maho
When the positrons are at the top, they attract negative charges into the top end-cap. This is called an "image charge". When the positrons are close to the bottom end-cap, the image charge into bottom end-cap. This forms a current, the "image current". The more positrons you have, the larger the image current.
Since the image current (on the order of femtoamperes) has to flow through the large resistor, it is turned into a voltage that can be amplified and measured by cryogenic amplifiers. But it has a second effect: The voltage "back-acts" on the positrons, damping their motion. If you have more positrons in the trap, this damping gets stronger, because each positron experiences the back-action of all other positrons.
In the paper, you can see pictures of the driven axial motion, where you take an RF excitation and sweep the frequency over the resonance, recording the positrons' amplitude as a response. The more positrons you have, the "wider" this resonance, because of the damping effect.
As you reduce the number of positrons by doing a "dip" (making the trap really shallow, hoping that some, but not all, positrons escape), you can see the width getting smaller and smaller in discrete steps. That's how you know you are dealing with individual particles.
I haven't worked on Gabrielse's setup, but I have worked on other, very similar (better, ha!) experiments 10 years ago. I don't see what's so special about this trap, but putting antimatter into it always makes for a nice headline.
This is absolutely not cool.
This is a horrible future to consider.
The more I think about it, the more I come to the conclusion that a society that bans ads is a healthier, more robust society, and I am not alone.
Typically, spherical harmonics are introduced as a complex function over spherical coordinates, which makes them much easier to derive, but imo hides their beauty.
The real-valued, cartesian form of regular spherical harmonics is also called "solid harmonics" or "harmonic polynomials", in case you want to dig deeper.
If a doctor even _hints_ there might be cancer, the patient will have a terrible 6 months (with actual, measurable negative health impacts of the added stress). Also, at some uncertainy-level (say, 10% chance of cancer) the doctor _has_ to say something and has to schedule expensive followups to not risk liability, even though in 90% of the cases it is not only unnecessary, but actively harmful to the patients.
When, on average, the cost of the screening + the harm done by a false positive outweighs the benefits of an early detection, you shouldn't do the screening in the first place.
It's a bit more technical. And it has a three-letter acronym. Gotta have a three letter acronym.
For sequence-diagrams, nothing beats https://sequencediagram.org/ (I am not connected with them in any way, just a happy user)
It's mostly broadband noise that can be simulated by simpler methods, but visualizing possible resonance patterns for the low-frequency emissions from the compressor (which typically runs at 20Hz, 40Hz, ..., 120 Hz) would be good to know.
Although I am not sure how the 2d simulation result carries over to the 3d world...
Sadly, it is no longer maintained.
What kind of stack should I use so that tools like Darwin (or just plain old copilot) can be most effective?
It was a race between me placing items on the conveyor belt and them ringing the items up. Oh the embarrassment when they told me the total as I was placing the last item on the conveyor belt.
Or is it because the Penning trap measures "inertial mass" but they really want a measurement of "gravitational mass"? But wouldn't inertial mass fluctuate the same way?
- syntax is really close to PlantUML
- it's rendered in the browser -> immediate feedback
- great autocomplete and syntax-check in the code editor
- great connection between graphic and text (click on element -> jump to relevant line)
- graphical drawing and reordering
- presentation view (fullscreen + keeps actors "sticky" on top)
Especially dragging/dropping actors around is a lot of fun when you try to find the most suitable presentation format for complex diagrams. I'm not aware of any other editor that has this good integration between the code-editor and the visual editor.
It's not open source, but it's been around for free for a long time.
I have some (ancient) experience in RAD. Once per year I try picking up React/Vue/Angular or whatever is the current fashion, but I get stuck. It's just so _insane_.
It allows me to quickly slap a GUI on an existing script that accepts command-line-arguments. In the end, I get the best of both world: Discoverability from the GUI, automation through the script, and automatic feature parity between the two.
Downside: Control over the GUI layout is basic, and only "standard" GUI features work, but I never felt limited when using it.
But boy am I glad that I took the decision to join a "Studentenverbindung" (fraternity) in my university days! Three times per semester we put on suits, sit around a long table, drink beer, and sing nonsensical songs. This has been going on without fail for 140 years -- well, almost without fail, there were gaps during ww1, ww2, and covid. I go to about 1/3 of these events. I meet my old university friends, their families, and a bunch of young students. I expect to continue doing this for many years to come.
I don't mean to be negative of the solution, I am just curious.
http://embomolmed.embopress.org/content/early/2018/04/04/emm...
I have oteosclerosis with accompanying inner-ear damage after stapedectomy or -dotomy, I forgot. I lost 10-20dB on one ear, 20-40dB on the other. I am amazed how much psychoacoustics save the day. Music does feel a little different, but it is no less beatiful to listen to. In some pieces I discovered brass sections I never truly appreciated, but most songs did not change by much. More importantly, my kids and I are still able to sing together as before.
The bothersome bits about hearing loss are having to ask "could you repeat that?" a lot, not hearing quiet sounds (kid's breathing at night, oncoming cars at a distance), and being more sensitive to loud noises. But so far, music stayed beatiful.
ps: If anyone from Netflix is reading this, it would be amazing if I could set a N-second delay for subtitles so that they don't spoil the jokes for me and everyone else. Even better would be if I could view them on my cell phone while we all watch on the big screen. I don't need subtitles all the time, just occasionally, for the bits I didn't understand.
I have never seen a hologram that is also a volumetric display. To me, this would be the holy grail of hologramming, since you could use interference for occlusion effects.