I today tried to explain my teacher solution of easy riddle school (Columb egg) and my teacher concluded that I didn't understand this riddle because he thinks that some formula or function describes this riddle and I though that it's matter of repetition numbers in eggs.
@Danu Ok so Berkeley has Bousso who does exactly what I want to do, has better name recognition than UCSB, I have a couple of close friends who will also be going there but cons are Bousso is really the only one there I want to work for and he's really popular so I'll have to compete to get into his group although he did email me a couple of weeks ago
@Danu UCSB on the other hand has like 4 people I'd be happy working for (Gary Horowitz, Don Marolf, Joe Polchinski, and Steve Giddings) but their research interests aren't an exact match with mine; they also have a strong CMT department so collaboration is always possible; they have KITP so that's a great way to make connections with prominent people and possible collaborations but cons are the school has less name recognition than Berkeley (at least in general, not necessarily in physics)
@Danu also I have a skype with Gary Horowitz soon so I can ask him what exactly his future research interests will be but I know he's definitely taking students
@Danu seems like Gary is mainly interested in global properties of spacetimes, stability properties of higher dimensional black holes, and holographic CMT
Bousso is more interested in firewalls, generalized area laws for black holes, and local notions of black hole horizons that can be used in quantum gravity
@hubot i am preparing for JEE exams and IPhO, so as far they both are concerned relativity and QM are not included, but i have started doing it (not with my full speed), but i will do QM and relativity after may-2017
@0celo7 wow, I'm impressed - really, I'm not being sarcastic. I can't concentrate enough to make it worth dipping into a heavyweight book like HE. I have to sit down with no other distractions.
@Sᴋᴜʟʟᴘᴇᴛʀᴏʟ I find these days I'm too impatient for the answer. For example I keep meaning to read up on geodesics in the Rindler coordinates but every time I start there seem to be pages and pages of preamble that I find boring.
I realise the preamble is important stuff that I'll need to understand the meat of the book, but it just seems such a chore working through it.
@0celo7 well, yes, but if I really understood it I would really understand the twin paradox. Right now whenever I attempt a calculation I can't make it work.
I can do a rough calculation in the accelerating twin's frame, and it should calculate the proper time of the earth twin. But it misses a huge chunk of proper time somewhere.
@JohnRennie The whole point of coordinate invariance is that you can choose whatever frame is convenient for a calculation of invariants. Insisting on doing it in one particular frame seems...not very relativist.
The Newtonian model of an expanding Universe gives Friedmann's equation exactly for non-zero spatial curvature $k$ (see http://hyperphysics.phy-astr.gsu.edu/hbase/astro/expuni.html). Instead of using the concept of spatial curvature the Newtonian model introduces $k$ as a constant that is proport...
@JohnRennie I think it is "accidental" in the sense that there is no deep reason for the relativistic corrections to the Newtonian result to be zero in this case, it just turns out they are zero, probably because of the high symmetry of the issue. The quantum harmonic oscillator is also surprisingly exactly described by many semi-classical formulae, but that's also just an indication that a harmonic oscillator is a really simple and symmetric system, not of anything deep.
@JohnRennie I am trying to organize my thoughts and then reformulate it into a new question. I don't want to confuse people in that post by mixing two views. If I have time I will do it. Thanks again for the response.
@user507974 yes, exactly. the bell thm is quite "tight" in preventing a large "swathes" of hidden variables but there are some very subtle loopholes. a similar scenario happened with einsteins reasoning about SR vs newtonian space. strangely physics went the other direction (it was too solidified at the point bell showed up) and insisted that the bell thm forbade all possible LHVs instead of realizing that it points toward subtle exceptions that evade the subtle assumptions of the thm.
According to your question there is no frictional force therefore all forces are conservative.
Now, if the forces are conservative, then you just need to identify the energy at $t=0$ and when the motion(or whatever) ends.
In your question i am shifting my refernce line just below the box (onl...
@DeNiSkA It may be that friction of body moving down is the same of friction of body moving up then the same of time body is moving up. If I did something wrong then forgive because soon I'll have to finish.
in our everyday life friction doesn't decelerate us, so only gravity accelerates and decelerates , so if we try to run up and down with same speed then time will be equal...........
but to explain why it is easy we need work-energy, are you ready?(it is simple)
@0celo7 If "a function" is supposed to be the function that is being integrated, then no. The endpoints are a zero measure set and hence do not contribute to the integral.
I think that: If we neglect friction then should be no difference is this body moving up or down. But if we assume that is friction then the time of descent from the height h is longer than the time of ascent to the height h. Just in case tentatively.
The usual statement about mollifiers is that if you take the sequence of ever narrower mollifiers (a nascent $\delta$), $\tilde{f}$ converges to the original function in the $L^p$ norms; this should also hold for the derivatives if I'm not mistaken, i.e. the derivative of $\tilde{f}$ converges against the (weak) derivative of $f$ in the $L^p$ norms as the mollifier gets narrower
According to your question there is no frictional force therefore all forces are conservative.
Now, if the forces are conservative, then you just need to identify the energy at $t=0$ and when the motion(or whatever) ends.
In your question i am shifting my refernce line just below the box (onl...
