arXiv subjects

Emanuele Rosi

Publications and source records attributed to Emanuele Rosi.

4 recordsLinked to original sources

arXiv2026

The classical two-loop amplitude at leading logarithmic accuracy for graviton emission in multi-Regge kinematics

Using the gravitational shockwave formalism, we compute the classical part of the $\mathcal{O}(G^{7/2})$ five-point amplitude at leading logarithmic accuracy describing the emission of a graviton in the collision of two massless scalars in multi-Regge kinematics (MRK). The result splits into a two-particle reducible term and a three-particle reducible one, the latter being the radiative counterpart of the $H$-diagram with the emission taken in MRK limit. The same amplitude can be equivalently calculated as the ultrarelativistic limit of the corresponding massive amplitude by applying the optical theorem according to the conjectured universality of the leading logarithmic amplitudes in classical gravity.

hep-th↗

arXiv2026

Gravitational Radiation from Shockwave Scattering in the Self-Force EFT

We investigate the high-energy collision of two spinless bodies within the Self-Force Effective Field Theory (EFT), taking one of them to be massless and highly energetic, such that it generates a gravitational shockwave (GSW) background. The GSW is perturbed by the second body, either massless or massive, satisfying respectively $E_2/E_1\ll1$ or $m_2/E_1\ll1$. Although the Self-Force expansion for shockwaves is frame-dependent, we freely choose a frame in which this EFT manifests its power, obtaining results valid to all orders in Newton's constant that make the underlying resummation patterns evident. Specifically, we push the expansion to 1SF order and prove the all-order vanishing of the so-called recoil operators in light-cone gauge. We obtain the exact graviton propagator on the shockwave background, matching previous results, and use it to compute the on-shell waveform at 1SF order in momentum space, specialising to the massless-massless collision. The waveform is computed to all orders in the Post-Minkowskian, or weak-field, expansion. In the trans-Planckian regime, its resummed form is proved to yield a UV-finite angular spectrum of radiated energy.

gr-qc↗

arXiv2026

Analytic structure of the high-energy gravitational amplitude: multi-H diagrams and classical 5PM logarithms

We investigate the high-energy, small-angle limit of two-body gravitational scattering. Using power counting arguments and dispersion relations in an effective field theory for the Regge regime, we derive the general loop expansion that determines how the leading Regge logarithms and their complex structure arise as a power series in $t/s$. Focusing on the tower of multi-H diagrams that govern the leading logarithmic behavior, we compute the leading double logarithm at four loops (5PM) using both effective field theory methods and the multi-Regge expansion, finding complete agreement. Finally, using the aforementioned dispersion relations, we extract the single logarithmic contribution to the imaginary part of the eikonal phase at 5PM in the Regge limit.

hep-th↗

arXiv2026

Gravitational amplitudes in the Regge limit: waveforms, shock waves and unitarity cuts

Motivated by recent progress in the high-energy description of gravitational scattering, we develop a systematic Regge-theory framework for $2\to2+n$ amplitudes describing the scattering of two massive particles with $n$ graviton emissions, including spin effects. Working in the ultra-relativistic limit at leading logarithmic accuracy, the massive result smoothly reduces to its massless counterpart. We describe both quantum (Regge trajectory and BFKL $t$-channel evolution) and classical ($s$-channel multi-$H$ evolution) contributions using both an exponential representation of the S-matrix and a shock-wave formalism in light-cone quantisation. In the latter approach, gravitational Wilson lines evolve in rapidity space under a boost-invariant Hamiltonian, providing a space-time realisation of the high-energy dynamics and making contact with recent effective field theory descriptions in the forward limit. As an application, we compute the leading-logarithmic contribution to the massive spinless $2\to2$ amplitude at 5PM-2SF order, recovering the previously determined massless result, and derive the tree-level $2\to3$ amplitude and its associated scattering waveform for Kerr black holes in the ultra-relativistic limit.

hep-th↗