/sci/ - Science & Math

Theoretical physics is BULLSHIT and NOT SCIENCE. String theory, relativity and quantum shit are pseudo-religious concepts opposing SCIENCE.

be gone science heretic!

warp engines how do they work?

>>4350378
What's the deal with string theory? Is it likely to be widely accepted? If so, are we likely to be able to do anything cool with it?

doesnt theoretical physics include all classic physicis from newton to fluid mechanics, electrmagnetism? why do people think of string theory everytime?

Why not include consciousness into current theory? I would imagine, since we are the ones interpreting the universe, our consciousness would play heavy into the ultimate theory of everything.

Is the topology of the universe such that if you travel in one direction, eventually you will come back to where you started?

Do you think gravitons exist? If so, wouldn't gravity be a field rather than something that causes space-time curvature?

>>4350395
>Is it likely to be widely accepted?
Define accepted? There are a HUGE amount of peolple working on it.
>are we likely to be able to do anything cool with it?
Cool math, for sure.

>>4350397
If you're asking what kind of questions, then yes of course. I like questions with nice math the most.
>why do people think of string theory everytime?
which people and at what times?

>>4350404
Do you know how to model consciousness? Many would argue that it's just the brain doing things and as such a side product of the fundamental physics that makes up any matter

>>4350409
nobody knows (assuming by "travel in one direction" you mean along a geodesic). It would simeplify the math if the universe is compact, so I wish for it to be like that.

>>4350415
I don't like the term "exist" too much, especially regarding physical theories. What I do think, is that it's possible to build a model, which explains real world phenomena and which involves gravitons

>>4350390
>>4350395
>>4350397
>>4350404
>>4350409

Senior Physics undergrad, accepted to grad, let's satiate these questions until OP gets back

>warp engines
magic

>What's the deal with string theory?
It's 'just another theory' just like the standard model is, only much less tested or test-able. Acceptance (or rejection) is probably 30-50 years further down the road. Newtonian mechanics is the only very "intuitive" theory to humans but we do cool stuff daily with quantum and relativity, so my hunch would be yes.

>why do people think of string theory?
Media, and there are a lot of researchers on it. It's a pretty big investment in an unknown return.

>consciousness
Sure, give us an operational definition of consciousness

>you will come back to where you started?
Doubtful but my astro is too rusty to be sure.

>>4350430
that's me btw., I'll now write "OP" and hoe I don't forget.

>>4350434
what do you do/thesis?

fuck. okay, from now on.

>>4350430
But wouldn't a graviton be a particle associated with a fundamental force? Are you suggesting the photons don't "exist"?
Also, you didn't answer whether you think gravity is akin to an electromagnetic field or whether it's a force that curves space-time.
You didn't answer

>>4350378
All reality is contained within consciousness, correct?

Is there any chance of dark matter being baryonic?

Also wouldn't that be mathematics? Just rigorous logic, transferrable concrete ideas of the mind?

>>4350449
No. Now you're being a philosophical faggot.
/not OP

>>4350456
Prove that all reality is not contained within consciousness.

What is the curvature of the universe?

Also, Lawrence Krauss is speaking at my UNI next week. Jelly?

>>4350430
>>4350409
>Is the topology of the universe such that if you travel in one direction, eventually you will come back to where you started?

>nobody knows (assuming by "travel in one direction" you mean along a geodesic). It would simeplify the math if the universe is compact, so I wish for it to be like that.

Yes, I did mean "if you travel along a geodesic".

Followup: how could there have been a Big Bang if the universe is not compact? Wouldn't that imply that at some point in time it suddenly jumped from finite to infinite in extent?

>>4350447
A graviton would be a particle associated with what we now call fundamental force, yes? I don't make statements about what exists or not and I don't argue about if F=ma is "true" or not. F=ma certainly works to compute several stuff. If there "are" no particles with simultaneously sharp position and momenta, then the acceleration concept dosn't work like that - that's not preventing people from learning it. Regarding the last point, people say 'it's not a force' in general relativity, so 'a force that curves space-time' is an uncommon formulation. In any case, it's a (Tensor-)field in general relativity as well.

>>4350449
not really theoretical physics, since I don't have a precise way of talking about consciousness.

>>4350450
I'm afraid I will not be able with any questions containing the word "dark", sorry.

Are there going to be non-meta physics questions as well?

We know that time is relative and that there is no absolute measure of time. So what does it mean when one says the universe is 13.75 years old?

Is that the same number for every intertial frame?

>>4350484
13.75 billion, I meant. Of course.

>>4350484
And I meant "inertial".

Biophysics PhD student here.

1) What is your opinion of biophysics?

2) What is your favorite cereal?

>>4350465
>What is the curvature of the universe?
In general relativity, it's equal to

http://upload.wikimedia.org/wikipedia/en/math/2/e/6/2e6cc7e59bd3cbdf4f1251e97ce42d4c.png

where c is some constant, T is the energy momentum tensor, g is the metric and \Lambda is the cosmological constant. That's really just the Einstein field equations solved for the curvature tensor.

http://en.wikipedia.org/wiki/Einstein_field_equations

The answer is that it heavily depends on the matter in it

http://en.wikipedia.org/wiki/Energy_momentum_tensor

>>4350467
yeah, well spatially compact of course. the universe as a whole, the 4-dimensional manifold, always has this time dimension, but the point is that the space parts are supposed to go together like a cone.

>>4350484
http://en.wikipedia.org/wiki/Cosmic_time

also
>here is no absolute measure of time
is somewhat wrong. there is no absolute measure to meassure the time between two events (because that value depends on the observer), but of course ever observer can meassure his own time without problems.

>>4350497
depends on what/which field you mean by biophysics. I'm intrigued by non-equilibrium thermodynamics.

and müsli at the moment, if that counts.

explain the higgs field to me.

why haven't you fags found the higgs particle OR gravity particle yet?

Theoretically speaking, what are the chances that I will get laid in the next 5 years?

>>4350512
Exactly zero.

>>4350378

what are electrons made of?

What is vacuum energy?

Are you satisfied with the Copenhagen interpretation of QM or do you think we need to go in another direction, like Bohmian Mechanics?

Ask a guy with a theoretical degree in physics anything.

I almost know what I'm talking about

>>4350537
tiny strings? I don't know, they are elementary particles in the Standard Model of physics, which means they are no composite of something else.

Could there be entirely different realities one vibrational level higher or lower than our current reality frequency? Complete with other beings and different laws of physics? :o

Let's say a body of mass m is at a distance R from another body of mass M. How do you find the acceleration of the body of mass m in the referential of the body of mass M, in respect to time? (t=0 when r=R)

We have a(r) = G(m+M)/r² , but what about a(t)? I feel like I'm having a brain fart here

>>4350503
> en.wikipedia.org/wiki/Cosmic_time
Excellent. Thanks.

>the universe as a whole, the 4-dimensional manifold, always has this time dimension, but the point is that the space parts are supposed to go together like a cone.

I don't quite follow. [BTW, I have a PhD in math, so i'm not confused by the terminology. But I've never learned any of the physics that motivated the study of Ricci flow and whatnot. Which is kind of irritating.]

When you say the "4-dimensional manifold", you mean 4 spacial dimensions (for any fixed time), I would assume. Right? I've wondered about this: I would guess that the universe is (spacially) a 3-manifold embedded into higher dimensional space. Do we have a good guess at what is the minimum dimension of this larger space? Is it 4?

I don't get the "cone" bit.

Is there a reference you can recommend on this topic?

>>4350378
what uni(s) did you get your degree(s)?
also, do you think you'll find a job

Do you think you'll ever see a resonance cascade?

>>4350546

I do know that they're considered as "elementary" from standard physics, but I kinda dislike the axiomatic approach for real systems, it's kinda too abstract and you should have a definition for something that is not "composed from something else"

>>4350544
Satisfied is certainly the wrong word. But usually I take an operational approach.

>>4350540
I'm not sure how to go at this. The wikipedia article is pretty long, have you read it? If you have any specific question, I'm glad if I can help. For now let me just point out that the "vacuum" is just the ground state of the quantum theory, and the emptiness concept is not the naive one from classical mechanics.

>>4350554
I don't know which frequency you speak of but I certainly don't know how to make statements about other universes.
>Could this be true? Yes, it does.
(not sure if quoted correctly)

>>4350557
>PhD in math
ah, very good.
>Ricci flow
that concept is certainly not necessary here.
Anyway, reformulate the question, and I'll correct my formulation in your terms.

>>4350562
only going to answer actual theoretical physics questions here, but a european university, and yes, I don't think that's a problem at all.

>>4350564
is that a real question?

>>4350544
I'm the guy who posted >>4350557 , not OP.
I know a mathematical physicist who rages about this. He is a huge proponent of Bohmian Mechanics and thinks that most theoretical physicists are bone-headed on the topic. I can't weigh in (it's not my field), but I've often wondered if he's correct.

>>4350574
there is a definition, but it's a mathematical one of course. other than that I'd say the axioms are the axioms of the theory describing reality, they are not axioms of reality themselves. But this is getting fuzzy.

do you have an explanation behind why matter is chosen over antimatter

>>>4350564
>is that a real question?

Its a half life reference. Jesus, what were you doing as a kid? studying!?

>>4350595
>Ricci flow
>that concept is certainly not necessary here.
I know. Just sayin' I wish I knew more of the physics that motivated so much of the math I've learned. But it's hard to find sources that explain theoretical physics to a person who a) has no problem with the math, but b) knows very little basic physics.

>Anyway, reformulate the question, and I'll correct my formulation in your terms.

Well, it's tough. I wasn't sure what you meant by "the space parts are supposed to go together like a cone." I'm reading http://en.wikipedia.org/wiki/Shape_of_the_Universe right now ...

>>4350608

Shouldn't we try to find a non axiomatic definition for not falling into the "godel effect"?

is there an antimatter version of myself? Do you speak spanish?

>>4350621
not really, and I don't find that particularly interesting. The inbalance is, but which ones wins doesn't matter, does it.

>>4350652
okay, so no question, I guess? And you could just start to read books. You can eighter start reading books for physics undergrads, with boring math for you, or start reading books with nices math, but then you don't get the physics fed to you. Arnolds Classical Mechanics would be a start in that direction, I guess.

>>4350661
incompleteness? that's not really a proplem, is it. Also, how would axiomatising stuff resolve that point? Incompletness is found in perfectly axiomatized systems.

>>4350663
no and no, where the first question is kinda strange, if it refers to "another universe" is not particularly physicals.

>>4350682
Cute girl ruins her looks with shitty hair dye and dreads... All of my why

Isn't all physics theoretical? Isn't all of science theoretical? I mean the models of objects we call atoms could be something else entirely.

What's your opinion on black holes. Do they exist and if they do, what happens to the information?

>>4350687
Josef complained to me you're still banning him. (Not implying he would come back, but he still is banned now and then)

>>4350696
Well, no matter what concepts you introduce to talk about it, you still can find applications, and that's where the non-theoretical part comes in.

There are not too many questions about some specific physical theories on this board, are there?

When will we have a working plasma fusion reactor that meets net energy?

>>4350709
How can communicate with Josef when he is dead?

>>4350709
Josef deserves to be banned. This way he has enough time to figure out why 0.999... does not equal 1.

>>4350707
yeah, I think they are there. But I'm not well educated on the holographic principle.
Like most physicists, I will not be able to give you information regarding unsolved questions alla big bang, dark matter, dark energy, the inside of black holes etc., sorry.

What if gravity does not really slow time but motion? It may sound like wordplay, but wouldn't thinking of accelerating forces as slowing down all other motion make more sense than thinking they slow time?

I could need some good laugh.

So, Mr theoretical physics PhD, what is the highest math you know of?

>>4350726
Well, if you have a clock and move them along different paths, both from A to B, then they will show something different. Clocks are usually defined as periodic processes. You're suggesting that one should change back to an absolute time and change forces such that the clock ticks more slowly, right? I see two problems why that would be difficult (not to mention that it would produce the same results, thus being not a better theory): You have to change/introduce forces that have the same effect for very different matter/energy objects, i.e. if must affect the ticking of normal watches made of atoms just like watches made of light between mirrors, and you also would have to do this in the nonlinar way time and acceleration are related. Seems very unpractical to me. After all, nobody really has a philosophical problem with the GR understanding of time.

>>4350738
that sounds like an aggressive statement, don't know if I want to answer...
Under which conditions are you going to laught anyway.

>>4350757
Thanks for that.

What are some mind-bending theories or findings that you'd use to wow laymen about your field?

Hey OP, by PhD student,what do you mean?
I know there's a name for your kind.

>>4350789

scientist

>>4350682

I'm just saying that since physics is concrete and non abstract, the existance of axioms like "the electron is an elementar particle" are somewhat strange.
I mean, in math they are perfectly fine since we're dealing with a theorical model based on fixed rules (axioms) that cannot be disproved if you want to keep that model, but we're talking about real models, and if you accept a real axiom without looking for more explanations, there is something going wrong.

What will be the ultimate outcome of the accelerating expansion of the universe?

Looking for a job?

Are you working on anything interesting currently?

>>4350783
define "my field". What I do now is fairly practical, i.e. it has to do with macroscopic effects.
People like things like
http://www.youtube.com/watch?v=Ws6AAhTw7RA
http://www.youtube.com/watch?v=-uAYDGgXB7E

Otherwise it's sometimes difficult to explain why something is elegant of beautiful, if most of it is in the math...

>>4350789
Trying to earn my PhD.

>>4350835

no i mean, there'san official name for you guys.
Pre-doc?
post-masters?
I'm just wanting a very rough list of post-graduation academia landmarks.

>>4350840
-undergrad student
-grad student/PhD student/PhD candidate
-post grad
I think thats it, however, I'm not from america.

>>4350814
I don't know what you mean with these two levels of models or how you see the world.
I'm pretty sure there is a reality, and what people do (i.e. phyiscs) is associating names with things they observe and then build a mathematical model to predict things, always in therms of the things they came up with in the first place. There are newtonian particles and F=ma, there is the Newtonian Gravitational Force, there are particles in quantum mechanics, the Schrödinger equation, gravitons in string theory, smooth curved specetime in general relativity, there is thermodynamics and so on. These things have to exists in any way, but from an operational point of view, they all have practical meaning. We don't have a name for temperature squared, but we came up with classical trajectories. What if there is some alien species, where the individuals are intelligent but microscopically small, or huge. What if they are not bound to a compact material body like we are? What if they perceive the world in a totally different way, and so they never introduces classical particles in the first place. What if they are so small that the wave way of thinking about matter is totally natural to them. What if they found T^2 to be a useful quantity in their theoris and not just the temperature T. I don't think one should take any of the things like electrons, spacetime and etc. too literal. There is no guaranty that there is a "theory of everything" or that all physica effects are explainable in mathematical terms. But you know, it's obviously possible to come up with models, and in the end you get an iPod.

>>4350840
-undergrad student
-grad student/PhD student/PhD candidate
-post grad
I think thats it, however, I'm not from america.

>>4350814
I don't know what you mean with these two levels of models or how you see the world.
I'm pretty sure there is a reality, and what people do (i.e. phyiscs) is associating names with things they observe and then build a mathematical model to predict things, always in therms of the things they came up with in the first place. There are newtonian particles and F=ma, there is the Newtonian Gravitational Force, there are particles in quantum mechanics, the Schrödinger equation, gravitons in string theory, smooth curved specetime in general relativity, there is thermodynamics and so on. These things have to exists in any way, but from an operational point of view, they all have practical meaning. We don't have a name for temperature squared, but we came up with classical trajectories. What if there is some alien species, where the individuals are intelligent but microscopically small, or huge. What if they are not bound to a compact material body like we are? What if they perceive the world in a totally different way, and so they never introduces classical particles in the first place. What if they are so small that the wave way of thinking about matter is totally natural to them. What if they found T^2 to be a useful quantity in their theoris and not just the temperature T. I don't think one should take any of the things like electrons, spacetime and etc. too literal. There is no guaranty that there is a "theory of everything" or that all physica effects are explainable in mathematical terms. But you know, it's obviously possible to come up with models, and in the end you get an iPod.

>>4350895
>iPod

reported for apple marketing

>>4350895
thanks for the names.

you deleted your post two-three times for some reason,different picture each time.

have you read the PhD webcomic?
>pic related

>>4350905
I deleted it, because I forgot the "OP" name, both times.

I haven't read a single of these comics, but I saw the movie
http://www.imdb.com/title/tt2066040/

>>4350913
I hadn't heard of this, I guess I'll go watch it.
thanks!

by the way, when you delete your post it deletes the image as well so you can reuse it again without issue.

>dying of alpha radiation
>MFW

Is there a lot of Math in Theoretical Physics? I really adore Math and also a little less, how the world works and this field sums up both. Also, what is the average salary for people who get PhD's in the field.

>>4350931
I know, but every time I delete a post, I have to refind the thread and the pics are obviously just random.

>>4350944
there is a lot of math. Ask me about salary in some years.

Is the universe finite? Is it bounded?

Why don't you tripfag?

>>4350953
read the thread. Obviously nobody knows for sure

What is 1/0 ?
Is 0.999.. = 1 ?
Is infinity * 0 = 0 ?
What is 6/2(1+2) ?

>>4350956
Wait, let me reformulate:
How can the universe be infinite according to the big bang theory? How can it be bounded if the universe is defined as the entirety of space?

>>4350962
not OP, but still: READ THE THREAD. The question has already been asked.

>>4350962
the second question is more easy to answer than the first. If, as someone said, you come back if you'd go in one direction, like the surface of a ball or a torus, then it's compact. (bounded is the wrong word, since like the surface of the ball, there is no bound).
The infinity thing gets overshadowed by the horizon of observable things. I can't explain all the singularity magic here, but let me just point out that it's allowed, that there are places in the universe, which are truly seperated from each other. Practically speaking, things tend to leave "each others universe".

http://en.wikipedia.org/wiki/Cosmic_light_horizon

But seriously, I'm not too fond of all these hardly answerable cosmology questions.

>Refusing to answer questions about dark matter

Well you're no fun.

>>4350987
maybe that's a better link regarding the specific point I wanted to make
http://en.wikipedia.org/wiki/Event_horizon#Particle_horizon_of_the_observable_universe

>>4350987

How do I into physics professorship? Is mathematical physics most rigorous physics major? How should I prepare for undergraduate research? Any suggestions?

I am prepared to work until I die, thrice. I really want this.

>>4350959
>What is 1/0 ?
Utter nonsense.

>Is 0.999.. = 1 ?
Yes.

>Is infinity * 0 = 0 ?
If you define the extended real numbers <span class="math">[-\infty,\infty][/spoiler] for the purposes of defining Lebesgue integration, you define <span class="math">\infty\cdot 0=0[/spoiler], because a line segment (infinite length, zero width) has area 0. But note that certain properties of the real number system does not carry over to the extended reals. For instance, <span class="math">\infty[/spoiler] has no additive inverse, nor a multiplicative inverse.

>What is 6/2(1+2) ?
9, assuming you do not intend to include everything to the right of / as part of the denominator. Another set of parentheses will eliminate any ambiguity.

>>4351032
>line segment
Drop the "segment". Don't know why I put that there.

>>4351021
>undergraduate research

mathematical physics is most rigorous physics, yet. It differs from theoretical physics (if you want to make that distrinction) in that they are concerned with some mathematical problems the theoretical physics people (lets say Standard Model particle physicists) don't care too much about and "the problem" is that they don't produce too usefull results. Complete theories in mathematical physics usually don't describe nature, but well, it's of course 50% mathematics.

My very general suggestions are that you read a lot and write down everything you understand (once you do) and make a draft of how you think things work. That's a very tiresome thing to do, but if you don't write down what you think/how you guess things work, you'll overwrite it with what you learn later about the subject. Also, you have to formulate your vague ideas.

I can't tell you much about the american educational system.

yet = yes.

>>4350987
>(bounded is the wrong word, since like the surface of the ball, there is no bound).

A compact manifold with no boundary is still bounded. "Bounded" just means there is a finite upper bound on the pairwise distance between all pairs of points on the manifold; "distance" is the minimum arclength along all geodesics connecting the two points.

The only thing theoretical is OP's PhD. Bazinga

>>4350895

that's exactly what I wanted to say.
it's just the fact that from a rational point of view I find it really hard to digest that something like an "elementary undivisible particle" does exist.

anyway another question, why we accepted the QCD as "good" even if there are massive math errors in the theory?

>>4350378
What's your field of research?

>>4351073
yeah, I doubt the matematical usage of the term (which makes a space without boundary a bounded space) would have been very helpful.

>>4351105
I was against the usage of the term "exist" all along
>>4350430

>>4351114
PhD wise, physical chemisty. Have been doing (very) high energy physics before.

Oh, and I don't know which *errors* your talking about.
There is just the *challenge* of renormalization. ;)
But that's a beautiful thing on it's own. Also, there are many people now regarding pretty much any QFT as effective, so that's not too problematic from this side.

How does it feel that a 12 year old knows more physics than you?

>>4351138
but there are significant approximations.
don't they lead to non trascurable errors?
(last question then I'm done)

>>4351159
I'm not completely sure if you're talking about the general problems in the formalism or some specific problems. All predictions in quantum field theory are just approximations, if you will. Computations of Feynman diagrams only up to some order. Beyond 5th order (at the very best) is usually not computable.
I'm not aware of errors in the "really wrong prediction" sense which can't be explained away by the fact that the taken approximations are not allowed.

>>4351180

mainly concerned about the formalism, I believe that there are some flaws, heck it's not even a problem of believing, there are some flaws.
doesn't this cause any problems?
I'm not really a lab rat.

>>4351189
lab rat?
I've never worked in a lab.
I'm not sure we are talking about the same thing here.
As far as the infinities in QFT go, people have a good understanding of why they are there and it became to be a pretty neat (meta-)theory on it's own.

>>4351198

I'm sorry I didn't want to offend you in any way.
Just wanted to say that I'm not connected with the experimental physic.
my main concern was about the mathematical formulation of the QCD.
but I see that it's, sadly like I was taught, a problem inherent in the standard model.

OP, correct me if I am wrong, but would this image be accurate from a human perspective?

>>4351204
lol, I didn't see any offence, and I have nothing against people working in labs. I mean there is one 10 meters from my desk.
And again, I wouldn't formulate it as an "error" or "problem of the theory" per se.

here the related wiki readings
http://en.wikipedia.org/wiki/Renormalization
http://en.wikipedia.org/wiki/Regularization_%28physics%29
http://en.wikipedia.org/wiki/Renormalization_group

How do you deal with the fact that there will never be a theory of everything?

>>4351221
what does 'still point in the universe' mean?
consider the situation from the point of view of the black hole. If the object is such that it truly doesn't change the positition, with respect to all systems, then the distance to the black hole would never change. other than that, if it just gets sucked up, then yes, if you still think of the object as existing inside the black hole like that, then it must stay in there, obviously. The black hole will of course get heavier.

>>4351236
how do you deal with the fact that some flowers are red?

>>4351244
So you accept it as being a fact?

How was the earth made by God in under 7 days? And why do we have micro-evolution but not macro. And why is The USA nr.1

>>4351249
mhm, thats not what I wanted to say, but it sound okay. The expression "deal with the fact" implyies that I'd see it as a problem, which I don't.

>>4351256
Well I was considering going into theoretical physics to figure out a theory of everything, but then I learned there would never be a theory of everything, the closest you could get to one, at least in our lifetimes, would be formal logic/philosophy. Of course a physics background would help, but the nitpicky math would not be so helpful, rather the concepts instead since they could be used as a 'check' to make sure your philosophical ideas/logic coincided with 'reality'.

>>4351244
>what does 'still point in the universe' mean?
precisely what you said: it isn't moving,so the distance between it and the singularity is only changing because the singularity itself is moving.

So I am correct in assuming that, in spite of it's lack of motion in space, it would still be trapped within the EH and 'towed along' within the EH,or would it rather just be drawn into the singularity instantly rather than still existing as a separate object from the perspective of the singularity?

>in other news I just had an image in my head that, assuming God is real, then he made black holes feasible for the purpose of being an already existing defense to protect earth from gamma ray bursts and extinction asteroids and such.
>>4351253
>how god 7 days?
that's how long it took him to compile the universe.
>why micro no macro?
because physics.
>why usa #1?
because biggest military with best guns. also because of our long time alliance with the jews making hem have their monetary operations here.

>>4351271
>>4351244
oh,and what if the magical still point object was stuck in one point in time instead of space?

Can you explain the standard model to me? I get the basic ideas, but I'm not sure on a few points. For example, pions, kaons, mesons in general, confuse me. What do they do, and how come they don't annihilate when they're composed of quark-antiquark pairs? Similarly, all those baryons, do they do anything specifically that we care about? Also, can you explain quasiparticles?

What is up with those punks known as neutrinos?

>>4351281
what's your background?

http://en.wikipedia.org/wiki/Pions
here I just want to point out that picture, where you see that it's not a pair of say up and anti-up, but different particles.

>do anything specifically
except for being stable composite particles/resonances which make up matter?

>Also, can you explain quasiparticles?
like phonons? If you know some QM, then you can just think of them as a handy set of states suitable for describing the whole ensamble, which make up the system.

>>4351296

"Do anything specifically" as in purpose in the standard model. Where do they show up? How do they interact with or help explain fundamental forces?

In regards to phonons, they can just be considered the quanta of sound waves, correct?

Also, I forgot to ask this before, but is there an intuitive way to think about why electrons emit radiation when they're accelerated, or is it simply a result of Maxwell's equations?

>>4351314
the stable composite particles let you explain what's going on without reference to quarks or guons (the actual fundamental particles). Mesons like pions let you explain the interactions of barions, like protons, like photons explain interaction between electrons or glouns for quarks. Notice that the "hard particles" are fermions (quarks, electrons, protons) and the interaction particles are the bosons (gluons, photons, pions and also phonons waves in solids). See also Yukawa Theory.

And I donno, momentum density conservation (if there is radition, then there is another pointing vector)?

And I'm off now, this was a terrible experience.