[QUOTE=JohanGS;47172292]I thought you were just taking a piss when you called it my homework, that's why I didn't call you out on it.[/QUOTE]
I did tell you the approach lol, how was I taking a piss?
"It's not your homework" is just like a User agreement saying that "whatever happens to your grade has nothing to with me."
Believe it or not, I have good grades. You needn't worry.
[editline]19th February 2015[/editline]
I mean, I share your hatred for copying solutions so I guess that's why I got offended.
So, I got to play around in a tiny 1kW nuclear reactor buried under my uni today. I have a number of probably awful pictures I snapped on my phone. Would those be good to post in here or another thread?
[URL="https://www.dropbox.com/s/ogj28mmwf385qpf/mininuketank.jpg?dl=0"]Here's a picture of the reactor from the top of the tank[/URL]. It's not all that exciting, but hey, how often do you get to see the insides of a research reactor in person?
Today was Einstein's birthday. RIP you fabulous bastard.
[img]http://i.imgur.com/nO8ApTM.jpg[/img]
Image processing is fun
[IMG]http://i.imgur.com/EcND5qu.png[/IMG]
It could do a bit better in separating background/foreground but I couldn't be bothered to continue messing around with parameters...
I've started typing up a set of companion notes for Peskin and Schroeder as I study from it that will hopefully serve summarize the text and also work out all the nitty gritty details of anything I don't immediately see as clear.
It's probably gonna take me basically forever but I'll be damned if I don't understand QFT by the end of it.
Has anyone taken the SAT physics subject test? Is it really conceptual or are there alot of calculations?
I have to self study a few subjects like thermal physics and optics because I'm in regular physics :/
I get to visit my universities plasma propulsion and plasma physics lab on Thursday :D
I'll try to grab some pictures if anyone wants them. Run by a pretty prestigious and accomplished professor, and I think it has the fusion reactor prototype and a few ion engines as well. I'm unbelievably excited to check it out.
Im not a physics or science student but science is more of a hobby for me. Right now I have really only done astronomy stuff, but nuclear physics interests me a great deal, and I have really been wanting to build a cloud chamber, which is probably the cheapest thing relating to that that I could build.
A cloud chamber is a pretty rudimentary detector but it can detect all sorts of particles if you fine tune it enough. I would probably want to get a radioactive source in it at some point, and with a camera setup I could probably make some observations of various types of particles.
Well I feel like shit. Had the second last exam that I'll ever sit yesterday (and the last 'proper' exam; next week I have an oral exam that I'm going to ace) and I ballsed it up entirely. Every last mark I get this year dictates if I get a scholarship next year, and if so how good a scholarship I'll get, and I fucked up one of the two exams I have this year.
Statistical mechanics has never been a strong point of mine, but I was doing so much better this year than in the past. Oh well.
So, I've been reading up on Bremsstrahlung radiation and electrostatic accelerators. Needless to say I'm wanting to figure out how can I compute a safe electric field gradient to slow down a stream of protons and/or alpha particles (At say 100MeV) to safer energies (Less than 10keV or near standstill preferably) for active radiation protection.
My goal is to not only slow them down, but slow them down so that the most probable photons released due to bremsstrahlung are non-ionizing as they traverse the gradient.
I've read up that the [URL="https://en.wikipedia.org/wiki/Duane%E2%80%93Hunt_law"]Duane-Hunt law[/URL] can be used to determine the minimum wavelength cutoff for just such a way to compute the most probable energies across the whole potential. But I don't know if/how the distance between the two plates (ergo the e-field gradient) will affect this. For example, will 10kV over a meter distance have the Duane-Hunt distribution at higher photon energies (higher acceleration maybe?) compared to 10kV over 100 meters?
Just scheduled classes at uni next year. I am doing a physics math double major. Pretty excited for this
[QUOTE=shadowdude14;48005556]Just scheduled classes at uni next year. I am doing a physics math double major. Pretty excited for this[/QUOTE]
That's a fun major combo. If you can, pick up a CS minor though if you're not 100% certain you will be going on to a graduate program in a discipline with good funding. A CS major or minor will make you much more employable.
This is coming from someone who hates coding. It sucks but I would be way better off right now with a minor in it probably.
[QUOTE=JohnnyMo1;48005663]That's a fun major combo. If you can, pick up a CS minor though if you're not 100% certain you will be going on to a graduate program in a discipline with good funding. A CS major or minor will make you much more employable.
This is coming from someone who hates coding. It sucks but I would be way better off right now with a minor in it probably.[/QUOTE]
Well, after my undergrad if I really don't want to go for the PhD anymore, I would just get a masters in engineering. I kinda wanna take a year maybe 2 year break in between my undergrad and grad school, so the cs minor would probably help getting employed in that interval of time
[QUOTE=JohnnyMo1;48005663]That's a fun major combo. If you can, pick up a CS minor though if you're not 100% certain you will be going on to a graduate program in a discipline with good funding. A CS major or minor will make you much more employable.
This is coming from someone who hates coding. It sucks but I would be way better off right now with a minor in it probably.[/QUOTE]
I'm taking CS as my degree because normal people think it's wizardry when reality I'm just using toddler-tier maths to automate a metric shitload of text manipulation, and if I need to calculate anything harder than division there's probably an open source tool I can plagiarise and jury-rig until the output looks like something other than red text vomit. I'm bad with numbers. My minor is a language at another university. :rolleyes:
Numerical simulation of a (1D) quantum walk of a wave packet (an electron) in a periodic potential (in a binary lattice of atoms) with a varying electric field (that's why it looks like ramen). So basically you let it loose and then the wave packet will split into other tiny wave packets that will follow their own path. It's called the Bloch-Zehner quantum walk. You can see the wave packets interfering when they converge. The horizontal axis is time and the vertical axis is the probability density to find it at a position x. Not sure why it bounces of the side, guess it's the confinement effect.
[IMG]http://i.imgur.com/EhVGYVg.png[/IMG]
I had to investigate it for a computational physics task, never thought it'd give such pretty pictures.
Oh and these are Bloch Oscillations:
[IMG]http://i.imgur.com/wj7NeUL.png[/IMG]
This happens if you apply a DC current.
[QUOTE=Number-41;48042681]Numerical simulation of a (1D) quantum walk of a wave packet (an electron) in a periodic potential (in a binary lattice of atoms) with a varying electric field (that's why it looks like ramen). So basically you let it loose and then the wave packet will split into other tiny wave packets that will follow their own path. It's called the Bloch-Zehner quantum walk. You can see the wave packets interfering when they converge. The horizontal axis is time and the vertical axis is the probability density to find it at a position x. Not sure why it bounces of the side, guess it's the confinement effect.
[IMG]http://i.imgur.com/EhVGYVg.png[/IMG]
I had to investigate it for a computational physics task, never thought it'd give such pretty pictures.
Oh and these are Bloch Oscillations:
[IMG]http://i.imgur.com/wj7NeUL.png[/IMG]
This happens if you apply a DC current.[/QUOTE]
I did my undergrad final year project on quantum random walks which my old supervisor and I are currently in the process of writing a paper about. We discovered some pretty interesting properties when large ensemble averages are taken in certain systems that there's no mention of in the literature (at least that we can find). Bouncing indeed occurs due to confinement (which is surely evident from how you built up the Hamiltonian/adjacency matrix).
Good to know I'm on the right track because the report has to be handed in tomorrow :v: Was stuck in my code for ages because the Chebyshev time propagation scheme had a single wrong letter in some expression
[QUOTE=sltungle;47977466]Well I feel like shit. Had the second last exam that I'll ever sit yesterday (and the last 'proper' exam; next week I have an oral exam that I'm going to ace) and I ballsed it up entirely. Every last mark I get this year dictates if I get a scholarship next year, and if so how good a scholarship I'll get, and I fucked up one of the two exams I have this year.
Statistical mechanics has never been a strong point of mine, but I was doing so much better this year than in the past. Oh well.[/QUOTE]
And I got 98.75% on the [I]last[/I] exam I'll ever do. Suppose that'll do. Thank god quantum mechanics is so easy.
Is Hartle's [I]Gravity[/I] a good GR intro?
[QUOTE=Number-41;48088730]Is Hartle's [I]Gravity[/I] a good GR intro?[/QUOTE]
I don't know a whole lot about the content but the format is a little stupid imo. He tries to do everything "physically" first and doesn't introduce any serious differential geometry for 400 pages (the last part of the book). I dunno what would possess someone to do that.
so my guess is it's probably pretty hand-holdy for a serious GR intro.
What would be better then?
I like Carroll the best of what I've seen. Strikes a good balance between the sophistication of something like Wald and an introduction. Be aware that it is math-heavy. I took GR with it my junior year and felt it was perfectly appropriate.
The reviews for Hartle on amazon are good, though. It probably all depends on what you want. One that I saw basically said, "Other books put the hard math first! Ugh. This book doesn't do that." So it seems like what I said is probably true. But I like the math...
Wow yeah I started in Hartle and after 40 pages I was still waiting to get hit with my first tensor :v: I'll check out Carroll then.
I should mention also that if you want to "try before you buy" so to speak with Carroll's book, significant portions of it which are pretty similar to the final product are available for free as the lecture notes that the book grew out of:
[url]http://arxiv.org/abs/gr-qc/9712019[/url]
[URL="http://pages.pomona.edu/~tmoore/grw/"]Thomas A. Moore's, 'A General Relativity Workbook'[/URL] is really good and it's what I'm using at the moment (in conjunction with Carroll) to self teach GR.
Excellent talk for laypeople (lol, or rather physicists who are not string theorists) about how string theory smooths out UV divergences.
[media]http://www.youtube.com/watch?v=H0jLD0PphTY[/media]
Hey guys, doing my first year in physics, learning basic stuff.
Struggling in class, I would highly appreciate if someone could direct me to some good website or books to self teach physics.
I love you very much! thank you!
Apparently my requested perma wore off, so I guess I'll drop in here every once in a while. The Wikipedia article on the Hamiltonian operator in QM says that it corresponds to the total energy of the system, but qualifies that statement with a "most of the time" tacked on the end. In classical mechanics the Hamiltonian of a system with rheonomic contstraints will generally not (never?) correspond to the total energy of the system. Is there an analogous situation in QM in which the Hamiltonian operator doesn't correspond to the total energy of the system?
Let me revive thread a bit:
Brian May, astrophysicist was also guitarist in rock band Queen.
[url]https://en.wikipedia.org/wiki/Brian_May[/url]
[editline]26th July 2015[/editline]
[QUOTE=JohnnyMo1;48141124]Excellent talk for laypeople (lol, or rather physicists who are not string theorists) about how string theory smooths out UV divergences.
[media]http://www.youtube.com/watch?v=H0jLD0PphTY[/media][/QUOTE]
Johhny, do you understand everything of that?
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