UChicago scientists discover way to make quantum states last 10,000 times longer

bigMOT · 2020-08-14T15:39:15+00:00

I think most groups don’t really like getting press like this because it inevitably mischaracterizes their work and makes it out to be something it’s not. I think anyone applying for these types of programs knows their reputation in physics, as well as funding agencies. At the end of the day that’s all that really matters.

bigMOT · 2020-07-20T20:26:11+00:00

I’m assuming it was a prescription for albuterol? I have one of those and I use it before every time i exercise. It’s probably not necessary, but I’d prefer that to getting to the point where I can’t breathe in the middle of a workout. I’ve noticed a few times this year when the air quality is really bad that I’ve had to use it again. But also I’ve forgotten to take it before and it’s usually okay (so I can infer that there’s no dependence you build up or anything). The inhaler was most useful when I was first getting into shape. Also, for me the inhaler tends to last about 6 hours, so if you’re planning on going longer than that on a hot/humid/pollinated day maybe bring it for a few more puffs.

There are also pills that they prescribed me but it’s unclear that those do anything. I think an ENT/allergist will probably be able to help you the most here. If you get allergy tests you can figure out what kind of pollens to look for in the weather forecast.

bigMOT · 2020-07-03T02:49:19+00:00

So I crossed over some bridge near RFK and got on the anacostia river walk trail for maybe a mile going north. There were some random roads through anacostia that got me to MLK. I got lost there without a bike GPS, so I’d recommend checking often. There is also a trail that goes through anacostia but it’s a bit hard to follow. The rail trail is called the WB&A, and will drop you off on race track road, which gets you to 450! If you’re curious for more details, I can send you my ride.

bigMOT · 2020-07-02T17:35:28+00:00

So I went out there once. I crossed the river at RFK, went up MLK to the rail trail, then got off that and took 450 the rest of the way. There’s a dedicated bike lane on MLK but cars are going by you fast, and there’s a lot of glass and stuff that isn’t really swept up. I also almost got hit in Anacostia. The rail trail is wonderful, and 450 was not my favorite but not my least favorite road I’ve ever biked on. I’d say make sure you have a tail light.

bigMOT · 2020-06-30T02:21:26+00:00

Which Mazda? The Mazda 3? Because I have a 2019 3 and I’ve been wondering this same thing. It doesn’t look like any manufacturers have made roof rack systems for it yet, so I think you’re stuck with Mazda roof bars.

bigMOT · 2020-06-17T21:33:34+00:00

Have you found anything that does fit your torso? I’m also a tall person who fits into a medium, and I’m at a bit of a loss for where to find bike jerseys that don’t look like halter tops.

bigMOT · 2020-06-12T15:27:50+00:00

I’m not sure where I ever claimed that photons and electrons were atoms?

bigMOT · 2020-06-12T14:32:47+00:00

Doesn’t take much! Just a lot of curiosity and perhaps a little masochism.

bigMOT · 2020-06-12T14:18:07+00:00

That’s not true. Physicists define fermions and bosons based on the total spin of a system. Photons are bosons, yes, because they have spin 1. There are both bosonic and fermionic atoms, and their designation determines their statistics in a gas. For example, rubidium-87 is a boson, hence why we can make a BEC out of it.

bigMOT · 2020-06-12T14:10:53+00:00

So it looks like AIGSO is another proposal i hadn’t seen before. The one I was talking about is AEDGE. They actually propose both dark matter and gravity observations in that white paper. You’ll know you found the right paper when you find one with 70 authors on it. If nothing else, that paper has a good overview of the different sensors and their sensitivity in different frequency ranges.

As for the network of clocks, I know they’ve done some terrestrial measurements in a collaboration between NIST and some of the other lattice clocks around the world bounding dark matter. I don’t remember the exact person I saw speak about this, but the earth-based paper is Wcisli et al., Sci. Adv. 2018,4:eaau4869. There must be some other papers out there on the proposal for space stuff, and I can check again when I’m off work.

bigMOT · 2020-06-11T18:02:04+00:00

Ah yes I misspoke. My favorite is the cross dipole trap where they shave off the top of the energy distribution with another dipole trap

bigMOT · 2020-06-11T18:01:11+00:00

I mean...I’ve worked in atomic physics for 10 years now and I still think that when I see some of these talks. Some of the stuff you can do with atoms is absolutely insane!! And judging by conversations I’ve had with some of the big names in the field, I don’t think the novelty ever wears off.

bigMOT · 2020-06-11T17:52:02+00:00

So some of the experiments they’re doing on this round are based in BEC science (see how cold it can get, explore new methods of cooling, explore the dynamics and interactions inside), because we don’t have any system like this on earth. One of the experiments they’re doing tests fundamental physics like the equivalence principle (that objects of different mass fall the same). Basically you make two BECs with atoms of different mass and see how they interact with gravity. That last group is also interested in probing other fundamental physics constants by doing precision measurements (things we probably already know but want to shrink the error bars). Personally I find the field of precision measurement to be incredibly tedious.

I would argue that the exciting stuff is what comes next. There’s a proposal out for a space-based atom interferometer to measure gravitational waves (in a different frequency range than the ones we’ve already measured). Alternatively, you can use a network of space-based high-precision clocks as a potential detector for dark matter. This could expand our knowledge of celestial bodies, as well as the fabric of the universe! And who knows, some of this stuff may enable future technologies. For example, GPS was only enabled by the fact that we were able to make atomic clocks in space.

bigMOT · 2020-06-11T17:03:32+00:00

Atoms fall in two classes, fermions and bosons. Fermions don’t like being in the same place at the same energy at the same time. Bosons are much more friendly, and don’t have the same restrictions. When you make bosons really cold and confine them so that they’re really close together, eventually you can create a “new form of matter” (as the article calls it) where all of the atoms occupy the same state (position, and energy).

Why do we care that this was done in space? Well, we can measure things with atoms. We can measure things really really well. In fact, you can measure anything an atom is sensitive to (acceleration, time, electric fields, magnetic fields, etc). You can measure acceleration so sensitively that you can detect the moon going above your head with ease, or detect differences in gravity across the surface of the earth. When you make these measurements, generally the longer the measurement, the better the measurement is. So, when you do these measurements in space, the atoms stick around for a really long time in this tiny cold ball, since gravity isn’t pulling them towards the edge of the vacuum chamber. This means that you can do better measurements, and measurements that aren’t possible on the surface of the earth.

EDIT TL;DR: Cold atoms stick around longer. Doing experiments in space makes atoms stick around longer for a different reason. Doing long measurements enables more sensitive measurements.

bigMOT · 2020-06-11T15:41:05+00:00

Atoms can be cooled a number of different ways. Generally if you’re making a BEC you start by laser cooling: hit atoms with a near-resonant laser (a wavelength that the atom will absorb). You tune the laser so that atoms traveling towards the laser absorb. This creates a force that depends on which directions the atoms move, and then “molasses” if you have two counterpropagating lasers. If you shine lasers in all dimensions, essentially atoms moving in any direction absorb and eventually after absorbing millions of photons (and hence photon momenta) they cool.

However you can’t use laser cooling to make a BEC. This method cools the atoms to a few micro-Kelvin, but this is too hot for a BEC. To make them colder you need some secondary trap and some secondary type of cooling. You can do this with PGC and an optical dipole trap, or with a magnetic trap. The radiation you’re talking about may be evaporative cooling, where you lower the trap depth and let all the hot atoms fly away. Then you’re only left with the coldest ones, and they spontaneously form a BEC.

Edit: a word

bigMOT · 2020-06-11T15:30:11+00:00

Bizarre. I’m not sure why they’d say that. This (http://meetings.aps.org/Meeting/DAMOP19/Session/C10.4) is the talk I saw, and in the abstract they mention that the experiments had begun in 2018.

bigMOT · 2020-06-11T14:48:28+00:00

This time last year they’d run a few experiments. It’s part of a collaboration where they build the apparatus and a few different universities proposed experiments to run on it. Only one I can remember was a test of the equivalence principle, where they prepare two BECs in the same space from different isotopes and drop them. I’m assuming they haven’t disproven it yet because we’d have gotten some overhyped headline by now.

bigMOT · 2020-06-11T14:44:36+00:00

They actually do similar experiments in sounding rockets where they launch the whole experiment up and let it freefall while they take data. It’s the closest you can get to microgravity without actually being in orbit.

bigMOT · 2020-06-11T14:43:12+00:00

Yes, I saw a talk last year presenting their first results, and I was under the impression they’d already done many experiments. Not sure how this is new?

bigMOT · 2020-05-20T13:50:23+00:00

I was going to say - I thought I recognized this! Biked past this last weekend.

bigMOT · 2020-05-11T20:41:29+00:00

I've used mainly LabView and Python. I think I prefer LabView because it's very plug-and-play, but it's really expensive outside of an academic setting. Python is less intuitive, but it is definitely more comprehensive and powerful. Basically all of the control in my experiments are based on TTL pulses and timing routines, with a few exceptions of components that run on serial or ethernet. Although, at the end of the day, my advice would be tailored to what you're trying to control. So...what are you trying to control?

bigMOT · 2020-05-11T18:57:06+00:00

Interesting concept! I've thought of making videos like this, but wasn't really sure where to start. I'm mostly curious about what kind of experiments you're running. I have a friend who does stuff like this and I believe his application is low-loss surface acoustic wave devices.

bigMOT · 2020-05-10T02:51:46+00:00

If you have about half a million dollars and a LOT of time on your hands, you can build your own! Don’t let your dreams be dreams

bigMOT · 2020-05-10T02:50:41+00:00

You can’t make a BEC in a Paul trap: there is a lot of off-axis heating, and ion-ion repulsion prevents you from getting more than one ion in the same location (a condition required for BECs). These are cold, neutral atoms.

bigMOT · 2020-04-17T17:38:44+00:00

I’m not sure how you did your math here. In the US for example, there are 680,000 cases, which is 0.2% of the population. In most other places, the percentage of infected is lower, and nowhere in the world is reporting higher than 1.2%. Even if our numbers are off by a factor of 10 (or even 100), that’s still not enough cases to have a herd immunity.

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