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463111
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location Princeton, NJ
age 26
visits member for 3 years, 1 month
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I am a graduate student studying astrophysics at Princeton. I received my bachelor's in physics and mathematics from Caltech (2011).

My primary interest is in general relativistic magnetohydrodynamics simulations of black hole accretion.


22h
comment What is Quantum Mechanics really about?
It seems your first course in QM was like 99% of all such courses, focusing on the Hilbert space $L^2(\mathbb{R})$, where wavefunctions were projections of kets onto (all the elements of) the position "basis." But that's just one particular application of QM. Not all applications involve that particular Hilbert space and its wavefunctions.
23h
comment Can FTL-Communication between two points in the same frame of reference break causality?
You've reinvented the tachyonic antitelephone. The real flaw in your reasoning is that you've invented inconsistent rules for your universe. The communication works only if you are at rest with respect to the device -- this simply cannot be, for it means that two different observers will disagree on whether or not an event (the signal being sent) ever happens. Relativity allows observers to disagree on when something happens, but not on whether something happens.
23h
comment Kayaking against the wind is faster than with wind in my back?
Sounds like you were measuring your speed based on the ripples in the water. But since these move with the wind faster than the water underneath them, when going into the wind you get an apparent forward velocity that doesn't reflect your velocity with respect to the bulk water, or with respect to land.
23h
comment Bragg Scattering of Thermal Neutrons
Note that our policy is to not do people's homework for them, including checking their work. This is being flagged as off-topic, and indeed it appears to be a check-my-work problem. But if you really just want answers to what you've labeled "questions" you should be fine. Since we don't really need to see your work to answer those questions, I suggest removing it (but leaving the original problem statement).
23h
comment Solving Laplace's Equation for a point charge at orgin with Fourier transform?
"I know and understand why the Fourier transform of the Dirac delta function will just be one." Are you so sure?
1d
comment When/why does the principle of least action plus boundary conditions not uniquely specify a path?
I'm inclined to leave this open as the other question is in the context of QFT, and it would do well to have general-purpose answers that don't rely on QFT (lack of) intuition.
2d
comment How to start using IDL in 2015?
Definitely second not using IDL. Also, if you're in a university, does the astronomy department not have any licenses? Most of them do -- you should ask around.
2d
comment Do you know any graphing software for graphing equipotential lines?
Equipotential lines are known as contours in the plotting community, and every plotting package out there should be able to make a contour plot.
Aug
30
comment Are these two writings of Planck's Law the same thing?
By the way, that is Greek $\nu$ (nu) for frequency, not $v$.
Aug
30
comment Why are GPS transmitting signals made so weak?
This may well say more about the quality of your receiver than anything to do with the satellites. I've never lost a GPS signal except in cities, and I'm pretty sure the US military doesn't lose track of its position when it rains.
Aug
29
comment Tensors, indices and matrix notation - is there a common convention?
This is a good question that too many authors neglect to clarify. For my own part I always intend for the first index to index rows, and I never stack indices vertically except maybe on $\delta$, but I can't say for sure this is universal.
Aug
29
comment Certain doubts regarding the movie 'Interstellar'
GRRR. Why does everyone think Interstellar is some sort of documentary?! It is nothing of the sort, nor did it ever claim to be. The movie was meant to entertain. It was meant to explore the human condition, specifically its relation with science. It was not meant to provide any scientific facts, and indeed there was no hard science to be found in it. If you're looking for scientific interpretation, then you have completely missed what the director was trying to convey.
Aug
28
comment What defines a unit system and how many constants can we set to 1?
Note that you are describing the preferred unit system of relativistic astrophysics (Gaussian CGS + $c=1$), and that it forces $\mu_0$ to be dimensionless $4\pi$. Often too this $4\pi$ is absorbed into a redefinition of the units of electric/magnetic fields (the two being the same in this system), making it disappear from some equations but appear in others.
Aug
27
comment Why don't lakes have tides?
This question explores the myth of the globe-encircling tidal bulge.
Aug
27
comment Removal of heat from a closed system using electricity
The two answers both come with the caveat that you can't violate the 2nd law of thermodynamics, but it really seems like you are trying to violate it. Take this to heart: you can't just turn absolute heat into electricity or any other material/substance/condition that could possibly be used to do work. You can only tap into heat differences; i.e. you can only cool an object by moving its heat (and then some) somewhere else.
Aug
27
comment Do rotating magnetic fields violate all physical rules?
I tried reading through this, but I can't really understand the problem. Could you highlight where exactly the discrepancy lies? Also some better formatting wouldn't go amiss. For example, specifying what the result of each calculation is -- not just the number and/or units, but what it is supposed to represent.
Aug
26
comment Why is centre of mass taken as integral of x.dm and not m.dx?
You will find this same thing come up again and again in math and physics, under names like expected value and moment.
Aug
26
comment Paradox with Gauss' law when space is uniformly charged everywhere
@Shing I'm saying we don't have a self-consistent mathematical framework to describe such a physical system. So you could say it is "possible" physically, but it is not readily describable by our physical theories.
Aug
24
comment Pouring oil on choppy water to calm it , does it work and if so how?
An amazing quote from Ben Franklin via Tanford's Ben Franklin Stilled the Waves quoted in the first article, attesting to the efficacy of this method: "the oil, though not more than a teaspoonful, produced an instant calm over a space of several yards square, which spread amazingly, and extended itself gradually till it reached the lee side, making all that quarter of the pond, perhaps half an acre, as smooth as a looking glass." This from a teaspoon of presumed olive oil.
Aug
22
comment Are there tides in the atmosphere?
Well, you could take data for a couple millenia and extract a periodic signal at the end ;) What's interesting is you'll find lots of people advocating barometers for finding altitude to within ~5 m, as long as they are calibrated that day. But if I did the math right your chart shows the readings could drift by ~30+ m each hour, and the trend could continue unabated all day.