Related papers: Comment on ``Validity of certain soft-photon ampli…
Vaidman's analysis of the photon's past is based on incorrect interpretation of quantum probability amplitudes. The confusion stems from his original work [{\it Phys. Rev. Lett.} \textbf{60}, 1351 (1988)], which missed the connection…
This is the second one of a series of four papers devoted to a first calculation of the scalar and spinor QED four-photon amplitudes completely off-shell. We use the worldline formalism which provides a gauge-invariant decomposition for…
We present a theoretical analysis of two-photon absorption of classical and squeezed light valid when one-photon absorption to an intermediate state is either resonant or far-detuned from resonance, and in both the low and high intensity…
Applying the technique of partial-wave analysis, there are cases where more than one set of underlying complex-valued amplitudes can describe the measured observables. These ambiguities can sometimes be resolved using additional…
The possibility to constrain the meson distribution amplitude from the transitions of virtual photons to pseudoscalar mesons is investigated. It is shown that for a large range in the two photon virtualities the transition form factors are…
We present analytical results for all six-photon helicity amplitudes. For the computation of this loop induced process two recently developed methods, based on form factor decomposition and on multiple cuts, have been used. We obtain…
We present analytic expressions to evaluate at O(alpha) the effects of soft-photon emission, and the related virtual corrections, in non-leptonic decays of the type B,D -> P1 P2, where P1 and P2 are scalar or pseudoscalar particles. The…
Laboratory (laser and Z-pinch) opacity measurements of well-characterized plasmas provide data to assist inertial confinement fusion, astrophysics and atomic-physics research. In order to test the atomic-physics codes devoted to the…
The infrared singularities of scattering amplitudes have historically contributed to much development in understanding fundamental structures in physics. However, the fate of the leading soft singularities of amplitudes in non-trivial…
We calculate two-photon exchange amplitude for the elastic electron-proton scattering in the framework of dispersion relations. The imaginary part of the amplitude is determined by unitarity. Since in the unitarity relation intermediate…
We apply recently developed path integral resummation methods to perturbative quantum gravity. In particular, we provide supporting evidence that eikonal graviton amplitudes factorize into hard and soft parts, and confirm a recent…
Interpretation and understanding of the evidence for neutrino oscillations depends on knowledge of the atmospheric neutrino beam. In this talk I assess how well various features are known. The goal is to determine to what extent…
The key question of this letter is whether the K-nucleus optical potential is deep, as it is prefered by the phenomenological fits to kaonic atoms data, or shallow, as it comes out from unitary chiral model calculations. The current…
We present a general theory to describe two-photon interference, including a formal description of few photon intereference in terms of single-photon amplitudes. With this formalism, it is possible to describe both frequency entangled and…
The soft photon theorem, in its standard form, requires corrections when the asymptotic particle states carry magnetic charges. These corrections are deduced using electromagnetic duality and the resulting soft formula conjectured to be…
Techniques to deal with Feshbach resonances are applied to describe resonant light scattering off one dimensional photonic crystal slabs. Accurate expressions for scattering amplitudes, free of any fitting parameter, are obtained for…
New formulae for the resonant scattering and the production amplitudes near an inelastic threshold are derived. It is shown that the Flatte formula, frequently used in experimental analyses, is not sufficiently accurate. Its application to…
I point out that the results stated in the recent articles on photon splitting by Wunner, Sang, and Berg and by Wentzel, Berg, \& Wunner directly contradict an earlier analytic and numerical calculation that I performed of the same process…
We apply the recently proposed amplitude reduction at the integrand level method, to the computation of the scattering process 2 photons -> 4 photons, including the case of a massive fermion loop. We also present several improvements of the…
Scattering amplitudes in quantum field theories are of widespread interest, due to a large number of theoretical and phenomenological applications. Much is known about the possible behaviour of amplitudes, that is independent of the details…