From Dr Peter Woit’s 14 June 2015 Not Even Wrong blog:
Last week Princeton hosted what seems to have been a fascinating conference, celebrating the 50th anniversary of studies of the CMB. … The third day of the conference featured a panel where sparks flew on the topics of inflation and the multiverse, including the following:
Neil Turok: “even from the beginning, inflation looked like a kluge to me… I rapidly formed the opinion that these guys were just making it up as they went along… Today inflation is the junk food of theoretical physics… Inflation isn’t radical enough – it’s too much a patchwork. It all rests on rare initial conditions… Akin to solving electron stability with springs… all we have is proof of expansion, not that the driving force is inflation… “because the alternatives are bad you must believe it” isn’t an option that I ascribe to, and one that is prevalent now… we should encourage young to … be creative (not just do designer inflation)
David Spergel: papers on anthropics don’t teach us anything – which is why it isn’t useful…
Slava Mukhanov: inflation is defined as exponential expansion (physics) + non-necessary metaphysics (Boltzmann brains etc) … In most papers on initial conditions on inflation, people dig a hole, jump in, and then don’t succeed in getting out… unfortunately now we have three new indistinguishable inflation models a day – who cares?
Paul Steinhardt: inflation is a compelling story, it’s just not clear it is right… I’d appreciate that astronomers presented results as what they are (scale invariant etc) rather than ‘inflationary’… Everyone on this panel thinks multiverse is a disaster.
Roger Penrose: inflation isn’t falsifiable, it’s falsified… BICEP did a wonderful service by bringing all the Inflation-ists out of their shell, and giving them a black eye.
Marc Davis: astronomers don’t care about what you guys are speculating about …
I was encouraged by Steinhardt’s claim that “Everyone on this panel thinks multiverse is a disaster.” (although I think he wasn’t including moderator Brian Greene). Perhaps as time goes on the fact that “the multiverse did it” is empty as science is becoming more and more obvious to everyone.
Inflation theory, a phase change at the Planck scale that allows the universe to expand for a brief period faster than light, is traditionally defended by:
(a) the need to correct general relativity by reducing the early gravitational curvature, since general relativity by itself predicts too great a density of the early universe to account for the smallness of the ripples in the cosmic background radiation which decoupled from matter when the universe became transparent at 300,000 years after zero time. (The transparency occurs when electrons combine with ions to form neutral molecules, which are relatively transparent to electromagnetic radiation, unlike free charges which are strong absorbers of radiation.)
Thus, inflation is being used here to reduce the effective gravitational field strength by dispersing the ionized matter over a larger volume, which reduces the rate of gravitational clumping to match the small amount of clumping observed at 300,000 years after zero.
Another way of doing the same thing is to a theory of gravitation as being a Casimir force resulting from dark energy, which correctly predicts G from dark energy and makes the gravitational coupling G a linear function of time, so at 300,000 years G is merely 2.3 x 10^{-5} of todays’s value, and furthermore it is even smaller at earlier times (the smallness of the CBR ripples is not determined solely by the curvature when they were emitted, but the time-integrated effect of the curvature up to that time). The standard “no-go theorem” by Edward Teller (1948) used against any variation of G is false, as we have shown, because it makes an implicit assumption that’s wrong: the Teller no-go theorem assumes that G varies with time in one specific way. Teller assumes for the sake of his no-go theorem, that the gravitational coupling varies inversely with time as Dirac assumed, rather than linearly with time as a Casimir mechanism for quantum gravity as an emergent effect of dark energy pushing masses together. He also assumes implicitly that G varies only by itself, without any variation of the Coulomb coupling. Teller thus relies on an assumed imbalance between gravity and Coulomb forces to “disprove” varying G, as well as assuming that any variation of G is inversely with time. All he does is to disprove his own flawed assumptions, not the facts!
These assumptions are all wrong, as we showed. Gravity and Coulomb forces are analogous inverse square law interactions so their couplings will vary the same way; therefore, no devastating Teller-type imbalance between Coulomb repulsion of protons in stars and gravitational compression forces arises. The QG theory works neatly.
(b) Inflation, like string theory, is defended by elitist snobbery of the dictatorial variety: “you must believe this theory because there are no alternatives, we know this to be true because we don’t have any interest in taking alternatives seriously, particularly if they are are not hyped by media personalities or “big science” propaganda budgets, and if anyone suggests one we’ll kill it by groupthink “peer” review. Therefore, like superstring theory, if you want to work at the cutting edge, you’d better work in inflation, or we’ll kill your work.”
That is what it boils down to. There’s an attitude problem, with two kinds of scientists, defined more by attitude than by methodology. One kind wants to find the truth, the other wants to become a star, or, failing that, at least to be a groupie. This corruption is not confined to science, but also occurs in political parties, organized religion, and capitalism. Some people want to make the world a better place, others are more selfish. Ironically, those who are the most corrupt are also the most expert at camouflaging themselves as the opposite, a fact that emerged with the BBC’s star Jimmy Saville. (While endlessly exaggerating correlations between temperature and CO2 and snubbing others, and making money from the taxpayer, they present themselves as moral.)
Quantum field theory 