Cosmologic philosophy: multiverse/string theory die! (Introduction)

by David Turell , Sunday, September 06, 2015, 14:10 (3366 days ago) @ David Turell
edited by David Turell, Sunday, September 06, 2015, 14:23

Another friendly article on the current state of string theory:-http://www.symmetrymagazine.org/article/august-2015/looking-for-strings-inside-inflation-"Two theorists recently proposed a way to find evidence for an idea famous for being untestable: string theory. It involves looking for particles that were around 14 billion years ago, when a very tiny universe hit a growth spurt that used 15 billion times more energy than a collision in the Large Hadron Collider.-"Scientists can't crank the LHC up that high, not even close. But they could possibly observe evidence of these particles through cosmological studies, with the right technological advances.-***-“'If new particles existed during inflation, they can imprint a signature on the primordial fluctuations, which can be seen through specific patterns,” says theorist Juan Maldacena of the Institute for Advanced Study in Princeton, New Jersey.-"Maldacena and his IAS collaborator, theorist Nima Arkani-Hamed, have used quantum field theory calculations to figure out what these patterns might look like. The pair presented their findings at an annual string theory conference held this year in Bengaluru, India, -***-"As a system of mathematics, string theory makes a tremendous number of predictions. Testable predictions? None so far.-"Strings are thought to be the smallest objects in the universe, and computing their effects on the relatively enormous scales of particle physics experiments is no easy task. String theorists predict that new particles exist, but they cannot compute their masses.-"To exacerbate the problem, string theory can describe a variety of universes that differ by numbers of forces, particles or dimensions. Predictions at accessible energies depend on these unknown or very difficult details. No experiment can definitively prove a theory that offers so many alternative versions of reality.
(wow, how honest!)
-***-"Scientists could find the patterns of particles with greater than spin 2 in subtle variations in the distribution of galaxies or in the cosmic microwave background, according to Maldacena and Arkani-Hamed. Observational cosmologists would have to measure the primordial fluctuations over a wide range of length scales to be able to see these small deviations.-"The IAS theorists calculated what those measurements would theoretically be if these massive, high-spin particles existed. Such a particle would be much more massive than anything scientists could find at the LHC.-***-"The patterns proposed by Maldacena and Arkani-Hamed are much subtler and much more susceptible to interference. So any expectation of experimentally finding such signals is still a long way off.-"But this research could point us toward someday finding such signatures and illuminating our understanding of particles that have perhaps left their mark on the entire universe."