Search results for "LESS"
showing 10 items of 2452 documents
Quantum nonlocality in extended theories of gravity
2020
We investigate how pure-state Einstein-Podolsky-Rosen correlations in the internal degrees of freedom of massive particles are affected by a curved spacetime background described by extended theories of gravity. We consider models for which the corrections to the Einstein-Hilbert action are quadratic in the curvature invariants and we focus on the weak-field limit. We quantify nonlocal quantum correlations by means of the violation of the Clauser-Horne-Shimony-Holt inequality, and show how a curved background suppresses the violation by a leading term due to general relativity and a further contribution due to the corrections to Einstein gravity. Our results can be generalized to massless p…
Infrared singularities of QCD amplitudes with massive partons
2009
A formula for the two-loop infrared singularities of dimensionally regularized QCD scattering amplitudes with an arbitrary number of massive and massless legs is derived. The singularities are obtained from the solution of a renormalization-group equation, and factorization constraints on the relevant anomalous-dimension matrix are analyzed. The simplicity of the structure of the matrix relevant for massless partons does not carry over to the case with massive legs, where starting at two-loop order new color and momentum structures arise, which are not of the color-dipole form. The resulting two-loop three-parton correlations can be expressed in terms of two functions, for which some genera…
Computation of form factors in massless QCD with finite master integrals
2016
We present the bare one-, two-, and three-loop form factors in massless Quantum Chromodynamics as linear combinations of finite master integrals. Using symbolic integration, we compute their $\epsilon$ expansions and thereby reproduce all known results with an independent method. Remarkably, in our finite basis, only integrals with a less-than-maximal number of propagators contribute to the cusp anomalous dimensions. We report on indications of this phenomenon at four loops, including the result for a finite, irreducible, twelve-propagator form factor integral. Together with this article, we provide our automated software setup for the computation of finite master integrals.
Born amplitudes in QCD from scalar diagrams
2005
We review recent developments for the calculation of Born amplitudes in QCD. This includes the computation of gluon helicity amplitudes from MHV vertices and an approach based on scalar propagators and a set of three- and four-valent vertices. The latter easily generalizes to amplitudes with any number of quark pairs. The quarks may be massless or massive.
Fermions and the scattering equations
2014
This paper investigates how tree-level amplitudes with massless quarks, gluons and/or massless scalars transforming under a single copy of the gauge group can be expressed in the context of the scattering equations as a sum over the inequivalent solutions of the scattering equations. In the case where the amplitudes satisfy cyclic invariance, KK- and BCJ-relations the only modification is the generalisation of the permutation invariant function $E(z,p,\varepsilon)$. We present a method to compute the modified $\hat{E}(z,p,\varepsilon)$. The most important examples are tree amplitudes in ${\mathcal N}=4$ SYM and QCD amplitudes with one quark-antiquark pair and an arbitrary number of gluons. …
Correlation patterns from massive phonons in 1+1 dimensional acoustic black holes: A toy model
2018
Transverse excitations in analogue black holes induce a mass like term in the longitudinal mode equation. With a simple toy model we show that correlation functions display a rather rich structure characterized by groups of parallel peaks. For the most part the structure is completely different from that found in the massless case.
A circularly polarized wideband high gain patch antenna for wireless power transfer
2018
This article deals with a microstrip patch antenna working at 868 MHz, suitable for the radio frequency wireless power transfer and energy harvesting applications. The proposed monolithic antenna is compact, lightweight and it is printed on a thick substrate in order to maximize the total gain in the broadside direction. The antenna radiates at 868 MHz with a fractional impedance bandwidth of 5% and it shows a gain of 4.14 dB.
Parathënie
2020
Prefazione al volume "Mirdita në Arkivin e Propagandës Fide në shekujt XVII-XIX" contenente una raccolta di documenti storici - trascritti e tradotti in albanese da Arben Ndreca - sulla regione di Mirdita nell'Albania settentrionale, i cui originali sono conservati presso l'Archivio Storico di Propaganda Fide in Vaticano. Si tratta principalmente di relazioni che i prelati della Chiesa Cattolica in Albania inviavano periodicamente alla Congregazione di Propaganda Fide durante un periodo di oltre tre secoli (prima metà XVII sec. - fine XIX sec.) e che oggi costituiscono una preziosa fonte di dati per la storia di quella regione. Preface to the volume "Mirdita në Arkivin e Propagandës Fide në…
From the theory of “congeneric surd equations” to “Segre's bicomplex numbers”
2015
We will study the historical pathway of the emergence of Tessarines or Bicomplex numbers, from their origin as "imaginary" solutions of irrational equations, to their insertion in the context of study of the algebras of hypercomplex numbers.
The Old English term heoru reconsidered
2004
L’articolo prende in considerazione il lessema anglosassone ‘heoru’ e i suoi numerosi composti, allo scopo di dimostrare come il significato di ‘spada’ ad esso attribuito dalla maggior parte dei dizionari e delle grammatiche sia in realtà non del tutto corretto. Alla luce di un’analisi completa dei passi letterari - in tutto il corpus anglosassone - in cui occorrono tali termini, e sulla base anche di un confronto con le kenning anglosassoni ad essi collegate, si dimostra che nella maggior parte dei casi il termine assume, mediante meccanismi di tipo metonimico, dei valori traslati che andrebbero registrati nei dizionari per una efficace comprensione dei testi in questione.