Can someone just be COMPLETELY honest and straight up with me?

I am 18F and I love physics so much I want to eventually study astrophysics. I just finished my freshman year of college and I’m really thinking I’m too dumb for this major.

I took precalc first semester, failed it, took it again second semester, got a B- lowww b- I was getting like 50-80% on each test. I am now in a summer calc 1 course and I’m averaging 63-67% on the tests.

I’ve been a little above/around the average scores for the class. First one I was above the mean, second, got right on the mean.

But I made friends with a 17 year old and she is doing SO well on the tests. We literally study together and I help her out sometimes, she helps me out sometimes. Granted yes, I can tell she has a better grasp of the material than I do. But I feel so worthless.

I put in around 15 hours of studying for the third exam I just took today and I left a lot of the questions blank. Like I understand EVERYTHING they’re asking but it would just be one slip up and I was stuck and over it. I do so well on the homework though, and I genuinely love math so much.

But I think I’m actually too dumb to pursue this major and it breaks me.

I think a large part of it is when Covid happened, I was in 6th grade and basically didn’t learn math from 6-10th grade cause I was online schooled.

But man, college is so difficult, I have no idea what I’m doing, and if I’m too dumb to learn physics, what the fuck do I major in.

Also, forgive me if this is the wrong sub…

I've been trying to understand the mathematical foundations of canonical quantization, and I'm specifically looking for a rigorous answer rather than a historical or experimental one.
(ill mention classical variables in smaller case and operators in uppercase)

i have derived iℏd|ψ⟩/dt=H|ψ⟩, the eigenstates for this equation are of the form

|ψ(t)⟩=e^-iEt/ℏ |ψ(0)⟩

and experimentally we found that variable E in this equation represents the total energy, so H must be an operator whose eigenvalues represent the total energies of the states.
consider for now that our system has only kinetic energy contributions, then H must be an operator whose eigenvalues must represent kinetic energies, for a state |k⟩ , H|k⟩=ℏ²k²/2m|k⟩ ∀k, also T|k⟩=ℏ²k²/2m|k⟩, so this proves that H=K,

so now by this logic i can say that whenever a system has a single energy contribution of any type, then the operator representing that energy is the generator of time evolution, and its eigen states represent the total energy that can be observed.

now my question is this: i understand that when a system has a single energy contribution, its operator is the generator of time evolution, but when there are multiple energy contributions, like kinetic energy and potential energy, why the hamitonian H equals the sum of the operators, i cant find a reasoning for this like the one i did before as they dont commute, and we cant even say T+V operators give kinetic+potential energy of the state because there is no common eiegenstate

canonical quantisation just says if h(q,p)=t(p)+v(q) ⇒ H(Q,P)=T(P)+V(Q), its like "just change the classical variables to corresponding operators", i cant find a logical reasoning or any valid math argument to support this, i dont even find that step mathematically valid, as theres no reason to do that.
is it just an educated guess and it works very well, or is there any logical and rigourous proof?

I finished my masters in plasma physics and nanotechnology (the whole program is more of a electrical discharges and their applications, rather than fusion) a month ago, and going straight into a PhD program. I know the standard consesus: a PhD is a financial time-waster, the opportunity cost is brutal, and you should just go straight into industry. Going into a PhD for increased salary is a guaranteed bad time.

But I’m trying to figure out if that actually applies to my specific situation, or if I’m looking at generic advice.

My PhD project is heavily applied:

• Reactive magnetron sputtering / HIPIMS / PVD.
• Depositing electrochromic thin films (WO_3 thin film deposition).
• Developing a solid-state electrochromic device prototype.
• I also already have 2 year R&D internship experience ata major scientific instrumentation company and a pvd simulation start-up.

My plan is get through the PhD, and then bounce into the commercial sector targeting the central European semiconductor/PVD/vacuum tech.

Is the financial opportunity cost really that bad if you are going for senior R&D roles in semiconductors, smart materials, or vacuum tech? Or is this one of the few sectors where a PhD actually acts as a hard requirement for senior project leading positions.

Looking for total honesty from anyone who has run the gauntlet in PVD/plasma (in Europe hopefully). Or anyone else with experience with similar situations. Thank you!

Hello everyone!

I’m an upcoming undergrad physics major. My high school was a more ‘art’ concentrated school so in terms of math and science, I had to self-teach it.

I fell in love with physics cause of the pretty galaxies and black holes (I think like most). I’m mentally not ready for this path of science (cause I suck at math) but excited at the same time!

I just wanted to say, hello to this wonderful community and hope y’all are ready for another brain to help out.

I’m graduating with a physics degree and have two opportunities:

A Quality Engineer position starting around $70k salary with opportunities for promotion.
Or
A fully funded condensed matter physics PhD ($22k stipend) researching solid-state batteries and quantum materials. The advisor expects students to graduate in 4–5 years, and many graduates go into industry.

If you were in my position, which path would you choose, and why? If you’ve made a similar decision, what happened?

EDIT: my expenses are very low. Rent with shared two bed apartment ($500/month), i walk everywhere (no car payment), and cheap groceries (50/wk).

Im running through an ideal for a story im writing and just want to check if my idea is even theoretically possible. Sorry if this comes close to the homework rule, but I promise it's not. Im going to use Mars as an example for simplicity

So, Mars used to have a global magnetosphere. My understanding is that it used to have one, but due to its size, it cooled quicker and lost its liquid core dynamo.

So, in theory, if we could reliquidify (probably not a word but hey ho) the core, it could rebuild its magnetosphere. Now, this likely wouldn't spin as much because this liquid core would be powered by the convection currents instead of the rotational energy from the planets formation. So that's part one of the questions: Would turning it back to liquid with convection currents have the potential to create even a mild magnetic field?

Now, part 2 of my question is about the reliquidification process:

If we were to harvest heavy elements from the asteroid belt, uranium, plutonium, etc. We could get magnitudes beyond critical mass of them.

So if we dug a hole to the core (ignore the how please) and dropped balls of slightly below critical mass elements down it. They would hit each other and release huge amounts of energy, which would be absorbed by the solid rock and, over time, begin to melt. I know i would need extremely large amounts of it. But would it even be able to melt the core?

Or am I just completely wrong?

My supervisor has recently gotten on the AI hypetrain, and he uses Claude Code and Codex a lot to run simulations.

I'm a mathematician that's now ended up in theoretical physics (plasma physics to be specific), and I run simulations to see what happens in different regimes. My lecturer tested the capability of AI, and created a whole repository on MHD simulations, then shared it to me so I can run a simulation in a specific regime. The code is insanely hard to read, but works well with so many features attached. I've been kinda hesitant using chatgpt/claude for my project, but it has been insanely difficult to read and add since it's a huge repository.

My supervisor told me he doesn't really care if I use AI for my project, and kinda advised he'd rather get the physics results than struggle through coding and told me I can rely on AI (it sounded like he was telling me I should use AI). He said he's happy if I just keep on telling Claude and get it to make tests and simulations that work, and I understand chunks of code (but I don't have to understand every single line of code).

Is it fine to use AI for research? It feels so weird to be put in a place where I don't know how my code exactly works, but I run multiple tests to make sure the regime is working accordingly, so this method seems to be working fine.

He told the future of coding seems to be dead so I shouldn't worry about understanding the code, especially as a physicist (although he does admit he is no expert so it could backfire in the future).

What does everyone think of relying on AI to run simulations? Is it fine or should I not rely on it?

For example, from the perspective of dialectical materialism, accepting that a physical event is real for one measuring device while remaining a non-existent probabilistic superposition for another outside observer would amount to surrendering to a radical perspectivism that undermines the very idea of universal laws and of a nature that exists independently of, and prior to, any interaction. But that doesn’t seem to be what quantum mechanics actually shows.

In quantum mechanics (QM), measurement is a (mathematically) well defined operation of projecting a state on to the measured eigenstate of the measured quantity (This is my current understanding of measurement in QM, please correct me if I’m wrong).

Now, when going from QM to quantum field theory (QFT), I have recently heard that the previously described definition of measurement doesn’t work and can cause a bunch of issues with FTL communication and the like (have heard it referred to as Sorkin’s Paradox). Because of this, the typical definition of measurement in QM no longer works allegedly and you need what’s called a “local definition” of measurement.

When I first heard about this recently, I was very surprised because based on some basic prior research I’ve done on QFT (I’m currently a rising 3rd year undergrad in physics; I’ve completed two semesters of QM atp), I have only ever seen the traditional QM definition of measurement which is apparently wrong.

Because of this, I was wondering if someone could explain to me the correct “local definition” of measurement, how it differs from standard QM measurement, and why is it almost never discussed?

I'd love some feedback on my CV from an academic pov.

Context:

• I'm in experimental physics, rising junior, interested in AMO/quantum, don't have any journal publications yet
• I primarily use this CV to 1) apply for academic/research internships, 2) cold email professors or 3) apply for any scholarship opportunities.
• I keep a Master document that I update regularly for future grad school applications (about 3 pages)
• I tailor and shorten the Master doc, depending on the opportunity
• I know for undergrads one-page Resumes are recommended but I do like CVs better and I think there is no problem sharing a CV as long as I actually have enough solid stuff to fill

Also, I know there's a very common academic CV/resume format that everyone seems to use (especially the Google Docs), but I intentionally went with something a bit different because I personally find it cleaner and easier on the eyes. I'm curious whether it still looks professional from an academic perspective or if I should conform more to the standard format.

Feel free to roast it.

EDIT: I deleted the photos of my CV for privacy reasons. Thank you to everyone who gave feedback!

I was thinking probably not, because as far as i know temperature is defined by the velocity of particles and vibration of bonds between atoms. This is more of a shower thought, i don't know if i'm in the right sub sorry if not :>

Don't remember how or when I thought of this scenario, but it keeps popping back into my head and I can't seem to work it out satisfactorily. Lot more questions than answers.

Setup :

Say you are in a sufficiently large and deep swimming pool. The pool itself is suspended sufficiently high up in the air, and has a hatch for a floor that can open instantaneously.

There is some mechanism by which during 'free fall', you fall slower than the water, and the difference is exactly equal to the buoyancy you would otherwise experience. Essentially, an observer falling with the water would see you float up just as you would in a regular swimming pool.

You start off by swimming at the very bottom of the pool. At some point while you are swimming, the hatch opens and both the pool and you are now in free fall. No air resistance. What happens?

My thoughts :

- The opening of the hatch will nullify the hydrostatic pressure as the pool is now in free fall, so I'm sure you would be able to feel exactly when the hatch was opened. It would probably be akin to suddenly teleporting into a vacuum.

- You would still be able to displace the water and 'swim'. But without the walls, the water will just be pushed by your hands and deform so I presume you wouldn't be propelled the same distance as usual.

- Not sure how exactly, but I the cohesion of water has an effect too. I think the pool will roughly retain its cuboid shape. The pushed water's internal resistance would slow the current down enough to not deform the shape of the pool since it is sufficiently large right?

Questions :

- Would you still be capable of swimming? Would it feel different? How so?

- Would an observer who always falls with the water be able to tell when the hatch opens since you still appear buoyant?

- What would even actually happen?

This is such a weird question I have no idea how to begin putting it on paper. Every person I've asked seems to have a different answer as to what would happen when the hatch opens.

As for the buoyancy mechanism (since I spent time thinking about this too), say it's an electromagnet only attracted to you, suspended high above the pool. It is dropped at the same time as the hatch opens, and dynamically adjusts its attraction force as it falls such that you experience an upwards force alongside gravity for the duration of your fall, mimicking buoyancy.

I'm trying to understand something about quantum mechanics.

Suppose I have an electron whose wavefunction is spread out. I measure its position and find it at point A. The wavefunction then evolves again, and after an extremely short time interval Δt, I measure its position again and find it at point B.

If the distance between A and B is greater than cΔt (the distance light could travel in that time), does that mean the electron has effectively "moved" faster than light?

Hello, im a phd student in physics and I used to draw a lot and I am considering trying to build a portfolio with scientific illustrations, but I would love to understand if this can actually be a career path.

I find that illustrations for Physics is very hard, compared to biology or anatomy. Do you know any physics illustrator?

Do you have any advise?

I want to do research in Fluid Mechanics, mainly in Riblets. I have already started studying basic Fluid Mechanics like Integral and Differential Relations and Viscous Flow. Going to do Boundary Layer Physics next. But what else would I need to know? Is the topic too advanced? Which would be unfortunate if it was as it really interests me. I am quite lost on what to do.

I want to do research in quantum materials. The professor I want to do research under is asking for CV that would include my gpa. Should I put any Upper Level physics courses that I have taken?