Abstract: Theories of low-energy Lorentz violation by a fixed-norm “aether” vector field with two-derivative kinetic terms have a globally bounded Hamiltonian and are perturbatively stable only if the vector is timelike and the kinetic term in the action takes the form of a sigma model. ❋ Sean (2008)
One is to try to reinvent string theory a fresh, completely non-perturbatively. ❋ Sean (2007)
That does not mean there is none, only that critical strings are under much better control, especially when considered non-perturbatively. ❋ Sean (2006)
Ruthless and violent and described as “perturbatively unstable” he quickly establishes his reputation. ❋ Sean (2006)
Count Iblis, the point is that if you have a renormalizable theory you can to some degree expect to be able to define it perturbatively, since order by order nothing undefined happens. ❋ Sean (2006)
No, I was simply saying that to my knowledge N = 4 had not been non-perturbatively defined. ❋ Mark (2005)
The question which do and which do not, and whether one can do it perturbatively or not, are very interesting open issues, not a lot is known about them currently. best, ❋ Mark (2005)
It's silly because a lattice formulation is just one among infinitely many ways to define physics of a field theory non-perturbatively. ❋ Unknown (2010)
Marcos Mariňo is going to remodel the topological string, both perturbatively and nonperturbatively. ❋ Unknown (2010)
The second boundary comes from the need, for a well-behaved theory, to be "computable": a too large value of the Higgs mass makes the Higgs coupling "blow up" at large energies, such that the theory loses the property of being perturbatively calculable. ❋ Unknown (2009)
You can see as a function of the logarithm of the energy scale Lambda at which the SM is supposed to be a valid, perturbatively-calculable theory, the range of Higgs masses which make this possible. ❋ Unknown (2009)
At the first pass, one might try to write down string theory in flat space; it’s solvable (at least perturbatively) and valid as long as your not in the vicinity of some black hole or something. ❋ Unknown (2008)
So QCD can’t be perturbatively calculated at arbitrarily soft scales, so nobody knows how to directly calculate from first principles whats happening inside of hadrons. ❋ Unknown (2008)
Clarkson and Mann’s solutions are perturbatively the lowest-energy states in their asymptotic class, meaning that the two may have found what could possibly be the ground state for all solitons of this type. ❋ Edward Willett (2006)
There’s no indication this matters for QED, little for QCD, but maybe it is important for completely understanding the SM, since it is a chiral gauge theory, and we don’t fully understand it non-perturbatively. ❋ Sean (2007)
Just take away from that the fact that there are really wonderful things we’d like to do - such as define a string theory non-perturbatively without reference to strings, and then recover them in perturbative limits (just like we learned from M-Theory!) - and this is what these models do for you. ❋ Cjohnson (2005)
The moral of the story I think that that Peter is right that we should worry about what the final shape of the theory and dynamics are once we’ve allowed for fully non-perturbative physics to take over, but that is not reason to abandon the program altogether because it might not look too much like it does perturbatively. ❋ Sean (2005)
A lattice description is just one possible realization of a field theory among many; for a theory to be non-perturbatively consistent or well-defined, it's in no way necessary to find a lattice description; the existence of a lattice description may improve the "utility" of a theory but not its "validity": in fact, the importance of many field theories is connected exactly with the difficulties with their lattice description (chiral gauge theory will be discussed later) ❋ Unknown (2010)
[It slipped] into the wrong hole and she was not at all [perturbed] by this [perturbation]. ❋ Perturbation (2018)
Kelly and Stepanie were quite perturbed when their pet [camel] would not do as they said, causing Stephanie, an animal lover, [to strike] [the camel] in the thigh. ❋ Emily F (2005)
Your new [haircut] perturbed [me when I] first [saw] it. ❋ This Site's Demand For A Unique Name Is Retarded (2008)
[It slipped] into the wrong hole and she was not at all [perturbed] by this [perturbation]. ❋ Perturbation (2018)
[Bootsy] becomes very [perturbed] when you [poke] him stomach. ❋ Ashley (2003)
mom when you say [i have issues] i get really [pi]...[perturbed] ❋ Courtney D. (2005)
I was perturbating to A Japanese Woman Fries An Egg And Asks You About Your Day the other day and right after I finished I realized how [screwed up] it was.
...Then [I did it] again the next night and came to the same horrible [revelation].
Perturbation is so great. ❋ TheK3vin (2009)
Unsure of when my [French train] would actually [depart], I tried to kill time, but the best I could manage was a [perturbation]. ❋ Monkeyinsurgency (2015)
Tyler: Wassup?!
[Kai]: I'm [perturbed] for the [coming up] test!!!! HEEEEEEEEEELP!!!!!! ❋ Kai S (2019)
Omg did you see that video [with that] [fish] perturbering that [other fish]? ❋ Pluckey (2004)
