Einstein Definition and 809 Threads

Greg Bernhardt submitted a new PF Insights post How Well Do You Know Albert Einstein? Continue reading the Original PF Insights Post.

Hi everybody, I was doing one asignment form class, I was tasked to prove that in one system, the arimetic mean of FD and BE distributions is equal to MB's distribution for undishtingable particles. After doing the numbers I found out that it actually was, but I don't know why this happens, can...

“Hence it is clear that the space of physics is not, in the last analysis, anything given in nature or independent of human thought. It is a function of our conceptual scheme [mind].” It is true that Einstein said it? What does this means?

Einstein wrote in a letter to Max Born that he feels that QM is not the true Jacob, quote: "Quantum mechanics demands serious attention. But an inner voice tells me that this is not the true Jacob. The theory accomplishes a lot, but it does not bring us closer to the secrets of the Old One. In...

Homework Statement Explain the conditions under which Bose-Einstein condensation occurs and show this happens for density ##\rho \equiv N/V > \rho_C(T)##, where $$\rho_C(T) = A(kT)^{3/2} \int_0^{\infty} \frac{x^{1/2}}{ e^x − 1} dx .$$ Suppose the energy of the particles on the lattice is now...

Homework Statement [/B] (a) Find the christoffel symbols (b) Find the einstein equations (c) Find A and B (d) Comment on this metric Homework Equations \Gamma_{\alpha\beta}^\mu \frac{1}{2} g^{\mu v} \left( \partial_\alpha g_{\beta v} + \partial_\beta g_{\alpha v} - \partial_\mu g_{\alpha...

If say a hundred or more objects, at a human scale, are connected by a string, and they can be made to synchronize in an oscillation, could that be considered a bose einstein condensate?

I'm looking at the informal arguements in deriving the EFE equation. The step that by the bianchi identity the divergence of the einstein tensor is automatically zero. So the bianchi identity is ##\bigtriangledown^{u}R_{pu}-\frac{1}{2}\bigtriangledown_{p}R=0##...

While trying to understand special relativity, i came across the following explanation several times: Imagine a train moving at c/4 from left to right. If a person A, inside the train standing near the back of the train, flashes a light, the light is supposed to travel in the direction of the...

The principle of least action states that the evolution of a physical system - how a system progresses from one state to another- is given by a stationary point of the action. So I think this is varying the path and keeping two points fixed- the points of the initial and final state I know...

“Concerning matter, we have been all wrong. What we have called matter is energy, whose vibration has been so lowered as to be perceptible to the senses. There is no matter.” Albert Einstein Einstein really said that? Or It's another fake quote from him in the internet?

How do you represent einstein field equations with levi civita symbol or jacobian determinant? I saw a lot of work that involves this but I don't know how and why. Besides how is the jacobian determinant related to the levI civita symbol?

How does efe takes into special relativity? Is it due to efe been based on spacetime which takes into account the time component? But how does it takes into account the limiting speed of light?

Who was greater (in your opinion), Einstein or Newton? and Why?

Hey everyone! So I have that the low temperature limit of a paramagnet is Ω=(Ne/Ndown)Ndown while the low temperature limit of an einstein solid is Ω=(Ne/q)q. How could I explain that these two equations are essentially the same considering their respective limits (Ndown<<N and q<<N) and that...

Hi, I'm looking at 'Lecture Notes on General Relativity' by Sean M.Carroll. I have a question about p. 227, solving for ##a(t)## in the dark energy case. So for dust and radiation cases it was Friedmann equations you solve. But in the case of a non-zero cosmological constant Eienstien equation...

I have been looking through some notes on fermion wavefunction operators and noticed some summations involving indexes repeated 3 times.I know this is not allowed when using the Einstein summation convention. So my question is : is the Einstein convention not used in Quantum mechanics ? and do...

Hi, According to Newton, F= (GM¹M₂)/r² Einstein proved that light bends around massive bodies, due to gravity. (because space bends around these bodies) Mass of light = zero, but its being affected by gravity. So, is Newton's equation not universal?

Lets suppose we used Einstein Velocity Addition equation and we found a result this is the same for every observer isn't it ?

I was reading "The foundation of the general theory of relativity" by Albert Einstein. I faced some difficulty to understand his derivation of "geodetic line", stated in "The equation of the geodetic line. The motion of particle" headed section. I will try to describe my problem clearly and in...

How to solve EFE without using the vacuum solution like how you did in schwarzschild metric?

Homework Statement (a)Find Christoffel symbols (b) Show the particles are at rest, hence ##t= \tau##. Find the Ricci tensors (c) Find zeroth component of Einstein Tensor Homework EquationsThe Attempt at a Solution Part (a)[/B] Let lagrangian be: -c^2 \left( \frac{dt}{d\tau}\right)^2 +...

Dear friends, There is something related to the history of theory relativity that has been bothering me this whole time. This is about the two postulates of special relativity. At the time of its invention, probably even up to now (I'm not sure since I'm not theoretical physicist), there had...

Hello, if you have ever heard of the TOE then you may be able to answer my question on this theory. The theory explains that there are tiny little strings in all atoms. Imagine the universe being an atom, the stings in this atom would be the size of a tree here on Earth. That is how small they...

Do the Einstein field equations explain why this locomotive is sinking into the Bolivian sand?

My confusion isn't exactly with a homework problem, but more with an example that is key to understanding a homework problem. So I am posting here anyway. 1. Homework Statement The example is of an Einstein solid, with N=3 oscillators. The book lists the multiplicity of each macrostate, with...

according to the theory, when an object is moving in the speed of light, the object will lose it mass and the lost mass will transform into energy.so when the object is moving,if we provide the same energy the object losses to it, will the mass of the object changes?

I'm looking at solutions to Einsten's equation with the cosmological constant included ,##G_{uv}=- 8 \pi GT_{uv} - \lambda g_{uv} ##, with the FRW metric at hand - i.e, ## R_{uv} ## has been computed from this metric. I have a question from these notes...http://arxiv.org/abs/gr-qc/9712019 they...

What happens if you apply EFE to a small particle like electron? Is it where efe breaks down and have to be replaced with quantum gravity? My apologies for such a dumb qns as I just started.

So Einstein Equation: ##G_{uv}= 8 \pi G T_{uv} ##, Justifying the cosmological constant can be included is done by noting that ## \bigtriangledown^{a}g_{ab} =0 ## and so including it on the LHS, conservation of energy-momentum tensor still holds. I'm not sure why ## \bigtriangledown^{a}g_{ab}...

Some sources seem to have: ##G_{uv}=8\pi G T_{uv} ## Whereas others have: ##G_{uv}=-8\pi G T_{uv} ## I thought that it may have been covered by how ##G_{uv}## is defined on the sources, but in both cases it is given as ## G_{uv}=R_{uv} - \frac{1}{2}g_{uv}R ## I'm confused. Thanks.

Is EFE an equation to help us find the curvature cause by mass? Like the schwarzchild metric? In addition, is it a must to use polar coordinate for EFE to work since it contains dr? Can we used the ordinary Euclidean coordinate in minkoswki space for EFE? If we can't is it because there is no...

Dears, What do you think, hypothetically, Einstein should think about String Theory?. Obviously, if he was here to study it.

I have to give a a speech(?) about this experiment at university. I know what happens there roughly speaking, but I want know more about some conditions, materials and so on. Could you recommend some articles about this effect? Sorry for my English, I really don't know if I explained my...

Hi guys, I am writing a philosophical article about Leibniz's famous question "Why is there something rather than nothing?" and in this context I also discuss scientific theories about the origin of the universe, among these the inflationary theory proposed by Guth. Now since it is going to be...

According to Einstein's theory it is the bending of space that keeps the Earth moving on its orbit around the sun and not any invisible force. Why they still teach gravitational force in school ?

The swartzchild metric, the kerr metric etc. where constructed with specific goals in mind, how does one go about doing that with goals in mind? Any help or comments appreciated. I don't expect a guide, I doubt one exists,

I am hoping someone can help me with something. I want to go into the field of temporal physics and I was wondering if someone could help me understand why Einstein's E=mc2 isn't combined with Lorentz's factor ϒ=1/√1-(v2/c2) to further prove the light-speed barrier?

Homework Statement I have the following equation Aab= c ua ub Where Aab is a rank 2 tensor and ua is a vector and c is a scalar and a,b = {0,1,2,3}. I know both Aab , ua and ua I want to find c explicitly but I don't know how to interpret or calculate c = Aab / ( ua ub ) Does anyone...

Hi guys. I am trying to understand einstein field equation and thus have started on learning tensor. For metric tensor, is it just comprised of two contra/covariant vectors tensor product among each other alone or does it requires an additional kronecker delta? I am confused about the idea...

i was pressured into engineering, and not allowed to pursue physics. I see that every year (or even semester) that passes by, i am missing out on my dream. I wish to be a physicist, and even if it will mean that i will have to study it all myself. I just want you to recommend some self study...

Among the new Einstein papers that are online now, there is this letter from Einstein to M. Curie: http://www.vox.com/xpress/2014/12/6/7342171/trolls-einstein-curie The link spins it as advice about trolls, but it is clear to me from Einstein's exceptionally deferential and complimentary tone...

Einstein education was just formal , then how did he got to know all about current research at his time. So did he studied all by his own?

Einsteins papers are now publicly available online: http://www.theverge.com/2014/12/5/7340029/digital-einstein-archives-princeton

Since yesterday, Einstein's collected papers are freely available for viewing on the Princeton University website: http://einsteinpapers.press.princeton.edu/ http://blog.press.princeton.edu/2014/12/05/princeton-university-press-launches-the-digital-einstein-papers/...

In the following program http://www.bbc.co.uk/programmes/b02144gl Penrose asserts that Einstein regretted the term relativity because it gave ammunition to those who assert that there is not one truth or that reality is a social construct. Does anyone have exact quotes from Einstein asserting...

I have been recently working with Schwarzschild's solution: ds2= - (1- (2GM/rc2))c2dt2 + dr2/(1-2GM/rc2) + r2(dθ2 + sin2(θ)d∅2) Now, when deriving the various general relativistic tensors for this metric such as the Ricci tensor, I found the calculations to be painfully tedious and monstrous...

In the Einstein-Hilbert action wikipedia page, the following paragraph is written: I thought for treating spin, we need to consider Einstein-Cartan theory! This is really surprising to me. Can anyone suggest a paper or book that explains this in some detail? Thanks

I was wondering if anyone could comment on this experiment: https://www.atom.uni-frankfurt.de/publications/files/Schmidt2013PRL.pdf, which supposedly experimentally realized Einstein's thought-experimental objection to Bohr at the Fifth Solvay International Conference on Electrons and Photons in...

The question that ponders upon the thought if the speed of light really is constant is a fairly common question. However, I was wondering about something and MAYBE this can provide some backup to the theory that the speed of light isn't constant, please point out any mistakes I make in stating...