The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
Jacopo Ghiglieri - One of the best experts on this subject based on the ideXlab platform.
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The Polyakov loop Correlator at NNLO and singlet and octet Correlators
arXiv: High Energy Physics - Phenomenology, 2011Co-Authors: Jacopo GhiglieriAbstract:We present the complete next‐to‐next‐to‐leading‐order calculation of the correlation function of two Polyakov loops for temperatures smaller than the inverse distance between the loops and larger than the Coulomb potential. We discuss the relationship of this Correlator with the singlet and octet potentials which we obtain in an Effective Field Theory framework based on finite‐temperature potential Non‐Relativistic QCD, showing that the Polyakov loop Correlator can be re‐expressed, at the leading order in a multipole expansion, as a sum of singlet and octet contributions. We also revisit the calculation of the expectation value of the Polyakov loop at next‐to‐next‐to‐leading order.
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polyakov loop and Correlator of polyakov loops at next to next to leading order
Physical Review D, 2010Co-Authors: Nora Brambilla, Antonio Vairo, Peter Petreczky, Jacopo GhiglieriAbstract:We study the Polyakov loop and the Correlator of two Polyakov loops at finite temperature in the weak-coupling regime. We calculate the Polyakov loop at order g{sup 4}. The calculation of the Correlator of two Polyakov loops is performed at distances shorter than the inverse of the temperature and for electric screening masses larger than the Coulomb potential. In this regime, it is accurate up to order g{sup 6}. We also evaluate the Polyakov-loop Correlator in an effective field theory framework that takes advantage of the hierarchy of energy scales in the problem and makes explicit the bound-state dynamics. In the effective field theory framework, we show that the Polyakov-loop Correlator is at leading order in the multipole expansion the sum of a color-singlet and a color-octet quark-antiquark Correlator, which are gauge invariant, and compute the corresponding color-singlet and color-octet free energies.
Zarb K Adami - One of the best experts on this subject based on the ideXlab platform.
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implementation of a direct imaging and fx Correlator for the best 2 array
Monthly Notices of the Royal Astronomical Society, 2014Co-Authors: Griffin Foster, Jack Hickish, Alessio Magro, Danny C Price, Zarb K AdamiAbstract:A new digital backend has been developed for the BEST-2 array at Radiotelescopi di Medicina, INAF-IRA, Italy which allows concurrent operation of an FX Correlator, and a direct-imaging Correlator and beamformer. This backend serves as a platform for testing some of the spatial Fourier transform concepts which have been proposed for use in computing correlations on regularly gridded arrays. While spatial Fourier transform-based beamformers have been implemented previously, this is to our knowledge, the first time a direct-imaging Correlator has been deployed on a radio astronomy array. Concurrent observations with the FX and direct-imaging Correlator allows for direct comparison between the two architectures. Additionally, we show the potential of the direct-imaging Correlator for time-domain astronomy, by passing a subset of beams though a pulsar and transient detection pipeline. These results provide a timely verification for spatial Fourier transform-based instruments that are currently in commissioning. These instruments aim to detect highly-redshifted hydrogen from the Epoch of Reionization and/or to perform widefield surveys for time-domain studies of the radio sky. We experimentally show the direct-imaging Correlator architecture to be a viable solution for correlation and beamforming.
Nora Brambilla - One of the best experts on this subject based on the ideXlab platform.
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polyakov loop and Correlator of polyakov loops at next to next to leading order
Physical Review D, 2010Co-Authors: Nora Brambilla, Antonio Vairo, Peter Petreczky, Jacopo GhiglieriAbstract:We study the Polyakov loop and the Correlator of two Polyakov loops at finite temperature in the weak-coupling regime. We calculate the Polyakov loop at order g{sup 4}. The calculation of the Correlator of two Polyakov loops is performed at distances shorter than the inverse of the temperature and for electric screening masses larger than the Coulomb potential. In this regime, it is accurate up to order g{sup 6}. We also evaluate the Polyakov-loop Correlator in an effective field theory framework that takes advantage of the hierarchy of energy scales in the problem and makes explicit the bound-state dynamics. In the effective field theory framework, we show that the Polyakov-loop Correlator is at leading order in the multipole expansion the sum of a color-singlet and a color-octet quark-antiquark Correlator, which are gauge invariant, and compute the corresponding color-singlet and color-octet free energies.
Chiahao Chang - One of the best experts on this subject based on the ideXlab platform.
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amiba wideband analog Correlator
The Astrophysical Journal, 2010Co-Authors: Chaote Li, Derek Kubo, Warwick Wilson, Mingtang Chen, Paul T P Ho, Chungcheng Chen, Peter Oshiro, Pierre Martincocher, Chiahao ChangAbstract:A wideband analog Correlator has been constructed for the Yuan-Tseh Lee Array for Microwave Background Anisotropy. Lag Correlators using analog multipliers provide large bandwidth and moderate frequency resolution. Broadband intermediate frequency distribution, back-end signal processing, and control are described. Operating conditions for optimum sensitivity and linearity are discussed. From observations, a large effective bandwidth of around 10 GHz has been shown to provide sufficient sensitivity for detecting cosmic microwave background variations.
Jungang Miao - One of the best experts on this subject based on the ideXlab platform.
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A 3.5-8 GHz Analog Complex Cross-Correlator for Interferometric Passive Millimeter-Wave Security Imaging Systems
2018 Progress in Electromagnetics Research Symposium (PIERS-Toyama), 2018Co-Authors: Chao Wang, Xiuzhu Ye, Xi Chen, Bingyuan Liang, Zhiping Li, Anyong Hu, Jungang MiaoAbstract:The detection of concealed-weapons and explosives on human body is important for protection against terrorist threats. Due to the low intrusiveness and the ability to pass through clothing and atmospheric occlusions, millimeter wave imaging technique has been gaining interest in security sensing applications. Interferometric imaging technique is well suited for passive millimeter wave security imaging systems since interferometric imaging has the benefits of high imaging rate and large field of view. For interferometric imaging systems, the cross-Correlator is a vital component since it performs cross-correlation measurement of the outputs of the antenna pairs in the imaging system. In this paper, the design, analysis, and implementation of a 3.5-8 GHz analog complex cross-Correlator for interferometric passive millimeter-wave security imaging applications are presented. The Correlator achieves large bandwidth with low cost by using the “add and square” detection scheme which employs zero-bias Schottky diodes and simplified RF network. The bandwidth requirement for the security imaging system is also analyzed. In order to investigate the performance of the Correlator, single-frequency test with different input power levels is applied to the Correlator. The measurement results reveal the input power dependent property of the Correlator. The frequency dependent property of the quadrature error presented in the Correlator is also demonstrated. The proposed Correlator is applied to a Ka-band passive millimeter-wave security imager which consists of 256 receivers, the image of a point source and an actual imaging scenario are produced in order to show the validity and performance of the Correlator. From the single-frequency test and the imaging system test, the Correlator is well suited for interferometric security imaging applications.
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Design and implementation of an analog complex Correlator for passive millimeter wave imaging system
2016 13th International Bhurban Conference on Applied Sciences and Technology (IBCAST), 2016Co-Authors: Muhammad Kashif, Anyong Hu, Jungang MiaoAbstract:In this paper the design of an Analog Complex Correlator has been described. The Correlator is intended to be used with a Passive Millimeter Wave Imaging System. The Correlator performs complex multiplication of the signals received by each antenna pair of the Interferrometric Array to compute the so called Visibility function. Instead of conventional multipliers, the Correlator has been realized using "add and square" detection scheme using power combiners and detectors for reduced complexity and improved dynamic range.
