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 Newtonâ€™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...