18,156 research outputs found

    EPR Test with Photons and Kaons: Analogies

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    We present a unified formalism describing EPR test using spin 1/2 particles, photons and kaons. This facilitates the comparison between existing experiments using photons and kaons. It underlines the similarities between birefringence and polarization dependent losses that affects experiments using optical fibers and mixing and decay that are intrinsic to the kaons. We also discuss the limitation these two characteristics impose on the testing of Bell's inequality.Comment: 12 pages, 5 figure

    Observation of Bell Inequality violation in B mesons

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    A pair of B0Bˉ0B^0\bar B^0 mesons from Υ(4S)\Upsilon(4S) decay exhibit EPR type non-local particle-antiparticle (flavor) correlation. It is possible to write down Bell Inequality (in the CHSH form: S2S\le2) to test the non-locality assumption of EPR. Using semileptonic B0B^0 decays of Υ(4S)\Upsilon(4S) at Belle experiment, a clear violation of Bell Inequality in particle-antiparticle correlation is observed: S=2.725+-0.167(stat)+-0.092(syst)Comment: Conference Proceeding for Garda Lake Workshop 2003 "Mysteries, Puzzles and Paradoxes in Quantum Mechanics

    CP Measurement in Quantum Teleportation of Neutral Mesons

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    Quantum teleportation using neutral pseudoscalar mesons shows novel connections between particle physics and quantum information. The projection basis, which is crucial in the teleportation process, is determined by the conservation laws of particle physics, and is different from the Bell basis, as in the usual case. Here we show that one can verify the teleportation process by CP measurement. This method significantly simplifies the high energy quantum teleportation protocol. Especially, it is rigorous, and is independent of whether CP is violated in weak decays. This method can also be applied to general verification of Einstein-Podolsky-Rosen correlations in particle physics.Comment: 7 page

    On predictability of rare events leveraging social media: a machine learning perspective

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    Information extracted from social media streams has been leveraged to forecast the outcome of a large number of real-world events, from political elections to stock market fluctuations. An increasing amount of studies demonstrates how the analysis of social media conversations provides cheap access to the wisdom of the crowd. However, extents and contexts in which such forecasting power can be effectively leveraged are still unverified at least in a systematic way. It is also unclear how social-media-based predictions compare to those based on alternative information sources. To address these issues, here we develop a machine learning framework that leverages social media streams to automatically identify and predict the outcomes of soccer matches. We focus in particular on matches in which at least one of the possible outcomes is deemed as highly unlikely by professional bookmakers. We argue that sport events offer a systematic approach for testing the predictive power of social media, and allow to compare such power against the rigorous baselines set by external sources. Despite such strict baselines, our framework yields above 8% marginal profit when used to inform simple betting strategies. The system is based on real-time sentiment analysis and exploits data collected immediately before the games, allowing for informed bets. We discuss the rationale behind our approach, describe the learning framework, its prediction performance and the return it provides as compared to a set of betting strategies. To test our framework we use both historical Twitter data from the 2014 FIFA World Cup games, and real-time Twitter data collected by monitoring the conversations about all soccer matches of four major European tournaments (FA Premier League, Serie A, La Liga, and Bundesliga), and the 2014 UEFA Champions League, during the period between Oct. 25th 2014 and Nov. 26th 2014.Comment: 10 pages, 10 tables, 8 figure

    Properties of the one-dimensional Hubbard model: cellular dynamical mean-field description

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    The one-dimensional half-filled Hubbard model is considered at zero temperature within the cellular dynamical mean-field theory (CDMFT). By the computation of the spectral gap and the energy density with various cluster and bath sizes we examine the accuracy of the CDMFT in a systematic way, which proves the accurate description of the one-dimensional systems by the CDMFT with small clusters. We also calculate the spectral weights in a full range of the momentum for various interaction strengths. The results do not only account for the spin-charge separation, but they also reproduce all the features of the Bethe ansatz dispersions, implying that the CDMFT provides an excellent description of the spectral properties of low-dimensional interacting systems.Comment: J. Phys.: Condens. Matter, in pres

    Multiplicative random walk Metropolis-Hastings on the real line

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    In this article we propose multiplication based random walk Metropolis Hastings (MH) algorithm on the real line. We call it the random dive MH (RDMH) algorithm. This algorithm, even if simple to apply, was not studied earlier in Markov chain Monte Carlo literature. The associated kernel is shown to have standard properties like irreducibility, aperiodicity and Harris recurrence under some mild assumptions. These ensure basic convergence (ergodicity) of the kernel. Further the kernel is shown to be geometric ergodic for a large class of target densities on R\mathbb{R}. This class even contains realistic target densities for which random walk or Langevin MH are not geometrically ergodic. Three simulation studies are given to demonstrate the mixing property and superiority of RDMH to standard MH algorithms on real line. A share-price return data is also analyzed and the results are compared with those available in the literature

    Bell's inequality tests: from photons to B-mesons

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    We analyse the recent claim that a violation of a Bell's inequality has been observed in the BB--meson system [A. Go, {\em Journal of Modern Optics} {\bf 51} (2004) 991]. The results of this experiment are a convincing proof of quantum entanglement in BB--meson pairs similar to that shown by polarization entangled photon pairs. However, we conclude that the tested inequality is not a genuine Bell's inequality and thus cannot discriminate between quantum mechanics and local realistic approaches.Comment: 5 page

    How Course 2-A is paving the way for interdisciplinary engineering education at MIT

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    Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 38).In 2004, The National Academy of Engineers (NAE) released a report calling for changes to be made to the current engineering education system in response to the growing need for engineering graduates who would be able to understand engineering problems in a larger context. The present study hopes to gain a better understanding of the growth of flexible engineering education by determining differences in student characteristics and their effect on a student's choice of academic program, identifying the perceptions of the MIT community of flexible and traditional engineering programs and how these perceptions changed over time, and establishing whether or not a correlation exists between students' perceived self-efficacy in engineering and professional abilities and his or her career plans. An online survey was developed and administered to the Course 2 and Course 2-A student body. Significant differences in motivation, opinion of Course 2 and Course 2-A, as well as perceived self-efficacy were found between Course 2 and Course 2-A students.by Shanette A. Go.S.B

    Generation of bipartite spin entanglement via spin-independent scattering

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    We consider the bipartite spin entanglement between two identical fermions generated in spin-independent scattering. We show how the spatial degrees of freedom act as ancillas for the creation of entanglement to a degree that depends on the scattering angle, θ\theta. The number of Slater determinants generated in the process is greater than 1, corresponding to genuine quantum correlations between the identical fermions. The maximal entanglement attainable of 1 ebit is reached at θ=π/2\theta=\pi/2. We also analyze a simple θ\theta dependent Bell's inequality, which is violated for π/4<θπ/2\pi/4<\theta\leq\pi/2. This phenomenon is unrelated to the symmetrization postulate but does not appear for unequal particles.Comment: 5 pages and 3 figures. Accepted in PR
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