Tuesday, January 24, 2006

Like Totally Cosmicur

Having created "cosmicur", one should, properly, define it.

cosmicur: (neologism) pertaining to trans-planckian cosmology; beyond cosmic; short-hand for speculation about physical phenomena pre-inflation and exact solutions to quantum gravity at the Planck limit.

Fortunately, as it happens, I was at a Stephon Alexander seminar on exact solutions for Quantum Loop Gravity yesterday afternoon, so I am all inspired.
Talk was good fun and quite interesting, discussing a postulated exact solution of a scalar field using Ashtekar variables, an extension of the Kodama solution. I was not a 100% convinced, but it was an interesting and bold approach and may provide some insight into pre-inflationary physics, and in principle predictions for further CMB measurements.

Here is a lazy pointer to the actual research

Here is the abstract on that particular result:

High Energy Physics - Theory, abstract

From: Stephon Alexander H. [view email]
Date (v1): Wed, 3 Sep 2003 22:03:21 GMT (28kb)
Date (revised v2): Wed, 28 Jul 2004 22:14:15 GMT (28kb)
Quantum Gravity and Inflation

Authors: Stephon Alexander, Justin Malecki, Lee Smolin
Comments: 18 Pages, 2 Figures; major corrections to equations but prior results still hold, updated references
Journal-ref: Phys.Rev. D70 (2004) 044025
Using the Ashtekar-Sen variables of loop quantum gravity, a new class of exact solutions to the equations of quantum cosmology is found for gravity coupled to a scalar field, that corresponds to inflating universes. The scalar field, which has an arbitrary potential, is treated as a time variable, reducing the hamiltonian constraint to a time-dependent Schroedinger equation. When reduced to the homogeneous and isotropic case, this is solved exactly by a set of solutions that extend the Kodama state, taking into account the time dependence of the vacuum energy. Each quantum state corresponds to a classical solution of the Hamiltonian-Jacobi equation. The study of the latter shows evidence for an attractor, suggesting a universality in the phenomena of inflation. Finally, wavepackets can be constructed by superposing solutions with different ratios of kinetic to potential scalar field energy, resolving, at least in this case, the issue of normalizability of the Kodama state.


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