Recent content by Narasoma

We know the Big Bang Theory states that our universe was started from a hot-dense point. But should't it became black hole and every matter and radiation pulled to singularity? We would not be her if that is the case.

My question assumed a distinction between the measured (quantum system) and the apparatus (classical). I did not consider that they are indeed both quantum systems. So, thanks.

Well. I think I understand the conclusion better this way. Perhaps, I should read solid state physics more. Thanks man.

I don't undestand how to conclude that the UP is due to the nature of the system from statistical variance. Classical system has variance as well, right? But the UP does not emerge from it.

1. When I said, measurement, I also said "unbreachable." Unlike classical physics, in which measurement of any physical quantities can be made arbitrary precise, for example due to the technological advancement. Let me put my question another way. If the UP is due to the nature of the system...

We know from basic quantum mechanics that the Heisenberg uncertainty states that position and momentum can not be measured simultaneously with arbitrary precision. My question is, is this relation is due to the nature of the quantum system itself, or "merely" unbreachable limitation to our...

Okay. Well noted. Thanks all.

We can derive the constancy of the speed of light from Maxwell equations. My questions are: 1. Why it is then need to postulate it when we can obtain it from Maxwell equations? 2. It is stated in many books that gravity wave also propagates with the same speed, c. How do we conclude that? Is...

I understand the mechanism of defining the curvature of a 2D manifold via triangle. But I don't understand how this works in 3D. Meanwhile, Lawrence Krauss mentioned in his book A Universe from Nothing it does. How does this work in 3D?

Everyone who is currently studying GR must be familiar with this picture. We find Riemann curvature by paraller transport a "test vector" around and see whether the vector changes its direction. My question. How does it work with one dimensional Ring? A geomteric ring is intuitively curved but...

Ah, sorry. Legendre transformation. That was what I meant. But doesn't it always exist?

What does it means for a physical theory to have hamiltonian, if it is formulated in lagrangian form? Why doesn't someone just apply the lagrangian transformation to the theory, and therefore its hamiltonian is automatically gotten?

Maybe some books of classical mechanics with constraints for undergraduate theoretical physics student will help. Thanks.

I understand "basic" Lagrangian and Hamiltonian mechanics, but I don't get the understanding about constraint. Constraint of the first kind, constraint of the second kind... What is that?

I need a brief introduction to constrained dynamics. Any article, paper or books will help. If you know sources related to that matter, please tell me...