Very cool! There's some wild ideas about antimatter capture in space via giant arrays of superconducting magnets trapping naturally occurring antimatter.
Apparently, nanograms / micrograms is enough to create a "antimatter catalyzed" fission/fusion propulsion system with enormous specific impulse / efficacy.
Exciting results. The electron's magnetic moment is probably the most precise standard model prediction, and Gabrielse's group has measured it with 13 digits of accuracy. The positron is predicted to have exactly the same magnetic moment, but this has not been measured since 1987. With the new trap, they should be able to finally match the electron's precision.
I don't get how they know they have exactly one in there. I mean they're measuring the magnetic field but how on earth do you make sufficiently precise measurements to detect a single particle!?!
> In order to determine ωz and the number of trapped
positrons, the axial oscillation of a positron is driven with
oscillating potentials applied to the trap electrodes. The
frequency of the drive ωd is swept through resonance with
ωz.
> For the center-of-mass axial motion of
more than one positron, the damping (and hence the observed signal width) increases in proportion to the number of particles. A confirmation that only one positron
is trapped comes from spin flip observations that are discussed presently
They let it go and listen for the pop? Let it fall from the magnetic containment and you should see a predictable emission as it collides with some normal matter. Detecting single photons is what detectors are all about.
I think this is a fascinating technology. I wonder if it is currently energy positive (so that we can engineer it into a functional source) or at least if it can be extended to be captured in bulk (antimatter rockets!).
Energy positive? That made me laugh. Making antimatter is more energy negative than building a 747 out of gold. They burn through enough power to light a town in order to capture a literal handful of antimater particles.
In a rocket it would not be useful. It has the energy but would emit it as all sorts of highly penetrating radiation rather than hot gas for a rocket nozzle to turn into thrust.
One particle has enough energy to, maybe, if it hit a speck of dust it might result in a perceptible twitch of that speck of dust... if you were watching the spec under a good optical microscope.
I know you’re being facetious but a 747 made out of gold is going to be ~24 billion dollars if you are doing a weight conversion. A 747 by itself is ~$400 million. The entire CERN annual electricity cost is $~25-50M.
No way this experiment had that kind of funding. I would bet the experiment itself had a few million dollars in funding at most + another few for the salaries. Max 10M all in. Probably closer to 2-5M. Expensive but not prohibitive like a 747. But for a single particle.
Scaling up no one really knows because we only do this for single particles and that’s really inefficient. At scale it’s unclear what it could look like.
But electrons/positrons cannot become fuel. Positrons repel each other. So to make any real amount of antimater, beyond counting individual particles, you need anti-protons to keep the positrons happy and containable at scale. Creating the sort of anti-hydrogen one might want to collect as fuel, THAT requires golden 747s of energy.
I could be wrong but my understanding is that’s purely a function of our technological limitations in how we create antimatter, not in the fundamental energy required. Our tech of a particle acceleration is ~1e9 times less efficient than the actual energy required because most of the energy is lost, not converted. A gram would be $~6.2M/gram if we could get to 1% energy conversion efficiency. No one bothers of course to even try because it’s not worth it - expensive, difficult, and huge energy losses. Fusion reactors for space ships will probably come before antimatter gets cracked as a battery source.
In this case they are using 22Na that produces positrons. A quick search says that they cost like $50-$300. (I guess I'm in yet another list now.) I used one in the physic lab a few years ago. They are good enough to get a few blips in a Geiger counter or something similar.
I agree that if someone wants to make enough antiprotons and positrons to make enough antimater to power a rocket, the cost is prohibitive and there is absolutely no hope to make it cost efficient.
Positrons aren’t useful because they annihilate to produce gamma rays, which can’t be contained. However, anti-proton annihilation produces a bunch of particles, including pions, which could be contained in a magnetic bottle and directed for thrust.
Similar work is done at the LHC facility, where they can deliver antimatter to your door. Got a couple of hours? Check out Marco Reps' tour: https://www.youtube.com/watch?v=Yibef6nLCv8
It gets complicated, because protons and anti-protons are composite particles.
To simplify somewhat, one quark from each will annihilate, leaving four quarks and a lot of energy, which re-arrange into mesons (two quarks each), which then decay into photons, electrons, positrons and neutrinos.
Annihilation. At low collision energies the antiproton and proton go through an interaction which ultimately results in photons (light energy). Matter is converted into energy as e = mc^2. Though the interaction passes through a number of exotic intermediate stages first.
As the sibling comments say, it's a single positron so the energy released is tiny. I tried to find positrons sources in common life, the best I could find was https://en.wikipedia.org/wiki/Positron_emission_tomography The relevant paragraph are
> For a typical dose (245 MBq) of FDG, one of the most common radiotracers used for PET neuroimaging and cancer patient management,[48] the effective radiation dose is 4.7 mSv.[49]
and
> This limitation restricts clinical PET primarily to the use of tracers labelled with fluorine-18, which has a half-life of 110 minutes and can be transported a reasonable distance before use.
Where "245 MBq" means 2*10^8 positrons per second for. And "110 minutes" means a half disappears every 2 hours, so the total sum is equivalent to 4 hours but I'm missing some small constant and they ae probably averaging the dose. I guess "3 hours" is a good compromise but multiply it by 2 or 4 if you prefer a smaller or bigger number. Anyway, 3 hours are 10^4 seconds, so the total numbers of positrons in a PET is approximately 2*10^8 * 10^4 = 2*10^12.
And whether it’s a positron or an electron (beta+ or beta- decay) doesn’t seem to matter that much as far as equivalent dose is concerned, the energy deposited is only fractionally higher in the case of a positron. (But PET can only work with positrons because it’s exactly the pairs of 0.511 MeV annihilation gammas that it’s designed to detect!)
In addition to knowing how much stuff is released by one particle, we have a decent handle on how much is needed in order to be dangerous, due to us being constantly bombarded by various cosmic rays. That's how we can say that it's not dangerous.
The article is behind a paywall, but it seems likely that the bigger safety concern is whatever produced the large quantity of particles needed to have a chance of trapping just one. And those kinds of experiments are conducted in regulated facilities for good reason.
The end annihilation was actually the electron switching to backwards through time. At the beginning of the experiment the positron switches back to forward and continues on its way.
whats up with all the comments making analogies with AI torture repository?
One might measure the "amount of computation going on" as a proxy for consciousness, but "number of dissipative logic gates" can't be right since one can construct larger reversible circuits containing the same computation (and hence dissipation is a poor measure), although one could then use the total number of bits (including trash bits) as the measure.
but I don't understand why particle physics?
having all other comments (at the time of writing) be about consciousness of individual particles, seems to indicate these commenters specifically believe particle physics or antimatter to directly describe consciousness?
Or is this some kind of "disinfo inoculation campaign" to render us immune to "sentient rights propaganda"?
Don’t worry! If the single electron theory is correct, then this torture only represents an infinitesimal portion of its total lifetime, which is actually experienced in reverse and so it may feel increasing relief over time rather than increasing anxiety over being trapped.
That's matter cruelty. We need more ethical ways to study those poor things. Does anyone know what happened after the experiment ? Did they finally let it go?
The parents of the anti-matter particle then freeze time just as the containment is about to explode, allowing Picard and Geordi to wander
around the facility looking for clues - until one scientists head slowly turns - they are also awake !!
Apparently, nanograms / micrograms is enough to create a "antimatter catalyzed" fission/fusion propulsion system with enormous specific impulse / efficacy.
PDF: https://www.niac.usra.edu/files/studies/final_report/1071Bic...
https://en.wikipedia.org/wiki/Alpha_Magnetic_Spectrometer
Edit: this is explained pretty extensively in the paper (https://cfp.physics.northwestern.edu/documents/2026OnePositr...). I'm gonna need to do some background reading though...
> In order to determine ωz and the number of trapped positrons, the axial oscillation of a positron is driven with oscillating potentials applied to the trap electrodes. The frequency of the drive ωd is swept through resonance with ωz.
> For the center-of-mass axial motion of more than one positron, the damping (and hence the observed signal width) increases in proportion to the number of particles. A confirmation that only one positron is trapped comes from spin flip observations that are discussed presently
I think this is a fascinating technology. I wonder if it is currently energy positive (so that we can engineer it into a functional source) or at least if it can be extended to be captured in bulk (antimatter rockets!).
In a rocket it would not be useful. It has the energy but would emit it as all sorts of highly penetrating radiation rather than hot gas for a rocket nozzle to turn into thrust.
One particle has enough energy to, maybe, if it hit a speck of dust it might result in a perceptible twitch of that speck of dust... if you were watching the spec under a good optical microscope.
No way this experiment had that kind of funding. I would bet the experiment itself had a few million dollars in funding at most + another few for the salaries. Max 10M all in. Probably closer to 2-5M. Expensive but not prohibitive like a 747. But for a single particle.
Scaling up no one really knows because we only do this for single particles and that’s really inefficient. At scale it’s unclear what it could look like.
I agree that if someone wants to make enough antiprotons and positrons to make enough antimater to power a rocket, the cost is prohibitive and there is absolutely no hope to make it cost efficient.
What would need to be true for the capability of creating and using antimatter to become feasible?
Or cut to the chase at the 'antimatter factory', at https://www.youtube.com/watch?v=Yibef6nLCv8&t=3186s
To simplify somewhat, one quark from each will annihilate, leaving four quarks and a lot of energy, which re-arrange into mesons (two quarks each), which then decay into photons, electrons, positrons and neutrinos.
The link is cherry picked from a very good explanation by Gemini https://www.google.com/search?q=antiproton+hidrogen+colissio...
> For a typical dose (245 MBq) of FDG, one of the most common radiotracers used for PET neuroimaging and cancer patient management,[48] the effective radiation dose is 4.7 mSv.[49]
and
> This limitation restricts clinical PET primarily to the use of tracers labelled with fluorine-18, which has a half-life of 110 minutes and can be transported a reasonable distance before use.
Where "245 MBq" means 2*10^8 positrons per second for. And "110 minutes" means a half disappears every 2 hours, so the total sum is equivalent to 4 hours but I'm missing some small constant and they ae probably averaging the dose. I guess "3 hours" is a good compromise but multiply it by 2 or 4 if you prefer a smaller or bigger number. Anyway, 3 hours are 10^4 seconds, so the total numbers of positrons in a PET is approximately 2*10^8 * 10^4 = 2*10^12.
Good. Reject electrons. Positive vibes only.
The article is behind a paywall, but it seems likely that the bigger safety concern is whatever produced the large quantity of particles needed to have a chance of trapping just one. And those kinds of experiments are conducted in regulated facilities for good reason.
https://en.wikipedia.org/wiki/One-electron_universe
One might measure the "amount of computation going on" as a proxy for consciousness, but "number of dissipative logic gates" can't be right since one can construct larger reversible circuits containing the same computation (and hence dissipation is a poor measure), although one could then use the total number of bits (including trash bits) as the measure.
but I don't understand why particle physics?
having all other comments (at the time of writing) be about consciousness of individual particles, seems to indicate these commenters specifically believe particle physics or antimatter to directly describe consciousness?
Or is this some kind of "disinfo inoculation campaign" to render us immune to "sentient rights propaganda"?
"Wild? I was absolutely livid!"