I don't really get the arc length parameterization thing. I could have sworn when I looked at geodesics the equation I euler-lagranged was identical regardless of parameterization... I don't have Carroll ( @0celo7 ) but whatever, I'll figure it out. I've been away from a pencil/paper since I had the thought.
@bolbteppa It's funny that you refer to Lev Landau simply as "the man behind the scenes" of Susskind's course. Landau won the Nobel prize in the 60s, and the motivation was in part his pedagogical work done with his books ;-)
...that were the minimal requirement to be considered for a position in his school....
When you think of a lightbulb and you know physics, e.g. you can understand everything, electrons flowing through copper wire passing through a tungsten filament colliding with the Tungsten atoms transmitting energy raising it's electrons to higher levels only to then revert back to their original states, releasing light in the process, and why it's enclosed in a gas case etc...
How about with a computer or laptop? Where should I read to find out how to start from the plug socket and end up knowing exactly how my computer let me type this message to you?
I mean, when I think of something like c programming, I have no idea what's really going on by thinking how it relates to the plug socket, same with typing this message, any ideas?
anna v also have a similar view I wonder, if everything is in a steady state, or in thermodynamic equilibrium (which can happen in heat death), does it mean time ceased to have meaning?
Opportunistic self-centered meta-question: Is there anyway I can improve the visibility of a question I asked, without spamming or other poor behavior? I feel it's probably going to remain largely unnoticed under the deluge of new questions posted since.
@Slereah I have read the papers you and Yuggib referred
Give me a sec when I fetch my comments...
@Slereah @yuggib http://rspa.royalsocietypublishing.org/content/royprsa/470/2164/20130632.full.pdf Ok I have read this in full Cannot say I fully understand it, but it seems the key idea is that the author think quantum nonlocality can be formulated by considering n relativistic particles each having its own evolution in time and these thus can trace out a bunch of worldines that depends on how we choose the space to be foilated. The resulting wavefunction will then not only be dependent on the position of each particle, but also their individual evolution with time
So if I understand correctly, multiple time variables in this context is a tool to resolve a highly nonlocal interaction involving n particles and the evolution of the wavafucntion that describe it, into the n particles evolving independently according to their own times an with the final wavefunction to depend on this instead, thus doing away the problem of correlations
Do you guys think that it would be appropriate to ask a question on classical Yang-Mills field theory, without knowing too much to start with? I don't want to be one of those guys who "hasn't shown enough independent research" but I am finding the literature quite impenetrable if I am honest.
@0celo7 the article was written by Philip Gibbs, see the authorship notes at the top. The URL is math.ucr.edu/home/baez/physics/Relativity/SR/rocket.html . It's legit. If you move real fast you are subject to time dilation such that you can traverse the galaxy in say 12 years of your own time.
@PyRulez : it sure does. Aw, it's just a hypothetical scenario. And if you were really travelling through the galaxy at some speed close to c, one little rock could curtail the mission in a dramatic fashion.
okay, well my starting point is CFT, I understand mathematically that you can have a given action that with a given Lagrangian gives EOM however, I just can't grasp why it is important in the larger sense... Maybe because my background is not in phys I don't know.. what is it giving us?
@AngusTheMan It's fine to ask questions if you don't know much about the subject. Just make sure that the answer can't be found in the corresponding Wikipedia article or another obvious search result.
On the topic of questions.... Anyone familiar with magnets 'n stuff want to take a stab at my question? Shameless pandering, I know; but in my defense, I, uh... did put some effort into my question at least physics.stackexchange.com/questions/207800/…
@WilliamBudd This site is not really about quick answers, though. You have to be a little patient until someone comes along who find your question & knows the answer & has the time and motivation to answer it.
@0celo7 I know vaguely about path integrals, but admittedly not enough. Is that a good starting point even though I am interested in classical mechanics?
1. The age of homework I got over it for a while 'and in fact, before someone would change my request, asked general information about it, not the resolution of the year that comes as a result. 2. The formula that you have linked the know but in this case I do not understand how to apply it and for this reason I have asked for lights to you experts. Thank you. — Manu1 min ago
Can someone translate 1. for me?
"resolution of the year" is supposed to mean the "specific answer to the question" or something?
I think he is saying " I got over the age of receiving homework a while back. In fact before I change my question, I asked general information about the topic.
the last bit ... hmm.... no idea... maybe " I came here to discuss questions not my homework year"? or perhaps "the answer I seek will come as a result of the specific way I have formulated the question"
I seem to recall that a friend of mine did something about Seiberg-Witten theories which only have "local Lagrangians" which do not properly define the physical theory we actually want to look at or something like that
@ACuriousMind I don't think we can be friends then :p .. I don't know, I have always been taught quantum mechanics on my degree. And all classical mechanics was to me, was Newton's laws and the Rayleigh-Jeans law. And one of them doesn't work! But when I saw Lagrangians and Hamiltonians I fell in love "que music"
@Slereah true, I still think there is really important things to learn for chemists! Most of our molecular mechanics is based on Newton's second law. I wonder if we used other approaches (Liouville etc) would there be benefits?
I tend to have a habit of getting some mathematical object, and describe it as if it is a physical entity, with all its properties replaced by its closest physical counterpart
For example, I tend to think of a long line as an alien like rubber band that points stay where they are even when you stretch it
This forms the basis of most of my visualisation, and is one of the major sources of the misleading QM visualisation questions I asked, such as the De Broglie one that got me into the warning banner
So in this interpretation, doing very hard maths is the same as fiddling with many alien objects on your table and figuring out a way to assemble them into something you want
this is how visualisation motivate me to do sometimes very tedious algebra and guide me on what's the next step I should take to tackle a problem
Therefore, for every mathematical object and computation I can visualise lossleesly (i.e. the diagram or analogy is used is so good that it coontains nearly all the properties of the matheamtical object in question and ability to handle pathological cases with little issues), it is the same as owning an alien object from the matheamatical world that I can mix and match (or react like chemicals) to give the desired result I want
@Secret I do not believe that is possible. How do you describe a ring?
Or how do you deal with non-Hausdorff spaces? Those are pretty much impossible to really visualize because you are not allowed to think of "seperate points".
My question was put on hold 5 days ago.
The mechanics of accelerating a massive body in a Vacuum
The mechanics of accelerating a massive body in a Vacuum [closed]
I did edit the question as I was told that it was on hold because it was too vague.(and that I should amend it)
I hoped I had narr...
I am not sure that those diagrams are very helpful
They remind me of that joke physics paper
" Since superpeas contain arbitrary dimensions, they easily allow nonperturbative calculations; for example, we have infinite-loop bubble graphs such as "
@Secret That...doesn't make much sense. Essentially you just replaced the precise mathematical terminology by vague words and call that a "visualization": "Element" -> "Blob", "addition" -> "clumping", "multiplication" -> "another type of clumping", etc. This analogy does not enable you to see anything about rings without resorting to precise mathematical language. You can't see what things like "prime elements" or "ideals" are in this picture easily.
I mean, I can "visualize" an arbitrary algebraic structure in the way you describe there, but...it doesn't tell me anything about the structure, so it's useless.
Visualizing things like vector fields as determining flows or something like that, in contrast, is helpful because then there is an actual physical picture (fluid dynamics) you can use to gain intuition which statements should be true or false without going through the math.
@Slereah (At least for me...) Fields= the above alien space where rings live in, but that symmetry exists also in the clump 2 reaction and thus the mixing of the clump 1 and 2 reactions becomes independent of history (commutativity in multiplciation leads to distibutivity to be two sided distributive)
Rng=there's no nothingness like blob, thus opposites don't nullify completely (no identity element)
Group=only the clumping reaction with symmetry exists, and the reaction is directional,and blobs don't become something else after reaction (identity, inverses, associativity, closure)
@Manishearth : time travel is not "mainstream research". It's science-fiction woo promoted by the sort of people who peddle popscience books to gullible kids. Object do not move along world lines. World lines are abstract things. You cannot point up to the clear night sky and say look, there's a worldline. A CTC isn't something you can travel around to go back in time. There is no way you can move such that everything else not only moves back to where it was, but never moved at all. — John Duffield31 mins ago
O.o
This is on a post specifically talking about Tipler cylinders and other mainstream CTCthings
I read that an object at rest has such a stupendous amount of energy, $E=mc^2$ because it's effectively in motion through space-time at the speed of light and it's traveling through the time dimension of space-time at 1 second per second as time goes forward.
This is wrong.
What troubles...
@ACuriousMind (cont.) For that, I can of course say an ideal is "for some blobs, when they react via clump 2 reaction, they can only interconvert between themselves can never beomce blobs that don't have this property", but then it is the same "reballeing" (or Slereah Penrose notation problem) thing as you mentioned.
But this property of Ideals is not a consequence of the ring axioms, but just an extra condition imposed so that you have a subgroup of rings behaving like that, so how does one expect it exists just from the definition of rings?
My question was put on hold 5 days ago.
The mechanics of accelerating a massive body in a Vacuum
The mechanics of accelerating a massive body in a Vacuum [closed]
I did edit the question as I was told that it was on hold because it was too vague.(and that I should amend it)
I hoped I had narr...
I read that an object at rest has such a stupendous amount of energy, $E=mc^2$ because it's effectively in motion through space-time at the speed of light and it's traveling through the time dimension of space-time at 1 second per second as time goes forward.
This is wrong.
What troubles...
