40,848 reputation
1877160
bio website ellipsix.net
location Wuhan, China
age 28
visits member for 4 years, 1 month
seen 23 mins ago

I'm a postdoc doing research in high-energy particle physics. I also have a hobby interest in computer programming.

You can find me on Twitter, or check out my blog and personal website! Or you can email me at stack@ellipsix.net.

Please don't contact me through any other channel about something that should be handled through this site. If you do, I'll probably just tell you to post it here.

Any responses to moderator messages, or comments on official moderation actions here, will be ignored if sent through external channels!


5h
comment Forces on inclined cube
@glance a better way to handle this: flag the question to have it put on hold, then the poster can modify it to get it reopened. That's the entire reason the "on hold" (a.k.a. "closed") designation exists. (Just for future reference.)
15h
comment Concept of Chern number
What exactly do you need to know that you can't get from the results of a web search for Chern number, such as the Wikipedia page linked in your question?
18h
comment Why $2j+1$ number of states?
@hwlau the reasoning doesn't work for half-integers but the expression $2j+1$ is still valid.
23h
comment In physics, what is the importance of distinguishing between a matrix and a group?
Or rather, the authors who use the terminology in this way have a misunderstanding. Illegal Immigrant, do you have an example you could reference so we could see if there is some reason the author might be doing this? (Not that I can think of one)
23h
comment How do we know that electron wave function extends to infinity?
Well, you do have an objectively wrong statement in your answer: that if a wavepacket is infinite (which I take to mean $\psi(x) \neq 0$ for arbitrarily large $x$) the probability is infinite. I couldn't say whether that's the reason you were downvoted, but it seems plausible.
1d
comment How do we know that electron wave function extends to infinity?
Think about this: what assumption would you suggest as an alternative?
2d
comment Why are the quantum numbers $n$ and $\ell$ denoted with those letters?
Hi Roll - it seemed that you were asking two completely separate questions here. We prefer to have one question per post, so I removed your second question, but I'd encourage you to post it separately.
2d
comment Could this planetary superalignment happen?
Well, it's your question, but I really think including the extra material makes your question substantially more confusing.
2d
comment Could this planetary superalignment happen?
With the latest edit to this question, making it about whether the alignment could happen at all, it's a perfectly good question, but the stuff about how large the gravitational effect would be is now pretty irrelevant. So I'd suggest taking that out entirely.
Dec
24
comment What are absolute space & time? Why are they not absolute in reality?
Comments are not for extended discussion; this conversation has been moved to chat.
Dec
24
comment Determining Parity of Decaying Quantum System
Hi Smiley Sam - our etiquette here on Stack Exchange is that you don't end your posts with things like "Thank you" or "Any help would be appreciated". For many people who post here, such things are just an unnecessary distraction from the main content of the post.
Dec
24
comment Relating momentum fraction to rapidity in a high-energy collision
Thanks for the attempt. I should have mentioned that the masses are small but $p_{(1,2)\perp}$ are not. So $p_i^- = \frac{p_{i\perp}^2}{2p_i^+}$ for $i=1,2$.
Dec
24
comment How much of theoretical physics research involves contemplation and reflection?
Please don't edit your post so much, by the way.
Dec
24
comment How much of theoretical physics research involves contemplation and reflection?
@PhilipGibbs I'm curious to hear how you justify this being on topic for us
Dec
22
comment Are wave functions real physical objects?
Comments are not for extended discussion; this conversation has been moved to chat.
Dec
22
comment How to calculate speed and distance from gyro, orientation and acceleration data?
A suggestion: it's no use to talk about CMDeviceMotion or the CoreMotion APIs because this is a physics site and you can't expect people here to know anything about them. The way you've described other attributes in terms of what they physically mean is good.
Dec
22
comment Lambert's orbit problem
This question appears to be off-topic because it is about a software recommendation.
Dec
22
comment Relating momentum fraction to rapidity in a high-energy collision
The minus components can be whatever they need to be, given the restriction that $p_0^-$ is small (as mentioned in the question). There may be some additional restriction on the minus components that is required for $y_1 - y_0$ to (approximately) equal $\ln\frac{1}{\xi}$, but I don't know what it might be. Ideally a good answer would explain that.
Dec
21
comment Does Hardy's paradox represent a proof against Bohm's interpretation of the quantum mechanics?
Sofia, please take care not to edit your posts too much. Making 3 or 4 edits to a post is fine, but any time it seems like you might have more edits than that, save up your changes and only make an edit when you have a substantial amount of stuff to change. Editing a single post 8 or 10 or more times is usually too much.
Dec
21
comment Physics & derivatives written in a weird way
@marmistrz in physics, derivatives are viewed as ratios of small changes in the limit as the size of the change goes to zero. The functions we work with are generally well-behaved enough that this is valid.