So I recently heard about Lisi's E8 Theory, but it looks to me as though it violates the Coleman-Mandula no-go theorem. I don't know nearly enough about GUTs to know if this is somehow circumvented, but if this is the case, why are so many people rallying behind it?
Are people rallying behind Lisi's theory? I thought it had been largely dismissed. I recall that Jacques Distler pointed out a major flaw in it though I forget the details.
Nobody takes this stuff seriously, people knew for decades that $E_8$ wouldn't be good enough because it only admits real irreps, $E_6$ is the best one can do to get complex irreps (needed for things like chiral fermions) and people have talked about $E_6$ as a GUT
@bolbteppa photoshopped crowd of women in bikinis is a "strong takedown" of his theory? lol!
@NiharKarve am not going to contradict room owner JRs take on it as "largely dismissed" but you might find the vignette/ profile/ interview in hossenfelders Lost In Math interesting/ amusing, or maybe merely entertaining :) amazon.com/Lost-Math-Beauty-Physics-Astray/dp/0465094252
I had to restrain myself from including that one/sole proviso (from a person with their own charitable perspective on how bad theoretical physics is nowadays) about people taking it seriously haha
are you saying hossenfelder has a "charitable pov on how bad theoretical physics is nowadays"? actually it seems quite uncharitable at times but it seems also that was her intention o_O but personally find the brouhaha of hossenfelder talking facetiously about lisi to be kinda funky... one clown joking about another one? hard to say exactly...
A huge problem with quantizing GR is renormalizability issues, this has happened in the past:
"The non-renormalizability of the V-A theory of weak interactions has led to a long search for renormalizable theories. The problem was not solved by finding a new method to deal with the divergences of the V-A theories. Rather, it was solved by considering the V-A theory as a special limit ($M_w = \infty$) of a unified gauge theory of weak and electromagnetic interactions. The success of this approach was due to the theoretical proof that the gauge theories are renormalizable"
Those experimental proofs took years also, these critics are criticizing physicists who extend modern day theories for doing the exact same thing that was done in the past, like for literally following the same path which has worked before, it really is astounding and should be called out for being pure anti-science especially since the target audience is laymen
It's important to bear in mind that it's the rabid ends of the spectrum that make the most noise and get the most attention. Most physicists are interested in anything that seems to have a chance of working and don't feel the need to shout about it.
huh, this new book by smolin comes up on related list wrt hossenfelder, dont think noticed it previously. looks very cool, gotta get/ read this asap! Einstein's Unfinished Revolution: The Search for What Lies Beyond the Quantumamazon.com/Einsteins-Unfinished-Revolution-Search-Quantum/dp/… just from the title alone, am sure all the copenhagenists will strongly disapprove!
In a gas molecule electronic transitions are always associated with a change in the vibrational and rotational quantum numbers.
So we never see a sharp line, we see a mass of sharp lines corresponding to different changes in the rotational and vibrational quantum numbers.
But these lines are closely spaced, and at all but the lowest pressures these lines are broadened by collisional broadening so the merge into a single broad absorption.
If you Google for uv absorption spectra of ozone you'll find you can just about see the wiggles in the spectrum corresponding to the different vibrational transitions.
@ACuriousMind: The PM that I sent you was just before you dealt with the problematic user. Thanks for that. And yes, since you've done that, thanks for stepping in, and there is no necessity to respond to my PM.
@123 There are also technical reasons we want a potential - you can write down a Lagrangian formulation of electromagnetism with the 4-potential as the dynamical variable but you cannot find a (nice) Lagrangian formulation where the electromagnetic field is the dynamical variable; but even without that it's often more convenient to think in terms of the potential - a single number - instead of the electric field that's a vector.
The potential makes manifest that there are not three independent quantities here.
I'm looking for a specific lab equipment but I don't know the exact English words to describe it so my searches are useless. To give an idea I'm interested into a gyroscope with gimbals and a motor to sustain the spinning over the time.
Does this type of question is accepted in the Physics are of...
how are tauons and tauon-neutrinos produced? I see muons and muon-neutrinos can be produced by the decay of pions. So what kind of particle can decay to produce tauons and tauon-neutrinos?
When we use the word "connection" on a vector bundle in physics are we referring to the matrix of 1-forms that acts on entire frame fields or a single 1-form that acts on individual vector fields?
Just to be sure I've got this right, if I have a vector valued p-form and I partially contract it with $p$ vectors, does the resulting scalar (from the partial contraction) just multiply the components of the resulting vector?
Why does (2) extend the definition of (1) to all real numbers except the non positive integers? By the way, for $\alpha=0$, $\Gamma(-1)$ in (2). Is this defined?
It is easy to see that the Earth’s gravitational acceleration g and the vertical direction k depend upon position. The Earth is approximately a symmetric sphere which exerts its gravitational force as if all its mass were at its centre. Thus, if the value of g at a point on the Earth’s surface is g1, then the value of g at a height of 6,400 km (the Earth’s radius) must be g1/4 approximately.
