112 citations · 549 across the 17 of their papers we have counts for
14 papers · 1 filter
Classification of Theories Of Inflation And The Uniqueness of Starobinsky Model
Marco Piva
We classify theories using a mathematical analogy between slow-roll inflation and the renormalization-group flow. We derive the power spectra and spectral indices class by c…
Power Spectra in Double-Field Inflation Using Renormalization-Group Techniques
Bohdan Grzadkowski, Marco Piva
A perturbative strategy for inflation described by two-inflaton fields is developed using a mathematical analogy with the renormalization-group. Two small quantities, and ,…
High-energy behavior of scattering amplitudes in theories with purely virtual particles
Marco Piva
We study a class of renormalizable quantum field theories with purely virtual particles that exhibits nonrenormalizable behavior in the high-energy limit of scattering cross sectio…
Renormalization of Massive Rank-1 Field Theory Nonminimally Coupled to Quantum Gravity
Marco Piva
We consider a self-interacting, massive rank-1 field coupled to quantum gravity. The theory is renormalizable by power counting and contains a massive spin-1 field and a massive sc…
Higher-Derivative Quantum Gravity with Purely Virtual Particles: Renormalizability and Unitarity
Marco Piva
We review the formulation of quantum field theories with purely virtual particles, a new type of degrees of freedom that can mediate interactions without ever appear as external on…
Massive Higher-Spin Multiplets and Asymptotic Freedom in Quantum Gravity
Marco Piva
We consider massive higher-spin multiplets coupled to quantum gravity and compute their contributions to the gravitational beta functions at one loop. Such theories, if quantized w…
Renormalization-group techniques for single-field inflation in primordial cosmology and quantum gravity
Damiano Anselmi, Filippo Fruzza, Marco Piva
We study inflation as a "cosmic" renormalization-group flow. The flow, which encodes the dependence on the background metric, is described by a running coupling , which parametr…
Predictions of quantum gravity in inflationary cosmology: effects of the Weyl-squared term
Damiano Anselmi, Eugenio Bianchi, Marco Piva
We derive the predictions of quantum gravity with fakeons on the amplitudes and spectral indices of the scalar and tensor fluctuations in inflationary cosmology. The action is $R+R…
On The Behavior Of Gravitational Force At Small Scales
Marco Piva
We point out the idea that, at small scales, gravity can be described by the standard degrees of freedom of general relativity, plus a scalar particle and a degree of freedom of a…
Quantum Gravity, Fakeons And Microcausality
Damiano Anselmi, Marco Piva
We investigate the properties of fakeons in quantum gravity at one loop. The theory is described by a graviton multiplet, which contains the fluctuation of the metric, a m…
The Ultraviolet Behavior Of Quantum Gravity
Damiano Anselmi, Marco Piva
A theory of quantum gravity has been recently proposed by means of a novel quantization prescription, which is able to turn the poles of the free propagators that are due to the hi…
Perturbative unitarity of Lee-Wick quantum field theory
Damiano Anselmi, Marco Piva
We study the perturbative unitarity of the Lee-Wick models, formulated as nonanalytically Wick rotated Euclidean theories. The complex energy plane is divided into disconnected reg…
A new formulation of Lee-Wick quantum field theory
Damiano Anselmi, Marco Piva
The Lee-Wick models are higher-derivative theories that are claimed to be unitary thanks to a peculiar cancelation mechanism. In this paper, we provide a new formulation of the mod…
Finite quantum gauge theories
Leonardo Modesto, Marco Piva, Leslaw Rachwal
We explicitly compute the one-loop exact beta function for a nonlocal extension of the standard gauge theory, in particular Yang-Mills and QED. The theory, made of a weakly nonloca…