## Monday, October 23, 2006

### Henry Tye: predictions of brane inflation

Henry Tye has written
full of cosmic predictions of string theory, especially those of the brane inflation, one of the natural realizations of inflation within string theory. The distance between D3-branes and anti-D3-branes - an open string mode - plays the role of the inflaton scalar field. When the branes and antibranes collide, the inflation ends. This relates the inflationary scale with the string scale and is expected to be close to the GUT scale in these models.

Tye explains that the brane inflation is compatible with all existing observations and future, more accurate observations will be able to decide between various more detailed models. He also writes about the production and evolution of cosmic superstrings.

A related comment: Ottawa Citizen offers an article by

Jim Cline, an achieved cosmologist who describes himself as a former traditional skeptic in string theory, uses analogies from the car industry and the free markets (analogies that General Motors Inc. won't necessarily like) to explain that the recent criticism of string theory only underscores its success as a path to a unified description of nature.

Of course, he is not the first one to think about these market analogies. Besides your humble correspondent, this way of looking at things was also used by Prof. Barton Zwiebach who described various market corrections that have appeared in the past.

String theory has become the status quo, Cline explains. The rationally justified expectation that it is the most likely framework to explain the world at a deeper level has already been partially "priced in" - which always happens whenever partial information is available and before a complete evidence is given - and the underdogs will have to offer similarly impressive technical results that a former underdog called string theory did, if they want to attract the interest of researchers. Slandering is not good enough.