and Loss in Mesoscopic Quantum SystemsAug 15 2016Jan 30 2017Motivated by recent experiments, we analyse the phonon-assisted steady-state gain of a microwave field driving a double quantum-dot in a resonator. We apply the results of our companion paper, which derives the complete set of fourth-order Lindblad dissipators ... More

Keldysh meets Lindblad: Correlated Gain and Loss in Higher-Order Perturbation TheoryAug 15 2016Jan 30 2017Motivated by correlated decay processes producing gain, loss and lasing in driven semiconductor quantum-dots, we develop a theoretical technique using Keldysh diagrammatic perturbation theory to derive a Lindblad master equation that goes beyond the usual ... More

Controlling electron spin dynamics in bichromatic Kapitza-Dirac scattering by the laser field polarizationJan 21 2017May 21 2017Spin-dependent Kapitza-Dirac scattering of electron beams from counterpropagating bichromatic laser waves in various polarization geometries is studied. The corresponding scattering probabilities are obtained by analytical and numerical solutions of the ... More

Spin-polarizing interferometric beam splitter for free electronsJul 29 2016Feb 03 2017A spin-polarizing electron beam splitter is described which relies on an arrangement of linearly polarized laser waves of nonrelativistic intensity. An incident electron beam is first coherently scattered off a bichromatic laser field, splitting the beam ... More

Localization in coupled heterogeneously disordered transport channels on the Bethe latticeFeb 26 2013Mar 29 2013We study the Anderson localization in systems, in which transport channels with rather different properties are coupled together. This problem arises naturally in systems of hybrid particles, such as exciton-polaritons, where it is not obvious which transport ... More

Transversality and lattice surgery: exploring realistic routes towards coupled logical qubits with trapped-ion quantum processorsJan 22 2018Active quantum error correction has been identified as a crucial ingredient of future quantum computers, motivating the recent experimental efforts to encode logical quantum bits using small topological codes. In addition to the demonstration of the beneficial ... More

Noise-robust quantum sensing via optimal multi-probe spectroscopyJan 30 2018The dynamics of quantum systems are unavoidably influenced by their environment and in turn observing a quantum system (probe) can allow one to measure its environment: Measurements and controlled manipulation of the probe such as dynamical decoupling ... More

Titanium hidden in dustFeb 06 2019Cassiopeia A, one of the most intriguing galactic supernova remnants, has been a target of many observational efforts including most recent observations by ALMA, Hubble, Herschel, Spitzer, NuSTAR, Integral, and other observatories. We use recent gamma-ray ... More

Research Challenges in Management and Compliance of Policies on the WebJul 30 2008In this paper we argue that policies are an increasing concern for organizations that are operating a web site. Examples of policies that are relevant in the domain of the web address issues such as privacy of personal data, accessibility for the disabled, ... More

Abelian monopoles in finite temperature lattice gauge fields: Classically perfect action, smoothing and various Abelian gaugesSep 20 1998Using the renormalization group motivated smoothing technique, the large scale structure of lattice configurations at finite temperature is characterized in terms of Abelian monopoles identified in the maximally Abelian, the Laplacian Abelian, and the ... More

Gauge invariant properties of Abelian monopolesSep 21 1998Using a renormalization group motivated smoothing technique, we investigate the large scale structure of lattice configurations at finite temperature, concentrating on Abelian monopoles identified in the maximally Abelian, the Laplacian Abelian, and the ... More

On the continuum limit of Landau gauge gluon and ghost propagators in SU(2) lattice gauge gluodynamicsMar 14 2013We continue the systematic computation of Landau gauge gluon and ghost propagators of SU(2) gluodynamics using a sequence of increasing lattice sizes L^4 up to L=112 with corresponding \beta-values chosen to keep the linear physical size a(\beta)L ~ 9.6 ... More

Interfering Doorway States and Giant Resonances. I: Resonance Spectrum and Multipole StrengthsApr 17 1997A phenomenological schematic model of multipole giant resonances (GR) is considered which treats the external interaction via common decay channels on the same footing as the coherent part of the internal residual interaction. The damping due to the coupling ... More

Transverse Velocity Dependence of the Proton-Antiproton Ratio as a Signature of the QCD Critical EndpointMar 17 2008Sep 27 2008The presence of a critical point in the QCD phase diagram can deform the trajectories describing the evolution of the expanding fireball in the $\mu_B-T$ phase diagram. If the average emission time of hadrons is a function of transverse velocity, as microscopic ... More

Functional Materials for Information and Energy Technology: Insights by Photoelectron SpectroscopyMar 02 2015Mar 18 2015The evolution of both information and energy technology is intimately connected to complex condensed matter systems, the properties of which are determined by electronic and chemical interactions and processes on a broad range of length and time scales. ... More

Interfering Doorway States and Giant Resonances. II: Transition StrengthsApr 17 1997The mixing of the doorway components of a giant resonance (GR) due to the interaction via common decay channels influences significantly the distribution of the multipole strength and the energy spectrum of the decay products of the GR. The concept of ... More

Advances in sequential measurement and control of open quantum systemsNov 13 2018Jun 25 2019Novel concepts, perspectives and challenges in measuring and controlling an open quantum system via sequential schemes are shown. We discuss how similar protocols, relying both on repeated quantum measurements and dynamical decoupling control pulses, ... More

When Do Composed Maps Become Entanglement Breaking?Jul 03 2018Jun 17 2019For many completely positive maps repeated compositions will eventually become entanglement breaking. To quantify this behaviour we develop a technique based on the Schmidt number: If a completely positive map breaks the entanglement with respect to any ... More

Motor-driven Dynamics of Cytoskeletal FIlaments in Motility AssaysApr 17 2011Jun 10 2011We model analytically the dynamics of a cytoskeletal filament in a motility assay. The filament is described as rigid rod free to slide in two dimensions. The motor proteins consist of polymeric tails tethered to the plane and modeled as linear springs ... More

Fisher information from stochastic quantum measurementsJun 16 2016The unavoidable interaction between a quantum system and the external noisy environment can be mimicked by a sequence of stochastic measurements whose outcomes are neglected. Here we investigate how this stochasticity is reflected in the survival probability ... More

Verifying quantum superpositions at metre scalesJul 06 2016Jul 15 2016While the existence of quantum superpositions of massive particles over microscopic separations has been established since the birth of quantum mechanics, the maintenance of superposition states over macroscopic separations is a subject of modern experimental ... More

Vertices of Lie ModulesSep 09 2013Let Lie(n) be the Lie module of the symmetric group S_n over a field F of characteristic p>0, that is, Lie(n) is the left ideal of FS_n generated by the Dynkin-Specht-Wever element. We study the problem of parametrizing non-projective indecomposable summands ... More

Topology without cooling: instantons and monopoles near to deconfinementSep 29 1997In an attempt to describe the change of topological structure of pure SU(2) gauge theory near deconfinement a renormalization group inspired method is tested. Instead of cooling, blocking and subsequent inverse blocking is applied to Monte Carlo configurations ... More

Southern-Hemisphere AGN Monitoring on (Sub-)Parsec Scales: The TANAMI ProgramMay 07 2012The Very Long Baseline Interferometry (VLBI) monitoring program TANAMI provides bi-monthly, dualfrequency (8GHz and 22GHz) observations of extragalactic jets with milliarcsecond resolution south of -30 deg declination using the Australian Long Baseline ... More

Inter-molecular structure factors of macromolecules in solution: integral equation resultsApr 19 1999The inter-molecular structure of semidilute polymer solutions is studied theoretically. The low density limit of a generalized Ornstein-Zernicke integral equation approach to polymeric liquids is considered. Scaling laws for the dilute-to-semidilute crossover ... More

Fault-tolerant protection of near-term trapped-ion topological qubits under realistic noise sourcesOct 22 2018The quest of demonstrating beneficial quantum error correction in near-term noisy quantum processors can benefit enormously from a low-resource optimization of fault-tolerant schemes, which are specially designed for a particular platform considering ... More

Semiconductor-to-Metal Transition in the Bulk of WSe2 upon Potassium IntercalationJan 23 2017We present electron energy-loss spectroscopic measurements of potassium (K) intercalated tungsten diselenide (WSe2). After exposure of pristine WSe2 films to potassium, we observe a charge carrier plasmon excitation at about 0.97 eV, which indicates a ... More

Automated Reconstruction of Particle Cascades in High Energy Physics ExperimentsJan 08 2008Sep 08 2008We present a procedure for reconstructing particle cascades from event data measured in a high energy physics experiment. For evaluating the hypothesis of a specific physics process causing the observed data, all possible reconstruction versions of the ... More

The Flavours of the Quark-Gluon PlasmaDec 26 2008Quarks of other flavours than up and down, i.e. $s$, $c$, and $b$ quarks, have been long recognized as effective probes of the structure of hot QCD matter. In this talk, I review some of the motivations for their investigation and discuss the salient ... More

Phenomenology of Jet Quenching in Heavy Ion CollisionsAug 20 2002Mar 23 2003We derive an analytical expression for the quenching factor in the strong quenching limit where the $p_T$ spectrum of hard partons is dominated by surface emission. We explore the phenomenological consequences of different scaling laws for the energy ... More

Quark Matter 2005 -- Theoretical SummaryAug 29 2005Nov 14 2005This is a review of the latest developments in the theory of superdense nuclear matter, formed in relativistic heavy ion collisions or in the core of collapsed stars, as they were reported and discussed at the Quark Matter 2005 conference in Budapest ... More

Erdmessung mit Quanten und RelativitätAug 30 2016Recent developments in fundamental physics (in theory as well as in technology) provide novel capabilities for geodetic applications such as refined observations of the Earth`s gravity field. We will focus on two new concepts: one applies atomic interferometry ... More

A metric approach to Fréchet geometryDec 14 2006Jun 16 2007The aim of this article is to present the category of bounded Frechet manifolds in respect to which we will review the geometry of Frechet manifolds with a stronger accent on its metric aspect. An inverse function theorem in the sense of Nash and Moser ... More

Epsilon-non-squeezing and $C^0$-rigidity of epsilon-symplectic embeddingsMay 03 2018An embedding $\varphi \colon (M_1, \omega_1) \to (M_2, \omega_2)$ (of symplectic manifolds of the same dimension) is called $\epsilon$-symplectic if the difference $\varphi^* \omega_2 - \omega_1$ is $\epsilon$-small with respect to a fixed Riemannian ... More

Ideal quantum glass transitions: many-body localization without quenched disorderSep 04 2013Nov 06 2013We explore the possibility for translationally invariant quantum many-body systems to undergo a dynamical glass transition, at which ergodicity and translational invariance break down spontaneously, driven entirely by quantum effects. In contrast to analogous ... More

Evidence for structural and electronic instabilities at intermediate temperatures in $κ$-(BEDT-TTF)$_{2}$X for X=Cu[N(CN)$_{2}$]Cl, Cu[N(CN)$_{2}$]Br and Cu(NCS)$_{2}$: Implications for the phase diagram of these quasi-2D organic superconductorsJul 23 2001We present high-resolution measurements of the coefficient of thermal expansion $\alpha (T)=\partial \ln l(T)/\partial T$ of the quasi-twodimensional (quasi-2D) salts $\kappa$-(BEDT-TTF)$_2$X with X = Cu(NCS)$_2$, Cu[N(CN)$_2$]Br and Cu[N(CN)$_2$]Cl. ... More

On Gradient Flows with Obstacles and Euler's ElasticaMar 01 2019We examine a steepest energy descent flow with obstacle constraint in higher order energy frameworks where the maximum principle is not available. We construct the flow under general assumptions using De Giorgi's minimizing movement scheme. Our main application ... More

Dynamical sensitivity of recurrence and transience of branching random walksJul 27 2009Dec 07 2009Consider a sequence of i.i.d. random variables $X_n$ where each random variable is refreshed independently according to a Poisson clock. At any fixed time $t$ the law of the sequence is the same as for the sequence at time 0 but at random times almost ... More

Consequences of a possible jet-star interaction in the inner central parsec of Centaurus AFeb 10 2015Apr 24 2015The jet-counterjet system of the closest radio-loud active galaxy Centaurus A (Cen A) can be studied with Very Long Baseline Interferometry (VLBI) on unprecedented small linear scales of ~0.018pc. These high-resolution observations provide essential information ... More

Nanoscale tunnel field effect transistor based on a complex oxide lateral heterostructureApr 23 2019We demonstrate a tunnel field effect transistor based on a lateral heterostructure patterned from an $\mathrm{LaAlO_3/SrTiO_3}$ electron gas. Charge is injected by tunneling from the $\mathrm{LaAlO_3}$/$\mathrm{SrTiO_3}$ contacts and the current through ... More

Probing the Aoki phase with N_f=2 Wilson fermions at finite temperatureNov 28 2005In this letter we report on a numerical investigation of the Aoki phase in the case of finite temperature which continues our former study at zero temperature. We have performed simulations with Wilson fermions at $\beta=4.6$ using lattices with temporal ... More

The monopole content of topological clusters : have KvB calorons been found?Dec 18 2004Feb 02 2005Using smearing of equilibrium lattice fields generated at finite temperature in the confined phase of SU(2) lattice gauge theory, we have investigated the emerging topological objects (clusters of topological charge). Analysing their monopole content ... More

A note on the volume flux of smooth and continuous strictly contact isotopiesJul 25 2011This note on the flux homomorphism for strictly contact isotopies complements the recent paper [MS11a] by P. Spaeth and the author. We determine the volume flux restricted to symplectic and volume-preserving contact isotopies and their C^0-limits for ... More

On the von Neumann rule in quantizationMar 25 2019Jun 22 2019We show that any linear quantization map into the space of self-adjoint operators in a Hilbert space violates the von Neumann rule on post-composition with real functions.

Applying the index theorem to non-smooth operatorsJun 15 2015Oct 10 2016We give a simple way to extend index-theoretical statements from partial differential operators with smooth coefficients to operators with coefficients of finite Sobolev order.

On low-degree representations of the symmetric groupNov 22 2015Jul 07 2016The aim of the present paper is to obtain a classification of all the irreducible modular representations of the symmetric group on $n$ letters of dimension at most $n^3$, including dimension formulae. This is achieved by improving an idea, originally ... More

MPPhys - A many-particle simulation package for computational physics educationMar 07 2014In a first course to classical mechanics elementary physical processes like elastic two-body collisions, the mass-spring model, or the gravitational two-body problem are discussed in detail. The continuation to many-body systems, however, is defered to ... More

Heavy Ions -- Prospects at the LHCOct 07 2004Oct 13 2004This is a review of the physics prospects for relativistic heavy ion collisions in the CERN Large Hadron Collider. The motivation for the study of superdense matter created in relativistic heavy ion collision is the prospect of observing a novel state ... More

Quark Matter '99 --- Theoretical Summary: What Next?Jun 09 1999Jul 15 1999I review the three broad areas where major progress has been reported: The phase structure of strongly interacting matter, the properties of matter at the instant when it freezes out into individual hadrons in the final stage of the expansion of the hot ... More

Parton Energy Loss in Strongly Coupled AdS/CFTOct 20 2010Nov 30 2010This is a brief review of the theory and phenomenology of parton energy loss in strongly coupled field theories with a gravity dual and its comparison with parton energy loss in QCD at weak coupling.

F-pure threshold and height of quasi-homogeneous polynomialsFeb 24 2017We consider a quasi-homogeneous polynomial $f \in \mathbb{Z}[x_0, \ldots, x_N]$ of degree $w$ equal to the degree of $x_0 \cdots x_N$ and show that the $F$-pure threshold of the reduction $f_p \in \mathbb{F}_p[x_0, \ldots, x_N]$ is equal to the log canonical ... More

Neutrino Emission as Diagnostics of Core-Collapse SupernovaeApr 24 2019With myriads of detection events from a prospective Galactic core-collapse supernova, current and future neutrino detectors will be able to sample detailed, time-dependent neutrino fluxes and spectra. This offers enormous possibilities for inferring supernova ... More

$J$-holomorphic disks with pre-Lagrangian boundary conditionsApr 09 2017Apr 28 2017The purpose of this paper is to carry out a classical construction of a non-constant holomorphic disk with boundary on (the suspension of) a Lagrangian submanifold in $\mathbb{R}^{2 n}$ in the case the Lagrangian is the lift of a coisotropic (a.k.a. pre-Lagrangian) ... More

Special temporal functions on globally hyperbolic manifoldsApr 09 2009Oct 22 2012In this article, existence results concerning temporal functions with additional properties on a globally hyperbolic manifold are obtained. These properties are certain bounds on geometric quantities as lapse and shift. The results are linked to completeness ... More

A note on closed isometric embeddingsMay 30 2008May 20 2016This note is about a little extension of Nash's embedding theorem in the case of complete manifolds.

Black holes in Einstein-Maxwell TheoryJul 18 2016Oct 06 2018We prove variants of known singularity theorems ensuring the existence of a region of finite lifetime that are particularly well applicable if the solution admits a conformal extension, a property satisfied e.g. by maximal Cauchy developments of Einstein-Maxwell ... More

A note on invariant temporal functionsFeb 09 2015Jul 18 2016The purpose of this article is to present a result on the existence of Cauchy temporal functions invariant by the action of a compact group of conformal transformations in arbitrary globally hyperbolic manifolds. Moreover, the previous results about the ... More

Central limit theorem analogues for multicolour urn modelsApr 11 2016Mar 12 2019The asymptotic behaviour of a generalised P\'olya--Eggenberger urn is well--known to depend on the spectrum of its replacement matrix: If its dominant eigenvalue $r$ is simple and no other eigenvalue is `large' in the sense that its real part is greater ... More

Branch dependence in the "consistent histories" approach to quantum mechanicsJun 07 2005Nov 12 2006In the consistent histories formalism one specifies a family of histories as an exhaustive set of pairwise exclusive descriptions of the dynamics of a quantum system. We define branching families of histories, which strike a middle ground between the ... More

Numerical Chladni figuresAug 26 2013Chladni patterns of vibrating membranes or thin plates faszinated the people already in the eighteenth century. As a simple way to visualize acoustic phenomena it is a valuable experiment for beginners' courses. In this paper I present NumChladni, an ... More

Investigation of Hot QCD Matter: Theoretical AspectsSep 29 2013Oct 12 2013This lecture presents an overview of the status of the investigation of the properties of the quark-gluon plasma using relativistic heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). It focuses on the ... More

Statistical Fluctuations as Probes of Dense MatterNov 04 2001The use of statistical fluctuations as probes of the microscopic dynamics of hot and dense hadronic matter is reviewed. Critical fluctuations near the critical point of QCD matter are predicted to enhance fluctuations in pionic observables. Chemical fluctuations, ... More

Simulations of the Glasma in 3+1DApr 08 2019May 20 2019The Glasma is a gluonic state of matter which can be created in collisions of relativistic heavy ions and is a precursor to the quark-gluon plasma. The existence of this state is a prediction of the color glass condensate (CGC) effective theory. In many ... More

The Group of Hamiltonian Homeomorphisms in the L^\infty-normMay 08 2007The group Hameo (M,\omega) of Hamiltonian homeomorphisms of a connected symplectic manifold (M,\omega) was defined and studied in [7] and further in [6]. In these papers, the authors consistently used the L^{(1,\infty)}-Hofer norm (and not the L^\infty-Hofer ... More

Problems of Harmonic Analysis related to finite type hypersurfaces in R^3, and Newton polyhedraAug 31 2012This article, which grew out of my lecture at the conference "Analysis and Applications: A Conference in Honor of Elias M. Stein" in May 2011, is intended to give an overview on a collection of results which have been obtained jointly with I.I. Ikromov, ... More

Uniform approximation of homeomorphisms by diffeomorphismsJan 08 2009May 22 2014We prove that a compactly supported homeomorphism of a smooth manifold of dimension greater or equal to 5 can be approximated uniformly by compactly supported diffeomorphisms if and only if it is isotopic to a diffeomorphism. If the given homeomorphism ... More

Decompositions of rational functions over real and complex numbers and a question about invariant curvesFeb 25 2015We consider the connection of functional decompositions of rational functions over the real and complex numbers, and a question about curves on a Riemann sphere which are invariant under a rational function.

Asymptotic flexibility of globally hyperbolic manifoldsOct 05 2011In this short note, a question of patching together globally hyperbolic manifolds is adressed which appeared in the context of the construction of Hadamard states.

Metrizability of spaces of homomorphisms between metric vector spacesMay 22 2009Nov 29 2014This note tries to give an answer to the following question: Is there a sufficiently rich class of metric vector spaces such that sufficiently large spaces of continuous linear maps between them are metrizable?

Invariants of 3-manifolds from representations of the framed-tangle categoryMar 03 2002A new class of 3-manifold invariants is constructed from representations of the category of framed tangles.

Minimax principles, Hardy-Dirac inequalities and operator cores for two and three dimensional Coulomb-Dirac operatorsMar 04 2016For $n\in\{2,3\}$ we prove minimax characterisations of eigenvalues in the gap of the $n$ dimensional Dirac operator with an potential, which may have a Coulomb singularity with a coupling constant up to the critical value $1/(4-n)$. This result implies ... More

A criterion for transience of multidimensional branching random walk in random environmentMay 14 2007We develop a criterion for transience for a general model of branching Markov chains. In the case of multi-dimensional branching random walk in random environment (BRWRE) this criterion becomes explicit. In particular, we show that \emph{Condition L} ... More

Cheeger-Gromov compactness for manifolds with boundaryAug 20 2018We prove Cheeger-Gromov convergence for a subsequence of a given sequence of manifolds (with boundary) of bounded geometry.

Analysis of invariant PDO's on the Heisenberg groupAug 12 2014In these lecture notes, the representation theory of the Heisenberg group as well as Howe's construction of the metaplectic group by means of twisted convolution operators with generalized, complex Gaussians are reviewed, and it is shown how these tools ... More

Which spacetimes admit conformal compactifications?Sep 29 2014Nov 21 2014We consider the future causal boundary as a tool to find obstructions to conformal extensions, the latter being a slight generalization to conformal compactifications.

The Axiom of Determinacy Implies Dependent Choices in MiceJul 05 2019We show that the Axiom of Dependent Choices, $\operatorname{DC}$, holds in countably iterable, passive premice $\mathcal{M}$ construced over their reals which satisfy the Axiom of Determinacy, $\operatorname{AD}$, in a $\operatorname{ZF}+\operatorname{DC}_{\mathbb{R}^{\mathcal{M}}}$ ... More

A Central Limit Theorem for Lipschitz-Killing Curvatures of Gaussian ExcursionsJul 22 2016Feb 20 2017This paper studies the excursion set of a real stationary isotropic Gaussian random field above a fixed level. We show that the standardized Lipschitz-Killing curvatures of the intersection of the excursion set with a window converges in distribution ... More

Optimizing entangling quantum gates for physical systemsApr 12 2011Sep 15 2011Optimal control theory is a versatile tool that presents a route to significantly improving figures of merit for quantum information tasks. We combine it here with the geometric theory for local equivalence classes of two-qubit operations to derive an ... More

Optimal Phonon-to-Spin Mapping in a system of a trapped ionApr 11 2015We propose a protocol for measurement of the phonon number distribution of a harmonic oscillator based on selective mapping to a discrete spin-1/2 degree of freedom. We consider a system of a harmonically trapped ion, where a transition between two long ... More

Spin flip loss in magnetic storage of ultracold neutronsJul 19 2013We analyze the depolarization of ultracold neutrons confined in a magnetic field configuration similar to those used in existing or proposed magneto-gravitational storage experiments aiming at a precise measurement of the neutron lifetime. We use an approximate ... More

The spin-$\frac{1}{2}$ XXZ chain system Cs$_2$CoCl$_4$ in a transverse magnetic fieldJul 10 2013Comparing high-resolution specific heat and thermal expansion measurements to exact finite-size diagonalization, we demonstrate that Cs$_2$CoCl$_4$ for a magnetic field along the crystallographic b axis realizes the spin-$\frac{1}{2}$ XXZ chain in a transverse ... More

Unifying machine learning and quantum chemistry -- a deep neural network for molecular wavefunctionsJun 24 2019Machine learning advances chemistry and materials science by enabling large-scale exploration of chemical space based on quantum chemical calculations. While these models supply fast and accurate predictions of atomistic chemical properties, they do not ... More

Laboratory spectroscopy of 1,2-propanediol at millimeter and submillimeter wavelengthsAug 22 2014Ethanediol is one of the largest complex organic molecules detected in space thus far. It has been found in different types of molecular clouds. The two propanediol isomers are the next larger diols. Hence, they are viable candidates to be searched for ... More

Temperature dependence of the slip length in polymer melts at attractive surfacesApr 05 2008Using Couette and Poiseuille flow, we extract the temperature dependence of the slip length, $\delta$, from molecular dynamics simulations of a coarse-grained polymer model in contact with an attractive, corrugated surface. $\delta$ is dictated by the ... More

Optimal Number of Transmit Antennas for Secrecy Enhancement in Massive MIMOME ChannelsSep 06 2017This paper studies the impact of transmit antenna selection on the secrecy performance of massive MIMO wiretap channels. We consider a scenario in which a multi-antenna transmitter selects a subset of transmit antennas with the strongest channel gains. ... More

Cyclic motion and inversion of surface flow direction in a dense polymer brush under shearAug 30 2007Using molecular simulations, we study the properties of a polymer brush in contact with an explicit solvent under Couette and Poiseuille flow. The solvent is comprised of chemically identical chains. We present evidence that individual, unentangled chains ... More

Atom interferometry in an optical cavitySep 25 2014We propose and demonstrate a new scheme for atom interferometry, using light pulses inside an optical cavity as matter wave beamsplitters. The cavity provides power enhancement, spatial filtering, and a precise beam geometry, enabling new techniques such ... More

Environmental Enhancement of Loose Groups around Rich Clusters of GalaxiesNov 27 2002We have studied the properties of Las Campanas Loose Groups in the neighbourhood of rich (Abell, APM and X-ray) clusters of galaxies. These loose groups show strong evidence of segregation measured in terms of the group richness and the group velocity ... More

Insights from experiment and $ab\,initio$ calculations into the glass-like transition in the molecular conductor $κ$-(BEDT-TTF)$_2$Hg(SCN)$_2$ClOct 24 2017Feb 09 2018We present high-resolution measurements of the relative length change as a function of temperature of the organic charge-transfer salt $\kappa$-(BEDT-TTF)$_2$Hg(SCN)$_2$Cl. We identify anomalous features at $T_g \approx\,63$ K which can be assigned to ... More

Controlled oxygen vacancy induced p-type conductivity in HfO{2-x} thin filmsNov 11 2011We have synthesized highly oxygen deficient HfO$_{2-x}$ thin films by controlled oxygen engineering using reactive molecular beam epitaxy. Above a threshold value of oxygen vacancies, p-type conductivity sets in with up to 6 times 10^{21} charge carriers ... More

Feature Importance Measure for Non-linear Learning AlgorithmsNov 22 2016Complex problems may require sophisticated, non-linear learning methods such as kernel machines or deep neural networks to achieve state of the art prediction accuracies. However, high prediction accuracies are not the only objective to consider when ... More

Statics and dynamics of a cylindrical droplet under an external body forceAug 14 2007We study the rolling and sliding motion of droplets on a corrugated substrate by Molecular Dynamics simulations. Droplets are driven by an external body force (gravity) and we investigate the velocity profile and dissipation mechanisms in the steady state. ... More

Learning from Label Proportions in Brain-Computer Interfaces: Online Unsupervised Learning with GuaranteesJan 25 2017Objective: Using traditional approaches, a Brain-Computer Interface (BCI) requires the collection of calibration data for new subjects prior to online use. Calibration time can be reduced or eliminated e.g.~by transfer of a pre-trained classifier or unsupervised ... More

High spectral resolution observations of HNC3 and HCCNC in the L1544 prestellar coreNov 28 2017HCCNC and HNC3 are less commonly found isomers of cyanoacetylene, HC3N, a molecule that is widely found in diverse astronomical sources. We want to know if HNC3 is present in sources other than the dark cloud TMC-1 and how its abundance is relative to ... More

Automated generation of lattice QCD Feynman rulesApr 02 2009Apr 20 2009The derivation of the Feynman rules for lattice perturbation theory from actions and operators is complicated, especially for highly improved actions such as HISQ. This task is, however, both important and particularly suitable for automation. We describe ... More

Nonreciprocal Atomic Scattering: A saturable, quantum Yagi-Uda antennaAug 11 2017Nov 09 2017Recent theoretical studies of a pair of atoms in a 1D waveguide find that the system responds asymmetrically to incident fields from opposing directions at low powers. Since there is no explicit time-reversal symmetry breaking elements in the device, ... More

Statistical analysis of electronic and phononic transport simulations of metallic atomic contactsJul 19 2019We adapt existing phonon heat transport methods to compute the phononic thermal conductance of metallic atomic contacts during a stretching process. Nonequilibrium molecular dynamics (NEMD) simulations are used to generate atomic configurations and to ... More

Infrared Spectroscopic Study of Vibrational Modes across the Orthorhombic-Tetragonal Phase Transition in Methylammonium Lead Halide Single CrystalsMar 28 2018Single crystals of the methylammonium (MA) lead halides MAPbI3, MAPbBr3, and MAPbCl3 have been investigated using infrared spectroscopy with the aim of analyzing structural and dynamical aspects of processes that enable the ordering of the MA molecule ... More

Calculation of geometric phases in electric dipole searches with trapped spin-1/2 particles based on direct solution of the Schrödinger equationMar 04 2014May 23 2014Pendlebury $\textit{et al.}$ [Phys. Rev. A $\textbf{70}$, 032102 (2004)] were the first to investigate the role of geometric phases in searches for an electric dipole moment (EDM) of elementary particles based on Ramsey-separated oscillatory field magnetic ... More

Geometric phases in electric dipole searches with spin-1/2 particles from spin dependent Schrödinger equationJul 17 2013Jul 20 2015Geometric phases of trapped particles have been recognized as potential sources of false signals in experiments searching for a permanent electric dipole moment of the neutron. We present a new analysis that treats the spin fully quantum mechanically ... More