# All Questions

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### Thermal AdS3 in Chern Simons

I am currently working with (2+1) gravity in Chern-Simons formulation and I have a question about thermal AdS. The way I understand that one retrieves thermal AdS is by Wick rotation and ...
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### How much electric charge can a copper sphere, made of N atoms, contain?

If somebody wants to charge a cooper sphere made of N atoms, what is the maximum positive charge the sphere can reach? Same question about a negative charge. Source For example if the sphere is ...
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The question is the very last sentence at the end of this post. In this post, I'll demonstrate how I reach to a contradiction(the conditions mentioned in conjecture 1 should be satisfied by all ...
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### How is my guitar cable picking up clear radio-signals?

I've recently noticed radio-signals coming through my guitar amplifier. I'm on the top floor of a building in a densely populated city, with a clear visual path to many other buildings. My guitar ...
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### Why do magnetic forces scale down so poorly?

Im told by experts in MEMS and nanotech that magnetic forces scale down very poorly. This is one reason we have many MEMS devices based on electric forces/electrostatics but not on magnetics. Can ...
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### Heat Capacities ratio equal to 1

In which situations can be found the ratio between $C_{P}$ and $C_{V}$ to be equal to the unity? I have read in other places that it happens for liquids and solids because they can be assumed to be ...
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### What does the Scattering Amplitudes tell us about the interactions of matter

I am confused as to the role of the wave function in quantum mechanics. My understanding is that the wave function/state vector is purely a algorithm or mathematical means to compute the results of ...
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### Proof of Lagrangian

I'm having some trouble with some math on a problem for a physics class (looking for help with some partial derivatives, not an answer). Let $$L'=L+\dfrac{dF}{dt},$$ where $L$ is a Lagrangian and $F$ ...
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### Creation of entangled electrons

If one obtains two entangled in polarization photons by parametric down conversion and one of them is accepted by and electron 1 and other by electron 2 - are this electrons now entangled in spin?
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### Target space Lorentz symmetry of superstrings in noncritical dimensions

Is the target space Lorentz symmetry of noncritical strings ($D \neq 26$) or superstrings ($D \neq 10$) broken or is it not? Naive arguments suggest that the mentioned anomaly does not exist, since ...
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### Argument of a Cosine function (referring to Principles of QM by R. Shankar)

On Page 72, Shankar solves the differential equation: $$\frac{d^2}{dt^2}\langle m\rvert\psi(t)\rangle=-\left(\frac{m^2\pi^2}{L^2}\right)\langle m\rvert\psi(t)\rangle$$ as:  \langle m\rvert\psi(t)\...
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### Where does E8 come from in M-Theory?

Where does the E8 symmetry comes from in M-Theory? For example when you compactify one of the dimensions on a line you get E8xE8 heterotic string theory. Or if you compactify 11D Supergravity ...
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### Fraunhofer diffraction at circular aperture - integration of bessel function

I'm trying to understand the calculation here: http://en.wikipedia.org/wiki/Fraunhofer_diffraction_(mathematics)#Circular_aperture for the solution by integration, but I plain and simple fail to see ...
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