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HNQ
4:53 AM
1
Q: What's considered a small time step?

Jlee523I was looking at the following identity that's often used in time evolution: $$ (e^{xA/n}e^{xB/n})^n \approx (e^{x(A+B)/n})^n$$ This holds when $(\frac{1}{2}(x/n)^2[A,B])^n$ is small. I'm wondering what "small" means. If we consider a physical system with $H = K+V$ (a kinetic and potential term)....

 
 
9 hours later…
HNQ
1:48 PM
1
Q: Does the particle interfere with itself, or the observer?

HierarchistIn the double slit experiment, the observer doesn't know which slit the photon went through so the wavefunction is modelled as going through both slits at once and thus there's interference on the other side. But this seems too observer dependent because two different observers who have access to...

 
 
10 hours later…
HNQ
11:31 PM
5
Q: Were Alchemists right?

Rao Hammas HussainWhen i was in school, in 10th class (according to our education standard), I studied a few lines about Alchemists that they were some people (scientists) who were trying to convert other materials in Gold and failed. Whenever i studied or read something about them, they were portrayed as kinda fa...

 
HNQ
11:55 PM
1
Q: What exactly is the difference between a Ricci-flat manifold and Minkowski space?

gabr1eL44Minkowski space describes a flat spacetime and a Ricci-flat manifold is a solution of GRT without curvature. Shouldn't they be the same? So, what's the difference?

 

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