154 citations · 633 across the 26 of their papers we have counts for
19 papers · 1 filter
Bouncing Unitary Cosmology II: Mini-Superspace Phenomenology
Sean Gryb, Karim P. Y. Thébault
A companion paper provides a proposal for cosmic singularity resolution based upon general features of a bouncing unitary cosmological model in the mini-superspace approximation. T…
Bouncing Unitary Cosmology I: Mini-Superspace General Solution
Sean Gryb, Karim P. Y. Thébault
We offer a new proposal for cosmic singularity resolution based upon a quantum cosmology with a unitary bounce. This proposal is illustrated via a novel quantization of a mini-supe…
Superpositions of the cosmological constant allow for singularity resolution and unitary evolution in quantum cosmology
Sean Gryb, Karim P. Y. Thébault
A novel approach to quantization is shown to allow for superpositions of the cosmological constant in isotropic and homogeneous mini-superspace models. Generic solutions featuring…
-Epistemic Quantum Cosmology?
Peter W. Evans, Sean Gryb, Karim P. Y. Thébault
This paper provides a prospectus for a new way of thinking about the wavefunction of the universe: a -epistemic quantum cosmology. We present a proposal that, if successfully im…
Regarding the `Hole Argument' and the `Problem of Time'
Sean Gryb, Karim P. Y. Thebault
The canonical formalism of general relativity affords a particularly interesting characterisation of the infamous hole argument. It also provides a natural formalism in which to re…
Schrodinger Evolution for the Universe: Reparametrization
Sean Gryb, Karim Thebault
Starting from a generalized Hamilton-Jacobi formalism, we develop a new framework for constructing observables and their evolution in theories invariant under global time reparamet…
Is Spacetime Countable?
Sean Gryb
Is there a number for every bit of spacetime, or is spacetime smooth like the real line? The ultimate fate of a quantum theory of gravity might depend on it. The troublesome infini…
Observing Shape in Spacetime
Sean Gryb
The notion of "reference frame" is a central theoretical construct for interpreting the physical implications of spacetime diffeomorphism invariance in General Relativity. However,…
Time Remains
Sean Gryb, Karim Thebault
On one popular view, the general covariance of gravity implies that change is relational in a strong sense, such that all it is for a physical degree of freedom to change is for it…
Symmetry and Evolution in Quantum Gravity
Sean Gryb, Karim Thebault
We propose an operator constraint equation for the wavefunction of the Universe that admits genuine evolution. While the corresponding classical theory is equivalent to the canonic…
Right about time?
Sean Gryb, Flavio Mercati
Have our fundamental theories got time right? Does size really matter? Or is physics all in the eyes of the beholder? In this essay, we question the origin of time and scale by ree…
2+1 gravity on the conformal sphere
Sean Gryb, Flavio Mercati
We show that there are 2 equivalent first order descriptions of 2+1 gravity with non-zero cosmological constant. One is the well-known spacetime description and the other is in ter…
Shape dynamics and Mach's principles: Gravity from conformal geometrodynamics
Sean Gryb
In this PhD thesis, we develop a new approach to classical gravity starting from Mach's principles and the idea that the local shape of spatial configurations is fundamental. This…
The role of time in relational quantum theories
Sean Gryb, Karim Thebault
We propose a solution to the problem of time for systems with a single global Hamiltonian constraint. Our solution stems from the observation that, for these theories, conventional…
The gravity/CFT correspondence
Henrique Gomes, Sean Gryb, Tim Koslowski +1
General Relativity can be formulated in terms of a spatially Weyl invariant gauge theory called Shape Dynamics. Using this formulation, we establish a "bulk/bulk" duality between g…
Einstein gravity as a 3D conformally invariant theory
Henrique Gomes, Sean Gryb, Tim Koslowski
We give an alternative description of the physical content of general relativity that does not require a Lorentz invariant spacetime. Instead, we find that gravity admits a dual de…
A Definition of Background Independence
Sean B. Gryb
We propose a definition for background (in)/dependence in dynamical theories of the evolution of configurations that have a continuous symmetry and test this definition on particle…
Implementing Mach's Principle Using Gauge Theory
Sean B. Gryb
We reformulate an approach fist given by Barbour and Bertotti (BB) for implementing Mach's principle for nonrelativistic particles. This reformulation can deal with arbitrary symme…
Jacobi's Principle and the Disappearance of Time
Sean B. Gryb
Jacobi's action principle is known to lead to a problem of time. For example, the timelessness of the Wheeler-DeWitt equation can be seen as resulting from using Jacobi's principle…