相关论文: Quantum Primordial Standard Clocks

Making use of the primordially isocurvature fluctuations, which are generated in inflationary models with multiple scalar fields, we make a phenomenological model that predicts formation of primordial black holes which can account for the…

According to the inflationary scenario of cosmology, all structure in the Universe can be traced back to primordial fluctuations during an accelerated (inflationary) phase of the very early Universe. A conceptual problem arises due to the…

After a brief review of the different approaches to predict the possible quantum gravity corrections to quantum field theory, we discuss in some detail the formulation based on a Gaussian reference frame fixing. Then, we implement this…

In the ``natural inflation'' model, the inflaton potential is periodic. We show that Planck scale physics may induce corrections to the inflaton potential, which is also periodic with a greater frequency. Such high frequency corrections…

We present preliminary results on the possible effects that primordial magnetic fields can have for a warm inflation scenario, based on global supersymmetry, with a new-inflation-type potential. This work is motivated by two considerations:…

We characterize good clocks, which are naturally subject to fluctuations, in statistical terms. We also obtain the master equation that governs the evolution of quantum systems according to these clocks and find its general solution. This…

Local operators are the basic observables in quantum field theory which encode the physics observed by a local experimentalist. However, when gravity is dynamical, diffeomorphism symmetries are gauged which apparently obstructs a sensible…

We construct explicit models of multi-field inflation in which the primordial metric fluctuations do not necessarily obey Gaussian statistics. These models are realizations of mechanisms in which non-Gaussianity is first generated by a…

Primordial magnetic fields could explain the large-scale magnetic fields present in the Universe. Inflation and phase transitions in the early Universe could give rise to such fields with unique characteristics. We investigate the…

We study the generation of primordial fluctuations in pure de Sitter inflation where the quantum scalar field dynamics are governed by polymer (not Schrodinger) quantization. This quantization scheme is related to, but distinct from, the…

The microscopic quantum field theory origins of warm inflation dynamics are reviewed. The warm inflation scenario is first described along with its results, predictions and comparison with the standard cold inflation scenario. The basics of…

We consider reheating in a class of asymptotically safe quantum field theories recently studied in \cite{Litim:2014uca, Litim:2015iea}. These theories allow for an inflationary phase in the very early universe. Inflation ends with a period…

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…

Vacuum fluctuations in quantum field theory impose fundamental limitations on our ability to measure time in short scales. To investigate the impact of universal quantum field theory effects on observer-dependent time measurements, we…

A model of inflation is presented where the inflaton field is a complex scalar field coupled to a U(1) gauge field. Due to the axial symmetry of the potential, the inflation is driven by the radial direction while the angular field is…

Inflationary scenarios in string theory often involve a large number of light scalar fields, whose presence can enrich the post-inflationary evolution of primordial fluctuations generated during the inflationary epoch. We provide a simple…

The theory of cosmological fluctuations assumes that the pre-inflationary state of the universe was the quantum vacuum of a scalar field(s) coupled to gravity. The observed cosmic microwave background fluctuations are then interpreted as…

Cosmological perturbations, originating in the quantum fluctuations of the fields that drive inflation, are observed to be nearly scale invariant at the largest scales. At smaller scales, however, perturbations are not severely constrained…

Simple models of single-field inflation in the very early universe can generate the observed amplitude and scale dependence of the primordial density perturbation, but models with multiple fields can provide an equally good fit to current…

It is well-known that first order phase transitions in the early universe can be a powerful source of observable stochastic gravitational wave backgrounds. Any such gravitational wave background must exhibit large-scale anisotropies at…