The h Bar

Q: Dupe specific Physics.SE question on Math.SE and Engineering.SE for different perspectives

5:48 AM

morning

Physics Meta

7:54 AM

0

Currently there is a terrric question open asking how to measure surface area. It is clear that from an engineering perspective there would be a variety of different methods proposed, while from a mathematical perspective the answer is "ill defined question". I would like to re-ask the question ...

discussion

12:24 PM

It seems that the 2018 Particle Data Group was indeed the last one available on paper

Quite sad

1:20 PM

@Slereah What do you want the dead-tree edition for?

@ACuriousMind Murder someone with it

I...don't know what I expected.

Q: Why don’t people on an airplane experience “weightlessness”?

1:47 PM

@JohnRennie woooooooooooow! What is that? Seems some soybean and bread!!!?

@JohnRennie Cool keyboard btw... XD :)

@ACuriousMind what? you don't know what you expected? doesn't makes sense...

Emilio Pisanty

2:04 PM

1

People in the ISS feel weightless because they are in perfect orbit around the Earth, and only gravity is pulling on them. By that logic, why aren’t people in airplanes weightless? A plane stays at a relatively constant altitude, meaning that it technically orbits around the Earth. What’s the dif...

gravity aircraft

any bets on how long until this hits HNQ?

@ACuriousMind It looks good in the library :p

Emilio Pisanty

@Slereah the CRC Handbook of Chemistry and Physics is still available in hard copy, you know

get you a chance to do some real physics ;-)

@EmilioPisanty I do actually want to get it

But it is way expensive

While the PDG book is free!

2:22 PM

Does anyone here believe in real life ghosts...? or have ever dared to enter haunted place?

@AbhasKumarSinha Define "real life ghosts"

@AaronStevens get feelings not words...

@AbhasKumarSinha What do you mean?

@AaronStevens no, nothing.. I mean that's not required to answer.

2:36 PM

This is reallllllllllllly the hardest Exams of the world!!!

jagranjosh.com/articles/…

I'm taking sheets and classes everyday for it... still they are of no use.

@AaronStevens Fadeev-Popov

@Slereah How can you drop a raw egg onto a concrete floor without cracking?

Drop it from a very small height

@Slereah answer - Concrete floors are very hard to crack!

^this cracked me up!

"Answer: Alphabet ‘T’ comes before ‘U’ and therefore T is before U."

Those are all stupid questions

is that how they decide how to hire people there

2:46 PM

@Slereah lol, they are designed to test presence of mind after written exam which is called prelims, the hardest exam of the world to get into IFS, or Diplomacy area... They are made to test how your mind reacts when it's angry, insulted and you can manage to have good sense of humor between dimplomatic talks...

Bad idea to take out a knife then

Mithrandir24601

@DanielSank Would there be any chance that you'd know whether the Q&A session after John martinis' talk at Caltech was recorded?

@Slereah didn't get that.

@Slereah youthincmag.com/toughest-exams-world

@Slereah personally, I feel that exam is a waste of time... not only chances to get into are very less, but diplomacy is a skill very few people need

@AaronStevens have you seen real life ghosts? (assuming you now know what that means)

@AbhasKumarSinha No, at least not that I know of. I haven't been able to test whether or not everything I have seen wasn't a ghost though, so who knows :)

@AaronStevens ah okay....

anyone here?

2:55 PM

@AbhasKumarSinha Have you?

@AaronStevens no, that's why I'm searching for someone who has :P :)

@AbhasKumarSinha Why?

Emilio Pisanty

@AbhasKumarSinha is this really the right place for this?

@AaronStevens something very complex... I know this is strange, but I can't have a better place than this for that.

@EmilioPisanty looooong story... won't create fuss here.

@AbhasKumarSinha Saw a TED talk one time where it was a scientific-paranormal investigator. She said she really wants to find evidence of ghosts, because she thinks that would be so cool. But she has never found evidence. All reports have some other explanation that is not paranormal.

2:59 PM

@AaronStevens ah okay, I've seen most of those, but those are useless. Will look up that video which you are telling...

3:09 PM

@AaronStevens qr.ae/TWxRQI creeeeeepy... The more I'm reading, more chills it is giving to me.

@NovaliumCompany you?

A very logical question, last question for today, these incidents make me uncomfortable. If you were in their place what you'd do to prevent these and stay safe?

see this - qr.ae/TWxT9k

qr.ae/TWxpMi

3:25 PM

@AbhasKumarSinha I'm not sure why it's useless to mention that someone who wants to find scientific evidence of ghosts hasn't found any yet. I think it's a pretty good point. It seems to make a pretty strong case that there isn't really a good reason to believe in ghosts.

@JMac not I'm not saying that video useless which @AaronStevens told, I used useless to most of the videos which exist on internet about ghosts claiming to be scientific, neither I've seen that video, but will surely look at it,

@AbhasKumarSinha The video I am referring to is saying ghosts are not scientific

I will try to find it, as I don't think it is easy to find with just the info I have given you

It's not really useless to investigate ghost reports scientifically. It helps to demonstrate either that ghosts are real, or not. The evidence so far seems to heavily suggest not.

@JMac I've not said I want to find the scientific evidence of ghosts. I just wanted to know if these events are occurring to those who are schizophrenic or there is someone, okay and the same happened to him. The existence of ghosts is questionable because there is not a single way in which they are described, there are multiple people describing them in multiple ways, but the problem comes when ALL OF THEM DESCRIBE A PARTICULAR GHOST IN THE SAME WAY

@AaronStevens there must be list of TED videos, I'll find with it later. :)

A scientific approach to the paranormal | Carrie Poppy

►

3:31 PM

@AaronStevens Ah thanks :)

@AaronStevens Should the existence of ghosts will be justified if hundreds of people describe the ghosts/haunted place exactly the same?

@AbhasKumarSinha More information is needed with that statement. For example, in many haunted locations people are primed with the same stories, so they might think they see the same thing

A more controlled experiment would need to be done

@AbhasKumarSinha Are all these people describing the exact same ghost unaware of others claiming to see that exact ghost? Are they all insulated from each other, or do they share a cultural background with the same myths, media, etc?

@JMac As far I remember, few russian and british foreigners also described it same.

DanielSank

@Mithrandir24601 I do not know.

Happy to try to answer stuff.

@AbhasKumarSinha Was this at some popular "haunting" site?

3:34 PM

@AbhasKumarSinha Plus, how is "exactly the same"?

IS it "I saw a figure that looked like a man"?

Everything felt cold!

@JMac hehehehehe XD :)

Mithrandir24601

@DanielSank Ah well, fair enough - thanks anyway! A couple of us on QCSE were just interested to see what was asked, I think (although there are a bunch of questions on the site)

(interested to see what was asked and how it was answered, of course)

@AaronStevens A mid aged women in white saree chasing them, no matter how fast they were driving. And a lot of sudden deaths too reported there. ( a lot of natural deaths) which is very very unusual.

@JMac yes, all at same site.

@AbhasKumarSinha I mean there are bound to be locations with much higher deaths than other locations. Statistically speaking. Earth is pretty large, and there are many people living on it

3:38 PM

@AaronStevens ofcouse.

it's bounded, not a very large place but a small area, usually can be covered on feet.

@AbhasKumarSinha The problem is anecdotal evidence is not scientific evidence. Without a controlled experiment you cannot conclude anything. Even if multiple people claim to have had the same experience

Additionally, memory is not always as reliable as we think it is.

Yeah that sounds like all the popular "haunted" spots near my home. Once you're primed to see something, you're more likely to report that you saw it. I can't say for sure that ghosts aren't real, but it seems highly unlikely to me.

@AaronStevens then how you'll explain natural deaths?

@JMac I understand

2 mins ago, by Aaron Stevens

@AbhasKumarSinha I mean there are bound to be locations with much higher deaths than other locations. Statistically speaking. Earth is pretty large, and there are many people living on it

2 mins ago, by Abhas Kumar Sinha

it's bounded, not a very large place but a small area, usually can be covered on feet.

3:41 PM

@AbhasKumarSinha ... And? Nothing Aaron said mentioned the size of the area...

@AaronStevens also why some british foreigner see/imagine something non existant in saree?

@JMac wait let me calculate

@AbhasKumarSinha once again, without a controlled experiment, common anecdotes do not constitute scientific evidence

If we believed anecdotes without further controlled experiments, then no one should be vaccinating their children

@AaronStevens ah okay... I understand, so youtubers can be considered reliable?

@AaronStevens why?

@AbhasKumarSinha I never said all youtubers are reliable.

@AaronStevens Mostly because "I vaccinated my child and they didn't get measles" is a really crappy anecdote. The same applies here though.

3:44 PM

@JMac Well I was going with the whole autism thing. But that is true too.

@JMac roughly less than 16 km^2

@JMac huh? didn't get it.

@AaronStevens That's what I mean. You don't see all the parents saying "I vaccinated my kids with MMR, they didn't get autism or measles, it was good." because it's not an interesting anecdote. It was a pretty good analogy to point out the issue.

@JMac no one says that. That's absurd...

@AbhasKumarSinha It's absurd to point out the vaccine worked and didn't cause issues, because it's considered normal. Anecdotally people claim that it causes autism in their children, so they don't vaccinate. It's because the first one is boring and no one really needs to say it; but then other people trust the anecdotes because they hear them more than the statistical truth.

The same can apply with ghosts. In that area, how many people walk through it without a ghost experience and just don't mention it to anyone?

@JMac I've never seen any claim like that before...!

@JMac Your reasoning makes sense.

3:50 PM

@AbhasKumarSinha Also, do you have statistics to show how much greater the concentrations of death in that area is compared to average? Then we might be able to compare that with how much it fluctuates normally across the world, and see if statistically anything there is significant.

@JMac yes, somewhere it was mentioned, it was about 7x more or some similar figure... (not reliable source though)

@AbhasKumarSinha Anti-vaccine (anti-vaxxers) is a pretty vocal minority in North America, possibly Europe too. They think vaccines cause autism, or are being used by the government to control people or something. en.wikipedia.org/wiki/Vaccine_hesitancy seems to cover a lot of cases. en.wikipedia.org/wiki/MMR_vaccine_and_autism This one was (way too) popular in NA.

@JMac ah, no one believes those here... Not anything when it comes to medicine...

Most of the ghosts stories (where no haunted place is associated) seem some accidents or technical failures...

@AbhasKumarSinha Those happen all over the world

@AaronStevens Can incidents happening to children of ages 2-6 be justified?

3:57 PM

@AbhasKumarSinha India still has some non-medicine based thinking too though. I don't think many places are completely clear of that problem.

@AbhasKumarSinha Yes? Bad things happen to children all of the time. You don't have to blame ghosts for it

@JMac not sure, very diverse country... I can only say of my state

@AaronStevens no children claiming paranormal stuff and their description is very ghost like (although there is no proper definition for that.

@AbhasKumarSinha I would say a child is an even less reliable source. They have great imaginations, and are not as good at explaining things

@AaronStevens oh okay...

@AbhasKumarSinha Didn't you tell me that you believed in homeopathy though? That's not really medicine either.

4:00 PM

@AbhasKumarSinha And once again.... anecdotes are not scientific evidence. Even if they are from children.

@AaronStevens I used to tell my parents I was afraid of elephants invading my room at night, and I firmly believed that elephants were trampling through my room for about half a year when I was about 4. My parents had to invent all manner of "defense" mechanisms so that I'd go to sleep at all.

@JMac I don't believe it, I just took it because there was no loss of doing that too, and it finally cured.

@ACuriousMind But did anyone scientifically prove there were not elephants roaming your room at night?

@ACuriousMind heheheh XD :) I used to ask my parents to go with me to the bathroom at night, because I was afraid to go alone.

I can related those.

@AaronStevens neither anyone scientifically disproved... XD :)

@AaronStevens Admittedly not. But if there were, they were very careful to not damage anything nor leave footprints or similar things behind ;)

4:03 PM

@ACuriousMind Ah yes. Those sneaky, careful elephants

@AaronStevens Did he ever even confirm with his parents that they didn't see the elephants? We might actually have 3 whole pieces of anecdotal evidence here which prove that elephants did indeed storm his room.

I still dream of these assassin elephants about twice a year - and it's still scary to dream-me!

@JMac Yes, we have a laugh about that story regularly. They didn't see any elephants, but that just means that I'm particularly elephant-sensitive!

@ACuriousMind Probably because they didn't believe in them. You have to resonate at the right frequency for these things.

I don't see ghosts very often, probably I scared them too much.

Now, i've to go to save the whole world from these.

signing off, your hero.

Abhas Kumar Sinha

Bye.

Now lizard people controlling the world. That's definitely real

4:10 PM

Given the state of the world, I feel that's slanderous to lizards.

@AaronStevens The only people denying that are lizard people, people paid off by the lizard people, or people who willfully ignore all the evidence.

Or robots like ACM who just see all humans the same as lizard people through their HUD.

@JMac Or lizard robots?

I, for one, welcome our new mecha-dragon overlords.

@AaronStevens Well now you just sound crazy.

@ACuriousMind Are we sure compliance means survival though?

4:16 PM

@AaronStevens No, but we'll have to fake it until our own robot army is ready anyway

@ACuriousMind Ah, I was unaware of a resistance building

Good. That means the cover is working

@ACuriousMind But now they could see this chat

They haven't figured out the internet yet - their claws are too big to type on normal keyboards.

well people have been dictating to writers for thousands of years, so do dragon overlords need to actually do the typing?

4:33 PM

Random side: Through my many experiences in tutoring physics, I am becoming more and more annoyed at problems that involve numbers. When problems have numbers so many students just grab an equation and start plugging in numbers without even thinking through the problem, the system the problem describes, the assumptions behind the equation they have grabbed, etc.

I know that future scientists need to know how to do calculations

But I wonder if introductory physics is the place to even focus on that

I feel like problems with numbers should be rarer than they are in intro physics classes

numbers are easier to grade

i think, at least

i stopped grading crap like 5 years ago

@KyleKanos If you only care about the final answer and not the process, then yes I suppose so

But I think a lot of physics homework can be done online now

if you have 400+ papers (exams, HW, etc) to grade, the final answer is what matters...

@KyleKanos Yeah, this is true...

I'm reasonably certain that it's human nature to be as lazy as possible

4:37 PM

@KyleKanos I'll second that

I just try to push for plugging in numbers at the very end

i told my wife that i was starting to get a little lazy at work since i know i'm getting december off (hurray for FMLA), but that my being lazy is still doing more work than most my colleagues :(

Well then you're being lazy wrong

no, they're working badly

and doing things wrongly

and thats why my company is in the sad state it is in

we had the opportunity ~1.5 years ago to fix things (hiring new head of dept), but he chose to keep same old instead of firing the crap out of the badly-working people

@KyleKanos Ah ok. Yeah that sounds frustrating

yes it is

and someone's brilliant solution was to just re-write the library we've spent ~10 years writing (in C++) in Java

because that can "fix" the issues. somehow.

4:44 PM

@KyleKanos Sounds legit

@AaronStevens exactly, I feel annoyed while thinking of physics teachers. Physics should be formula less...

@AbhasKumarSinha so qualitative descriptions only? how would that work?

@AbhasKumarSinha Well I am not advocating getting rid of equations

@KyleKanos ...? what you mean? that ghost story?

where did ghosts come from?!?

4:46 PM

@AaronStevens If you ever feel annoyed, then give them JEE Mains Questions, these are designed to trick students who don't understand the use of formula/equations

if physics is formula-less, then you only have qualitative descriptions of relations. i'm wondering how that would work in instructing anyone in physics

@KyleKanos then what were you talking about?

@AbhasKumarSinha No. My goal is not to trick students. I would much rather them learn effectively in a welcoming environment.

@KyleKanos solve questions...

@AbhasKumarSinha without formulas? again: how would that work?

4:47 PM

@AaronStevens I really liked engineering, because there was a lot of number problems, but it wasn't quite plug and chug. Often the numbers they gave weren't sufficient to solve the problem with just the textbook formulas. You had to assume something to get another variable, or to eliminate a variable. There were some cool conceptual questions too; but I liked the critical thinking number problems.

give an example, please

@AaronStevens trick them to make them understand that what's wrong. For example, if you give children fallacies, then they'll understand what's wrong with the use and will help them in concept building. There is nothing wrong in that.

@KyleKanos Know your assumptions, ask questions, connect things... This is how I do, without formulas

this might be time talking, but it has it's own goods.

@JMac I agree. Questions like that are awesome. I just think that at the intro physics level numbers sometimes lead to bad things haha. Mainly students who are too eager to plug in numbers

That's why I want to be an enginner... an enginner... Really?...

i'm a software engineer, sorta.

which is why Dilbert is such a great comic

4:51 PM

Hilbert you mean probably..?

@AbhasKumarSinha no, definitely meant Dilbert

Dilbert

Dilbert is an American comic strip written and illustrated by Scott Adams, first published on April 16, 1989. The strip is known for its satirical office humor about a white-collar, micromanaged office featuring engineer Dilbert as the title character. The strip has spawned dozens of books, an animated television series, a video game, and hundreds of Dilbert-themed merchandise items. Dilbert Future and The Joy of Work are among the most read books in the series. Adams received the National Cartoonists Society Reuben Award in 1997 and the Newspaper Comic Strip Award in the same year for his work...

ah, sorry, then I don't know more about it,

I'll become an entrepreneur then...

i think those that don't work in an office culture probably won't be as enthused or entertained by it, sadly

@AaronStevens Yeah, I definitely see where it becomes an issue. For me it was great, because they were basically brain teasers. People seem to get the impression it's the math that matters (I'm not sure how to fix that beyond just more passionate teachers), when really its setting up the equations that takes the real work most of the time.

@AbhasKumarSinha What kind of engineer?

Refer How to solve it - George Polya for more information.

@JMac AI

4:55 PM

How to Solve it is more about how a teacher should get students to think about problems than for students...

has chat become morse code only?

→ 25 messages moved to Trash

Stop it.

:52510973 Right, because we are forcing you to spam the chat with non-communication.

2

@ACuriousMind boring ;c

have some fun guyz

@NovaliumCompany Let's start another room for that. Our room our rules then XD :) hehe

@NovaliumCompany If you want to have a personal chat with dots, do it in a personal room. If people are telling you it's spam, don't keep doing it. Have some common sense guys...

4:59 PM

Why so serious? :}

@AbhasKumarSinha yay

Ugh, Low-Quality review is asking me about a question but i ran out of close votes hours ago :(

@NovaliumCompany yes. Okay commander...

@KyleKanos I am in the same place. I feel so powerless

@NovaliumCompany This is a shared room. Someone flooding the room with nonsense is distracting and not useful to the people who actually want to have a conversation here. You're free to post all the non-sense you want in your own side-room.

why haven't they fixed that yet? if close_votes_count ==0: skip_review(id)

5:00 PM

people should learn to not take the world too seriously. After all, you won't get out of it alive

@KyleKanos I think the optimistic belief behind that is that most LQ posts won't require a close vote

@NovaliumCompany I will

@ACuriousMind but if they do, then the logic is clearly flawed

I'm forming the dots dictatorship with my boy @AbhasKumarSinha

@KyleKanos Well, you can always click "Skip" and leave it for the next user that has a close vote

@NovaliumCompany yes sir. Roger that :)

5:02 PM

@ACuriousMind Or at least that the question will possibly not warrant one

@ACuriousMind yes, but then i don't get credit for the review

@KyleKanos Just say "Looks ok" haha

@KyleKanos Ah, the dark side of gamification rears its ugly head ;)

given that i'm some sort of glutton for review numbers, i'm not a huge fan of "skip" (except for knowledge cases)

@NovaliumCompany I wouldn't say it's "taking things too seriously" to ask you to stop spamming nonsense in a shared chatroom where people were having a conversation in English (the language the chat is meant for). I joke around here all the time; I don't take this chat very serious. Doesn't mean I want the entire feed to be dots...

5:04 PM

Come to join this room, if you like DOT Chat and AI and teen stuff..

$Mathematics$ Dot Chat (AI Chat)

This room is for teenagers and AI enthusiasts. It's just for r...

though i've fallen so far behind Rennie in First Posts queue :(

thank you lord chatroom for giving me a second chance. love you. sleep well

@NovaliumCompany Let's join and gather teen army there.

i had the top spot at one point, but not since i gave it up to focus on Late Answers

How lively the chat room looks XD hhehehehehehe.....

5:06 PM

i'm also slowly creeping up to ACM on being #1 overall voter, but i'm still like 4k behind :(

I'm so bad at keeping up with queues. The only one I regularly check is the LQP because it's usually short, and often an entertaining dumpster fire.

I just want the gold badges :P Although I am far from it on most of them

Only just got to 1000 in close votes recently

@AaronStevens Late Answers is HARD to get

@KyleKanos Yeah I have noticed haha

Took me like 4 or 5 months of hard focus on that one to get it

5:09 PM

@AbhasKumarSinha Why post a picture of that? We didn't want to have the dot conversation here, why post a picture of it?

Mast

Everything all-right in here? Flags were raised.

@Mast They just kept posting

@Mast Everything's under control.

"....." then made their own room for it, and came back to post a picture of that chat for some reason...

Mast

After being warned by a moderator not to do it?

Not particularly smart.

5:10 PM

Yes

3 messages deleted

:52511155 I think most people here made it clear the joke didn't really make sense here. You were told to stop posting dots. Why post a picture of them?

Further "dotage" will lead to more consequences than a 1-minute kick.

5

ah okay cool down, apologies...

@KyleKanos There was a time when I would go through all questions posted since I last logged in and vote on them. That'll get your vote count up (and consume a non-trivial amount of time :P)!

5:14 PM

@ACuriousMind You were on a roll with votes cast basically since you joined, right?

@ACuriousMind yeah, i'm not at that point. i do tend to pop open the ones i get in the queues and vote

Ah here's what I was thinking of physics.meta.stackexchange.com/questions/6754/… You were like a member for a year or two with most downvotes cast. That's pretty awesome.

@JMac I think it took me one or two weeks after my first question to really start participating, but after that, yes

I didn't start getting into the queues until recently. So much wasted time

hmm, not too much longer for ACM to even exceed that of Community now! (see query)

5:17 PM

I was eager at first, because it was a shiny new feature, then lost a lot of enthusiasm for them.

Apparently I also really suck at voting on questions. I've been less than 10 votes away from Electorate for... weeks now I think.

just find 10 questions to vote on

@JMac I believe in you

i've asked like 4 questions, you can vote on those

@KyleKanos I decided to just do it organically and see how bad it is. I've been surprised by how long it's taken me.

i didn't even know what badges were for a while

i think i first noticed them when i hit either the 10-score answer one or maybe Fanatic

5:22 PM

@KyleKanos Badges are the only reason I joined and still continue to participate

@AaronStevens Screw sharing knowledge, I'm in it for the numbers beside the colored circles.

@JMac It's an actual problem. There are users just casting 500 random votes to get the corresponding badge on every site.

@ACuriousMind That sounds pointless haha

Yeah, it is pointless - but potentially harmful especially on smaller sites where the voting totals aren't high to begin with

@ACuriousMind Sure, you gamify any system and people will abuse it. In the case of SE I find it a pretty hilarious concept. There's so little to gain. Even like peer recognition... I feel bad for anyone who cares about increasing badge numbers that much, especially if they don't even really use the particular site.

5:29 PM

@JMac At least one sock puppeteer on SO did it to be able to cite a "high-reputation SO account" in their applications...

actually badges and rep, to some degree, keep me from participating on other sites

because i've put so much time & effort into this site and i know i couldn't just ask & answer on other places, that i'd be putting waaaayy too much effort onto the other sites

(though the lack of time is a bigger hurdle to face, considering work actively blocks most sites & strongly discourages posting anything on work devices & that we're expecting another kid soon enough)

@ACuriousMind If that actually helped, that's especially sad, but regardless that seems super silly to me. Maybe it's just because I'm not in the software industry, so I may not understand SO's influence.

maybe it's because we're not looking for pure programmers, but i'd not care about someone's SO score

@KyleKanos Another kid? Congrats! (are you going for a world record? :P)

@ACuriousMind yep, #6 will be here in ~2.5 weeks

i think i need about 20 more kids to have some sort of WR on that, bu i'm reasonably certain i am not up for that many

5:35 PM

Woah, five kids heading into number six. I can see why finding free-time for participating in other SE sites might be an issue. That's gotta be a bit hectic.

good grief: how is this physics and on HNQ: physics.stackexchange.com/questions/513189/… ??

(at least SOX is saying it's HNQ)

@KyleKanos Became hot 5 mins ago.

ugh....i hate to see not-even-physics questions appear there

It won't anymore, I closed it.

well that solves that issue, thanks

Semiclassical

5:50 PM

"Water flows downhill. (I'm aware this is not new information ;)"

Who muted me?

Semiclassical

From the look of things, someone who was tired of you spamming the room and who had the authority to do so

I deserved it and I'm sorry. I'm just disappointed that a lot of people here lack basic sense of humor and constantly follow some dull rules. I understand those people have to be "professional" and do their moderator job but c'mon... People should get out of that box that they have put themselves into.

Mast

Don't force your humor upon others, especially after a warning.

@Mast Look the chat history. I stopped before anyone warned me.

@ACuriousMind thanks by the way

6:01 PM

@NovaliumCompany There's plenty of humor in this room. But when people don't find your jokes funny and ask you to not continue them, you should simply oblige them. This isn't about being humorless, it's about being considerate of others.

@ACuriousMind True. But again, I stopped with the dots right after you said.

@ACuriousMind I hug you, offer you peace. Let's remove the negative and be friends. Love and blessings for all.

@NovaliumCompany No need to be so dramatic about it ;) All you got was a one-minute kick - just keep it in mind next time and move on!

@ACuriousMind 30 minutes mute*

that's why I was gone for so long

tpg2114

6:18 PM

Moving back to talking about physics (and math I guess) for a minute -- if I have a Markov process that is always transient (so there is no state it will get stuck in) and non-recurrent (so it will never get back to its original state)... does it being a Markov process help me in any way, other than being a bit of trivia about the model?

It's in the context of a physics model -- if you solve the diffusion equation on a 1D line, but every so often in time, you take a part of the line and scramble it up, then keep solving the diffusion equation until the next scrambling time

I'm interested in either the expected value of properties along the line after several scramblings and/or long time, or the pdf of properties along the line as a function of how it was scrambled

Hidden Markov Models are cool

@tpg2114 Well, if you have that the process is transient and non-recurrent, then I don't see what difference it being "Markov" could make. The property of Markov to not depend on the history seems trivially true if the process never recurs in the first place.

Hm, no, wait - you could have history be important if there's more than one way to arrive at a given state

tpg2114

@ACuriousMind It could be non-Markovian if the scrambling depends on the entire time history of previous scrambles. But I agree -- in this case, I don't see the value that being a Markov process brings here

And I guess it depends on how one defines state too. If we imagine the line has 10 boxes in it, if I scramble the boxes and look only at which box ends up where, then the state doesn't depend on history. But if I move contents between nieghboring boxes and then scramble them and I want to know what's inside boxes, then I guess history does matter

@tpg2114 u doin som AI stuff?

tpg2114

@NovaliumCompany Not for this particular problem, no. This is turbulence modeling

Scalar diffusion on a line with periodic scrambling of the line is a model for turbulent diffusion of a scalar

And right now, it's very expensive to run simulations using it -- because the stirring has a random length of the line it affects and it can happen anywhere on the line, it takes long time averages or many ensemble averages to find the expected value of the diffusion rate

And if I want the pdf of diffusion rates, rather than the expected value, then it becomes even more expensive

I had the realization Friday that the scrambling process is Markovian -- it doesn't depend in any way on the current state of the line. But, after thinking about it all weekend, I don't think that actually gives me any new tools. It just seems to be trivia.

schn

9:05 PM

Can the last equality be right? Isn't it $|A|^2 \cdot 2(1+\cos{(ka)})$?

More Anonymous

@ACuriousMind would a question of this sort be welcome on physics stackechange?

physicsoverflow.org/42577/…

(hey)

9:25 PM

@MoreAnonymous Not in my eyes. It's a check-my-work question that additionally shows a lacking grasp of the proper terminology right away when it says that "Hamiltonians" are in equilibrium (systems can be in equilibrium, Hamiltonians can not!). It furthermore seems to conflate statistical probabilities with inherently quantum probabilities.