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/sci/ - Science & Math

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1380014 No.1380014 [Reply] [Original]

Ok guys. Ask me some theoretical physics questions and I'll answer them for you, or at least point you towards a link. I've been up all night and need something to keep me busy.

>> No.1380029

how come quantum fluctuations led to the universe as we know it?

what kind of degree do you have?

>> No.1380030

>Ask me some theoretical physics questions
Is string theory bullshit?

>> No.1380037

that pizza looks equilateral to me. you got a refund, right?

>> No.1380049

>>1380029
They're still working on that one. My best guess is that it was a energy to matter reaction, but in that case equal parts matter and anti-matter should have been created, cancelling each other out in a big explosion, converting everything back to energy. No answer that I'm aware of yet.
>>1380030
It has good explanatory value, explains very well why information is not lost in a black hole.
>>1380037
if you look closely the two sides that form the downward point are a bit longer than the one on the top. Plus I didn't take the pic.

>> No.1380054

>>1380029
heh, not physics, lets leave it at that. I'm an enthusiast, not a professional.

>> No.1380055

>>1380014
Is the theory of cosmic inflation correct, and if so, what are the details of this epoch? What is the hypothetical inflaton field giving rise to inflation? If inflation happened at one point, is it self-sustaining through inflation of quantum-mechanical fluctuations, and thus ongoing in some impossibly distant place?

>> No.1380057

Is light a particle or a wave?

>> No.1380060

>>1380057
both:
http://www.youtube.com/watch?v=DfPeprQ7oGc

>> No.1380061

>>1380014

has your career in theoretical physics been "worth" it so to speak, im not talking about the cash

>> No.1380065

i like the pizza, thats some cool portion allocation.

>> No.1380085

>heh, not physics, lets leave it at that. I'm an enthusiast, not a professional.
confirmed for sage

>> No.1380089

>>1380061
see
>>1380054
I think so, if you mean that space itself expanded after the big bang, as well as matter.
Basically space expanded at the same time matter did, allowing matter, relative to the central point of the bang, to travel faster than light. Imagine running in the direction a conveyor is moving and you'll get the idea. Dunno. Possibly, but I think not. Sorry for the short answers, but that's near my limit of expertise.

>> No.1380090

>>1380085
Please, judge me by my responses, not by me credentials (or lack thereof). I'll not bullshit you, If I don't know, I'll say so. I'll link you to somewhere that does though.

>> No.1380094

If we consider a particle which propagates in d-dimensional “target spacetime” <span class="math">R^{1,d−1} [/spoiler] with coordinates
<div class="math"> (t,x) = x^{\mu} </div>

What is the infinitesimal, Lorentz-invariant path length swept out by the particle if it sweeps out a path <span class="math"> x^{\mu}(\tau) [/spoiler] in spacetime, which is parametrized by a proper time coordinate <span class="math">\tau \in R [/spoiler] ?

>> No.1380101

>>1380090
Then respond to >>1380055

>> No.1380109

What's the core difference between theoretical physics and experimental physics?

>> No.1380116

>>1380101
I did. Not very well, but not innaccurately.
>>1380094
Yeah, math. Ummmm. Not equations here guys, I mean questions on the conceptual level. I didn't say "TEST ME," and if you already know, then why bother asking?

>> No.1380118

>>1380109

Funding

(no OP)

>> No.1380135

Hey guys.

I know nothing about theoretical physics. I have read a couple of pop science books, but even wikipedia articles are beyond me. Whenever I see any math I say "equations aren't for me"

wait..where was I...

oh yeh, ask me anything you want!!

>> No.1380136

>>1380109
Theoretical physics is speculation based on evidence for things that are too difficult for us to directly observe. Think black holes, higgs-bosons, etc. Experimental physics is exactly that, physics whose conclusions are based on experimental data directly. One is logical speculation, attempting to explain things we don't quite get yet. The other is the source of data, which theories are drawn from.

>> No.1380143

>>1380055
Not OP

Inflation helps explain cosmic background wave radiation and why everything seems to be spread out uniformly over very large distances. It is hypothesized that a quantum fluctuation happened before everything, due to the uncertainty princeple, which led to a scalar field, the inflaton field to be created. It caused inflation to happen, then dropped to a lower energy level and expelled all of it's energy as matter into all of the universe equally.

http://en.wikipedia.org/wiki/Inflation_(cosmology)
http://en.wikipedia.org/wiki/Inflaton
http://www.youtube.com/watch?v=fxNbXjBbzEo

>> No.1380150

>>1380135
yay, my very own troll. Where did you see "anything you want."
I specifically said.
>and I'll answer them for you, or at least point you towards a link

>> No.1380154

Not OP, would that be <span class="math">-\overdot{x}_0^2 + \overdot{x}_1^2 + \dots + \overdot{x}_{d-1}^2[/spoiler] where <span class="math">x_0[/spoiler] is the timelike dimension?

noob here

>> No.1380162

>>1380154
<span class="math">-\dot{x}_0^2 + \dot{x}_1^2 + \dots + \dot{x}_{d-1}^2[/spoiler]

>> No.1380171

>>1380162
I appreciate the help. Thank you.

>> No.1380203

What's the smallest particle known to man?

>> No.1380208

>>1380094

<div class="math"> dl = (-ds^2)^{\frac{1}{2}} = (-\eta_{\mu \nu} dx^{\mu} dx^{\nu})^{\frac{1}{2}} \equiv (-dx^{\mu} dx_{\mu} )^{\frac{1}{2}} </div>
where l is the proper time of the particle and <span class="math"> (\eta_{\mu \nu}) [/spoiler] is the flat Minkowski metric

>> No.1380230

>>1380208
Oh shit, I forgot the square root. But otherwise victory. ^^

>> No.1380234

>>1380203
Quarks and leptons. They have the smallest mass/energy.
I think it goes electron (smallest), up quark, down quark, etc.

>> No.1380247

Somebody recently proved ab initio that tachyons don't exist. What was the general nature of his proof, why didn't it get figured out before, and why did anybody hypothesize tachyons in the first place?

>> No.1380254

>>1380247
Didn't even know about that. Hopefully it is true, about time someone put tachyons out of the picture.

>> No.1380258

If I travel half of a journey, then another half, then another half then another half, etc. How do I still reach my destination?

>> No.1380259

>>1380247

source?

>> No.1380264

This thread is everything that is wrong with popular science.

>> No.1380276

>>1380208
<span class="math">\mathrm dx_\mu[/spoiler], woooot

>> No.1380295

How would one get into theoretical physics? How did you go about it?

>> No.1380298

>>1380258

keep fucking walking, Zeno

>> No.1380309

>>1380049
but information is lost in a black hole faggot

>> No.1380319

>>1380295

>implying OP is a theoretical physicist.

Do a physics undergrad and then a masters or Ph.D.

Some UK universities even offer a course on just Theoretical Physics.

It's not uncommon to do a maths undergrad and go into theoretical physics either.

>> No.1380350

>>1380298
wrong

>> No.1380383

>>1380295
I recommend reading the following:

Brief History of Time - Stephen Hawking
Fabric of the Cosmos - Brian Greene
Parallel Worlds - Michio Kaku

That's what I've done, and I'm currently working on my own research on the origin of the universe.

Don't worry about formal education of mathematics, they just obscure the nature of reality.

>> No.1380385

>>1380295
I'm not professionally involved in physics, and have no credentials to speak of. I'm an enthusiast, and have taken a couple of courses. Not an expert, just a knowledgeable layman.

>> No.1380386

>>1380309
That's not settled yet.

>> No.1380387

>>1380383
note the wrong tripcode

>> No.1380392

>>1380383
MASSIVE FACEPALM

>> No.1380396

>>1380386
If matter is energy slowed to near halt, time slows down as the matter enters the event horizon. When the matter reaches the singularity, the waves emitted are touching the event horizon. The information in the matter is transfered through these waves and released in the resulting radiation.

>> No.1380403

>>1380392
see
>>1380387

>> No.1380412

>>1380396
Indeed, Hawking radiation is what was going through my mind.

>> No.1380426

>>1380396

Oh dear.

facepalm.jpg

>> No.1380431
File: 205 KB, 512x384, vlcsnap-3407.png [View same] [iqdb] [saucenao] [google]
1380431

a perfectly cylindrical log is inserted in a split box, where the other half is air and the other seawater. the box is split vertically and the log fits perfectly, leaving no space for the water to flow anywhere. nevertheless, the log does not have friction with the box itself but it is in contact with the air and the water. the question remains... what happens? does the log spin?

>> No.1380450

>>1380396
- Matter isn't slowed down energy.
- Time slows down in arbitary distance to the mass (or energy-momentum) that creates the gravitational "field" (compared to the time at infinity of course).

>> No.1380463

>>1380383
You forget your Feynman, son. I am disappoint.

>> No.1380467

>>1380014
this was always an awesome image to me, but now that i think about it, isnt the common pizza slice an isosceles ?

>> No.1380471

>>1380467
It's not a triangle, at least not for angles much greater than 0.

>> No.1380474

>>1380396
I didn't make this up....looking for the source...

>> No.1380481

>>1380474
http://richarddawkins.net/articles/2846

>> No.1380486

>>1380481
doublefacepalm.jpg

>> No.1380489

>>1380481
http://physicsworld.com/cws/article/news/34239

>> No.1380494

>>1380489
http://www.physorg.com/news5794.html

>> No.1380499

>>1380489
http://www.physorg.com/news5794.html
best one. Bob and Alice analogy.

>> No.1380506

>>1380486
hush it, I just went with what I could find in google. That is an interview with Susskind, a theoretical physicist, just happened to be hosted there. Popular site, so its high on the search list.

>> No.1380511
File: 33 KB, 598x448, 884279-time_to_stop_posting_super.jpg [View same] [iqdb] [saucenao] [google]
1380511

>>1380506

>> No.1380513

22$ for a fucking pizza? Rip off

>> No.1380514

>>1380467
Crust is curved, not a line.

>> No.1380519

>>1380511
Point out the flaw. Do it. There isn't one. I've done my research and I've not seen better answers out of you.

>> No.1380526

>>1380519
>I've done my research

You don't know what research is

>> No.1380529

>>1380519
After reading through the first Susskind link you gave me, I read your post again only to find out that I had skipped all non-noun/verb words apparently. My answer wasn't wrong in terms of physics, but really had nothing to do with the statement that I wrote it for. I apologize.

>> No.1380540

>>1380529
Accepted. That's very gracious of you. Thank you!
>>1380526
Bite me.

>> No.1380550

>>1380540
So why didn't you go on doing theoretical physics if you're "only a layman"?

>> No.1380658

>>1380550
You mean why isn't it my profession? I don't want to spend my entire life doing math. After getting an A in college calculus 2, I found that it stressed me out a lot. Chose something that I liked the practice of more.

>> No.1380668

>>1380540
>That's very gracious of you

It's Josef, the gentleman of /sci/.

>> No.1380674

>>1380658
What did you choose?

>> No.1380683

>>1380668
I wouldn't know. Usually when I come here there's very little actual science discussion happening. Just Dawkins this, Kaku that, religion religion religion, airplane on a fucking treadmill. I had hoped to bring actual science discussion here, but since I'm not a Ph.D. in Physics it looks like nobody will take me seriously on the internet. I could have just lied and said I was getting a B.S. in physics or something, but that would be wrong.
>>1380550
That is very complimentary if I take your meaning as "you are good enough to at least have tried it." If so, thank you again.

I am still up for more questions (conceptual ones). I hope to get one to really stump me so that someone else will answer it and I'll learn something here.

>> No.1380703

>>1380674
You won't like it. Probably shouldn't say till the end of the thread. (NOT ENGLISH).

>> No.1380716

>>1380683
> I could have just lied and said I was getting a B.S. in physics or something

1) No one would care because an undergrad doesn't really know enough to start threads like these
2) You would have got called on it quickly

Starting discussion threads is fine. Starting threads asking for questions to answer when you don't really know anything is just stupid.

>> No.1380717

>>1380683
I don't judge anyone for not becoming a theoretical physicist. I mean I like theory, but I really do understand that one can hate it.
Apart from that, it looks like you're doing a decent job not being an expert yet knowing things that are at least a little more advanced.

>> No.1380736

>>1380716
I know some things, as evidenced by the thread. Anything I looked up was AFTER I answered.
>>1380717
Sigh, ok..... It looks like you are respected here, so maybe you'll back me up on the fact that I'm NOT full of shit. I'm a philosophy major. I was originally physical science, but did not enjoy it. I'm not one of those fruity spiritualist types, and don't believe in souls or ghosts, or what have you. Science and Philosophy go hand in hand for me.

>> No.1380765

>>1380736
I'm a physics student with philosophy as minor subject.
I couldn't study real philosophy because reading longer texts usually make me vomit violently (went though Husserl's Crisis or whatever it's called in English half a year ago, uuuah, and that's not even half Heidegger'ish), but I enjoy the general thinking.

Now replace philosophy and science in this post and it's most probably your viewpoint. :)

>> No.1380779

>>1380765
YES! You are my new hero man! I wrote papers on the hermeneutic cycle (holy shit, spelled it right on the first try). HUGE implications for science!

>> No.1380801

>>1380779
Oh sorry, That's a Heidegger reference.

>> No.1380807

>>1380779
All I know about hermeneutic is some passages by Gadamer, Apel, Rickert, Dilthey, and I hated them all. I was like "OH COME ON say what you want to say already" all the time, haha
Not sure whether all their texts are like that, but those I know were about humanities.

>> No.1380828

Oh, and philosophy is as useless as cosmology: there are no practical results. You can sure learn a way of thinking there that is useful to your life in the end, or that makes you happier at least, but there is no way you can ever transfer that to humanity like you could if you built a car that needed no fuel.
Why stuff like that is done is simple: because one can. It's playing with your own mind, seeing what the human brain is capable of, and determining the first reasons. The gap between physics and metaphysics closes on the rear end. :)

>> No.1380832

>>1380807
Super short version:
"We understand the whole by understanding its parts. We understand the parts by understanding the whole. When one understanding changes, we change the other, but then we have to change the other to fit the new understanding....ad infinitum."
Gadamer is a cool guy, he writes marxists aesthetics and doesn't afraid of red scare.

>> No.1380841

>>1380828
I'll agree to some extent, but our entire legal system is founded on John Locke (as just one example). There are practical applications, just no "jobs done" by it. It bakes no bread, but it might help you figure out why to bake bread, or if you should bake something else instead.....weird analogy, but an old one. (like, a few hundred years).

>> No.1380849

>>1380828
If you want a quick, easier, modern, and more scientific read, catch John Searle's "Mind, Language, and Society." or, Nagel's "What is it like to be a bat?" (silly title, but good read, short article.) I'm sure they're online somewhere, but your library at Uni probably has it too.

>> No.1380860

>>1380841
One of the greatest achievements of philosophy is our legal system is like saying one of the greatest achievements of particle physics is the invention of the internet. I support both statements.

>> No.1380866

>>1380807
Oh. Re-read that. You must hate continental philosophy. Look up analytic philosophy instead, way way more to the point, way less "out there."
Fucking Germans.

>> No.1380872

>>1380849
Read the bat text, was enjoyable. Short text, big impact. Someone should have told Gadamer+co to write like that.

>> No.1380875

>>1380860
Hell yes. Somebody has to get the ball rolling, get the basics down. Have to have a foundation for everything to stand on. Einstein (great scientist, good philosopher) said "I stand on the shoulders of giants." Baruch Spinoza had a version of the space-time continuum in the 1700s!

>> No.1380877

>>1380866 Fucking Germans
Guess where I'm from :P
But yeah, I've heard that the British philosophers are mostly way easier to read. I didn't know that was consensus though.

>> No.1380884

>>1380872
see
>>1380866
If you like Nagel, You'll love Searle. hell, If I hadn't loaned it out I'd be offering to MAIL you his book right now. Changed my life.
Nagel is analytic. The others are Continental. Branches make huge differences in philosophy, and that's the biggest dichotomy in it that I can think of as far as style and methodology! I'm SO glad there are some science dudes that "get" what philosophy is doing. I understand why it looks batshit retarded to most people.

>> No.1380889

>>1380877
OH GOD YES. Have you tried Kant yet? His sentences are paragraphs, and he makes up words on the fly. I swear I've seen 12 commas in one sentence before.

>> No.1380938

>>1380889 Have you tried Kant yet?
Haven't tried yet, but I know how it feels like. After some example sentences ("Aufklärung ist die ...") I really didn't feel like reading a whole book of sentences that take me about 15 minutes to understand on their very own.

What I like most about philosophy is when it intersects with physics/maths. There are so many patterns of thinking that can be used in both subjects, think of the implications of the uncertainty principle or the Schwarzschild radius. So this is where I started, philosophy of science; that's also when I found out that it's philosophy that actually defines what science is, and I stopped thinking that it's pretty arrogant to state that philosophy is a basis of all science (and for that sake, anything else as well).
Then metaphysics came, a term that is abused by esoteric bullshit people. The word alone hurt me in my stomach, but after some time I've learned what the philosophical metaphysics is all about, only to find out that that's basically the same thing as questions in fundamental research, namely: "But why? Where does it come from?" - So now, even metaphysics may exist from my royal point of view, haha

I think it would be really good for any scientific subject to learn something about philosophy in the first semesters; without that, you become pretty arrogant over time, thinking that you've basically learned what world is, when you've only used equations to calculate fucking imaginary magnetic fields.

>> No.1381020

>>1380938
I love you! I spent 6 hours on /r9k/ arguing with a determinist today who felt that we could predict the future exactly with computers. Kept telling him that cause and effect are only degrees of probability, ESPECIALLY in light of things like the dual-slit experiment, the uncertainty principle, etc. He wouldn't hear of it! link is >>>/r9k/10013559 if you are interested. Danke! Du est wunderbar! (pardon my very poor Deutsch!)

>> No.1381090

>>1381020
Predicting the complete future with computers is a logical fallacy in itself, regardless of whether determinism is right or not (QM tells us it's not, but anyway): A computer to calculate the universe would need enough memory to save the whole universe, which it is part of. It would thus have to save itself along with the rest of the universe in memory that can be maximally as large as the machine is. In the absurd scenario where the machine was the whole universe itself, there would be no way of getting the information from it, as we cannot leave our universe and look at it from the outside.

>> No.1381103

Has anyone really been far even as decided to use even go want to do look more like?

>> No.1381112

>>1381090
Bonini's Paradox, named after Stanford business professor Charles Bonini, explains the difficulty in constructing models or simulations that fully capture the workings of complex systems

"As a model of a complex system becomes more complete, it becomes less understandable. Alternatively, as a model grows more realistic, it also becomes just as difficult to understand as the real-world processes it represents" (Computer Simulation of Human Behaviour, 1971).

Copied from wikipedia. I'm doing a paper on "The Scientific Paradigm in Anthropology"

>> No.1381119

>>1381103
>Has anyone really been far even as decided to use even go want to do look more like?
Why would anyone even try to be as far to decided to go even want to like more to look at?

>> No.1381121

>>1381103
Don't forget putting his name when you're quoting Heidegger

Oh, and that's a really long wall of text on r9k you linked there. My contribution was my archive vote (2nd one total), not going to read through 100 pages that frustrated you :P

>> No.1381129

>>1381090
Also "The Final Question" - Issac Asimov
It's about entropic decay. Lovely.

>> No.1381133

>>1381112
Every time I come up with a nice paradox someone else has already proposed it a long time ago. Life is cruel

>> No.1381137

>>1381121
He came around in the end after the third link to the Dual Slit experiment video:
http://www.youtube.com/watch?v=DfPeprQ7oGc
I'm sure you know about it, but I link it as often as possible. Easiest way to understand that experiment that I know of.

>> No.1381138

Who was phone?

>> No.1381139

>>1381133
wikipedia the list of paradoxes. Mind=blown.

>> No.1381143

>>1381138
ME!

>> No.1381150

>>1381137 Easiest way to understand that experiment that I know of.
Understanding QM is impossible, all you can do is get used to it. ;)

>> No.1381161

>>1381150
True that. I feel like I'm just repeating it when I explain it. I can define the terms, but when somebody says "but, why?" I get to say spookily "nobody knows!"

>> No.1381175

>>1381150
>Understanding QM is impossible

I don't understand why people say that. I find the idea of electromagnetic fields no less absurd than anything in QM.

>> No.1381181

what shape best discribes the shape of the universe?

>> No.1381213

>>1381175
well we don't completely get the "why" of those either. We know the atoms have to line up positive to negative, but what causes the field exactly is still fuzzy. Can't wait for that grand unified field theory!
>>1381181
I'd say it looks roughly like my dick

>> No.1381231

>>1381175
I understood QM quite often in the past, only to be smashed down by a new problem that threw over everything I've known so far. Universe is solid - learn that solids behave like waves. This goes on like that. You learn how something works until you think you know it, then some crazy phenomenon appears. Last mindfuck was when I learned that white dwarfs don't collapse because of the uncertainty principle.

>> No.1381237

>>1381181
Flat. The universe is flat.
Now don't ask me what flat means, I don't feel like writing a book here. ;)

>> No.1381256

>>1381231
first physics statement on 4chong that didn't have math in it that confused the shit out of me. I thought the uncertainty principle was merely thus: "If you measure a subatomic particle's speed, you can't know its location at the same time." And the reverse. Care to enlighten me?

>> No.1381262

>>1381231
>Last mindfuck was when I learned that white dwarfs don't collapse because of the uncertainty principle.

Josef, Josef, Josef. I thought you were a cool guy, and then you go and pull this shit. Degeneracy pressure is first-year undergrad material.

>> No.1381264

>>1381256

You don't know the uncertainty principle???
Why are you hosting a thread taking questions on theoretical physics?

>> No.1381268

>>1381264
I thought that was it!

>> No.1381272

>>1381256
>If you measure a subatomic particle's momentum, you can't know its location at the same time

Fixed that for you

>> No.1381288

>>1381272
touche' thanks for the correction. I've been out of the field for a while. I don't know anybody personally that I can think of that I can look at and say "Uncertainty Principle" and have them know what I'm talking about. Part of the reason for this thread was to see how well I remember my shit. In philosophy QM and relativity come up often as examples of this or that, uncertainty principle, not so often.

>> No.1381291

given that one is mathematically provable to be two (http://en.wikipedia.org/wiki/Banach–Tarski_paradox)
how many posts have you made ITT?

>> No.1381300

>>1381291
Luckily, since posts aren't objects in space, but information on a drive, the posts you count by hand should be accurate.

>> No.1381313

>>1381300
damn

do you think I can still use this in court? I plan to get mcdonalds to pay me a few million dollars in change

>> No.1381330

>>1381313
Nope. I was criminal justice between physical science and philosophy.

>> No.1381337

>>1381330
:(

would it work in kansas?

>> No.1381356

>>1381337
and, to not make my posting here entirely worthless, why can't Non-locality be used for communication? If we can entangle more than 3 particles (as I believe we can) it should be possible, shouldn't it?

>> No.1381368

>>1381262
So what, you're surprised that I don't know everything or what?
(Also, I doubt that you did the calculation in your undergrad course)

>>1381288
The uncertainty principle says ... sorry, I have to do this.
<div class="math">\Delta A\cdot\Delta B \geq \frac{1}{2}|\langle [A,B]\rangle |</div>
Okay, that was for me, now for the explanation.
There are some things that can't be measured together, such as momentum and position. Take this classical analogy (educational example only, has nothing to do with QM): If you want to measure speed and location of a particle at the same time, you can start measuring the location. But to get the speed, you'll need a second point, then calculate the displacement per time travelled. But when the particle is at the second point, its location has already changed, so you cannot say that the speed you measured is exactly the speed the particle had at the initial location.
In QM, you can't measure position and momentum at the same time; a measure of one always influences the outcome of the other. There are many other things that follow that principle, for example energy and time*: If you know the exact energy of your system, you cannot say how long it will last (hence it's a stable state). On the other hand, if you know its lifetime exactly, its energy is undetermined. This one has practical implications as well, for example it broadens your spectra if you end a state.

*: For the sake of simplicity I won't elaborate on how that's fundamentally different from p and x. Theorists, don't eat me up now

>> No.1381381

>>1381368
Ok, so I was close. Concept was right, just not full.

>> No.1381392

>>1381356
I know there's a simple ("simple" as in "requires less than a page of calculation and can be understood in a matter of minutes/hours") explanation for this, but I cannot remember it, sorry.

>> No.1381394

>>1381368
>Also, I doubt that you did the calculation in your undergrad course

Obviously, but the fundamental awareness of it was in place. I'm surprised that people are surprised by the large-scale consequences of QM.

>> No.1381408

>>1381394
If you say it like that it sounds like it's a very nice example of the QM zoo, i.e. "where does QM occur in the big world". I guess they stopped after the double slit at my university.

>> No.1381427

>>1381408
Shirley you must have seen a little of Bose-Einstein Condensation?

>> No.1381431

>>1381392
if you give me the calculations I'll try to understand it. (or if you can recommend reading/etc)

>> No.1381442

>>1381427
Seen? No. Calculated, yes.
I think the nicest example I've seen so far is suprafluid He.

>> No.1381458

>>1381431
All sources I know of are my handwritten lecture notes. The topic occured in the last week of the semester, I don't understand them myself anymore, you really don't wanna try.
(I'm sure many books on basic QM talk about it though, but I don't have something both specific and English in mind right now)

>> No.1381509

>>1381458
So far I've tried A brief history of time and Quantum theory cannot hurt you, but neither have been that clear for me. I'll try these again, though

>> No.1381525

>>1381509
I was talking more about books on real QM, i.e. introductory theoretical physics books. I'm not sure whether there's a satisfying explanation for quantum teleportation in everyday language.

>> No.1381543

>>1381509

Josef's right, you should try textbooks.

I recommend http://books.google.co.uk/books?id=ffHdd6OVhGMC&pg=PA31&dq=introduction+to+quantum+informati
on+theory&hl=en&ei=GT06TMCAKMexnAeaoYSNBA&sa=X&oi=book_result&ct=result&resn
um=3&ved=0CDwQ6AEwAg#v=onepage&q=introduction%20to%20quantum%20information%20theory&f=fa
lse

>> No.1381581

That's it for me, time to go to bed. Thanks for the conversation.
Oh, and you've created a non-troll >100 replies thread. If you have a medal at home do use it right now. :)

>> No.1381618

Still here. Not as good as Josef (obviously!), but still here.

>> No.1381628

>>1381618
What's your research are? Was it hard getting funding considering most goes to experimental physics?

>> No.1381630

>>1381628
area* oops

>> No.1381631

>>1381628
see
>>1380736

>> No.1381651

>>1381628
Read the thread: this chap is more of an interested guy than a "professional" physicist. Still, nice to have a cool guy on board.

Btw, funding isn't that bad for theoretical studies. My Masters supervisor recently obtained £300,000 worth of funding and he doesn't even know what to do with it.

>> No.1381668

>>1381631

hmm ok. never mind.

>> No.1381676

>>1381651
I appreciate the sentiment. Next time I make one of these threads I'll be sure to state credentials before asked, in the spirit of transparency. Never made a thread over here before. I consider myself a jack of many trades, but I'm certainly no master of physics. I'm good with the concepts, shit at the math (very little practice, and that was long ago). I used to do fairly advanced calculus, but that was 5 years ago.

>> No.1381693

>>1381676

Theoretical physics is basically a branch of mathematics. You would do yourself great favours to learn some math.

>> No.1381707

>>1381693
That would be the case for me IF I intended on pursuing it. Its a hobby, for leisure, and math just doesn't fit that category for me much. Symbolic Logic on the other hand....

>> No.1381733

>>1381707
well cool, but even some of the most basic aspects of theoretical physics are impossible to explain without mathematics.

pop science and analogies are cool n'all, but you're missing out on all the good stuff.

>> No.1381738

>>1381733
Such as? I love this shit.

>> No.1381760

>>1381738
Stuff like quantum field theory, gauge theory, string theory (inb4 herp it's bullshit) and loop quantum gravity. Interesting shit man.

>> No.1381777

>>1381760
string theory is explainable in laymans terms to a degree. Lets see how close I get:
Matter at the fundamental level is vibrating tiny (tiny) strings. See also: >>1380396 for its usage in explaining conservation of information in a black hole scenario. Taken from links given later in thread.

>> No.1381796

>>1381777

That's like saying Goya's Saturn Devouring His Son is just a some paint on a canvas.

>> No.1381799

>>1381796
well, technically.....

>> No.1381801

>>1380396

>When the matter reaches the singularity, the waves emitted are touching the event horizon

waves of what? how are they emitted? what do you mean by a wave "touching" the EH?

>> No.1381811

>>1381801
Trying to find a more scholarly source that uses the analogies that were used to explain it to me. One moment.

>> No.1381817

>>1381811
So you don't actually understand it?

>> No.1381819

>>1381811
its susskind's idea, trying to get a good source....

>> No.1381827

>>1381819
http://www.physicsforums.com/showthread.php?t=411582&page=2
shitty source, but a source, still searching...

>> No.1381871

>>1381817
I do, but my explaination will likely sound like rubbish, and I tend to get terms a little off. String theory is odd that way. Here goes:
If you imagine matter as a spinning propeller, string theory says that that the center part of the prop is the matter, where as the spinning blades are the field vibration of the matter. It turns out that these vibrations get faster and faster as you get further away from the central point (the matter). As you pass the event horizon and move towards the singularity time slows down. You don't notice this, time being relative, but an outside observer would see you slow down to a crawl. They would start to see little propellers form on the tips of the blades, spinning faster. As you get closer, and slower, more and more propellers are visible on the ends of the new ones, and so on. Basically your field vibrations slow down. When you reach the singularity, you are stretch out and your matter is converted to energy (hawking radiation), transmitted through these field vibrations. Since it is transmitted, your information is preserved.

Hope that's clear enough.

>> No.1381876

>>1381871
change stretch to stretched. Then I think I'm good.

>> No.1381896

>>1381871
The reason that Hawking thought that matter was destroyed is that the singularity is very very far from the even horizon, and this matter to energy conversion happens pretty instantaneously, so he didn't think that the energy could be transmitted across the "empty" space. Susskind provides this string theory workaround. Its in his new book, which I have not read.

>> No.1381899

>>1381896
event. Damn my typing today.

>> No.1381926

Does everybody think that explanation is ok? It is accurate to what I've heard, but the analogy is....odd.

>> No.1381956

>>1381896
"information destroyed" not matter. Matter is converted to energy, he just though that the information didn't make the jump. See what I mean about my terms?

>> No.1381967

>>1381926

The inherent problem with the analogy is that it's an analogy. It's word soup.

>> No.1381970

kingdom of hearts 2 download
in megaupload form (for ps2, ofc)

>> No.1381983

>>1380014

How many terms are in the SM lagragian?

>> No.1382001

>>1381967
Only way I know to explain it. Makes sense to me. Wish I could be of more help.
>>1381983
dunno

>> No.1382003

>>1380011

WWＷ.AnＯloＬＴAＬK.Ｓｅ rＥPLＡCｅ_ｌｏｌ_ｗITｈ n
q hnu uudjblzbqkdbtmhl zczslui rymaqo lj

>> No.1382010

>>1381983
hope this helps http://en.wikipedia.org/wiki/Standard_Model#Lagrangian

>> No.1382017

>>1381983
wait, do you mean mass terms?

>> No.1382018

>>1380037
hurr durrf
Pizzas are normally cut into isosceles triangles.

>> No.1382022

>>1382018
not triangles, the crust is curved.

>> No.1382027

If you didn't have access to google, would you be able to answer any questions on theoretical physics?

>> No.1382034

>>1382027
Yes, the only thing I have looked up prior to answering was the SM lagrangian.

>> No.1382062

>>1380877
HURR DURFF
>don't like person's opinion
>sage (oh this'll teach him)
>implying sages FUCKING MATTER

>> No.1382070

>>1382062
that post isn't saging?

>> No.1382094

>>1380014
When is energy not conserved?

>> No.1382110

>>1382094
When it is converted to matter, I suppose. Are these just random questions, or "GOTCHA!" questions? I was hoping to actually help people here.

>> No.1382145
File: 6 KB, 184x184, 80663ac32ca48aa538053b5282261ebc216c31b0_full.jpg [View same] [iqdb] [saucenao] [google]
1382145

>>1382110
Yeah, the SM Lagrangian and the Energy conserved questions were.

FYI: You failed both.
You really don't seem to know too much physics. Do you even know what a Largragain is? A Hamiltonian? Do you know anything about the Calculus of Variations? Levi-Civita Notation?

What do you actually think you know?

>> No.1382186

>>1382110
Can you explain to be Global Gauge invariance?

>> No.1382188

>>1382145
I'm far better with overall concepts than most people. Honestly I didn't expect this board to be full of experts. I figured it was just another board on 4chan. On the actual conceptual questions (as opposed the the specific mathematical ones) I feel like I've done pretty well. I didn't expect a "I'm gonna get this guy!" thread. More of a "What's an accretion disk?" "How does relativity work" kinda stuff, not "How many higgs bosons does it take to screw in a photon?" kinda stuff. Never claimed to be an expert, I just wanted to get a good discussion going.

>> No.1382193

>>1382186
nope

>> No.1382198

>>1380014
How long would it take to reach the andromeda galaxy if we had a ship going 98% the speed of light?

>> No.1382209

>>1382188
Ok, well least your honest.

>> No.1382212

>>1382198
approximately 2,555,000 years. That is not taking into account the fact that it is coming towards us at about 300 km/s.

>> No.1382215

OP, I can't wrap my mind around this:

The photons we measure as the cosmic microwave background radiation peak at a wavelength λ = 1.9 millimeters.
Given that the universe expands, as described by the Big Bang theory, they had a wavelength shorter than today's wavelength.
Thus: λ_past < λ_now
Given that:
E = hc/λ, that means they lowered in energy.

Where did that energy go?

>> No.1382219

>>1382188
Ok, how does SR work?

>> No.1382223

>>1382209
Yeah. This is fun for me. People have been taking it too seriously! (inb4 internet science is srsbsns)

>> No.1382237

>>1382215
My guess is that it didn't "go" anywhere, but just spread out, since the universe is expanding. A guess.
>>1382219
please, no random abbreviations. SR could mean more than one thing in different contexts, I would assume.

>> No.1382251

>>1382215
Also, possible doppler effect?

>> No.1382252
File: 13 KB, 250x226, 001f.jpg [View same] [iqdb] [saucenao] [google]
1382252

>>1382212
No, another wrong answer.

http://www.phys.ncku.edu.tw/mirrors/physicsfaq/Relativity/SR/rocket.html

It only takes 28 years to reach andromeda. Yeah, just as I thought, you don't know SR.

It is cool that you are interested in physics, but you really need more math to learn shit like that.

>> No.1382262

>>1382252
Like I said, like 10 times in the thread, this is focused on concepts, I'm not an expert. The point here is to help out laymans. I didn't say "Quiz me, I know everything" at the beginning. Seriously, what's the point in asking if you already know?

>> No.1382274

>>1382252
Its 2.5 million light years away, and I said I didn't compensate for relative motion.

>> No.1382286
File: 61 KB, 407x536, I%20agree.jpg [View same] [iqdb] [saucenao] [google]
1382286

>>1382237

SR is the abbrevation for Special Relativty

GR is general relativity

QM is quantum mechanics

QFT is quantum field theory

CFT is classical field theory

CD is chromodyanmics

QCD is quantum chromodynamics

ED is electrodyanmics

QED is quantum electrodynamics

etc

see, you end up learning somthing too...lol

>> No.1382300

>>1382286
>>1382286
and that's the point.
If he had said special relativity I would have said that the speed of light is constant regardless of the relative motion of the observer. General relativity talks about the warping of space by gravity/mass and the slowing of time as you approach light speed. This shit I can do off the top of my head.

>> No.1382304

>>1382274

Really...just stop. You need math to actually understand Physics, okay? You really, really do. Additionally, the Andromeda question was (mostly) a conceptual and you can't even recognize that because - well - you are ignorant. Go open a real textbook instead of the watered down pop-science nonsense. And learn the damn math.

>> No.1382307

>>1382262

get the fuck out

>> No.1382311

>>1382304
You say that as if I am an aspiring physicist, I'm not. I'm a hobbyist. internet is srsbsns I know.
>>1382307
nah

>> No.1382314
File: 24 KB, 400x600, 1278649196555.jpg [View same] [iqdb] [saucenao] [google]
1382314

If an object moves along a vertical circular path (think ferris wheel) with a certain initial velocity and with no outside forces acting on it except gravity, how can I find an equation(s) giving its position as a function of time?

(not hw)

>> No.1382316
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1382316

>>1382262
>>1382274
Yes, it is 2.5 million ly or whatever.
But that doesnt mean that if my ship is going close to the speed of light it would take me 2.5 million years. Why would you use Galilean Relativity?

It only takes me 28 years becasue of SR, its basic time dilation.

>> No.1382320

>>1382314
If no outside forces were acting on it, it wouldn't move in a circular path.

>> No.1382327

>>1382320
It's trapped on a circular track-thingee. Centripetal force isn't an "outside" force (in my mind, anyway)

>> No.1382328

>>1382316
You didn't say from what perspective. I was using stop time. If you had said how long does it take as perceived by the people on the ship, and not the people on earth, then I would have at least linked you to an appropriate source. You didn't give me all the required info.

>> No.1382337

>>1382328

>perspective
>SR
fucking idiot

>> No.1382339

>>1382327
But the forces of the track acting on the object is an outside force. I'll see if I can find you something, can't pull that one out of my ass.

>> No.1382342
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1382342

>>1382311
>I'm a hobbyist

You're a jackass, that is what you are. All you are doing is talking out of your ass.

>> No.1382347

>>1382337
If I'm on earth, I experience the ship travelling in earth time. If I'm travelling with the ship, time slows down for me too. You know this.

>> No.1382356

>>1382327
http://www.myphysicslab.com/RollerSimple.html
roller coaster in a loop work? Sounds like what you are looking for.

>> No.1382357
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1382357

>>1382328
>stop time

WTF is stop time? is it fun just making shit up?

>> No.1382364

>>1382342
Yes, and you are certainly contributing to the scientific content of the thread. If you think I answer something wrong, correct me. This isn't a penis competition, its a 4chan forum on science. If you want to talk to experts you are in the wrong place.

>> No.1382372
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1382372

>>1380014
>>1380014
ITT: physicst hobbist = dumbshit

>> No.1382374

>>1382357
stop time, meaning my motion is close enough to 0% of the speed of light to essentially ignore time dilation. So I'm not using the scientific terminology, big deal!

>> No.1382378

>>1382328

WTF are you talking about? Let's look at the question:

How long would it take to reach the andromeda galaxy if we had a ship going 98% the speed of light?

Can you seriously not glimpse that the question is setting a reference point inside the rocket?

Dude, really...you do not know anything. You got a few ideas in your head and decided to come here to sound smart. You don't. You sound really, really stupid.

>> No.1382387
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1382387

>>1382364

>> No.1382388
File: 23 KB, 485x323, 20081111-hardcore-gay-sex_0.jpg [View same] [iqdb] [saucenao] [google]
1382388

>>1380014
you sound like a faggot (engineer)

>> No.1382390

>>1382378
You said how long does it take. You didn't say for who. Unless you specify these things I'm not going to pick apart the question. You don't like it, don't ask me anything.

>> No.1382404

Object A is moving with respect to object B. How can A's clocks run slow in B's frame while B's clocks run slow in A's frame?

>> No.1382407

>>1382364

that's quite demeaning to /sci/ that you thought you could educate us. some people on /sci/ are actually pretty intelligent/involved in academia.

>> No.1382409
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1382409

>>1380014
It's nice seeing 10 year olds try physics.
Maybe one day if you learn some math, you can do real science.

>> No.1382412

>>1382390
>You didn't say for who.
>Can you seriously not glimpse that the question is setting a reference point inside the rocket?

I don't think this faggot understands inertial reference frames.

>> No.1382416
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1382416

>>1380014

>> No.1382424
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1382424

>>1380014
>>1380014
>>1380014

>> No.1382438
File: 126 KB, 450x373, 1277329215232.jpg [View same] [iqdb] [saucenao] [google]
1382438

>>1380014
POP SCIENCE IS SHIT!

>> No.1382443

>>1382407
never been to /sci/ before. Figured I I'd jump in. The reaction before this recent wave of trolls was positive. I'm going to a fish fry now, ya'll have fun.

>> No.1382454
File: 19 KB, 400x297, wtf_is_this_shit.jpg [View same] [iqdb] [saucenao] [google]
1382454

>>1380014
GTFO

>> No.1382455

>>1382409
>>1382416
>>1382424
>>1382438
timestamps spell samefag. Reported for spam.
>>1382404

>> No.1382460
File: 181 KB, 720x540, you_gay.jpg [View same] [iqdb] [saucenao] [google]
1382460

>>1382443
>trolls

>> No.1382463
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1382463

>>1382443
DON'T COME BACK EVER!

>> No.1382468

>>1382443

No, these aren't trolls. If anyone is it's you.
The reaction wasn't positive, some guy called you up straight away.

The only positivity was some bullshit philosophy dick sucking.

>> No.1382469
File: 104 KB, 270x243, 1272267984722.png [View same] [iqdb] [saucenao] [google]
1382469

>>1382455

Removing your tripcode doesn't help.

>> No.1382480

>>1382463
global rule violations. Reported for the end of the thread.
3. Do not post the following outside of /b/: Trolls, flames, racism, off-topic replies, uncalled for catchphrases, macro image replies, indecipherable text (example: "lol u tk him 2da bar|?"), anthropomorphic ("furry"), grotesque ("guro"), or loli/shota pornography.

10.No spamming or flooding of any kind.

>> No.1382486

>>1380014
OP SUCKS THE COCK

>> No.1382498
File: 49 KB, 450x571, butthurt2.jpg [View same] [iqdb] [saucenao] [google]
1382498

>>1382480
ITT: Butt-hurt 10 year old faggot

>> No.1382523
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1382523

>>1382480
LMAO

I feel bad now. Its cool you like science and physics. But don't try an "take" questions, unless you really know your shit.

>> No.1382535
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1382535

>>1382480
So in addition to not knowing physics, you
don't understand what a internet "TROLL" is.
No one was trolling you.

>> No.1382549

>>1382535
apparently didn't read the "spamming, flaming, and image macro responses" portion

>> No.1382583

bump for the weirdest thread I've seen on /sci/ ever.

>> No.1382601
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1382601

>>1382455

>> No.1382633
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1382633

>>1382549
Serioulsy OP, u a 10 year old girl?

>> No.1382648
File: 64 KB, 446x354, fail~1.jpg [View same] [iqdb] [saucenao] [google]
1382648

>>1382633
No, a 10 year old girl has more balls then the OP.

OP SUCKS

>> No.1382655
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1382655

>>1382549

>> No.1382686

You just love bumping this thread don't you, macro guy?

>> No.1383522

I am detecting massive quantities of anonymous butthurt in this sector.