262 citations · 1.4k across the 28 of their papers we have counts for
29 papers
Summing bulk quantum numbers with Monte Carlo in spin foam theories
Pietro Dona, Pietropaolo Frisoni
We introduce a strategy to compute EPRL spin foam amplitudes with many internal faces numerically. We work with sl2cfoam-next, the state-of-the-art framework to numerically evaluat…
Spinfoams and high performance computing
Pietro Dona, Muxin Han, Hongguang Liu
Numerical methods are a powerful tool for doing calculations in spinfoam theory. We review the major frameworks available, their definition, and various applications. We start from…
Geometry from local flatness in Lorentzian spin foam theories
Pietro Dona
Local flatness is a property shared by all the spin foam models. It ensures that the theory's fundamental building blocks are flat by requiring locally trivial parallel transport.…
Radiative corrections to the Lorentzian EPRL spin foam propagator
Pietro Donà, Pietropaolo Frisoni, Edward Wilson-Ewing
We numerically estimate the divergence of several two-vertex diagrams that contribute to the radiative corrections for the Lorentzian EPRL spin foam propagator. We compute the ampl…
How-To compute EPRL spin foam amplitudes
Pietro Dona, Pietropaolo Frisoni
Spin foam theory is a concrete framework for quantum gravity where numerical calculations of transition amplitudes are possible. Recently, the field became very active, but the ent…
A Wick rotation for EPRL spin foam models
Pietro Dona, Francesco Gozzini, Alessandro Nicotra
We show that the Euclidean and Lorentzian EPRL vertex amplitudes of covariant Loop Quantum Gravity are related through a ``Wick rotation'' of the real Immirzi parameter to purely i…
Asymptotics of coherent invariant tensors
Pietro Dona, Marco Fanizza, Pierre Martin-Dussaud +1
We study the semiclassical limit of a class of invariant tensors for infinite-dimensional unitary representations of of the principal series, correspond…
The arrow of time in operational formulations of quantum theory
Andrea Di Biagio, Pietro Donà, Carlo Rovelli
The operational formulations of quantum theory are drastically time oriented. However, to the best of our knowledge, microscopic physics is time-symmetric. We address this tension…
Asymptotics of lowest unitary SL(2,C) invariants on graphs
Pietro Dona, Simone Speziale
We describe a technique to study the asymptotics of SL(2,C) invariant tensors associated to graphs, with unitary irreps and lowest SU(2) spins, and apply it to the Lorentzian EPRL-…
Numerical analysis of spin foam dynamics and the flatness problem
Pietro Dona, Francesco Gozzini, Giorgio Sarno
In this paper, we apply a recently proposed numerical algorithm for finding stationary phase points in spin foam amplitudes. We study a spin foam amplitude with three vertices and…
Searching for classical geometries in spin foam amplitudes: a numerical method
Pietro Dona, Francesco Gozzini, Giorgio Sarno
We develop a numerical method to investigate the semiclassical limit of spin foam amplitudes with many vertices. We test it using the Ponzano-Regge model, a spin foam model for thr…
Typical entanglement entropy in the presence of a center: Page curve and its variance
Eugenio Bianchi, Pietro Dona
In a quantum system in a pure state, a subsystem generally has a nonzero entropy because of entanglement with the rest of the system. Is the average entanglement entropy of pure st…
Numerical study of the Lorentzian Engle-Pereira-Rovelli-Livine spin foam amplitude
Pietro Dona, Marco Fanizza, Giorgio Sarno +1
The Lorentzian EPRL spin foam amplitude for loop quantum gravity is a multi-dimensional non-compact integral of highly oscillating functions. Using a method based on the decomposit…
Entanglement entropy of Bell-network states in LQG: Analytical and numerical results
Eugenio Bianchi, Pietro Dona, Ilya Vilensky
Bell-network states are loop-quantum-gravity states that glue quantum polyhedra with entanglement. We present an algorithm and a code that evaluates the reduced density matrix of a…
Numerical methods for EPRL spin foam transition amplitudes and Lorentzian recoupling theory
Pietro Dona, Giorgio Sarno
The intricated combinatorial structure and the non-compactness of the Lorentz group have always made the computation of EPRL spin foam transition amplitudes a ve…
Infrared divergences in the EPRL-FK Spin Foam model
Pietro Dona
We provide an algorithm to estimate the divergence degree of the Lorentzian EPRL-FK spin foam amplitudes for arbitrary 2-complexes. We focus on the "self-energy" and "vertex renorm…
SU(2) graph invariants, Regge actions and polytopes
Pietro Donà, Marco Fanizza, Giorgio Sarno +1
We revisit the the large spin asymptotics of 15j symbols in terms of cosines of the 4d Euclidean Regge action, as derived by Barrett and collaborators using a saddle point approxim…
Quantum reduced loop gravity: extension to gauge vector field
Jakub Bilski, Emanuele Alesci, Francesco Cianfrani +2
Within the framework of Quantum Reduced Loop Gravity we quantize the Hamiltonian for a gauge vector field. The regularization can be performed using tools analogous to the ones ado…
Non Bunch Davies group coherent states, and their quantum signatures in CMB observables
Pietro Dona, Antonino Marciano
We approach the problem of finding generalized states for matter fields in a de Sitter universe, moving from a group theoretical point of view. This has profound consequences for c…
A note on the semiclassicality of cosmological perturbations
Pietro Dona, Antonino Marciano
Moving from the consideration that matter fields must be treated in terms of their fundamental quantum counterparts, we show straightforward arguments, within the framework of ordi…
Dark Energy and Dark Matter from Yang-Mills Condensate and the Peccei-Quinn mechanism
Andrea Addazi, Pietro Donà, Antonino Marcianò
We analyze a model of cold axion Dark Matter weakly coupled with a dark gluon condensate, reproducing Dark Energy. We first review how to recover the Dark Energy behavior using the…
Asymptotic safety in an interacting system of gravity and scalar matter
Pietro Donà, Astrid Eichhorn, Peter Labus +1
Asymptotic safety is an attractive scenario for the dynamics of quantum spacetime. Here, we work from a phenomenologically motivated point of view and emphasize that a viable dynam…
Non-Perturbative Yang-Mills Condensate as Dark Energy
Pietro Donà, Antonino Marcianò, Yang Zhang +1
Models based on Yang-Mills condensate (YMC) have been advocated in the literature and claimed to be successful candidates to explain dark energy. Several instantiations of this sim…
Scattering amplitudes in super-renormalizable gravity
Pietro Donà, Stefano Giaccari, Leonardo Modesto +2
We explicitly compute the tree-level on-shell four-graviton amplitudes in four, five and six dimensions for local and weakly nonlocal gravitational theories that are quadratic in b…