*Feynman’s rainbow* Leonard Mlodinow

Warner books 2003

Notes:

In Feynman’s approach, to find the probability of an electrons final state, you need to add contributions from all possible paths. The quantum electron shoots around the universe from present to future to past, from here to everywhere in the universe and back. In following these paths it ignores orthodox rules of motion and acts as if nature had let go of the controls. These possible paths have to be included.

p. 28

He invented path integrals and Feynman diagrams. He presented his method at a conference in 1948 and was roundly attacked by star physicists. Freeman Dyson showed how Feynman’s approach was related to the usual one, and it slowly caught on.

P 29

String theory is also a theory of gravity.

Geoffery chew leader of S-matrix theory, for awhile the hottest thing around, but it did not pan out. Chew kept at it but got nowhere and was forgotten p99

In 1967, Murray Gell-Mann was lecturing on the striking regularities in data pertaining to the collisions of protons and neutrons. An Italian grad student, Gabriele Veneziano, became intriguged, and in a year he found a simple math function that would describe the regularities. The why it worked was presented in 1970 in the work of Leonard Susskind and Yoichiro Nambu. They found that Veneziano’s mathematical function would arise from the underlying theory if you modeled the protons and neutrons not as points, but as tiny vibrating strings. P 99

; a growing number of physicists work in an area of Quantum chromodynamics known as lattice theories, where the equations of q. chromodynamics in an infinite point space-time continuum are rewritten in terms of a finite lattice of points, which are then manipulated by a computer. P. 113

Quantum optics: one of the major issues was to describe how beams of laser light behave when they penetrate a material such as a crystal. P. 142

In 1984, John Schwarz and Michael Green resolved the last major inconsistency in string theory. This did not make the theory any easier to solve, but it convinced many leading physicists- especially Edward Witten- that the theory had too many miraculous properties to ignore. String theory then jumped from laughingstock to hottest thing in physics P. 169