4:21 AM
-2

The origin problem. Mark the current for each segment. There are three unknowns $I_0$, $I_1$, and $I_5$, therefore set up a set of 3 linear equations for these three unknowns. Then solve the coupled linear equations. Gook luck!

1 hour later…
5:26 AM
@Shing What if I'm thinking of molecules?

1 hour later…
6:39 AM
Here's the timeline for daily questions asked on Physics.SE
I wonder what happened on that one day in early 2016

2 hours later…
8:33 AM
You can just check
probably something physics related in the news

I think it's just a routine statistical anomaly
LIGO had published their paper about 5 days prior to that day, but only 8 questions are about gravitational waves

8 out of 100 could be enough to do that I guess

Apart from that, Boutros Boutros-Ghali passed away that day
don't think there's a correlation there
@Slereah for comparison, the day after the paper there were a whopping 28 posts with [gravitational-waves]

9:00 AM
there can be secondary effects - people are googling LIGO because it's in the news, find the popular posts from a few days earlier, then think "huh, this site is neat, let's ask this other question I've always had"
2

Also IIRC rise and fall of questions on PSE correlate a lot with school seasons

yeah, that's the overall periodic pattern you see there

1 hour later…
10:20 AM
the real question is about quality
I can make a query that uses the fraction of (non-deleted) [homework-and-exercises] questions as a proxy, but I'm not sure how effective that would be

3 hours later…
1:31 PM
@NiharKarve I recall the most recent one being Veritasium uploading his faster-than-wind video
which resulted in quite a few questions here about it

2:10 PM
I think Veritasium's one-way speed of light video has resulted in 100+ questions on this site
quite remarkable
3

2:57 PM
3

I have a naive question, is it possible to obtain the wavepacket dynamics that give rise to cyclotron orbits from a real space tight-binding Hamiltonian? Consider a square lattice in the presence of a constant magnetic field that amounts to say that the hopping elements acquire a phase. Let \$H = ...

3:29 PM
@NiharKarve quality is extremely hard to measure over time because as the userbase fluctuates, the number of voters does, too
additionally it's influenced by the topic - there are some tags where a total vote of 10 is very high, and some where it's merely quite good
votes per view is similarly a flawed metric because you don't know how many of these views are even elegible to vote
I would see HW questions as orthogonal to "quality" because you can have well-written questions that run afoul of the HW policy and complete garbage that is technically on-topic :P

3:45 PM
-2

From brief history of time- One can now see why all bodies fall at the same rate: a body of twice the weight will have twice the force of gravity pulling it down, but it will also have twice the mass. According to Newton’s second law, these two effects will exactly cancel each other, so the accel...

4:08 PM
@ACuriousMind do you know why there's a drop in the % of HW-tagged questions circa 2018?

Hi everyone!

I wanted to do a calculation, I have a matrix m = {{t,t+1},{t-1,t}}. I wanted to find an expression for m^n
in terms of t and n
wolfram isnt able to answer properly when the index is variable..
Any idea how to do this in mathematica?

@NiharKarve not off the top of my head, no
maybe Qmechanic got lazy tagging them :P

4:37 PM
and on that note, here is the progression of edits performed by Qmechanic as a fraction of all edits!
incredible consistency
...although sorry, the graph is a bit faulty (the consistency point still stands)

5:02 PM
0

I've seen the spoiler formatting used on other sites where, say, they discuss plot elements of movies and people don't want to give away a key element to someone who hasn't seen the movie and is browsing casually. I didn't realize that this was implemented by a generic feature of the markup that...

@NiharKarve did you recently learn SQL or why are you crawling SEDE for random data? :D

5:17 PM
I only discovered the graph feature today :)

@ACuriousMind SEDE?

stack exchange data explorer

5 hours later…
10:01 PM
I worry that the MMSE community might not have enough experts in this specific area yet to get a timely answer, does anyone know people working in this area?
7

I am looking for tools for symbolic calculation of quantum transport or quantum mechanics that involves Keldysh NEGF (non-equilibrium Green's function) formalism. The closest tool I heard/seen is symGF.m for Mathematica but I could not find the library/file for it. Have anyone seen this file o...