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Mar
29
revised Entanglement ladder algebra and quantization of entanglement
added 101 characters in body
Mar
29
answered Entanglement ladder algebra and quantization of entanglement
Mar
23
comment Proving the conservation of 4-momentum for a particle collision $A+B\to C+D$
you use the Schwartz inequality to prove that time-like four vectors are a group with the vector addition operation
Mar
23
comment Proving the conservation of 4-momentum for a particle collision $A+B\to C+D$
the sum of time-like four momentums is always time-like. This is proved with the Schwartz inequality
Mar
23
awarded  Citizen Patrol
Mar
19
answered What causes light to travel through a curved fountain of water?
Mar
3
comment Why did scientists need to invent light years?
I usually round the light-year to $10^{16}$ meters and call it the metric light-year. But seriously, you could call it also ten petameters, so the distance to alpha centauri is 43 petameters.
Mar
1
comment $U(1)$ 5-dimensional Kaluza-Klein topological defects
as in, electromagnetically.. how would the electromagnetic field behave near the defect?
Feb
28
comment $U(1)$ 5-dimensional Kaluza-Klein topological defects
If there were objects like these in the universe, how do I detect them?
Feb
28
revised $U(1)$ 5-dimensional Kaluza-Klein topological defects
added 93 characters in body
Feb
28
comment $U(1)$ 5-dimensional Kaluza-Klein topological defects
"it doesn't make sense to say the topology of a loop (1 compact dimension) can turn from one loop into two". The hose (or pant leg) becomes a T-shaped hose (or a T-shaped pant). The upper _ segment is supposed to be our full $M^4$, and the | of the T is supposed to be a four-dimensional manifold that connects with some compact region of the $M^4$. I'm just trying to get some rough predictions of how electromagnetism would distort near such defect
Feb
27
revised $U(1)$ 5-dimensional Kaluza-Klein topological defects
added 131 characters in body
Feb
27
comment $U(1)$ 5-dimensional Kaluza-Klein topological defects
@JamalS, true.. Although if I remember, the dilaton behaves just as a neutral scalar field? or does it couple to the electromagnetic field?
Feb
27
comment $U(1)$ 5-dimensional Kaluza-Klein topological defects
@CuriousMind Ok, I meant that the $X$ manifold is $U(1)$ far from the defect so that you recover electromagnetism in the asymptotic region. Agreed that 3-legged pant is a better pictorial description which is consistent with other textbooks on cobordism and such.
Feb
27
asked $U(1)$ 5-dimensional Kaluza-Klein topological defects
Feb
26
comment what does holographic principle from string theory say about the possibilities of wormhole travel?
"so you can't sidestep the classical instability of wormholes by appealing to quantum fairie dust" we already sidestep a lot of classically expected results thanks to 'quantum fairie dust'. Most significant case is quantum superconductivity, which is clearly a macroscopic effect, and entirely due to 'quantum fairie dust'
Feb
26
comment Why am I not accelerated by the reaction force applied by Earth on me?
you are, you are being accelerated by the earth's gravity at one G, and you are being accelerated by the earth's surface reaction force at minus one G. one G minus one G equals zero G for the points of your body that are receiving the reaction force (usually your feet)
Feb
22
revised QFT Perturbative analysis of multiple atom-level quantum computers close to each other
added 1 character in body
Feb
22
comment QFT Perturbative analysis of multiple atom-level quantum computers close to each other
@MarkMitchison, I edited the question with more concrete thinking, and a more concrete question
Feb
22
revised QFT Perturbative analysis of multiple atom-level quantum computers close to each other
added 1382 characters in body