Francesca Vidotto | |
|---|---|
| Born | November 22, 1980 Treviso, Italy |
| Nationality | Italian |
| Alma mater | University of Padova |
| Known for | Spinfoam Cosmology Planck stars |
| Scientific career | |
| Fields | Loop Quantum Gravity |
Francesca Vidotto (born November 22, 1980) is an Italian theoretical physicist.
She earned her UG/MA in theoretical physics at the University of Padova and the PhD as double-degree at the University of Pavia and the Aix-Marseille Université. Afterwards she was a postdoc researcher at the universities of Grenoble, Nijmegen and Bilbao. [1] She was awarded a Rubicon (2012) and a Veni (2014) fellowship by the Netherlands Organisation for Scientific Research. [2]
Since 2019 she is an Assistant Professor of Physics & Astronomy and Philosophy at the University of Western Ontario, where she holds a Canada Research Chair in Foundations of Physics. She is also a core member of Western's Rotman Institute of Philosophy. [3]
Her research explores the quantum aspects of the gravitational field, in the framework of Loop Quantum Gravity. Her work covers topics from the cosmological and astrophysical applications of quantum gravity to the reflections on the nature of space-time and the foundations of quantum mechanics. She is best known for two research directions: Spin foam Cosmology, and Planck stars, with special emphasis on white holes and black hole remnants.
Vidotto won the first prize (shared with Amanda Gefter) in the 2023 FQXi contest "How could science be different?" for her essay "How Could Science Be Different? Ask a feminist!".
Quantum gravity (QG) is a field of theoretical physics that seeks to describe gravity according to the principles of quantum mechanics. It deals with environments in which neither gravitational nor quantum effects can be ignored, such as in the vicinity of black holes or similar compact astrophysical objects, such as neutron stars as well as in the early stages of the universe moments after the Big Bang.
Cosmogony is any model concerning the origin of the cosmos or the universe.
A gravitational singularity, spacetime singularity or simply singularity is a condition in which gravity is predicted to be so intense that spacetime itself would break down catastrophically. As such, a singularity is by definition no longer part of the regular spacetime and cannot be determined by "where" or "when". Gravitational singularities exist at a junction between general relativity and quantum mechanics; therefore, the properties of the singularity cannot be described without an established theory of quantum gravity. Trying to find a complete and precise definition of singularities in the theory of general relativity, the current best theory of gravity, remains a difficult problem. A singularity in general relativity can be defined by the scalar invariant curvature becoming infinite or, better, by a geodesic being incomplete.
Loop quantum gravity (LQG) is a theory of quantum gravity that incorporates matter of the Standard Model into the framework established for the intrinsic quantum gravity case. It is an attempt to develop a quantum theory of gravity based directly on Albert Einstein's geometric formulation rather than the treatment of gravity as a mysterious mechanism (force). As a theory, LQG postulates that the structure of space and time is composed of finite loops woven into an extremely fine fabric or network. These networks of loops are called spin networks. The evolution of a spin network, or spin foam, has a scale above the order of a Planck length, approximately 10−35 meters, and smaller scales are meaningless. Consequently, not just matter, but space itself, prefers an atomic structure.
Hawking radiation is the theoretical thermal black-body radiation released outside a black hole's event horizon. This is counterintuitive because once ordinary electromagnetic radiation is inside the event horizon, it cannot escape. It is named after the physicist Stephen Hawking, who developed a theoretical argument for its existence in 1974. Hawking radiation is predicted to be extremely faint and is many orders of magnitude below the current best telescopes' detecting ability.
The Big Crunch is a hypothetical scenario for the ultimate fate of the universe, in which the expansion of the universe eventually reverses and the universe recollapses, ultimately causing the cosmic scale factor to reach zero, an event potentially followed by a reformation of the universe starting with another Big Bang. The vast majority of evidence indicates that this hypothesis is not correct. Instead, astronomical observations show that the expansion of the universe is accelerating rather than being slowed by gravity, suggesting that a Big Chill is more likely. However, there are new theories that suggest that a "Big Crunch-style" event could happen by the way of a dark energy fluctuation; however, this is still being debated amongst scientists.
In general relativity, a white hole is a hypothetical region of spacetime and singularity that cannot be entered from the outside, although energy-matter, light and information can escape from it. In this sense, it is the reverse of a black hole, from which energy-matter, light and information cannot escape. White holes appear in the theory of eternal black holes. In addition to a black hole region in the future, such a solution of the Einstein field equations has a white hole region in its past. This region does not exist for black holes that have formed through gravitational collapse, however, nor are there any observed physical processes through which a white hole could be formed.
The Big Bounce hypothesis is a cosmological model for the origin of the known universe. It was originally suggested as a phase of the cyclic model or oscillatory universe interpretation of the Big Bang, where the first cosmological event was the result of the collapse of a previous universe. It receded from serious consideration in the early 1980s after inflation theory emerged as a solution to the horizon problem, which had arisen from advances in observations revealing the large-scale structure of the universe.
Carlo Rovelli is an Italian theoretical physicist and writer who has worked in Italy, the United States, France and, since 2020, in Canada. He is also currently a Distinguished Visiting Research Chair at the Perimeter Institute, core member of the Rotman Institute of Philosophy of Western University in Canada, and Fractal Faculty of the Santa Fe Institute in The United States.
Gravitational collapse is the contraction of an astronomical object due to the influence of its own gravity, which tends to draw matter inward toward the center of gravity. Gravitational collapse is a fundamental mechanism for structure formation in the universe. Over time an initial, relatively smooth distribution of matter, after sufficient accretion, may collapse to form pockets of higher density, such as stars or black holes.
In physics, the topological structure of spinfoam or spin foam consists of two-dimensional faces representing a configuration required by functional integration to obtain a Feynman's path integral description of quantum gravity. These structures are employed in loop quantum gravity as a version of quantum foam.
Micro black holes, also called mini black holes or quantum mechanical black holes, are hypothetical tiny black holes, for which quantum mechanical effects play an important role. The concept that black holes may exist that are smaller than stellar mass was introduced in 1971 by Stephen Hawking.
The history of loop quantum gravity spans more than three decades of intense research.
In black hole physics and inflationary cosmology, the trans-Planckian problem is the problem of the appearance of quantities beyond the Planck scale, which raise doubts on the physical validity of some results in these two areas, since one expects the physical laws to suffer radical modifications beyond the Planck scale.
A dark-energy star is a hypothetical compact astrophysical object, which a minority of physicists think might constitute an alternative explanation for observations of astronomical black hole candidates.
In general relativity, the hole argument is an apparent paradox that much troubled Albert Einstein while developing his famous field equations.
An exotic star is a hypothetical compact star composed of exotic matter, and balanced against gravitational collapse by degeneracy pressure or other quantum properties.
Loop quantum cosmology (LQC) is a finite, symmetry-reduced model of loop quantum gravity (LQG) that predicts a "quantum bridge" between contracting and expanding cosmological branches.
In loop quantum gravity theory, a Planck star is a hypothetical astronomical object, theorized as a compact, exotic star, that exists within a black hole's event horizon, created when the energy density of a collapsing star reaches the Planck energy density. Under these conditions, assuming gravity and spacetime are quantized, a repulsive "force" arises from Heisenberg's uncertainty principle. The accumulation of mass–energy inside the Planck star cannot collapse beyond this limit because it violates the uncertainty principle for spacetime itself.
| International | |
|---|---|
| National | |
| Academics | |
| Other | |
   | This article about an Italian physicist is a stub. You can help Wikipedia by expanding it. |
