David L Wiltshire | |
|---|---|
 Wiltshire in 2024 | |
| Born | 5 May 1962 New Plymouth, New Zealand |
| Alma mater | |
| Awards | Dan Walls Medal (2023) |
| Scientific career | |
| Fields | |
| Institutions | University of Canterbury |
| Doctoral advisor | Gary Gibbons |
David Lauri Wiltshire is a professor of theoretical physics at the University of Canterbury, in Christchurch, New Zealand, where he leads the Gravity and Cosmology Group. [1]
Wiltshire completed undergraduate studies in physics and mathematics and an MSc at the University of Canterbury, Christchurch in 1983. [2] In 1987, Wiltshire completed a PhD in theoretical physics at the University of Cambridge, supervised by Gary Gibbons. [2] [3]
Following his PhD, Wiltshire held postdoctoral positions at the International Centre for Theoretical Physics in Trieste, Italy; the University of Newcastle upon Tyne, UK; and the University of Adelaide, South Australia, where he then began lecturing. In July 2001, he returned to the University of Canterbury to take up an academic position in the Department of Physics and Astronomy. [2]
Wiltshire's research interests include general relativity, cosmology and quantum gravity.
Wiltshire is best known for the timescape cosmology. [4] He reinterprets dark energy as a misidentification of gradients in gravitational energy in an inhomogeneous universe, in which the present epoch cosmic web is dominated by voids. [5] [6] His predictions about average cosmic expansion will be subject to precision tests including observations by the Euclid mission, the Dark Energy Survey, and the Dark Energy Spectroscopic Instrument (DESI).
On 19 December 2024, Wiltshire and colleagues announced [7] the results of a new model-independent statistical analysis of the Pantheon+ Type Ia Supernova catalogue. They found that the timescape model fit the data better than the standard ΛCDM model at 99% confidence level, providing evidence for a foundational change to cosmological models. [8]
In 2023 Wiltshire was awarded the Dan Walls Medal by the New Zealand Institute of Physics. [9]
The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. The notion of an expanding universe was first scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations. The earliest empirical observation of the notion of an expanding universe is known as Hubble's law, published in work by physicist Edwin Hubble in 1929, which discerned that galaxies are moving away from Earth at a rate that accelerates proportionally with distance. Independent of Friedmann's work, and independent of Hubble's observations, physicist Georges Lemaître proposed that the universe emerged from a "primeval atom" in 1931, introducing the modern notion of the Big Bang.
Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fundamental questions about its origin, structure, evolution, and ultimate fate. Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed those physical laws to be understood.
In physical cosmology, cosmic inflation, cosmological inflation, or just inflation, is a theory of exponential expansion of space in the very early universe. Following the inflationary period, the universe continued to expand, but at a slower rate. The re-acceleration of this slowing expansion due to dark energy began after the universe was already over 7.7 billion years old.
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General relativity, also known as the general theory of relativity, and as Einstein's theory of gravity, is the geometric theory of gravitation published by Albert Einstein in 1915 and is the current description of gravitation in modern physics. General relativity generalizes special relativity and refines Newton's law of universal gravitation, providing a unified description of gravity as a geometric property of space and time, or four-dimensional spacetime. In particular, the curvature of spacetime is directly related to the energy and momentum of whatever present matter and radiation. The relation is specified by the Einstein field equations, a system of second-order partial differential equations.
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, as well as in the early stages of the universe moments after the Big Bang.
In cosmology, the cosmological constant, alternatively called Einstein's cosmological constant, is a coefficient that Albert Einstein initially added to his field equations of general relativity. He later removed it; however, much later it was revived to express the energy density of space, or vacuum energy, that arises in quantum mechanics. It is closely associated with the concept of dark energy.
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Paul Joseph Steinhardt is an American theoretical physicist whose principal research is in cosmology and condensed matter physics. He is currently the Albert Einstein Professor in Science at Princeton University, where he is on the faculty of both the Departments of Physics and of Astrophysical Sciences.
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