Showing papers on "Measure (physics) published in 2014"
TL;DR: In this article, the authors define a quantitative measure of coherent delocalization, and prove that a set of recently introduced functions that characterize coherent superpositions never grow under such processes and thus are indeed valid measures.
Abstract: We define a quantitative measure of coherent delocalization; similarly to the concept of entanglement measures, we require that a measure of coherent delocalization may never increase under processes that do not create coherent superpositions. After a complete characterization of such processes, we prove that a set of recently introduced functions that characterize coherent delocalization never grow under such processes and thus are indeed valid measures.
211 citations
Book•
06 Oct 2014
TL;DR: This paper presents an overview of the modeling of Crowd Dynamics by time-Evolving Measures and generalizations of the Multiscale Approach.
Abstract: 1 An Introduction to the Modeling of Crowd Dynamics.- 2 Problems and Simulations.- 3 Psychological Insights.- 4 An Overview of the Modeling of Crowd Dynamics.- 5 Multiscale Modeling by Time-Evolving Measures.- 6 Basic Theory of Measure-Based Models.- 7 Evolution in Measure Spaces with Wasserstein Distance.- 8 Generalizations of the Multiscale Approach.- 9 Appendices: A Basics of Measure and Probability Theory B Pseudo-Code for the Multiscale Algorithm.
209 citations
TL;DR: An optical probe and single-photon detection is used to study the acoustic emission and absorption processes in a silicon nanomechanical resonator, and a measurement similar to that used by Hanbury Brown and Twiss is performed to measure correlations in the emitted phonons as the resonator undergoes a parametric instability formally equivalent to that of a laser.
Abstract: In optics, the ability to measure individual quanta of light (photons) enables a great many applications, ranging from dynamic imaging within living organisms to secure quantum communication. Pioneering photon counting experiments, such as the intensity interferometry performed by Hanbury Brown and Twiss to measure the angular width of visible stars, have played a critical role in our understanding of the full quantum nature of light. As with matter at the atomic scale, the laws of quantum mechanics also govern the properties of macroscopic mechanical objects, providing fundamental quantum limits to the sensitivity of mechanical sensors and transducers. Current research in cavity optomechanics seeks to use light to explore the quantum properties of mechanical systems ranging in size from kilogram-mass mirrors to nanoscale membranes, as well as to develop technologies for precision sensing and quantum information processing. Here we use an optical probe and single-photon detection to study the acoustic emission and absorption processes in a silicon nanomechanical resonator, and perform a measurement similar to that used by Hanbury Brown and Twiss to measure correlations in the emitted phonons as the resonator undergoes a parametric instability formally equivalent to that of a laser. Owing to the cavity-enhanced coupling of light with mechanical motion, this effective phonon counting technique has a noise equivalent phonon sensitivity of 0.89 ± 0.05. With straightforward improvements to this method, a variety of quantum state engineering tasks using mesoscopic mechanical resonators would be enabled, including the generation and heralding of single-phonon Fock states and the quantum entanglement of remote mechanical elements.
201 citations
133 citations
TL;DR: In this article, the quantum gravity partition function of M-theory on AdS 4 ×X 7 was computed by using localization techniques in four-dimensional gauged supergravity obtained by a consistent truncation on the Sasaki-Einstein manifold X 7.
Abstract: We compute the quantum gravity partition function of M-theory on AdS
4 ×X
7 by using localization techniques in four-dimensional gauged supergravity obtained by a consistent truncation on the Sasaki-Einstein manifold X
7. The supergravity path integral reduces to a finite dimensional integral over two collective coordinates that parametrize the localizing instanton solutions. The renormalized action of the off-shell instanton solutions depends linearly and holomorphically on the “square root” prepotential evaluated at the center of AdS
4. The partition function resembles the Laplace transform of the wave function of a topological string and with an assumption about the measure for the localization integral yields an Airy function in precise agreement with the computation from the boundary ABJM theory on a 3-sphere. Our bulk quantum gravity computation is nonperturbatively exact in four-dimensional Planck length but ignores corrections due to brane-instantons.
90 citations
TL;DR: In this article, a continuous path is modeled by a continuous random polymer interacting with a space-time white noise, and the strength of the interaction is determined by an inverse temperature parameter β, and for a given β and realization of the noise the path is a Markov process.
Abstract: Motivated by discrete directed polymers in one space and one time dimension, we construct a continuum directed random polymer that is modeled by a continuous path interacting with a space-time white noise. The strength of the interaction is determined by an inverse temperature parameter β, and for a given β and realization of the noise the path is a Markov process. The transition probabilities are determined by solutions to the one-dimensional stochastic heat equation. We show that for all β>0 and for almost all realizations of the white noise the path measure has the same Holder continuity and quadratic variation properties as Brownian motion, but that it is actually singular with respect to the standard Wiener measure on C([0,1]).
85 citations
TL;DR: Based on the skew information, a quantity, uncertainty-induced quantum nonlocality (UIN), was proposed in this article to measure the quantum correlation, which can be considered as the updated version of the original measurement-induced non-locality preserving the good computability but eliminating the non-contractivity problem.
82 citations
TL;DR: This work introduces and implements a coherent imaging spectroscopic technique, akin to magnetic resonance imaging, to validate a quantum simulation and uses this method to determine the energy levels and interaction strengths of a fully connected quantum many-body system.
Abstract: Quantum simulators, in which well-controlled quantum systems are used to reproduce the dynamics of less understood ones, have the potential to explore physics inaccessible to modeling with classical computers. However, checking the results of such simulations also becomes classically intractable as system sizes increase. Here, we introduce and implement a coherent imaging spectroscopic technique, akin to magnetic resonance imaging, to validate a quantum simulation. We use this method to determine the energy levels and interaction strengths of a fully connected quantum many-body system. Additionally, we directly measure the critical energy gap near a quantum phase transition. We expect this general technique to become a verification tool for quantum simulators once experiments advance beyond proof-of-principle demonstrations and exceed the resources of conventional computers.
71 citations
TL;DR: In this paper, the notion of path measure is introduced and some notions about path measures which appear naturally when solving the Schrodinger problem are presented and worked out in detail, as well as some definitions of path measures.
Abstract: We call any measure on a path space, a path measure. Some notions about path measures which appear naturally when solving the Schrodinger problem are presented and worked out in detail.
60 citations
TL;DR: In this article, the authors derived the inequalities of Mandelstam-Tamm (MT) and Margolus-Levitin (ML) type of lower bounds on the time it takes for a quantum system to evolve from one state into another.
Abstract: Inequalities of Mandelstam–Tamm (MT) and Margolus–Levitin (ML) type provide lower bounds on the time that it takes for a quantum system to evolve from one state into another. Knowledge of such bounds, called quantum speed limits, is of utmost importance in virtually all areas of physics, where determination of the minimum time required for a quantum process is of interest. Most MT and ML inequalities found in the literature have been derived from growth estimates for the Bures length, which is a statistical distance measure. In this paper we derive such inequalities by differential geometric methods, and we compare the quantum speed limits obtained with those involving the Bures length. We also characterize the Hamiltonians which optimize the evolution time for generic finite-level quantum systems.
47 citations
01 Jan 2014
TL;DR: The paper contains a review of the state of art measures including path based measures, informationbased measures, feature based measures and hybrid measures and the features, performance, advantages, disadvantages and related issues of different measures are discussed.
Abstract: Measuring semantic similarity between concepts is an important problem in web mining and text mining which needs semantic content matching. Semantic similarity has attracted great concern for a long time in artificial intelligence, psychology and cognitive science. Many measures have been proposed. The paper contains a review of the state of art measures including path based measures, information based measures, feature based measures and hybrid measures. The features, performance, advantages, disadvantages and related issues of different measures are discussed. This paper makes a review of semantic similarity measures with various approaches. Index TermSemantic Similarity; Path based measure; depth relative measure; information content based measure; hybrid measure; feature based measure.
TL;DR: In this article, the authors introduce an alternative method based on local quantum uncertainty to measure non-Markovianity for an open quantum system, which is defined by the minimum skew information from a local measurement perspective.
Abstract: We introduce an alternative method based on local quantum uncertainty to measure non-Markovianity for an open quantum system. The local quantum uncertainty proposed by Girolami $et al$. [Phys. Rev. Lett. 110, 240402 (2013)] is defined by the minimum skew information from a local measurement perspective. The measure effectively captures the characteristics of non-Markovianity and has a clearly physical interpretation: in correlated bipartite systems, the non-Markovian (Markovian) process of a considered open subsystem corresponds to the increase (decrease) of quantum uncertainty of local observables of another measured free subsystem. Then the local quantum uncertainty is further discussed by carefully handling the square root of the density operator for the bipartite $2\ensuremath{\bigotimes}d$ systems. Specifically, for a two-qubit system we give an explicit expression of the local quantum uncertainty. Furthermore, by applying the measure to three typical non-Markovian noise channels, we find that the conditions of detecting the non-Markovianity are consistent with the results of existing measures for non-Markovianity, i.e., information backflow and divisibility.
TL;DR: It is concluded that phenomenological models are currently the most accurate and suitable models of predicting the bulk acoustic properties in the whole audible frequency range.
Abstract: Over the past 50 years, the characterisation of porous sound absorbing materials has been of increasing interest to both the acoustic engineers and customers. It is particularly important that acoustic engineers are able to predict the acoustical behaviour of these materials to get a quantitative measure of the acoustic energy absorption. This paper reviews the relevant literatures over this 50-year period and concludes that phenomenological models are currently the most accurate and suitable models of predicting the bulk acoustic properties in the whole audible frequency range. This review also presents the physical parameters which provide the link between the acoustical and material properties, as well as current experimental methods used to measure these parameters. Furthermore, the most common numerical methods for modelling porous materials are described.
TL;DR: The 4D Regge action is invariant under 5?1 and 4?2 Pachner moves, which define a subset of (local) changes of the triangulation as mentioned in this paper.
Abstract: The 4D Regge action is invariant under 5?1 and 4?2 Pachner moves, which define a subset of (local) changes of the triangulation. Given this fact, one might hope to find a local path integral measure that makes the quantum theory invariant under these moves and hence makes the theory partially triangulation invariant. We show that such a local invariant path integral measure does not exist for the 4D linearized Regge theory. To this end we uncover an interesting geometric interpretation for the Hessian of the 4D Regge action. This geometric interpretation will allow us to prove that the determinant of the Hessian of the 4D Regge action does not factorize over four-simplices or subsimplices. It furthermore allows us to determine configurations where this Hessian vanishes, which only appears to be the case in degenerate backgrounds or if one allows for different orientations of the simplices. We suggest a non-local measure factor that absorbs the non-local part of the determinant of the Hessian under 5?1 moves as well as a local measure factor that is preserved for very special configurations.
TL;DR: The authors provided and validated a field survey measure of team mental models (TMMs) on the location of team member expertise, which integrates two important aspects into the expertise of team members.
Abstract: This research provides and validates a field survey measure of team mental models (TMMs) on the location of team member expertise. The measure integrates two important aspects into the expertise lo...
TL;DR: In this article, a negatively charged self-assembled quantum dot was used to measure the temperature of a three dimensional fermionic reservoir down to 100mK. The quantum dot is in tunnel contact with a thermal electron reservoir, a thermal occupation of the quantum dot spin states is enforced by co-tuning processes.
Abstract: Resonant laser spectroscopy of a negatively charged self-assembled quantum dot is utilized to measure the temperature of a three dimensional fermionic reservoir down to 100mK. With a magnetic field applied to the quantum dot the single charged ground state is split by the Zeeman energy. As the quantum dot is in tunnel contact with a thermal electron reservoir, a thermal occupation of the quantum dot spin states is enforced by co-tunneling processes. Resonant laser induced fluorescence is used in order to measure the thermal quantum dot spin state population.
TL;DR: In this paper, the uniform probability measure on a finite interval at a time can be given as a stationary measure of the one-dimensional discrete-time quantum walks by solving the corresponding eigenvalue problem.
Abstract: We obtain the uniform measure as a stationary measure of the one-dimensional discrete-time quantum walks by solving the corresponding eigenvalue problem. As an application, the uniform probability measure on a finite interval at a time can be given.
TL;DR: In this paper, it was shown that the existence of a strongly positive joint quantum measure on a set of experimental probabilities implies the Navascues?Pironio?Acin (NPA) condition and is implied by the stronger NPA condition.
Abstract: We introduce a framework for studying non-locality and contextuality inspired by the path integral formulation of quantum theory. We prove that the existence of a strongly positive joint quantum measure?the quantum analogue of a joint probability measure?on a set of experimental probabilities implies the Navascues?Pironio?Acin (NPA) condition and is implied by the stronger NPA condition . A related condition is shown to be equivalent to .
TL;DR: This three study process demonstrates that the new computer self-efficacy measure has superb psychometric properties and internal reliability, and demonstrates excellent evidence for several aspects of validity.
Abstract: Computer self-efficacy is an often studied construct that has been shown to be related to an array of important individual outcomes. Unfortunately, existing measures of computer self-efficacy suffer from several deficiencies, including criterion contamination, outdated wording, and/or inadequate psychometric properties. For this reason, the current article presents the creation of a new computer self-efficacy measure. In Study 1, an over-representative item list is created and subsequently reduced through exploratory factor analysis to create an initial measure, and the discriminant validity of this initial measure is tested. In Study 2, the unidimensional factor structure of the initial measure is supported through confirmatory factor analysis and further reduced into a final, 12-item measure. In Study 3, the convergent and criterion validity of the 12-item measure is tested. Overall, this three study process demonstrates that the new computer self-efficacy measure has superb psychometric proper...
TL;DR: It is shown that the Sugeno integral and the Choquet integral over an atom of monotone measure is maxitive linear and standard linear, respectively.
TL;DR: The 4D Regge action is invariant under 5-1 and 4-2 Pachner moves, which define a subset of (local) changes of the triangulation as mentioned in this paper.
Abstract: The 4D Regge action is invariant under 5--1 and 4--2 Pachner moves, which define a subset of (local) changes of the triangulation. Given this fact one might hope to find a local path integral measure that makes the quantum theory invariant under these moves and hence makes the theory partially triangulation invariant. We show that such a local invariant path integral measure does not exist for the 4D linearized Regge theory.
To this end we uncover an interesting geometric interpretation for the Hessian of the 4D Regge action. This geometric interpretation will allow us to prove that the determinant of the Hessian of the 4D Regge action does not factorize over 4--simplices or subsimplices. It furthermore allows to determine configurations where this Hessian vanishes, which only appears to be the case in degenerate backgrounds or if one allows for different orientations of the simplices.
We suggest a non--local measure factor that absorbs the non--local part of the determinant of the Hessian under 5--1 moves as well as a local measure factor that is preserved for very special configurations.
TL;DR: Dasti et al. as discussed by the authors developed a multidimensional measure of Islamic spirituality, which includes self-discipline, quest and search for Divinity, anger and expansion, self-aggregation, feeling of connectedness with Allah, meannessGenerosity, tolerance intolerance, and Islamic practices.
Abstract: The aim of the present study was to develop a multidimensional measure of Islamic spirituality. This research was undertaken in Pakistan. Domains of spirituality were operationalized and items were developed, followed by the evaluation of the questionnaire by religious/spiritual scholars and mental health experts. The questionnaire was administered to 813 students. After excluding items with low corrected item to total correlation in each domain (<.30), a Principal Component Analysis with Oblique (Promax) rotation was conducted on 101 items. Eight clear factors were extracted: (1) SelfDiscipline, (2) Quest and Search for Divinity, (3) Anger and Expansive behavior, (4) Self Aggrandizement, (5) Feeling of Connectedness with Allah, (6) MeannessGenerosity, (7) ToleranceIntolerance, and (8) Islamic Practices. Moderate to high internal reliability, good construct, and content validity were found. 48 Rabia Dasti and Aisha Sitwat
Patent•
14 Mar 2014
TL;DR: In this article, a drive motor is used to drive a treadmill, and an electrical current sensor is configured to measure the electrical current utilized by the drive motor to determine the weight of a person positioned on the treadmill.
Abstract: A treadmill may comprise a drive motor positioned and configured to drive a treadbelt, and an electrical current sensor configured to measure the electrical current utilized by the drive motor. The treadmill may also include a computer programmed and configured to analyze the measured electrical current usage by the drive motor to determine the weight of a person positioned on the treadbelt. A person's weight may be determined by driving the treadbelt with the drive motor while a person is positioned on the treadbelt, measuring an electric current utilized by the drive motor, and analyzing the measured electric current to determine the weight of the person positioned on the treadbelt of the treadmill. Additionally, the measured weight may be utilized to calculate calorie expenditure.
18 Jun 2014
TL;DR: Experimental results show that the proposed sensing system is capable of achieving the vision-based leader-follower formation flight without inter-vehicle communication.
Abstract: In this paper, we present a vision-based relative sensing system for UAVs to realize leader-follower formation flight without inter-vehicle communication. A monocular camera is mounted on the follower to detected the leader and measure the relative distance by using the geometry information of the leader without artificial markers. The measured relative distance is utilized to estimate the velocity and acceleration of the leader under the quasi-steady states assumption. Experimental results show that the proposed sensing system is capable of achieving the vision-based leader-follower formation flight.
01 Jan 2014
TL;DR: Although piezoelectric materials are often used as actuators in order to make small precise movements, it can be difficult to measure these displacements in an industrial environment.
Abstract: Although piezoelectric materials are often used as actuators in order to make small precise movements it can be difficult to measure these displacements in an industrial environment [1].
TL;DR: The aim of this paper is to establish fixed point theorems for condensing operators in the Frechet spaces by applying the technique of measures of noncompactness in conjunction with the Tychonoff fixed point theorem.
TL;DR: In this article, the authors introduce an experimentally accessible method to measure a unique degree of nonclassicality, based on the quantum superposition principle, for arbitrary quantum states, and formulate witnesses and test a given state for any particular value of this measure.
Abstract: We introduce an experimentally accessible method to measure a unique degree of nonclassicality, based on the quantum superposition principle, for arbitrary quantum states. We formulate witnesses and test a given state for any particular value of this measure. The construction of optimal tests is presented as well as the general numerical implementation. We apply this approach on examples such as squeezed states, and we show how to formulate conditions to certify a particular degree of nonclassicality for single- and multimode radiation fields.
TL;DR: It is shown that Jensen type inequalities for generalized Sugeno integral are valid for several choices of operators, and classes of functions for which the corresponding inequalities are satisfied are characterized.