Search results
Results from the WOW.Com Content Network
Loop quantum gravity (LQG) is a tentative theory of quantum gravity that attempts to unify both general relativity and key quantum mechanics. The areas of research, which involve about 30 research groups worldwide, [1] share the basic physical assumptions and the mathematical description of quantum space. Research has evolved in two directions ...
Loop quantum gravity (LQG) thus became related to topological quantum field theory and group representation theory. In 1994, Rovelli and Smolin showed that the quantum operators of the theory associated to area and volume have a discrete spectrum. [11] Work on the semi-classical limit, the continuum limit, and dynamics was intense after this ...
Loop quantum gravity is the fruit of an effort to formulate a background-independent quantum theory. Topological quantum field theory provided an example of background-independent quantum theory, but with no local degrees of freedom, and only finitely many degrees of freedom globally. This is inadequate to describe gravity in 3+1 dimensions ...
In 1988, Rovelli, Lee Smolin and Abhay Ashtekar introduced a theory of quantum gravity called loop quantum gravity.In 1995, Rovelli and Smolin obtained a basis of states of quantum gravity, labelled by Penrose's spin networks, and using this basis they were able to show that the theory predicts that area and volume are quantized.
In loop quantum gravity (LQG), a spin network represents a "quantum state" of the gravitational field on a 3-dimensional hypersurface. The set of all possible spin networks (or, more accurately, "s-knots" – that is, equivalence classes of spin networks under diffeomorphisms) is countable; it constitutes a basis of LQG Hilbert space.
The idea of the existence of a big bounce in the very early universe has found diverse support in works based on loop quantum gravity. In loop quantum cosmology, a branch of loop quantum gravity, the big bounce was first discovered in February 2006 for isotropic and homogeneous models by Abhay Ashtekar, Tomasz Pawlowski, and Parampreet Singh at ...
The precise understanding of this phase of black-hole evaporation requires a complete theory of quantum gravity. Within what might be termed the loop-quantum-gravity approach to black holes, it is believed that understanding this phase of evaporation is crucial to resolving the information paradox.
He has made contributions to quantum gravity theory, in particular the approach known as loop quantum gravity. He advocates that the two primary approaches to quantum gravity, loop quantum gravity and string theory, can be reconciled as different aspects of the same underlying theory. He also advocates an alternative view on space and time that ...