The h Bar

Eulb

2:02 AM

@SirCumference do you have a screenshot of the secret snake drawings question that was deleted?

danielunderwood

oh man I remember that question popping up in the queue

Eulb

I NEED TO SEE IT

10k users i summon thee

physics.stackexchange.com/questions/405934/…

r e v e a l t h e c o n t e n t s

danielunderwood

2:18 AM

there should be a "best of stack exchange" site lol

Semiclassical

r/stackUnderground

(no that's not a thing as far as I know)

Sir Cumference

@Eulb I have yet to see it :O

Secret

2:52 AM

science.sciencemag.org/content/early/2018/08/15/science.aas9437

Fighting laser chaos with quantum choas

I wonder if there are more precise controls, such as engineering the dynamics such that we have a filtered chaos, that is, the whole dynamics is still chaotic because of positive lynapov coefficient, topological mixing and dense periodic orbits, but the birfrucation or otherwise is controlled in such a way such that e.g period 5 orbits are supressed

Semiclassical

3:40 AM

@Secret about the only point of reference I have there is Sarkovskii's theorem, which says (for instance) that "if a discrete dynamical system on the real line has a periodic point of period 3, then it must have periodic points of every other period." in particular, it'll have period-5 points. But you can have period-7 points without needing to have period-3 or period-5 points.

Secret

6:40 AM

hmm... so that means period 3 points need to be suppressed without disrupting the topological mixing

because I recall once period 3 points started to appear, the system becomes very unstable locally and birfrucations and forking will start to happen frequently in a dense manner, giving rise to chaos

Captain Bohemian

7:04 AM

is chaos what happens to a non-equilibrium thermodynamical system?

Secret

7:23 AM

not necessary, you only need nonlinear dynamics of a certain kind to create chaos

Thought all real world process are not noise free, thus physical chaos has some stochastic and thermal components

mathvc_

8:48 AM

0

Q: How to send an email to a well-known professor for a possible PhD student position?

I am applying for graduate physics and I was wondering to work with a well-known professor in Caltech. He is a pioneer in the field that I am interested in. I have a kinda outstanding background, however, I am not sure if the professor is looking for exotic genius students who have completed thei...

any help is welcome!

John Rennie

9:29 AM

@mathvc_ have you read the linked question:

56

Q: How should I phrase an important question that I need to ask a professor?

When needing to ask a professor about something important and potentially delicate, what is an appropriate way to phrase the question or write the email? Examples include: Requesting a recommendation letter Asking for exceptions to policy (e.g., ignoring a course prerequisite, rescheduling an ...

etiquette communication

The advice in the top answer seems pretty good to me.

Jack Clerk

Goodmorning/night/evening for everyone!

I'm an undergraduate physics student, interrested (most of the time) in GR. But, sometimes other subjects catch me up like information.
I've already heard the terms like spintronics and so on and the brilliant other ways to manage the information of bits.
Well, here is another one that I read https://phys.org/news/2018-08-valley-electrons-congregate-ways-valleytronics.html

I would like to ask to you if exist some article that summarizes the current ideas, in scientific community, about new ways to manage information of bits.

catch me up,like information theory**

Captain Bohemian

10:41 AM

Is there a name for the orbit of the moon around Earth like the orbit of the sun is called ecliptic?

Anonymous

10:54 AM

"Elliptic" sounds more like an adjective rather than a name to me...

John Rennie

@Blue not elliptic, ecliptic

Anonymous

@JohnRennie Oops, I misread! I didn't know that they have a name for sun's apparent orbit around the earth.

Captain Bohemian

in Chinese the name of the orbit of the sun translated into English literally is "yellow route" while the name of the orbit of the moon translated into English literally is "white route". But why haven't I heard the name in English of the orbit of the moon around Earth?

John Rennie

@CaptainBohemian I don't know of any term for the orbital plane of the Moon

Anonymous

One moment, ecliptic is the apparent orbit of the sun or the plane in which it moves? I'm confused by the Wiki

Anonymous

11:05 AM

"It is the plane of this path, which is coplanar with Earth's orbit around the Sun (and hence the Sun's apparent orbit around Earth)"

Captain Bohemian

@JohnRennie do you know a nonEnglish language which has a name for the orbital plane of the Moon?

John Rennie

@CaptainBohemian no

ACuriousMind

@CaptainBohemian Is that actually a scientific term for the orbit or rather a historically astrological term?

@Blue With respect to sun and earth, the ecliptic is the plane in which both orbit each other. From a heliocentric viewpoint, it is the plane defined by the orbit of the earth around the sun, from a geocentric viewpoint, it is the plaine defined by the orbit of the sun around the earth.

Also @CaptainBohemian, note the above: "Ecliptic" is not the name for the orbit of the sun, it is the name for the plane in which it lies.

Anonymous

@ACuriousMind Ah, so it is a "plane" rather than an "orbit" (although that's the plane in which they "orbit" each other). The language was a bit confusing.

Captain Bohemian

@ACuriousMind Yellow route and white route in Chinese are scientific terms.

there are Wikipedia articles for them.

ACuriousMind

11:16 AM

There's also Wikipedia articles for every astrological sign, so that doesn't mean anything. :P

Captain Bohemian

but they sound very professional terms.

a lot of astronomical terms are also used in astrology, too.

Anonymous

@ACuriousMind Do astrologers even understand orbits ? All I hear them say is Mars and Venus are gonna come close to Earth and you're gonna have a bad time (translated from Bengali)....so buy this $500 gem from us :P

Anonymous

@CaptainBohemian Link?

Anonymous

Probably the citations will help

Anonymous

In case they have references to some paper

Captain Bohemian

11:20 AM

@Blue the links are in Chinese. You want it?

Anonymous

@CaptainBohemian Yeah, we all have our dear lord Google translate

Captain Bohemian

@Blue yellow route (sun's path): zh.wikipedia.org/wiki黄道 white route (moon's path): zh.wikipedia.org/wiki白道

@Blue sorry, this is not the original link. I don't know why copying the url containiing Chinese characters doesn't work here.

ACuriousMind

Chat doesn't like non-ASCII characters in links

Anonymous

Put the URL in backticks I gues link

Anonymous

@ACuriousMind Emojis work fine tho :P

ACuriousMind

11:31 AM

@Blue An emoji in a link works fine in chat?

I heavily doubt that

Anonymous

google.co.in😀/search?client=ms-android-samsung&ei=rAN4W_CpM5nb9QPvk‌ZKwBA&q=google&oq=google&gs_l=mobile-gws-wiz-serp.3..35i39l3j0i131i67l2.185.185..‌908...0.0..0.272.272.2-1......0....1.........0i71.EPb0Y0nu4pk

ACuriousMind

@CaptainBohemian For convenience, here are the links in clickable form: Yellow Route, White Route

Anonymous

Well it just neglects the part after the emoji

ACuriousMind

@Blue Exactly the same it does with the Chinese characters, then

Anonymous

Right, yeah. We need to copy the remaining portion separately. Or keep it within bacticks as a whole.

Anonymous

11:35 AM

Oh your [text](URL) trick worked

user1732

11:56 AM

i would've never guessed that germany has so few fields medalists and france has so many?

Anonymous

link vs link 2

Anonymous

Ah, it works both with and without utf encoding

Anonymous

link 3

Anonymous

It even takes in emojis lol

Anonymous

So it forces the part within to be a URL, nice

Captain Bohemian

12:34 PM

@ACuriousMind it turns out ecliptic is just the orbit plane of the sun, which I usually refer to ecliptic plane. I have the confusion that ecliptic is the sun's path because I treat ecliptic as the exact translation of the "yellow route" in Chinese, which sounds like a path more than a plane.

Captain Bohemian

12:50 PM

@ACuriousMind if there is an astrological term (rather than scientific term) in English for the moon's orbit (plane), I also want to know it, because it would give me convenience when referring to it, but I seem to have never heard of it.

Captain Bohemian

1:47 PM

@ACuriousMind but now I see in dictionary thefreedictionary.com/ecliptic that ecliptic can represent both "the apparent path of the sun among the stars over the course of the year" and "the plane defined by the earth's solar orbit, with the sun at its center, that extends throughout the solar system."

vzn

2:19 PM

in theory salon, 16 mins ago, by vzn

World's smallest transistor switches current with a single atom in solid state / Nanowerk

@JackClerk yes exciting field, new scientist has many articles on the subj & also try this new group, some substantial crosspollination with this one. also many links in my blog vzn1.wordpress.com/category/physics

The Classical Channel

General chat for Quantum Computing SE. For MathJax see meta.st...

3

Secret

2:39 PM

0

Q: I am writing some short stories and can't wrap my head around a time travel paradox

I put an object in a time-travel device (say something that looks like a microwave ). I am now going to transport the object in time, but leave it in the same position relative to the Earth. If it was into the future, that's fine. It could simply disappear and re-appear in 5 mins, BUT, if I trans...

science-fiction time-travel

huh, that's interesting, never thoght about this case before

Avnish Kabaj

Grandfather paradox 2.0

Secret

Let's play - Causality Gameplay

►

Luckily, Causality has a solution. Whoever code this game is a spacetime genius

Secret

3:48 PM

The most likely resolution is that you will trigger an annhilation process

because the past and present copies have to match up in such a way to ensure they obey particle physics conservation laws

If ripples have delay, then time travel in such a universe will be a very handy quantum entangling device

Akash. B

4:07 PM

Hi

@Secret time travel?

I would also like to know

Secret

What is the specific question?

Otherwise I will close this question as too broad

4

parvin

5:51 PM

Hi, sorry if my question is irrelevant I just don't know any where else to ask

I'm looking at some top universities courses, there are just some names and codes and some introductions about each course, I'm looking for the TEXT BOOKS and LECTURE NOTES that are introduced for each course, say, in Stanford university.

Is there any way I can get to find out what the lecture notes and text books are introduced for each cource?

rob

@parvin For textbook information, call the university's bookstore. For lecture notes, you might have to actually take the course.

ACuriousMind

At least here in Germany, that would be information that varies from year to year and would only be on the homepage of that semester's version of the course, which may or may not be publicly accessible.

parvin

Thank you @rob also I found out that there are some videos of classes and lectures on Youtube that introduce them, but they are rare. not for all courses.

@ACuriousMind thank you

Anonymous

6:19 PM

@parvin MIT OCW should be good enough, no?

Anonymous

They have lecture notes put up for almost 80% of their courses

Anonymous

And textbook recommendations for all courses

Anonymous

If you're looking for some specific topic, feel free to ask.

Anonymous

(Although keep in mind that the so-called top university courses are not always the best sources to learn from. The best study materials are probably lurking around in some of the less visited parts of the internet.)

bolbteppa

6:50 PM

@parvin another idea is to find the list of courses, find out who's teaching them and then go to that person's college webpage, usually they will have a page dedicated to the course they teach, and if not in one place like Stanford, MIT or some equivalent will have one

user54826

7:16 PM

can someone help me to find a popular question. it was about heavier (or bigger, i dotn remember), objects ending up at the bottom of a jar while the smaller objects would remain on the top

I tried google and starting to write a question here to see the suggested similar questions, to no avail

but I remember having read a popular question about that

nvm

user54826

7:40 PM

for the interested, it was the opposite of what I claimed physics.stackexchange.com/questions/141569/…

danielunderwood

8:52 PM

when NNs go bad

Emilio Pisanty

9:20 PM

Any mods around?

I'd like to understand how network-wide suspensions get their term extended from ten years into longer timespans while still in the middle of the suspension

Specifically this suspension which, last I checked (and at least as of November 2017) was scheduled until 2026, but now it says

> The suspension period ends on Mar 18 '92 at 16:28.

which I had never seen before.

Does that '92 mean 2092? as in seventy-four-years-from-now 2092?

like, forty-three-years-after-the-Blade-Runner-sequel scifi far-future 2092?

ACuriousMind

9:56 PM

@EmilioPisanty network-wide suspensions are solely imposed by CMs and we don't know any more than you do about their internal workings.

Semiclassical

CMs work in mysterious ways? :P

Emilio Pisanty

@ACuriousMind any chance you can ask in the teacher's lounge?

@Semiclassical exactly

Semiclassical

(not saying it's a good thing or a bad thing, but the system does seem deliberately opaque on that front)

ACuriousMind

@EmilioPisanty I predict the answer will be "we decided 10 years weren't permanent enough", probably caused by some early 10 year "permanent" SO suspension running out soon, but that's pure speculation on my part

Emilio Pisanty

@ACuriousMind if 10 years aren't permanent enough, why not just issue a permanent suspension and be done with it?

I mean, a 74-year suspension is just ridiculous.

(to be frank.)

ACuriousMind

10:06 PM

Again purely speculating; Because the system wasn't built with permanent suspension in mind and trying to fit them in would break all sorts of things. You'd be surprised how difficult superficially trivial changes in a large software can be

Emilio Pisanty

10:46 PM

btw @ACuriousMind did you look at the preprint?

ACuriousMind

@EmilioPisanty Just briefly at the pretty pictures ;) It went on the long list of things I want to read if I find the leisure

Emilio Pisanty

@ACuriousMind fair enough

it's the response to the 'many ways to spin a photon' paper that I've talked about a fair few times

Also it's where the representation theory on tensor products went

as well as the subgroups of SO(2)×SO(2)

which, I can now reveal, are also nicely understood as torus knots

ACuriousMind

@EmilioPisanty Yeah, I got that. It's neat there's also a meaningful interpretation for $\gamma$ not half-integer.

Emilio Pisanty

@ACuriousMind ::grin::

that's just monochromaticity acting as this restrictive box that you don't even notice is there

I'm here to break the literature out of that box

I mean, speaking in all modesty, of course

ACuriousMind

Of course :)

ACuriousMind

11:47 PM

@EmilioPisanty I've asked and it's indeed simply "as permanent as the system currently allows". As to what triggered the lengthening all I can tell you is that it wasn't a random act.

The Classical Channel

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