Related papers: The first data-driven bounds on the quantum decohe…
The theory of inflation provides a mechanism to explain the structures we observe today in the Universe, starting from quantum-mechanically generated fluctuations. However, this leaves the question of: how did the quantum-to-classical…
Since inflationary perturbations must generically couple to all degrees of freedom present in the early Universe, it is more realistic to view these fluctuations as an open quantum system interacting with an environment. Then, on very…
The decoherence of quantum fluctuations into classical perturbations during inflation is discussed. A simple quantum mechanical argument, using a spatial particle wavefunction rather than a field description, shows that observable…
We study the production, spectrum and detectability of gravitational waves in models of the early Universe where first order phase transitions occur during inflation. We consider all relevant sources. The self-consistency of the scenario…
According to the inflationary scenario for the very early Universe, all inhomogeneities in the Universe are of genuine quantum origin. On the other hand, looking at these inhomogeneities and measuring them, clearly no specific quantum…
The quantum nature of gravity remains an open question in fundamental physics, lacking experimental verification. Gravitational waves (GWs) provide a potential avenue for detecting gravitons, the hypothetical quantum carriers of gravity.…
We examine from first principles one of the basic assumptions of modern quantum theories of structure formation in the early universe, i.e., the conditions upon which fluctuations of a quantum field may transmute into classical stochastic…
Based on optical medium analogy, we establish a formalism to describe the interaction between an electromagnetic (EM) system with gravitational waves (GWs) background. After a full discussion on the classical treatment of the EM-GW…
The reheating of the universe after hybrid inflation proceeds through the nucleation and subsequent collision of large concentrations of energy density in the form of bubble-like structures moving at relativistic speeds. This generates a…
We study the inflationary quantum-to-classical transition for the adiabatic curvature perturbation $\zeta$ due to quantum decoherence, focusing on the role played by squeezed-limit mode couplings. We evolve the quantum state $\Psi$ in the…
We study the effect of quantum decoherence on the inflationary cosmological perturbations. This process might imprint specific observational signatures revealing the quantum nature of the inflationary mechanism being related to the…
Chain inflation proceeds through a series of first order phase transitions, which can release considerable gravitational waves (GW). We demonstrate that bubble collisions can leave an observable signature for future high-frequency probes of…
The reheating of the universe after hybrid inflation proceeds through the nucleation and subsequent collision of large concentrations of energy density in the form of bubble-like structures moving at relativistic speeds. This generates a…
In order to shed light on the quantum-to-classical transition of the primordial perturbations in single field inflation, we investigate the decoherence and associated quantum corrections to the correlation functions of superhorizon scalar…
One of the biggest problems faced by those attempting to combine quantum theory and general relativity is the experimental inaccessibility of the unification scale. In this paper we show how incoherent conformal waves in the gravitational…
The quite different behaviors exhibited by microscopic and macroscopic systems with respect to quantum interferences suggest that there may exist a naturally frontier between quantum and classical worlds. The value of the Planck mass…
Detailed measurements of the cosmic microwave background indicate the large-scale homogeneity of the universe. On very small scales, we observe however inhomogeneities such as galaxies, stars, planets and ourselves. In the context of hot…
In this short note we consider the decoherence of the minisuperspace background degrees of freedom due to the long wavelength scalar and tensor perturbations becoming unobservable within the Born-Oppenheimer approach to the quantum gravity.…
We put the upper bound on the gravitational waves (GWs) induced by the scalar-field fluctuations during the inflation. In particular, we focus on the case where the scalar fluctuations get amplified within some subhorizon scales by some…
We discuss the implications of purely classical, instead of quantum, theory of gravity for the gravitational wave spectrum generated during inflation. We show that a positive detection of primordial gravitational waves will no longer…