Results 31 to 40 of about 2,588,382 (336)
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2015 A brief review is given of why twistor geometry has taken a central place in the theory of scattering amplitudes for fundamental particles. The emphasis is on the twistor diagram formalism as originally proposed by Penrose, the development of which has now led to the definition by Arkani-Hamedet al.of the ‘amplituhedron’.
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Lorentzian LQG vertex amplitude [PDF]
, 2008 We generalize a model recently proposed for Euclidean quantum gravity to the case of Lorentzian signature. The main features of the Euclidean model are preserved in the Lorentzian one.
Pereira, Roberto
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S-duality and helicity amplitudes [PDF]
Journal of High Energy Physics, 2016 We examine interacting Abelian theories at low energies and show that holomorphically normalized photon helicity amplitudes transform into dual amplitudes under SL(2,Z) as modular forms with weights that depend on the number of positive and negative helicity photons and on the number of internal photon lines.
Colwell, Kitran, Terning, John
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Amplitude Control of Single Phase Capacitor Motor [PDF]
Kirkuk Journal of Science, 2010 The method is proposed to study the performance of single-phase capacitor motor with amplitude control. This is clearly shown by controlling the speed of the motor with varying the applied voltage to the control voltage while the excitation voltage is ...
Fatin.N. Barsoum
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Recovery of harmonic signal from discrete samples
Adaptivni Sistemi Avtomatičnogo Upravlinnâ, 2021 The change–over from direct analog methods of measuring signal parameters to digital methods based on the use of analog–to–digital conversion (ADC) and microprocessor devices can be promising in the construction of various sensors.
Т. Бондаренко, I. Зенів
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Probe of process of multiple-loop chains of parallel and consecutive joints [PDF]
E3S Web of Conferences, 2020 The article describes the formation of low-frequency currents in ferromagnetic oscillatory circuits. As a result of parallel and serial connection of multi-loop ferroresonance circuits, the frequencies of harmonics of the second-order amplitude of soft ...
Shаymamоv B. +4 more
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Positive amplitudes in the amplituhedron [PDF]
Journal of High Energy Physics, 2015 The all-loop integrand for scattering amplitudes in planar N = 4 SYM is determined by an "amplitude form" with logarithmic singularities on the boundary of the amplituhedron. In this note we provide strong evidence for a new striking property of the superamplitude, which we conjecture to be true to all loop orders: the amplitude form is positive when ...
Arkani-Hamed, Nima +2 more
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Lectures on celestial amplitudes [PDF]
The European Physical Journal C, 2021 AbstractLecture notes prepared for the 2021 SAGEX PhD School in Amplitudes hosted by the University of Copenhagen August 10th through 13th. Topics covered include: the manifestation of asymptotic symmetries via soft theorems, their organization into currents in a celestial CFT, aspects of the holographic dictionary, a literature guide, and accompanying
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STATISTIC OF SEASONAL AND DIURNAL VARIATIONS OF DOPPLER FREQUENCY SHIFT OF HF SIGNALS AT MID-LATITUDE RADIO PATH [PDF]
Radio Physics and Radio Astronomy, 2020 Purpose: An experimental study of signatures of traveling ionospheric disturbances (TID) observed in diurnal-seasonal variations of the parameters of probe HF signals propagating on theoblique single-hop RWM–LFO radio path, derived from the yearlong ...
A. I. Reznychenko +3 more
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Energy’s and amplitudes’ positivity [PDF]
Journal of High Energy Physics, 2010 In QFT, the null energy condition (NEC) for a classical field configuration is usually associated with that configuration's stability against small perturbations, and with the sub-luminality of these. Here, we exhibit an effective field theory that allows for stable NEC-violating solutions with exactly luminal excitations only.
A. NICOLIS +2 more
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