DEVELOPPEMENT MATHEMATIQUE ET APPLICATIONS DE LA GRAVITATION QUANTIQUE A BOUCLES. Thesis (PDF Available) · January. Des chercheurs de l’Institut Périmètre travaillent activement sur un certain nombre d’approches de ce problème, dont la gravitation quantique à boucles, les . 19 avr. A quantum theory of gravitation aims at describing the gravitational La gravité quantique à boucles étant toujours une théorie en cours de.

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The expressions for the constraints in Ashtekar variables; the Gauss’s law, the spatial diffeomorphism constraint and the densitized Hamiltonian constraint then read:. Paradigms Classical theories of gravitation Quantum gravity Theory of everything. Alors, on sait pas en fait. There is no experimental evidence to date that graviation string theory’s predictions of supersymmetry and Kaluza—Klein extra dimensions.

Retranscription: la gravité quantique à boucles – Podcast Science

The vanishing of the constraints, giving the physical phase space, are the four other Einstein equations. The background dependence of string theory can have important physical consequences, such as determining the number of quark generations. Using this the physical inner product is formally given by. Several research groups have attempted to combine LQG with other research programs: Parce que le gravitarion noir….


Podcast Science — Etes vous assez paresseux pour devenir riches…. LQG differs from string theory in that it is formulated in 3 and 4 dimensions and without supersymmetry or Kaluza-Klein extra dimensions, while the latter requires both to be true. Noncommutative geometrytwistor theoryentropic gravityasymptotic safety in quantum gravitycausal dynamical triangulationand group field theory.

That is, we construct what mathematicians call knot invariants.

There is the consistent gravitafion approach. These are the defining symmetry transformations of General Relativity since the theory is formulated only in terms of a differentiable manifold.

Loop quantum gravity – Wikipedia

They may help reconcile the spin quantiqus and canonical loop representation approaches. We start with the classical theory. The dynamics of such a theory are thus very different from that of ordinary Yang—Mills theory. Est ce que tu as un avis, David? A holonomy is a measure of how much the initial and final values of a spinor or vector differ after parallel transport around a closed loop; it is denoted.

And so we see that the Poisson bracket of two Gauss’ law is equivalent to a single Gauss’ law evaluated on the commutator of the smearings. English translation in Bohrpp.


The next chapter is about the classical theory, and studies how to discretise gravity in terms of first-order holonomy-flux variables. There were serious difficulties in promoting this quantity to a quantum operator. This result defines an explicit basis of states of quantum geometry, which turned out to be labelled by Roger Penrose ‘s spin networkswhich are graphs labelled by spins.


Thursday, April 19, – 2: The most well-developed applies to cosmology, called loop quantum cosmology LQCthe study of the early universe and the physics of the Big Bang. La nuit, tous les arbres sont-ils gris? To handle the spatial diffeomorphism constraint we need to go over to the loop representation.

We consider Gauss’ law only. The configuration variable gets promoted to a quantum operator via:. We solve, at least approximately, all the quantum constraint equations and for the physical inner product to make physical predictions.

The Chiral Structure of Loop Quantum Gravity

In this gravittation we have a generalized projection operator on the new space of states. The use of Wilson loops explicitly solves the Gauss gauge constraint.

The canonical approach seeks to solve the Wheeler–DeWitt equation and find the physical states of the theory. In general relativity, general covariance is intimately related to “diffeomorphism invariance”.