Newest Questions
244,124 questions
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The Æther, the speed of light and gravity
I've been thinking about several things lately, and one of them is the Æther, because when people say that electromagnetic waves don't need to be propagated by a medium, I immediately see that they're ...
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1
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Could other theories account for the presence of Cosmic Microwave Background (other than a Big Bang)?
Some scientists say CMB is "proof" of the Big Bang event, as no other source accounts for its presence (that I know of). However, I can think of a few things that seem to do so:
Over a long ...
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Infinitely many coserved currents in a free QFT
In a 1+1D integrable quantum field theory (e.g. the sine-Gordon model), there is a tower of infinitely many conserved currents with increasing spins. During a scattering, the existence of such a tower ...
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5
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Conservation of Power After Separating Reflected Waveguide Wave
Background: I was reading A General Waveguide Circuit Theory which mentioned that the sum of the average power of forward and backward waves is different from the average power of their sum. I ...
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Path integral formulation for selective paths in an energy shell $\delta(H(x,t)-E)$
Path integral formulation for selective paths in an energy shell $\delta(H(x,t)-E).$
I'm looking for a detailed calculation of this constrain condition.
All the publication I have access to didn't ...
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45
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Does gravitational information travel through a black hole or around a black hole?
I would like to know if information can travel through black holes. If a mass falls into a black hole will the radius grow via information traveling along the event horizon or through the black hole?
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Spacetime curvature and light deflection [closed]
Could you tell me if this reasoning is correct?
Radius of curvature in spacetime caused by the Sun 338421512319 meters
Radius (physical) of the Sun 696340000 meters
338421512319/696340000 = 486
The ...
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1
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Why integral curves of a null vector must be null geodesics?
In many General Relativity literature, the following question takes as a very obvious fact but I don't understand why or how it holds.
Why integral curves of a null vector on a null hypersurface is ...
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50
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Problem book in quantum mechanics [duplicate]
Can someone recommend problem book in quantum mechanics ? Without theory (or only as reference), with many problems/exercises.
(not Flügge)
5
votes
1
answer
133
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Does the value of the gravitational constant change due to dark matter?
Dark matter possess its own gravity. So doesn't it would mean that we will obtain different values of gravitational constant by doing experiments at different places?
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Time of flight to energy conversion (Jacobian) [duplicate]
Say we record intensity as a function of wavelength $f$($\lambda$) . I want to plot this as a function of energy ($E$), given that $E = hc/ \lambda$. I read that by the conservation of energy, this ...
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Is there a relationship between the contact points and coefficient of kinetic friction I am not aware of? [closed]
I have been working on a project to determine the kinetic coefficient of friction by sliding a puck down a ramp that I have glued a number of ball bearings onto (photo below).
According to Amontons’ ...
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50
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Why are exponential factors dimensionless? [duplicate]
Why are exponential factors dimensionless? While solving a question from JEE Advance MCQ, I faced a problem. The question was, the pressure depends on distance as P= (α/β)exp(-αz/kθ), where α, β are ...
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2
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62
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Is mass a representation of the amount of energy, or is it just another form of it?
I've just started learning about Nuclear Physics, and here's something I'm not able to quite understand.
I have been taught the following:
During a nuclear reaction, mass-energy is conserved.
During ...
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1
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60
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How to solve for orbital path from velocity vector and starting pos?
I���m trying to solve for an orbital path, $C$ (preferably a parametric equation of $(X(t),Y(t))$ such that at $t=0$, it equal the starting pos), from a starting vector $V$ and position $P$. I also have ...
