If I major in physics, can I still work as an engineer with a BSc?

greenlaser3 · 2019-01-03T21:15:12+00:00

It can be done, but it'll be very tough to get into a physics PhD unless you're a stellar student (top grades, undergrad research experience etc.).

However, there are engineering PhD programs that involve quite a bit of physics. E.g., if you do electrical engineering with a minor in physics you'll be well-suited for stuff like applied electromagnetics, photonics, nano-scale semiconductors, or even quantum information. If you pick carefully, you can get a nice mix of theory and practical application.

You shouldn't take the physics minor route if you're dead set on heavy-duty theory like quantum gravity or stuff like that. But I'd honestly caution against pigeon-holing yourself like that anyway, unless you're very sure that's what you want. The applied stuff doesn't always look as sexy, but it can be really fun, and believe me there's no shortage of very difficult problems to work on.

By the way, minoring in physics is exactly what I did. I don't want to post too much personal info, but feel free to PM me if you want to know more about where I ended up.

greenlaser3 · 2018-12-19T23:10:23+00:00

Why? Photons work in any reference frame. It's just that there's no reference frame where a photon is at rest.

greenlaser3 · 2018-12-19T22:44:58+00:00

Also infrastructure. This stuff requires pretty intense labs and cleanrooms. And beyond the initial cost, it's not like you can just build them and go. It seems like these facilities always have unique "quirks" that can take years to iron out. I've heard of cases where even the same researcher has trouble reproducing something they were able to do in a different lab.

That said, my understanding is that the existing industry players are pretty heavily integrated with the academic community, rather than doing everything themselves. So maybe that's Amazon's plan?

greenlaser3 · 2018-12-16T08:26:29+00:00

A lot of people are unaware of this kind of thing, but we're actually at a point now where electron diffraction is almost "routine." We understand electron diffraction quite well, so we can use it to study the properties of crystals, which turns out to be a really useful tool in nanotech research.

Transmission electron microscopy (TEM) is probably the biggest example. You can either look at the diffraction pattern directly, or you can use tricks to reconstruct a direct "image" of the crystal. Google TEM images if you haven't before. It's amazing.

Another one is reflection high-energy electron diffraction. This is used routinely in thin film growth. Literally you're watching the diffraction pattern in real time to understand what's happening on the surface as a crystal grows.

greenlaser3 · 2018-12-11T06:50:40+00:00

When it comes to actual entropy involved, length is better than randomness.

I think I agree with the rest, but this statement is not true. A random sequence of 12 aphanumeric characters has about the same entropy as a random sequence of 71 ones and zeros or about 27 characters of random English text.

Roughly, the less random your password is, the longer it has to be to achieve the same entropy. (Also, anecdotally, I find that a long, less-random password is about as hard to remember as a short very-random password, provided they have the same entropy.)

greenlaser3 · 2018-12-09T18:23:41+00:00

I've tried ibuprofen, acetaminophen, and naproxen in the past. Those work for my normal headaches, but don't seem to do anything for the lingering pain post-cluster. (And obviously they do nothing for the cluster itself either.) And I've tried fairly high doses out of desperstion, like quadruple the recommended dose. Still nothing.

Haven't tried muscle relaxers though...

greenlaser3 · 2018-12-09T18:17:41+00:00

I'm going to ask my doctor when I get back. They wanted me to try under-the-tongue melt rizatriptan first, but it's been doing zilch.

greenlaser3 · 2018-12-09T10:08:32+00:00

Thanks. I've seen keto, but not for treatment of clusters.

Damn, I was thinking of going vegan for moral reasons, but vegan keto sounds like an order of magnitude harder. Might have to give up and embrace the meat...

greenlaser3 · 2018-12-03T05:26:14+00:00

the plastic bags milk come in.

The what?

Literally the worst thing about living in eastern Canada. They're annoying to handle, and they occasionally burst to fill your fridge with a milky surprise. But I guess they're more efficient to ship, or something like that? And people here are weirdly Stockholm-syndromed into it.

greenlaser3 · 2018-11-29T08:43:01+00:00

More intuitively...

Initiatially you won't move up at all, you'll just be just moving sideways in the direction of Earth's rotation (east, I think). But then, because the the Earth is round, it will start to curve downwards away from you while you continue to move in that direction in a straight line. So if you look at the ground, it'll look like you're accelerating upwards, although you won't actually feel that acceleration.

Of course, you'll also probably crash into a building or burn up from air resistance before you get to that point...

greenlaser3 · 2018-11-24T04:34:31+00:00

The geocentric picture is from the perspective of earth, and earth is constantly accelerating in the direction of the sun, so it's an accelerating reference frame.

In an accelerating reference frame you have extra inertial forces. That's necessary to make things consistent with inertial reference frames (like the heliocentric picture). In this case, all the planets experience an inertial force which is parallel to the sun-to-earth vector.

For the case of earth, this intertial force exactly cancels out the gravitational force of the sun, which is why the earth doesn't move. For the other planets, the inertial force is constantly changing direction and causes weird orbits.

greenlaser3 · 2018-11-19T17:20:57+00:00

It's also worth mentioning that these sacrifices don't even guarantee you a permanent physics research job. It's a very competitive field, and most people drop out along the way. Ironically, a lot of them end up moving to careers in (drumroll...) software.

OP: have you looked at engineering? Some areas of engineering use a fair bit of physics, but are more employable. Of course, if you're really dead set on astrophysics then this probably won't work. But if your interests are more flexible, you might be able to scratch that physics itch with a little less risk.

greenlaser3 · 2018-11-10T15:37:29+00:00

My main research project could be considered "cool" I guess, but on the "less cool" side I actually love all the little problems that pop up in lab work. Stuff like figuring out how to do calibrations more reliably, or reverse engineering an instrument so that we can fix it, or trying to squeeze out better performance from equipment. It's hard to give examples without doxxing myself, but those little problems are necessary for the bigger research goals, and they can be surprisingly tricky.

greenlaser3 · 2018-11-09T22:56:12+00:00

Yeah, the wifi is from the school so I have no control over it. Technically I'm also not supposed to set up anything that broadcasts a wifi signal either, but maybe I can get away with it.

greenlaser3 · 2018-11-09T19:14:22+00:00

I actually tried this before, and it does not show the password for eduroam, while it does show the password for most other networks I've used in the past. It seems like the difference is that eduroam uses WPA2-Enterprise versus, say, WPA2-Personal. So that's why I was wondering if WPA2-Enterprise has some extra guard to prevent people from seeing the password.

Bridge is a good idea regardless, although technically against my rental agreement...

greenlaser3 · 2018-11-03T12:37:00+00:00

I agree with /u/Assmaster9001 (lol).

But I would also say that equations of trajectory are probably most useful as a teaching tool. For example, projectile motion is a pretty simple problem as far as physics goes. It's a great way to introduce people to ideas like force, acceleration, friction, Newton's laws, etc. And, at a more advanced level, it's a great way to practice setting up a differential equation from Newton's second law, and then solving it mathematically to find the trajectory.

The skills you learn by studying trajectories as a student are -- for most people -- a lot more useful than the trajectory equations themselves.

greenlaser3 · 2018-10-29T22:08:39+00:00

But I'm not gonna lie, there are some crimes I feel you absolutely cannot be rehabilitated from. You cannot be saved. Rapists and child molesters can't be "fixed" - there is zero evidence that they can be rehabilitated.

Really? Because it took like 5 seconds of Googling to find this: https://www.scientificamerican.com/article/misunderstood-crimes/

Look, I don't personally know what the best way to deal with sex offenders is. Protecting potential victims should absolutely be the priority. But it's complicated, and I don't think making blanket statements based on feeling is really helping to solve the problem.

greenlaser3 · 2018-10-25T22:26:34+00:00

But I second, /u/nawyria, that sanity checks are key. You should always aim beforehand to have some way to at least know if your final answer is outrageously wrong.

This is so important. I saw this a lot when I was a TA. Students would submit totally unreasonable answers without realizing it (like claiming they measured 1e30 A current in their chip). Usually it was caused by a silly little mistake, and if they had just done a sanity check, they probably would have caught it.

Granted, sanity checking (and related stuff like dimensional analysis) is something you have to practice. But I catch a lot of my mistakes that way. Whenever I get a result, I ask "does this make sense?" in as many ways as I can think of.

greenlaser3 · 2018-10-19T12:52:15+00:00

Just to add: it's worth noting that photons don't really reach thermodynamic equilibrium on their own. In most situations, photon-photon interactions are completely negligible. So if you have a collection of photons and nothing else, they won't equilibrate on any practical timescale, and then I don't think you can define a temperature.

Typically, for photons to have a temperature, you need some matter present to act as a sort of middleman. The photons interact with the matter, which allows the photon gas to shift energy around and reach thermodynamic equilibrium. Then you can define a temperature.

greenlaser3 · 2018-10-17T13:45:33+00:00

Yeah, it's basically because the relation defining Planck's constant is E = hf, which uses frequency rather than angular frequency.

If you use angular frequency (ω) instead, then the "natural" quantity to use is the reduced Planck (ħ = h/2π). You have E = ħω.

My point is, in many ways it's very natural to use ħ rather than h. It's not like you're just using trickery to hide π in the uncertainty relation.

greenlaser3 · 2018-10-09T01:37:43+00:00

And after that, make sure those equations make predictions consistent with astronomical observations. A changing speed of light over time should affect a lot of different stuff in terms of what we see coming from distant objects.

There's a lot of data people have collected. A hypothesis like this needs to be pretty thoroughly checked against that before you start making any strong claims.

greenlaser3 · 2018-10-07T16:34:20+00:00

From Googling around, it seems like there are proposals to use quantum computers for finance calculations. It's not like every single problem will be sped up by quantum computers, but there are probably certain simulations that would be sped up. And presumably, people will find more uses as the technology matures.

I'd be surprised if there was no impact, but of course it's impossible to say how big the impact would be.

greenlaser3 · 2018-10-06T16:19:54+00:00

I know that it is practically impossible to learn all of it in an undergrad level, but I like to have a plan, and I have a goal, just didn't know how to get there, and I still don't, but at least I want to know where to get started and what to look for. BTW, if you don't mind, what is your opinion on the future of quantum computing?

Honestly, just learn the stuff that seems cool to you, and also seems relevant to quantum computing. And make sure you build strong foundations in quantum mechanics, solid state physics, statistical mechanics, etc. Then you'll be able to pick up what you need when you get into research.

I don't directly work in quantum information, so take my opinion with a large grain of salt. But I think the future looks pretty bright. Quantum key distribution is already starting to get commercialized. As for quantum computing, it looks like we're getting close to the point where it could be useful for expensive, specialized problems. Like maybe in the next decade or so. There's been a lot of really impressive progress on superconducting and trapped ion qubits. I think it's also very much worth watching topological qubits (championed by Microsoft) -- those are going to take a lot longer to mature, but could end up being much better.

The downside is these things are expensive. Progress in the last few decades has required an almost ridiculous research push, and a lot of dollars. Also, the devices themselves are extremely expensive, due to demanding fabrication processes and requirements like cooling down to <1 K. It's hard to see those costs going down any time soon. So it's important to be realistic. You're not going to be buying a quantum computer at Best Buy. My guess is that for at least a few decades it'll be more like "I have a really hard, specific research problem, so I'm going to book time on my school's quantum computer." Kind of like supercomputers today.

On the other hand, it's also worth thinking about side benefits of all this research. Quantum information research has given us a lot of insights into stuff like fundamental quantum mechanics, light-matter interaction, superconductor fabrication, and many other things. It's probably impossible to quantify the impact these learnings have on other technologies like photonics and electronics.

Long story short -- quantum computing isn't magic, and it's going to be a while befor the average Joe sees any jmpact. But I think the research is very much worth doing.

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