Physicists Test Symmetry Principle With an Antimatter Beam 106
Hugh Pickens DOT Com writes "Jon Butterworth has an interesting article at The Guardian about the idea of standpoint-independence in physics and the absence of 'privileged observers.' The ASACUSA experiment at CERN plans to make a beam of antimatter, and measure the energy levels as the beam travels in a vacuum, away from the magnetic fields and away from any annihilating matter. The purpose of the experiment is to test CPT (Charge/Parity/Time) inversion to determine if the universe would look the same if we simultaneously swapped all matter for antimatter, left for right, and backwards in time for forwards in time. In string theory for example it is possible to violate this principle so the ASACUSA people plan to measure those antihydrogen energy levels very precisely. Any difference would mean a violation of CPT inversion symmetry. Physicist Ofer Lahav has some interesting observations in the article about how difficult it is these days for physicists to develop independent points of view on cosmology. 'Having been surrounded by a culture in which communication is seen as generally a good thing, this came as a surprise to me, but it is a very good point,' writes Butterworth. 'We gain confidence in the correctness of ideas if they are arrived at independently from different points of view.'
A good example is the independent, almost simultaneous development of quantum electrodynamics by Richard Feynman, Julian Schwinger and Sin-Itiro Tomonaga. They all three had very different approaches, and Tomonaga in particular was working in wartime Japan, completely cut off from the others. Yet Freeman Dyson was able to prove that the theories each had provided for the quantum behavior of electrons and photons were not only all equally good at describing nature, but were all mathematically equivalent — that is, the same physics, seen from different points of view. Whether we are using thought experiments, antimatter beams, sophisticated instrumentation, or sending spaceships to the outer solar system, Butterworth says the ability for scientists to loosen the constraints of our own point of view is hugely important. 'It is also, I think, closely related to the ability to put ourselves into the place of other people in society and to perceive ourselves as seen by them — to check our privilege, if you like. Imperfect and difficult, but a leap away from a childish self-centeredness and into adulthood.'"
A good example is the independent, almost simultaneous development of quantum electrodynamics by Richard Feynman, Julian Schwinger and Sin-Itiro Tomonaga. They all three had very different approaches, and Tomonaga in particular was working in wartime Japan, completely cut off from the others. Yet Freeman Dyson was able to prove that the theories each had provided for the quantum behavior of electrons and photons were not only all equally good at describing nature, but were all mathematically equivalent — that is, the same physics, seen from different points of view. Whether we are using thought experiments, antimatter beams, sophisticated instrumentation, or sending spaceships to the outer solar system, Butterworth says the ability for scientists to loosen the constraints of our own point of view is hugely important. 'It is also, I think, closely related to the ability to put ourselves into the place of other people in society and to perceive ourselves as seen by them — to check our privilege, if you like. Imperfect and difficult, but a leap away from a childish self-centeredness and into adulthood.'"
Feynman tutored me in QM at Caltech (Score:5, Interesting)
At first I understood quantum mechanics well enough to get good grades on my problem sets and exams, but I regarded it as delusional because I was heavily into the deterministic Newtonian idea of The Clockwork Universe.
He was able to give me a deep insight into QM without ever once doing a derivation or even simple arithmetic. For the most part it was purely conceptual discussions of the two-slit experiment.
What convinced me of quantum indeterminism in the end was Feynman pointing out that the two-slit also works for electrons, not just photons, and that one can use Shot Noise to determine when individual electrons are leaving the hot wire filament used to produce them.
Even if you send over just one electron at a time, you still get the rippled interference pattern at the detector.
It turns out that an antiparticle going back in time is exactly the same as a regular particle going forward in time. Just by watching an individual particle, or only a few of them, you cannot determine which direction time is going on.
It's only when you have enough particles for their measure of entropy to make sense that you can determine which direction time is going in. Entropy ALWAYS increases with time, so if you watch a system of particles, and their entropy is steadily decreasing, they are going backwards.
I've never heard anyone mention it, but what about smaller systems of particles, where entropy can be measured, but whose entropy fluctuates? Does time go back and forth? I don't know.
"MAYBE THERE'S JUST ONE ELECTRON!" Feynman once shouted.
We don't think that's the case - that just one electron goes from the beginning of the Universe to the end, then returns as a positron - because if there were significant amounts of antimatter in the Universe, we would expect there to be lots of 0.511 MeV gamma rays in the cosmic radiation but there is not.
I am STILL stymied by a question he asked once:
"Why does a mirror reverse left-and-right but not up-and-down?"
Re:Culture Dogma (Score:1, Interesting)
Who the hell modded up this bullshit. Fuck off, please.
There is good reasons to think there was a big bang, it has nothing to do with any ancient cultural ideas about the origin of the world.
Also, your assertions about evolution, geology are also totally bogus:
They are the antithesis of what Genesis says: namely that how the world was created is top-down, whereas science has shown us it is in fact bottom-up.
Please don't project your misunderstanding of basic scientific principles onto the entire science community.
Basically, you'd do well to just shut up about things you know very little about. You sound like a humanities student, frankly, stop embarrassing yourself.
Re:Cambridge Dogma (Score:5, Interesting)
Whoah. Are you even remotely aware of what is being done in cosmology these days?
Planck [esa.int] Sloan Digital Sky Survey [sdss3.org]
Square Kilometer Array [skatelescope.org]
Ice Cube [wisc.edu]
Large Synoptic Survey Telescope [lsst.org]
Euclid [esa.int]
Hardly "ideologically/branding driven pseudoscience". Who the hell modded you up?
Re:Feynman tutored me in QM at Caltech (Score:4, Interesting)
> Does time go back and forth? I don't know.
Or it could be both :-)
The classic fallacy of Scientists is duality. Matter behaving as _both_ a wave AND particle is the best proof that:
One truth does not negate another truth
But to answer your question, Time is multi-dimensional. It depends on which level you are talking about ...
From our human, biological perspective / perception time is linear (male) (to prevent insanity.)
The higher reality is that time flows in all directions (female) (non-linear) BUT one hasn't _experienced_ it all yet.
The Buddhists would say "There is only Now; the past, present and future are all Allusions" and they would partially be correct.
> "MAYBE THERE'S JUST ONE ELECTRON!" Feynman once shouted.
Indeed that is one possibility. That would explain the "Spooky Action From a Distance". It is the _same_ photon, just appearing in different phases at a different time/space.
That's the greatest thing about Feynman. He always kept an open mind. He was never a pseudo-skeptic. If he didn't know, he was motivated to suspend judgement until he knew more.
Modern science has become "Cargo Cult" thinking.
> because if there were significant amounts of antimatter in the Universe, we would expect there to be lots of 0.511 MeV gamma rays in the cosmic radiation but there is not.
First, the problem is we don't _know_ how much antimatter there is. We are making assumptions about 99.99999% of the universe based on less then %0.0000001 of what we can directly measure.
Second, how do you reckon that?
--
The question is not "Does extraterrestrial life exist?" but
"Why the hell do we look so similar??"
News in 2024.
Re:Cambridge Dogma (Score:5, Interesting)
What I found most interesting is what the head researcher found interesting:
In other words: Cambridge (Hawking) Dogma
Ofer Lahav didn't say anything of the sort. What Lahev said was the reason for non-independent viewpoints was "...these days we communicate continuously and too much. Developing independent points of view on cosmology, or indeed other matters, is therefore very difficult." - which has nothing to do with "Cambridge (Hawking) Dogma" (or anybody else's dogma for that matter).
Perhaps you didn't read TFA and simply decided you "knew" what Lahev was referring to just by reading the summary. In other words: you put words in Lahev's mouth to validate your fear of pervasive "ideologically/branding driven pseudo-science". In any case it looks like you have some ax to grind - and given the mods, you're not alone.