Monday, May 11, 2009

Cosmological Dark Energy

Sigh.  Supernova observations leading to the conclusion that the cosmological expansion rate is currently increasing instead of decreasing has lead to models of so-called “dark energy,” sometimes called “quintessence.”

There's a new paper by Dutta, Hsu, Rreb and Scherrer outlining a new dark energy model that has observable results, both in the astronomical-cosmological domain and in the particle-physics, collider domain.

Quoting directly from their paper:

In this paper we present a quintessence scenario in which the dark energy field can be coupled strongly enough to Standard Model particles to be detected in colliders, and which allows for a significant time variation in the equation of state. This time-varying w = w(z) has a characteristic form which depends on only a single parameter, and can thus be excluded by cosmological observations in the near future. Our model only requires a singlet scalar field (or, alternatively, a small gauge sector like SU(3) Yang-Mills theory; other possible realizations are also briefly outlined at the end of the paper) and a new energy scale on the order of milli-electron volts.

Here's my current question:  These symmetry-breaking ideas as an explanation for “dark energy” with a false vacuum and such sound exactly like the same types of models for inflationary cosmology from the 80s.  How does symmetry-breaking as an explanation for “dark energy” fit with symmetry-breaking for inflation?  I guess the answer will be something similar to:  Since this is a new form of energy, it's a different phase transition from the one that's typically associated with the currently known forces and inflation.  Maybe?