The post title is taken from the announcement for today's colloquium talk. The abstract:
Quantum gravity is the theory which is thought to underlie quantum theory and general relativity. I will introduce the subject, emphasizing recent results which suggest that spatial geometry is discrete. Such discrete geometry may have an observational signature, especially if it breaks Lorentz invariance. I will describe limits on such discrete geometry effects by astrophysical observations and will also argue that, in the not too distant future, quantum gravity may become physics and enjoy contact with observation and even experiment.
Well, at least there won't be anything controversial there...
(Actually, I suspect I may be the only one on the faculty who is up on the String Theory Wars. We used to have a visitor who was a string theorist, but he left quite a while ago, and none of the permanent faculty do research in cosmology or quantum gravity, so this is unlikely to ruffle that many feathers. Which is probably for the best...)
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Not sure if this was implied, but this is not a string talk, rather it sounds like one of our loopy friends. Also sounds like you'll be treated to the standard Popper as a morality play pep talk, sorry...
Not sure if this was implied, but this is not a string talk, rather it sounds like one of our loopy friends.
Yeah. We don't have any of those on the faculty, either. I don't know that there will be anybody there with a strong prior opinion about the various competing models of quantum gravity.
Moshe: yes, the talk is given by Seth Major of Hamilton College, who did his Ph.D. work with Lee Smolin on q-deformed loop quantum gravity.
Such discrete geometry may have an observational signature, especially if it breaks Lorentz invariance
"Allowed" anomalies must be consistent with prior observation in all venues at all scales. Discrete breaking of Lorentz Invariance is testable. It requires about $100 in consummables, an undergrad to grow opposite parity benzil crystals (J. Appl. Cryst. 4 333 (1971)); two days, two calorimeters.
A parity Eotvos experiment opposing space groups P3(1)21 and P3(2)21 single crystal alpha-quartz solid spheres will do. The experiment runs 90 days and costs ~$(US)250K. Cultured quartz is required for chemical purity and crystal lattice (mass distribution) perfection.
The speaker was apparently unaware of Hinchliffe's rule, which states that if the title of a talk or paper is in the form of a yes/no question, the answer is always no.
(Admittedly there is some dispute, as explained in the paper: "Is Hinchliffe's rule true?")