Physics
Predicting the Past vs Predicting the Future
Energy
Thoughts
Weinberg on EFTs
- Dont have to posit that the cannonical formalism is correct.
- Explains why we only consider renormalizible operators, all the others are there, but they are suppressed
- Lepton violation (nu-oscillations) first sign of higher dim operators for SM
- Baryon Number violation the next that should be seen (claim that the matter-antimatter asymmetry => it is likely there)
Frack Wilczek
- Strong Circumstantial evidence for GUTs:
- All gauge forces. Speack similar language
- Couplings appear to unify (esp. with SUSY)
- Matter feilds and Quantum numbers fit into larger multiplets (highly non-trivial)
- Expect nu-masses (seen) / p-decay (Not yet completely excluded) / SUSY
- Big bang makes a preffered coodinate frame
- Large scale structure homogeneous/isotropic in this frame
- This is why we can assign well-defined ages cosmologically
- Interesting take on QM interpretations: "We have the laws, they are deterministic, we just dont know (and fundamentally cant know) the wave function"
- re:Block Universe: The laws of physics arent formulated so thaty naturally describe the entire Space-time manifold all at once. Natural description is of one slice and then how that slice changes forward and backward in time.
- Degrees of freedom are finite whenever you include gravity. (See "no local variables") (Sean Carrol)
- Classical vs Intiutionist Mathematics -) Classical Mathematics: You have block universe: All information at a time slice. (Can be specified infinite past/past/ present of furture) -) Intuitionist Mathematics: Real numbers are a process. Information increases with time. Claim: "All of physics can be done with intuitionist mathematics"
- g-2 discrepancy larger than W/Z contribution
- The greatest scientific discovery was the discovery of ignorance. Once humans realized how little they knew about the world, they suddenly had a very good reason to seek new knowledge, which opened up the scientific road to progress.
- There are some Netrual Mesons live long enoug to transform into thier anti-particles D(uc) K(sd) / B(bd) / BS(bs) Note pi0 is its own anti-paticle. ditto (phi/jpsi/upsilon)
To describe the probability that a particle go from one place to another, you need to square the amplitude. The amplitude is a sum of a whole bunch of contributions, one from every possible path that the particle could have taken to reach the end point.
If some of those paths make a positive contribution and other make a negative contribution, they can interfere destructively and cancel each other out. Meaning the total amplitude will be zero and then the particle will never be found there at all,
Whereas, and here's the even crazier part, if I close off, one of the paths, the famous two-slit, experiment, where there are two slits that this particle could go through. If I block one of the two slits, we'll now I only have a positive contribution or only a negative contribution, depending on which threat I blocked. So now the particle can appear at that end point.
So to say it again, by decreasing the number of paths that a particle can take to get somewhere, I can increase the chance that it gets there. Forget about all the, the low-level details of physics. That could never happen, if the world were described by conventional probability theory. That is the sign that that to actually describe what physics is doing, we need different rules of probability, Which is a much more fundamental thing than you might have imagined the laws of physics even talking about at all. But but they do.