You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Good stuff! Do you think the classical lagrangian is unique? Or that it depends on how you take the classical limit?
In non perturbative QFTs there actually exist observables for which we don't have Lagrangians .. Do you mean unique modulo gauge symmetries & conserved global symmetries? Even the Dirac equation gives the same physics depending on if you use +-m
The uniqueness of the lagrangian, wholesale, is what I had in mind! Weinberg and friends made arguments for example about the uniqueness of GR’s lagrangian and that for other fields (conditional of course on the exclusion of things like higher derivatives)
Yea, i think it's a super interesting question. The restriction to being gauge symmetric and Renormalizable + Poincare invariant really restricts what you can write down.
Kinda curious what kind of observable we could find in a non-perturbative QFT that doesn't have a Lagrangian. Maybe something from QCD?
consider the operator e^(-1/φ^2)
i’m a physicist and this is still total gibberish to me 
that's because you study big things that go boom .. we study little things that go boop
"Modulo gauge symmetries" as in symmetries through transformations by some given integer multiple of some, say, n?
No, modulo just means "divided out" in this sense .. really it just means "ignoring"
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.
