The h Bar

Obliv

3:00 PM

@acuri How would you model a motion that is repeated in regular intervals with simple equations of motion?

Bernard Meurer

@ACuriousMind My classroom was right next to the kitchen, I'd get 'a little distracted' when going to the bathroom

Secret

@DanielSank They make use of something called "mutual information" ,which I currently have little knowledge of. This thing somehow account for the cooling behaviour (and second law will be good as usual when this is taken account of, they said)

DanielSank

@Obliv Fourier series.

Obliv

okay well let's say we're limited to algebra and basic calculus then lol

Bernard Meurer

@DanielSank I wasn't at home! I was microwaving grapes at school

I also did it at home and broke my microwave oven eventually :)

DanielSank

3:01 PM

@Obliv Then you can say things like f(t + T) = f(t) where T is the period.

ACuriousMind

@Obliv Well, that depends what motion. The only thing you can generally say about periodic functions is indeed that they are Fourier series, i.e. sums of sines/cosines, but most periodic functions are not simple harmonic motions.

@BernardMeurer lol

DanielSank

It would be interesting to see how useful that is without using Fourier series!

@Obliv as long as the oscillator isn't driven it oscillates at a single frequency, so you don't need arbitrary periodic motion.

(Assuming it's a harmonic oscillator, perhaps with damping)

Obliv

are you saying you would need to use sine/cosine to model that motion if you didn't have access to fourier series?

Bernard Meurer

@ACuriousMind Tell me something I don't know :)

user116211

@BernardMeurer yeh... was missing it ;))

Secret

3:03 PM

>In summary, we have studied thermodynamics of measurement, in particular dissipation and information gain by measuring a biased quantum dot with another quantum dot. The thermodynamic cost of obtaining information is dissipation in the measurement device so that the second law of thermodynamics is satisfied for the whole engine-measurement device compound. We have shown that the same setup can work as a Maxwell's demon device, which uses mutual information obtained in the measurement to produce negative entropy, which is bounded by the decrease in mutual information. The measurement and fe…

DanielSank

@Obliv Well, you can just be a mathematician and say "Here I have a differential equation. I will stuff a sine wave in and behold! it is a solution."

Bernard Meurer

@MAFIA36790 :)

user116211

@DanielSank: Hallo!

DanielSank

Then you can point out to the students that you can change the phase of the sine wave and it's still a solution.

@MAFIA36790 yo

user116211

Yuggib is gone :(

Bernard Meurer

3:04 PM

@MAFIA36790 Why?

ACuriousMind

@BernardMeurer There's a species of cephalopods that procreate by having the male filling a tentacle with sperm and then detaching it. The female then keeps it.

DanielSank

@Secret That looks interesting enough that I'll try to remember to read it.

Thanks.

Bernard Meurer

@ACuriousMind Like those crazy chicks that chop the guy's dick off?

user116211

@BernardMeurer Nay, I wanted to know something about Grillet.

DanielSank

@ACuriousMind Yes.

Octopuses are awesome.

Bernard Meurer

3:05 PM

@MAFIA36790 I see

ACuriousMind

@BernardMeurer Uhhhh...I think the detachment is voluntary in this case.

Bernard Meurer

@ACuriousMind Ah, I see, pretty cool :)

user116211

ACM loves biology o.O

user116211

Okay Lubos is a historian.....

Bernard Meurer

@ACuriousMind I'm never stepping a foot on Heidelberg, that'd mean I'd have to pay you all the beers I owe :p

DanielSank

3:07 PM

Blanket octopus

Tremoctopus is a genus of pelagic cephalopods, containing four species that occupy surface to mid-waters in subtropical and tropical oceans. They are commonly known as blanket octopuses, in reference to the long transparent webs that connect the dorsal and dorsolateral arms of the adult females. The other arms are much shorter and lack webbing. Tremoctopus violaceus exhibits the most extreme degree of sexual size-dimorphism known in any non-microscopic animal. Females may reach 2 metres (6.6 ft) in length, whereas the males are 2.4 centimetres. The weight ratio is at least 10,000:1, and can probably...

user116211

@BernardMeurer hahahahaha...

user116211

@BernardMeurer In case he comes in your den ;P

ACuriousMind

@BernardMeurer One day, I will hunt you down and make you pay up

DanielSank

So says the Batman.

@BernardMeurer I'd be afraid if I were you.

Bernard Meurer

@ACuriousMind :O

@DanielSank I'm very afraid, last time I got in trouble with people from northern Europe it wasn't easy

Reason why I'm still banned from a city in southern Denmark :)

DanielSank

3:10 PM

Story time!

John Rennie

@BernardMeurer that'll teach you to microwave their grapes

DanielSank

@JohnRennie Isn't that an offence against the crown in Denmark?

ACuriousMind

@BernardMeurer For someone so young you sure have gotten into a lot of trouble!

DanielSank

@ACuriousMind Banned from one city and sent to detention for microwaving grapes is a lot of trouble?

Jeez, when I was a kid my brothers would pass little plastic bags of flour around at school just to keep the security staff on their toes.

Secret

@DanielSank Last time I read something similar is how information in entanglement can be used as some kind of tradeoff to produce a cooling effect in the 3rd regime of 2nd law in a quantum scale

http://www.pnas.org/content/112/11/3275

ACuriousMind

3:13 PM

@DanielSank To me, it is

Alas, I've never really gotten into any trouble

DanielSank

@ACuriousMind Go do something stupid and see what happens!

ACuriousMind

@DanielSank I didn't say that I never did something stupid ;)

The trick is not to get caught :P

vzn

@DanielSank hi hope you were not miffed by the "just do it" offhand/ throwaway remark. my feeling is that it wouldnt require preparation if you dont want to, there is no travel required except to a keyboard, and there is likely some audience, & wouldnt be much different than a typical chat session which you already engage in except scheduled... not sure what else to do to convince you. understand that scientific presentations require preparation & think its up to you to decide what to apply....

DanielSank

@ACuriousMind indeed

@vzn Not miffed.

@vzn If there is some basic level of "support", i.e. we advertise a bit, then I'm very happy to do it.

vzn

@DanielSank admittedly now thinking thru it a bit more, this near free-for-all room culture may not be overly conducive to this idea, the guest will likely have to have a tough skin so to speak re all the edgy/ off-the-cuff/ and more verbiage that goes on in here.

DanielSank

3:18 PM

Also @vzn I think you should consider that any good presentation of any kind requires preparation, and in ways you may not be aware of. For example, I assume people would like to ask questions about my job. If I want that to be possible I need to go get trained by public relations folks at Google and make sure I understand the boundaries.

This would take considerable time.

Again, happy to do it.

But not for a random, nobody knows it's happening AMA. The alternative is to answer zero questions about Google.

vzn

@DanielSank DZ is nowhere to be found at the moment and not promising anything re publicity so am feeling a bit unsupported on that right now, but (this takes some effort on my part) do have the ability to personally create a web page with unique url announcing the event, and can post it myself at least on my web site, google+, and try meta on this site, but (from long experience) people can be very prickly about meta usage. :|

DanielSank

@vzn Meta isn't the right channel, but the rest is good.

Note that people who see an ad on G+ etc. can't come to the chat room though!

Need rep.

vzn

@DanielSank ok, you have to pick a day/ time, maybe we can create the event ourselves in the room event list, and can build the (brief) web page for you this wk if you tell me the day time.

DanielSank

@vzn Dude, we're still stuck on the venue.

People can't just roll into SE chat rooms.

vzn

@DanielSank oh yeah, good pt, an obvious oversight on my part, but some who hear the announcement have SE profiles etc

DanielSank

3:22 PM

@vzn Ok. So if the idea is to target SE users I think community ads are the way to go.

...along with shameless promotion in chat.

vzn

@DanielSank its pretty hard to get 6 votes on a community ad on short notice and sometimes even longer. honestly did not imagine doing all this without some solid mod support which is not forthcoming so far, thought it would easily materialize, maybe miscalculated. did succeed in getting a Computer Science ad approved recently (cs chat room), it has over 400 hits now. =D

Secret

Slereah and I knew about this some time ago

here's some follow ups on that article
http://demonstrations.wolfram.com/NonlocalityInTheDeBroglieBohmInterpretationOfQuantumMechanic/

http://arxiv.org/abs/1605.03023

http://arxiv.org/abs/1603.02862

DanielSank

@vzn So forget "short notice" :)

What's the rush?

Did you talk with any mods about it?

vzn

@DanielSank think this is all worthwhile but dont want to put a huge amt of energy into each guest, cant afford that myself, already feel like its kinda high, was hoping for something informal and not high effort (in line with the room culture) :(

DanielSank

@vzn Did you talk to any mods?

vzn

3:27 PM

@DanielSank it was DZs idea to begin with a few wks ago, he says hes open to it if someone else coordinates, am attempting to push it fwd. have long thought there is a lot of untapped talent in the room etc

DanielSank

I'm also not sure a community add is "high effort". I'd vote for it. You'd vote for it, @BernardMeurer would vote for it if I show him some skin...

@vzn Oh great.

vzn

@DanielSank it takes about at least an hr to build the ad, and some ppl will complain its not perfect, etc, maybe can try it. but already its close to more hrs effort by me than the actual chat session. (write up blog page, publicize it, build chat ad, cross fingers approved, lobby people to vote on it, etc)

DanielSank

@vzn If one hour is "high effort"...

:)

So what's the deal? Make an image, submit it, and people vote?

Well, if the ad is approved you can use it for a series of AMA's.

The effort would be have value multiplied by the number of AMA's done.

Sounds like DZ would vote for it. I already count four votes.

vzn

@DanielSank ok, a generic ad is different.

DanielSank

Oh, yeah, definitely.

Bernard Meurer

3:30 PM

@ACuriousMind I make an effort :)

@DanielSank No story time :p

vzn

@BernardMeurer thx for support

DanielSank

@BernardMeurer awwwww

Bernard Meurer

@DanielSank I'll vote for anything if you show me some skin :D

DanielSank

@BernardMeurer I knew you would.

Bernard Meurer

@JohnRennie Lol, that one didn't have anything to do with grapes

@DanielSank I'll just say it involved a girl, a sailor-in-training, her boyfriend, and what seemed to be some for of Danish gangster mob

DanielSank

3:32 PM

@BernardMeurer Sounds like the premise of a good movie.

"A boy, far from home..."

vzn

@DanielSank do you prefer me to start with a blog page or a chat ad? will cook up start of 1 or other & see what happens next

DanielSank

profile shot of @BernardMeurer

Bernard Meurer

@DanielSank Later that day at the train station in Flensburg I also got in trouble with a homeless dude

@ACuriousMind Flensburg has some crazy homeless people living in the train station dude

DanielSank

ಠ_ಠ

Bernard Meurer

Well, at 5 AM at least

DanielSank

3:35 PM

@vzn I'd go for an ad first. Also try to get a list of people interested in doing AMA's so when you write a blog post and discuss with people you have some established promise of content.

Note that you can ask other physicists you know to make accounts if they're interested.

vzn

@DanielSank ok lets see what happens will try to get to it this wk

DanielSank

@vzn Ok. Note that we're sort of competing with reddit AMA's, which may be sort of foolish.

Not sure.

The style here would be different because it's real time, so maybe worth a try?

vzn

@DanielSank reddit AMA is the 800 pound gorilla, a very impressive edifice etc

DanielSank

The reddit forum may be a better medium for AMA's.

vzn

@DanielSank you would be a pioneer =D

@DanielSank like reddit, do you have acct? its a whole other system, have no idea how to go about it there.

DanielSank

3:37 PM

@vzn Yes, I have a reddit account.

/r/science has an AMA series.

vzn

dont see us as "competing" with AMAs at all, an impossible feat, just "another flavor" maybe with some similar elements

DanielSank

Very active.

David Z

@vzn y'know, you haven't asked me for anything

vzn

@DanielSank wish there was list somewhere of all the AMAs by type etc

Bernard Meurer

/r/the-h-bar ?

DanielSank

3:39 PM

@DavidZ Ah, how typical.

vzn

@DavidZ lol. will you agree to a link on home page at some pt if we get it all arranged

Obliv

can someone give me second order differential equation that can be solved for a periodic function that isn't sinusoidal? Like the first image on this page en.wikipedia.org/wiki/Periodic_function

I thought $\frac{d^2x}{dt^2} = -kx^2$ but that's still sinusoidal

David Z

@vzn yep, if there is a chat event, we can put an announcement in the sidebar

vzn

@DavidZ awesome/ thx :) ... DS has big ambitions for publicity it seems :|

David Z

Hey, whatever y'all can pull off, go for it

Bernard Meurer

3:41 PM

@DanielSank: The Justin Timberlake of physics

David Z

Something else to consider is the realscientists Twitter account, and other rotating-curator accounts: I think that may be a better analogy to what we can do here than reddit AMAs. At least in terms of the format.

DanielSank

@vzn I just think it's worth doing some advertisement!

David Z

realscientists curators do a lot more "storytelling" than reddit AMA guests, which I think might work well here

vzn

@DavidZ are you talking about granting the guest an account for ppl who dont have SE accts already?

DanielSank

@DavidZ Excellent.

vzn

3:43 PM

@DanielSank agreed. work/ action item for me :|

Bernard Meurer

@DanielSank When/if I go to UCSB can I sweep the floor at the Martinis lab?

David Z

@vzn no... I mean, we can't grant people accounts. They have to create the accounts themselves. We can get them into chat once they have an account, but the creation is up to them.

vzn

@DanielSank but a link on the home page is a big advertisement.

DanielSank

@BernardMeurer No but you can do research in it.

Bernard Meurer

@DanielSank :O

::dies::

vzn

3:44 PM

@DavidZ so you could get someone (guest) in the chat room with 0 rep? that is acceptable

DanielSank

@BernardMeurer Hmm, can't do research any more.

David Z

@vzn If you can find someone with 0 rep, let's test that theory :-P

But yes, moderators can arrange exceptions to the 20-rep requirement

Bernard Meurer

vzn

@DanielSank we could do this nearly immediately by just creating the chat event (with date/ time) and then DZ posting that link to home page... would rather start simple but am willing to experiment with the chat ad also.

Bernard Meurer

:)

David Z

3:46 PM

Also bear in mind it doesn't have to be me who does all this stuff. You can ask the other mods for stuff too.

vzn

@DavidZ anyone is free to volunteer, youve been most available so far :)

DanielSank

@DavidZ @vzn any notion of what days people would actually show up for something like this?

David Z

Well... true. But then that just means I should disappear from chat when I get busy.

@DanielSank no idea

When we started the chat sessions, we did a survey on meta

DanielSank

Ah.

@vzn why not go put up a meta post asking when people would show up to an AMA?

David Z

I'm guessing US east coast evening is likely to be best, but I couldn't say with much confidence.

vzn

3:48 PM

@DanielSank not a big idea. again recommend just piggypacking on the recurring room event, think DZ would be ok with that, it gets substantial participation, have you been to one?

DanielSank

@vzn The biweekly chat session?

David Z

Well, the problem with that is that we already have things to do in the chat sessions.

Falco Alexander

I beg your pardon. due to a limited web access this site is not working at all. sqlfiddle.com/#!3/75245/5

vzn

@DanielSank think we need to "just do it" and people will start to give feedback about convenient times if they have opinions

Falco Alexander

can you agree???

vzn

3:49 PM

@DavidZ so you prefer it some other time? thought special guest could show up intermittently, but ok :|

DanielSank

@DavidZ I think vzn meant to put it directly afterwards.

Falco Alexander

sorry for being off topic

vzn

@DanielSank my idea was intermittent "featured" mtgs with the guest in same slot. cant get new guests that often. might be more exciting than discussing hw policy wink

David Z

Let me say this: I think if you want to get started with this guest series right away - like within the next couple weeks - I don't think it will work to put it in the same time slot as the chat sessions.

vzn

@DavidZ ok

Bernard Meurer

3:50 PM

@FalcoAlexander What?

David Z

@vzn That could work. Like, if we have a guest roughly every 3rd chat session, and the session is dedicated to conversation with that guest.

DanielSank

@DavidZ That has the advantage that people would come.

David Z

But it will take considerable advance planning (at least a month) as to which weeks we will have time for a guest.

vzn

@DavidZ every 3 sessions seems often/ ambitious to me, like idea, dont know where to get that many willing guests. (btw recently contacted Lubos in chat room, no response. and hes another dude who likes to chat on here.)

Falco Alexander

sorry, bye

DanielSank

3:52 PM

Well then how about just when you do have a guest propose it, and the mods can schedule for an upcoming chat session.

David Z

Yeah, that was just an example - could be every 5 or 10 or however often we can get people.

vzn

@DavidZ am ok with a long lead schedule that can help bulid up attendance also.

DanielSank

^ That

David Z

That works

vzn

@DanielSank exactly. intermittently.

DanielSank

3:53 PM

\o/ yay

vzn

\o/

David Z

Basically, just don't count on having the next chat session available for a guest. But if you coordinate it 2-3 chat sessions in advance, that should be fine.

DanielSank

@BernardMeurer Just tried cream soda #40. It's a good one.

vzn

@DavidZ ok sounds good of course, lol we want to hijack every session on a moments notice, joking

David Z

We wouldn't have to know who the guest is going to be, just that there is going to be one on a particular day.

vzn

3:55 PM

@DavidZ alas, guests are not beating down the doors, so yeah think we do have to nail down the exact guest 1st to some session wks in advance

Bernard Meurer

@DanielSank Name?

DanielSank

@vzn You know, after one or two runs of this, if it's popular, we can always move it to its own time slot. This has the advantage of people having attended and (in the successful case) decided it's worth their time.

2

vzn

@DanielSank yes, its all open to negotiation/ adjustment.

DanielSank

@vzn Well they can't beat down the doors until we advertise it :)

@BernardMeurer "Hippo Size Beverages Colossal Cream".

vzn

@DanielSank SE has a lot of very elite ppl in places but honestly, chat rooms tend to be something like ghettos or empty places compared to the main site. this chat room is a rare exception...

David Z

3:56 PM

We can be somewhat flexible - like, tentatively plan to have a guest on a certain day, and then keep the option to switch it with a preceding or following chat session if necessary

DanielSank

@DavidZ Try not to switch times on the guest, please.

vzn

@DavidZ the more elite the guest the more they are gonna want to just have a scheduled day and not be "waiting in wings at moments notice"

DanielSank

@vzn Elite has nothing to do with it.

David Z

I meant that the switch would be done to accommodate the guest's schedule requirements

DanielSank

If someone sets aside time to do a thing, they don't like to have it moved.

@DavidZ Oh. I see.

vzn

3:58 PM

@DavidZ we need some commitment from the guest too to a time slot.

DanielSank

@vzn Yes.

Just schedule far enough in advance and it should work out fine.

Bernard Meurer

@DanielSank How large was the bottle?

David Z

I do think the availability of the guest is going to be a key factor in deciding when this sort of event happens.

DanielSank

@BernardMeurer 12 oz. Pathetic idea of "colossal" IMHO.

@DavidZ Indeed.

Bernard Meurer

@DanielSank Tsc, that's not colossal!

DanielSank

3:59 PM

@BernardMeurer No, it's not, but it has COLOSSAL TASTE.

ACuriousMind

I have no idea how large or small 12 oz. are. Damn imperial units!

Bernard Meurer

@DanielSank I have to tell you something... that might hurt our friendship...

vzn

@DavidZ (fyi) DS is asking for a community ad for the chat event, am planning to cook that up this wk, it will be generic to start

DanielSank

@ACuriousMind google it

@BernardMeurer :(

vzn

anyway thx guys DS/DZ for all the feedback/ ideas/ guidance/ enthusiasm

David Z

4:01 PM

Ah... now that's up to the community, but I don't think community ads do so well for one-time events

Bernard Meurer

@DanielSank Yo that was @ACuriousMind !

@DanielSank I... I... I've never had cream soda

David Z

@vzn Cool, no problem. It's good to see other people helping out with stuff :-)

vzn

@DavidZ right, so it will be more generic in the sense of "heres info on latest/ scheduled physics AMAs"

DanielSank

@vzn Yes, that's how it ought to be.

David Z

Makes sense

DanielSank

4:02 PM

@BernardMeurer That's fine. Try it some time.

David Z

(you probably don't have to ping me every time btw)

DanielSank

There are terrible ones and good ones.

@DavidZ I do that so the mouse-over thing works. Too bad the sound effect is so jarring.

David Z

I guess now that I think about it I can just mute the tab... lol, forgot about that

DanielSank

@DavidZ o_O zomg how?

::braces self for a Let Me Google That For You link::

Bernard Meurer

@DavidZ ping

vzn

4:03 PM

@DavidZ sorry not following are you talking to me?

DanielSank

^ LOLOL

Bernard Meurer

LOL

Oh god I love this chat

David Z

@DanielSank In Firefox, right-click on the tab and "Mute Tab"

Not sure if other browsers implement it

DanielSank

@DavidZ Confirming Chrome has it!

Nice!

"I am DavidZ, web browser wizard. Ask me anything"

Bernard Meurer

Lol

DanielSank

4:07 PM

@BernardMeurer make my code faster.

David Z

Actually it was kind of a big deal when Firefox introduced this feature

Bernard Meurer

@DanielSank Which code? I'm glad to work on it

Not sure I'm a better coder than you but I can try :v

DanielSank

I'm a s--- coder.

vzn

@DanielSank "false humility" you gave me some big coding lessons on here awhile back :P

DanielSank

@BernardMeurer I haven't even profiled yet, so I'm not really going to ask someone else to optimize it :)

Bernard Meurer

4:08 PM

@DanielSank Just add the eventual comment to help my soul

DanielSank

@vzn Let's just say coding skill is best viewed on a log plot.

@BernardMeurer Comment?

Bernard Meurer

@DanielSank Yeah like this

DanielSank

@BernardMeurer Ah yes.

vzn

hey all @Slereah etc those who want Lubos as a guest plz ping him on this recent thread & maybe it could sway him. note that chat pings for him will not work in here until he visits within 7 days.

chat.stackexchange.com/rooms/39872/…

in Discussion between user7348 and Luboš Motl, 21 hours ago, by vzn

@LubošMotl hi, am a regular Physics chat room user, noticed that you were/ are active in chat lately. moderator David Z runs a regular 2 wk chat meeting and recently suggested the idea of special invited guests. your name has come up repeatedly among the group as a desired guest speaker. would you be available/ interested in a guest chat session on a topic of your choice, or Q/A to the physics chat audience? say 1-1½ hr long sometime?

DanielSank

I think you have it covered. No need for us to all ping him.

vzn

4:14 PM

@DanielSank he hasnt responded to me (yet) he might listen to you or others. :)

DanielSank

In fact, you might make a meta post for guest suggestions.

@vzn ah

David Z

Yeah, too many pings (or too much attention, in general) can drive a person away

vzn

@DavidZ lol like you are driven away? he can tell us to go away if he wants & will respect it... "cant get hung for trying" as my grandfather use to say, & better to beg for forgiveness than ask for permission etc

DanielSank

@vzn As I am fond of saying:

Online chat is an asynchronous communication protocol.

Give it time.

vzn

@DanielSank he already has another very active chat thread since/ after the one where he was pinged. can tell when being ignored. :( but he might be swayed by others.

Bernard Meurer

4:16 PM

Let's call his home number and pretend we are grapes asking how can we become plasma

that ought to do it

user116211

@lucas: Please don't add your answer to another one's answer unless there is a consent from OP. Contribute separately if you want.

user116211

@vzn Damn, it would be awesome if there is Lee Smolin too ;))

user116211

@yuggib: o/

vzn

@MAFIA36790 all for it have his book! ... luv contrarians/ troublemakers/ "sacred cow gorers" =D

user116211

You wanted Terry @yuggib :(

user116211

4:21 PM

And I too voted for him ;/

user116211

To remember everyone @vzn ;P:

user116211

May 3 at 15:11, by yuggib

do you want me and ACM to uselessly fight with him for an hour?

Bernard Meurer

^^ I'd like that

user116211

@BernardMeurer T__T

vzn

@MAFIA36790 actually have been thinking that DZ may want to set "ground rules" for this near-free for all room culture aka how to be nice/ respectful to the guest minimum no namecalling etc

user116211

4:26 PM

@vzn: Argument is necessary in debate ;P

vzn

← lol ok yeah lives that sometimes too

David Z

@vzn That should fall under our general "be nice" policy

but it might be reasonable to say we will be stricter about enforcement during chat meetings with invited guests

yuggib

@MAFIA36790 anyways, I still think professor Tao would provide an immensely more interesting chat session (no offence meant to lumo)

but you know, I may be biased on this ;-P

user116211

@yuggib I voted for him too!

user116211

But my like is Moretti too.

yuggib

4:38 PM

@MAFIA36790 there was no precise poll...

user116211

@yuggib C'mon don't be indifferent to the unofficial poll ;P

user116211

Okay, gotta go, bye @yuggib

yuggib

\o

vzn

@yuggib unsurprisingly huge interest in Tao expressed. invited Tao into this room on everyones earlier suggestion, no response, he is not recently active in chat, last msg 654 days ago. guess we can consider emailing guests but would be a bit )( surprised at much success on that.

yuggib

@vzn I see; he has a blog and maybe it is sufficient to contact him there

vzn

4:50 PM

@yuggib ok yes another idea.

btw, if anyone has general ideas/ suggestions for the generic featured guest ad, let me know, intending to cook something up soon. pictures, wordings, themes etc., heres the moment to say something, am not really wanting to participate in a lot of adjustment/ tweaking it based on all angles of feedback (spking from recent experience, a difficult task to highly please everyone in these areas).

@DavidZ something else to think about, general room dynamics during guest session, how ppl should phrase questions, topics, format, how starring should work (star questions that people want answered?) etc

@yuggib encourage everyone to try to contact whomever/ however they want to invite.

David Z

@vzn that's all your problem ;-)

vzn

@DavidZ hah ok fine, imagine it might take some finetuning/ adjustment/ experimenting etc

lucas

5:13 PM

@MAFIA36790 Sorry. I didn't want to bother anyone. That question was closed.

vzn

ahem let me try to rephrase that, maybe didnt state it clearly. before cooking up the ad, encourage/ want to fully hear all kinds of different ideas, brainstorming etc. after cooking it up, will still listen but its very timeconsuming to try to do adjustments that make everyone simultaneously perfectly happy at that pt... (may consider revising the ad after some "payoff" of a few successful sessions...)

(may run by a few sample ideas myself in the chat room over next few days...)

Slereah

@ACuriousMind I am pondering about 2D spinors

DanielSank

I'd imagine an icon of someone raising a hand and asking a question. Maybe a speech or thought bubble with a bit "Q" in it.

Perhaps superimposed over the site's Mexican hat logo.

Slereah

Why are they two components

The Lorentz group is simply connected, why are they even here

vzn

@DanielSank ok sounds good. want to maybe have something iconic about physics in it. black hole visualization or something else. gravity waves, something graphically flashy.

Slereah

5:23 PM

I mean I understand from like a physicist point of view

But the group theory I don't get

vzn

from a datapoint of 1 (or several, cs site), have noticed that maybe photos get more clicks than other more straightfwd ads.

Slereah

What's the difference between the left handed spinor and the right handed one, basically

DanielSank

@vzn Clarity is much more important than flashy.

Make sure the image makes the reader aware that there is a physics AMA.

vzn

fyi this one came up on cs site after a lot of criticism of another one... seems a bit bland to me but maybe more ppl would like it for that reason :|

in Computer Science, yesterday, by EvilJS

@DanielSank flashy gets more clicks + audience.

ACuriousMind

@Slereah "2D" as in "two spatial dimensions", "two spatial dimensions+1 time dimension" or "one spatial and one time dimension"?

Slereah

5:27 PM

1+1

DanielSank

@vzn Lot's of wasted space, and it looks like a discussion about git histories or some other tree structure.

vzn

@DanielSank lol thats the cs logo in the bubble (representing cs data trees). anyway its just a general idea for us. you mentioned speech bubbles which reminded me of it. (some cybersynchronicity there)

we could put the mexican hat in the speech bubble instead, hows that for "generic" :P

DanielSank

Is there a way to paste images in chat?

ACuriousMind

@Slereah It's not clear to me what a "spinor" in 1+1D is supposed to be.

Slereah

Well to me either

That's kind of the problem!

The Thirring model doesn't seem to mind, tho

ACuriousMind

5:37 PM

@DanielSank Click "upload" to the right of the text form you're typing in.

DanielSank

@ACuriousMind Neat

vzn

@DanielSank yes any url that ends with jpg or png gets image one-boxed and you can also upload images to the stack.imgur.com site.

DanielSank

@vzn imgur.com/ohVKtgZ

ACuriousMind

@Slereah I think you don't care about "group theory" and just take a representation of the Clifford algebra.

DanielSank

^ That's not a good version, but it's an idea.

vzn

5:39 PM

@DanielSank (got it) the url didnt have jpg or png on end so it doesnt onebox.

Slereah

Could be!

ACuriousMind

I.e. you're not seeking representations of the universal cover of the rotation group, you define a spinor to be a rep of the Clifford algebra that's not a linear rep of the rotation/Lorentz group

vzn

@DanielSank anyway wow dude, not bad! maybe you should do it =D

ACuriousMind

If you now look at 2D, you need to find the lowest dimension in which you can write two matrices with $[\gamma^i,\gamma^j]_+ = 2\eta^{ij}$

Unsurprisingly, these are 2x2 matrices, so your Dirac spinor has two components.

Defining the usual chirality projector, you get two 1D complex Weyl spinors.

DanielSank

@vzn Oh come on. That was five minutes of internet copypasta :P

vzn

5:42 PM

@DanielSank thats all it takes you mastermind :)

ACuriousMind

As to why the heck we should care about spinors in 2D as they don't arise through the usual projective representation/universal cover argument, I am currently clueless.

Slereah

And they both transform under the same Lorentz group, I suppose

But wait

DanielSank

@vzn Remind me and I can try to make a better one this weekend.

Slereah

If they transform identically under SO(1,1)

Are they actually spinors

ACuriousMind

@Slereah What do you mean with "same Lorentz group"?

Slereah

5:43 PM

And not just

vzn

@DanielSank lol am your reminder button/ calendar now? :P ... anyway was gonna do one by end of wk or so

Slereah

Some kind of scalar field

$GL(1,R)$

DanielSank

@vzn Just asking...

ACuriousMind

@Slereah One component rotates "left" under a usual rotation, the other rotates "right", as usual.

Slereah

yeah but the representation is still the same, tho, right?

Or do they not

ACuriousMind

5:44 PM

@Slereah I don't understand what you mean by that.

what representation is the same?

Slereah

Like if I have the rotation $\theta$

DanielSank

Stack exchange chat, y u no let me edit people's spelling mistakes?

Slereah

With the boost $e^{i\theta} \psi_R$ for the right component

Is the boost of the left component also $e^{i\theta} \psi_L$

Errr

$e^\theta$

No $i$

ACuriousMind

@Slereah Pretty sure it's $\mathrm{e}^{-\theta}$. You should be able to just calculate it: Choose $\gamma^0 = \begin{pmatrix} 0 & 1 \\ -1 & 0\end{pmatrix}$ and $\gamma^1 = \begin{pmatrix} 0 & 1 \\ 1 & 0 \end{pmatrix}$ and just compute what happens under $\psi \mapsto S\psi$ with $S = \exp\left(-1/4\omega_{ij}[\gamma^i,\gamma^j]\right)$.

A non-calculation way to see it: The chiral parts are eigenstates of $\gamma^0\gamma^1$. This means that $\exp(\theta/4 [\gamma^0,\gamma^1]) = \exp(\theta/2\gamma^0\gamma^1)$ acts as $\exp(\theta/2)$ on the positive-chiral part and as $\exp(-\theta/2)$ on the negative chiral part.

Slereah

Hm

I guess I should read some more Clifford algebras then

Slereah

6:16 PM

I guess it makes sense

Otherwise $\bar \psi_R \psi_L$ wouldn't be a scalar

Slereah

6:28 PM

I guess that the fact that the rep of the Lorentz group for scalars and spinors is basically the same helps for that whole bosonization business

Obliv

7:23 PM

guys what's a non-symmetric function at $x=0$?

nvm I think I got it

Slereah

what about $x$

John Duffield

8:46 PM

@vzn : Lubos called me a psychopath because he couldn't answer my question. I'm afraid he's renowned for that sort of thing, and might not find this "be nice" chatroom to his liking.

vzn

9:08 PM

@JohnDuffield uh, lol, yes, realized some contradiction on writing that wrt colorful chat guests who might even be capable of "turning the tables" in here. but thats maybe not something we want to encourage by anyone eh? ps thx for noticing the fractional spin article whereas virtually nobody else did. (ps was wondering about some of your unorthodox views but thought another room might be a better place to start.)

Bernard Meurer

@JohnDuffield If we were to exclude everyone who had heated arguments with you we might have an empty chat room

vzn

@BernardMeurer lol still havent had one but have noticed that record seems difficult to achieve/ sustain at length :|

3075

9:35 PM

@JohnDuffield LOL

I agree with him though (not about you being a psychopath)

Danu

Hey @DanielSank you'll surpass me in rep. soon :D

DanielSank

9:59 PM

Really? I haven't written any answers for a looong time.

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