The h Bar

finally stopped

my backpack is still wet

What country is this again?

hopefully it'll be dry in the morning

@Phase America

Oh, are you near the flooding?

we're having some hurricanes right now

@Phase no

12:13 AM

Yeah I heard. Sounds pretty nasty

I'm gonna come off for the night, thanks for humouring me again. Peace

night

@0ßelö7 Strangely, that word can refer to so many geographic areas, LOL.

I'm pretty sure in the context of countries, "America" refers to only one.

Yes, if it is countries.

And even without that context, no one unironically refers to their location as America except for Americans.

12:18 AM

I guess what I said was really stretching things too much.

Hurricane Harvey is bad.

But the floods around India have killed more than a thousand it seems.

Natural disasters are bad no matter where they occur. It's time to go full Matrix on the world.

Can't have natural disasters if the world is in ruins.

The worst one in recent times was the 2004 tsuanami that killed over 200,000.

We just need to get rid of the oceans.

Strange that most of the body and most of the earth is water.

*surface of the Earth

12:23 AM

The moral of the story is to drink lots of water to keep the doctor away, LOL.

leave the faucet on while brushing your teeth

@KyleKanos 'sup

@0ßelö7 Wait, I don't get that one.

@Jasper it wastes a lot of water

Oh, LOL.

I saw Balarka and your room, LOL.

@Jasper you should keep an eye out for the new Einsiedler book. It could displace Yosida/Reed-Simon/Rudin as the standard references

12:26 AM

@0ßelö7 The thing is functional analysis means so many things that a book with that title can treat so many different topics.

I do like Conway's book though.

I have it on my shelf. Good reference, though having 1000 exercises makes it a tough read

And of course, Conway has sort of a sequel to that book.

A course in functional analysis is followed by a course in operator theory.

Conway used to be the head of my department

@Jasper Have you read the second book?

@0ßelö7 Simon has written A comprehensive course in analysis, 5 volumes, AMS.

@0ßelö7 Nope.

@Jasper no one has time for 5 volumes lol

12:30 AM

@0ßelö7 I think that set replaces a large part of what the Reed Simon set does. More updated, with different titles to avoid confusion, LOL.

I find it amazing that none of the standard books have any decent treatment of nuclear or Montel spaces.

One has to go to specialized books like Schaefer for those.

And that one is also plagued by 1000 exercise syndrome.

Advanced books really should give references for the exercises. Do the exercise if you want but if you're researching and have to do an exercise in the process, it can be quite frustrating.

Especially because you might be lacking some lemma, etc.

I dislike books which leave important theorems to the exercises.

That is one reason I don't really like Rudin's books anymore.

@Jasper So, Conway.

I don't deny that doing exercises can be important in learning a subject, but some people only have time to read the text and not do ALL the exercises.

And sometimes, we don't even know whether there is a mistake in the exercise or not. Maybe it can't be done, lol.

Petersen's exercises are like that.

One could write papers trying to solve some of them. Third edition ones.

12:35 AM

LOL.

Do you have the 3rd edition?

No, I don't. For some reason, I thought you were German, LOL.

I think it's because of your username.

Look at this monster

LOL.

(8) makes absolutely zero sense

amazon.com/Comprehensive-Course-Analysis-5-set/dp/1470410982

Hmm...

12:39 AM

The last time I checked it was on Russian servers as well.

I am going to sleep. It is 8.40 AM here now. Good night!

Night

wow

@DanielSank Is S2 when N and co. appear?

1:20 AM

@BernardoMeurer can I count on Linux help this time tomorrow?

@0ßelö7 Let me check my schedule

(or any time after 5 pm my time)

Probably yes. I have a call tomorrow but dunno when yet and should be earlier than this

Sure thing

thanks

@0ßelö7

1:23 AM

yes please

although according to the phone we won't have rain for a week

HDE 226868

1:45 AM

@dmckee My astro professor cited your answer here in a discussion of centripetal force in the context of orbital mechanics.

7

that seems like a hack that works out

not a proof

HDE 226868

He termed it an "approximate derivation".

that's basically what physics is

2:05 AM

@BernardoMeurer yo can u do tikz?

@0ßelö7 I did a PERT diagram with it once and some Chem drawings

But I wouldn't say I know tikz

2:16 AM

@BernardoMeurer I need to get into it but I don't know how to begin

I need to draw some level sets in $\Bbb R^3$

DanielSank

2:34 AM

@0ßelö7 no idea what you're asking.

@0ßelö7 Just do a PERT diagram

Jaime Gallego

@0ßelö7 My first suggestion would be the pgf manual, but, as most other LaTeX references, it is obtuse. Skim through the chapters that interest you and go from there.

dmckee

@HDE226868 I'm duly flattered, but I'm going to have to tell myself it was selected for the presentation because the basic idea is certainly not original to me.

I'd say it most recently in Cutnell and Johnson's book and I'm fairly sure I first saw in my high school physics text in 1988.

my high school physics teacher didn't give a damn about derivations

she said that people who do derivations don't get paid much, so why bother

@JohnRennie Copyright is evil, I only laugh at free jokes (free as in freedom)

Jaime Gallego

2:46 AM

@BernardoMeurer My tech teacher loved to draw these.

Like cavemen

@BernardoMeurer no idea what that is

Jaime Gallego

He's a great guy, he just sold his soul to Siemens

@0ßelö7 Google

@BernardoMeurer must be some CS thing

@0ßelö7 No, it's a management thing

3:25 AM

@BernardoMeurer same thing

GPhys

for GR we're using Sean Carroll's book

lame

GPhys

our QFT course is being taught by the smart string theory guy 👀

lame

GPhys

3:41 AM

@0ßelö7 who is the ideal QFT professor for you?

I get the impression from faculty that the experimentalists never teach the course

or even the regular graduate QM I/II for that matter

@GPhys I can't imagine ever taking a QFT course

dmckee

4:14 AM

I just noticed that (with the one I just started we have a dozen active bounties right now! Wow!

Anonymous

5:01 AM

@EmilioPisanty Nice. Check out the last 30 days statistics for those. Many of the top 10 tags on that list have >70% unanswered rate. We should do something to get those answered.

Anonymous

Last 30 days statistics is what matters.

Q: Fixing Binary search bug from Bentley's book (programming pearls: writing correct programs)

5:30 AM

@Blue I very much disagree. There's too much noise and too little data. The 30-day numbers look pretty useless to me.

You only get numbers that high on very small tags that had three questions in that one-month period, as far as I can see

But maybe you can provide better data?

@dmckee nice (except for the mismatched parens =P

Anonymous

@EmilioPisanty By "small" tags I guess you are referring to the number of questions belonging to those tags? My point was that those tags are "small" because not many people ask questions on those and also not many people answer questions belonging to those tags.

Anonymous

If you are not content with 30 days, perhaps we could check out the data for last 1 year

Anonymous

I don't think it would be much different

Anonymous

Let's take superconductivity for example. 7 out of the 8 questions went unanswered in the last month

Anonymous

That's not healthy

John Rennie

7:05 AM

@SirCumference there is a Trash room and a Trashcan room. The latter is mod only I think. Presumably it's used when the mods want to keep a copy of offending messages for future investigation.

Anonymous

9

Binary search can be implemented in many ways-recursive, iterative, conditionals, etc. I took this from Bentley's book "Programming pearls: Writing correct programs" which is an iterative implementation, and that includes a bug. public class BinSearch { static int search( int [] A, ...

Anonymous

I was being taught the wrong code for Binary Search all this while

Anonymous

Huh

Anonymous

I wonder how people took decades to figure this bug :P

Anonymous

7:21 AM

Anonymous

How is the recurrence relation using $\leq$ rather than $=$? I don't understand

Anonymous

Shouldn't it be $T(N)=T(N/2)+1$ ?

Anonymous

Do you know? @JohnRennie

Anonymous

According to me the Time taken to binary search on an array of N elements should be equal to time taken to binary search on one half of the array + 1 (1 denotes the time taken to halve the array)

Anonymous

So there should be an equality, isn't it?

Anonymous

7:25 AM

Is it because $N/2$ may not be an integer?

Anonymous

That's one possibility...hmm

journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.204101

Will read this when back to comp

nature.com/ngeo/journal/v10/n9/full/ngeo3016.html

Balarka Sen

@Blue It says T(N) is the is the time taken to search in a subarray of size <= N though, not on the whole array of size N. Maybe that's it?

I wonder what happens if a planet atmosphere rotates at 100 times the planet. Should expect stormy weather. But what if the planet itself have difficulty keeping up with the rotation and result it's surface to behave effectively frictionless to its atmosphere:?

Anonymous

7:43 AM

Say, our sorted array is {1,2,3,4,5,6,7}. We need to show T(7)<=T(3)+1

Anonymous

So, say it searches on only the first 5 elements

Anonymous

But then T(3) could search on any 2 elements

Anonymous

Or even 1 element

Anonymous

How do we say that searching the first 5 elements takes less than or equal time (for searching the first two elements)+1

Anonymous

This doesn't make sense :P

7:45 AM

spacetelescope.org/news/heic1713 Planets e,f,g may have substantial water

Anonymous

@BalarkaSen I think the previous slide is most probably wrong. Other websites seem to state $T(N)=T(N/2)+O(1)$

Anonymous

Their definition of $T(N)$ doesn't make sense

Balarka Sen

vOv

8:40 AM

@Blue Because you might get lucky and e.g. hit the element you are searching for at the very first comparison. The $\leq$ means this is a worst case estimate for the duration of the search.

@Blue I think raw data of "% unanswered" won't tell me anything about how good the site is doing in these tags. Maybe the questions asked are just not very good so people don't want to waste their time answering them. Maybe the questions are really difficult and would require rather lengthy answers which no one has found the time to write yet. Maybe the questions are about a really obscure subfield where it's unlikely we have anyone versed in it.

9:10 AM

@Blue l? u? A? K? That disgusts me

I actually have to read the code and follow through with what it's doing in order to understand its function. That's... Just No

@Mithrandir24601 And how often have you committed the exact same sin in naming your variables? ;)

@ACuriousMind I learned programming from someone with a PhD in CS (actually the only teacher I had in school with a PhD :P ), then I went into (initially) a CS degree. So, never. It's been drilled into me never to do such a thing

9:26 AM

And you never gave in to temptation, not even for these tiny auxiliary functions you'll certainly get right and that no one else needs to read? :P

2

If so, I tip my hat to you, sir!

@BalarkaSen Give me some time. I'll get to it

@ACuriousMind what, loops? Of course :P

Admittedly, I have written bits of code that weren't well commented or well laid out before, but that's a different problem :P

Recently, inspired from some PhD presentation of glasses in a group meeting, was thinking about composite systems that might behave like an orientational glass

Consider the above simple model of a cube embedded with roughly spherical components. The components are locked in position thus they cannot translate nor vibrate. However, they are free to rotate in in place

@ACuriousMind I believe the closest I got to that was using 'long f0, f1, endValue, fCur, guess' for a bit of 4 line code for a programming exercise

Suppose each of these spherical components has a couple of rotational modes which can be excited when sufficient energy is supplied to the whole cube (e.g. in the form of heat, or light etc.), one interesting question will be the entropy of this cube

While the cube has a fixed volume, thus if each pixel of the cube is a (classical) particle in the statistical mechanics sense. Assuming the particles are independent of each other, then we would expect there will be at most 3N-6 degrees of freedom, where $N=\rho V$ is the number of particles in the whole cube

However the above cube contains not just isolated ensemble of particles that can freely move about in the cube, but also 64 spherical components that only have rotational degrees of freedom. Do we expect the entropy of this system to be less than a cube without these spherical components?

In addition, if the spherical components start to rotate due to excitation, since each rotating component introduce torque, I think I would expect the moment of inertia of the cube to increase

There are various things I am interested about this cube system:

1. Is it possible to pack more entropy into this cube by somehow introducing extra degrees of freedom in the form of rotations?

2. Will the cube's moment of inertia be dependent on the number of spherical components (and what rotation mode) is being excited as energy is supplied to it, despite the spherical components are locked in terms of translational and rotational degrees of freedom?

9:46 AM

@Blue Having actually looked at the data, it does look very different.

3. It is easy to see that if the spherical components are e.g. charged, has some magnetic ordering etc. will exhibit long range interactions with other parts of the cube. However, will long range interaction arises if the spherical components don't have any special states (e.g. neutral, non polarised, non magnetic and so on)?

Typo: The question marks should be :? (as otherwise this question is too broad or hw sounding), but comments are welcome

Q: Magnetic force and atoms of supercooled helium in a vacuum

@Blue That's a meaningless metric. Did you actually look at the questions involved?

The "100% unanswered in the past 7 days" means strictly this: this question

0

I'm trying to predict what would happen to supercooled helium atoms in a vacuum when a strong electromagnetic field was present nearby. I think that a Lorentz force would move the helium atoms away from the source of the magnetic field - is this correct?

electromagnetism superfluidity

was wrongly tagged and has not been answered

In tags with that little traffic, fluctuations of that sort can make up the entirety of your signal.

Similarly, the past-30-days metric includes such jewels as

-1

Q: Difference between levitating a magnet above a superconductor and a superconductor above a magnet?

I was wondering the difference in levitation criteria between levitating a magnet above a superconductor (assume type-I to ignore flux pinning) and a superconductor above a magnet? For the latter, I think you can consider the superconductor as a perfect diamagnet, meaning the criteria for levitat...

electromagnetism magnetic-fields superconductivity levitation

is this the kind of shiny example that you want to shove highly-qualified traffic to?

That also tells you that that Unanswered count does not discriminate against posts with negative score

which makes it unusable

that means: don't use it.

Oh and almost forgot:
4. Another interesting consideration is if the cube is at the nanoscale, where quantum effects become important and the rotational degrees of freedom are treated quantum mechanically. Perhaps some long range interaction will arise due to the rotational wavefunctions overlapping

I am interested in systems which has a fixed volume but very high entropy (or maybe the more approporiate term is the density of states). This is because such compact, high entropy systems, with significantly higher entropy than the surroundings, are expected to behave as very good energy sponges, which might help on dissipating heat from devices

If the answer to 2 is yes, then we can also have some kind of compact system where its moment of inertia can be tuned by its internal rotational degrees of freedom

10:10 AM

^ my eyes, they bleed

Just to be sure, the dipole moment is called the dipole because the simplest way to realize a charge distribution with a nonzero dipole moment - but vanishing all other moments - is a pair (therefore "di") of nearby charges. Similarly for quadrupoles, octupoles etc. (powers of two). However, that doesn't mean that the number of charges always has to be a power of two (and they have to be pointlike): almost any charge distribution carries almost all the multipole moments. Just trust the formulae instead of words, and don't misinterpret the words. — Luboš Motl Nov 16 '11 at 17:43

I never knew the dipole term can exist with just a single charge

10:27 AM

@Secret It's as a result of it not being on the origin...

The Cubli: a cube that can jump up, balance, and 'walk'

I was suspecting that, before I dimiss that idea from my mind because it felt too simple as an explanation, but make sense, for we knew that multipole moments are coordinate dependent

(Some supplementary info) What I said about moment of inertia can be roughly (insert suitable word) from here:

►

The difference being instead having one bulky mechanism within the cube, you have an array of them and they are not directly controlled by machinery

djsmiley2k

11:42 AM

whatup everyone, it's lunchtime \o/

Anonymous

@ACuriousMind In that case T(N) would be constant. But T(N/2) would be order log(N/2) (if we search for the subarray in which the element is not present. Hence the < sign would hold in such a case and not the = sign!

Anonymous

Got it

Anonymous

(I'm talking about the case where we hit the required element at the first shot )

11:57 AM

Hi everyone...

I have a question from thrmodynamics...

What should the graph of internal energy vs temperature look like for an isothermal process?

From first law dU=0 and temperature always remains constant in an isothermal process.... how should the graph of U vs T look like?

wait

I made that mistake few minutes ago

$U$ doesn't change because $T$ doesn't.

It's just a point

since $T$ isn't changing, so there's no 'trajectory'

Yeah that's what I presumed...

What's the answer, if you read that somewherE?

12:06 PM

I don't know the answer...

But that's what I also thought it should be...

Yep it is a point, on a $U-T$ graph. It can be wildly different on another graph though

Yeah

What about adiabatic process?

ugh no. I messed it all up

Mixed up isothermal and adiabatic :|

So dQ=0 in adiabatic

It'll be a curve this time. I don't know what kind though; I can't recall the relations

Because $T$ will definitely change, and so $U$ will too

12:15 PM

Yeah true

$\Delta U = \Delta W$

if I'm not wrong?

dU=-dW

I have comeup with something

Right, if you say so. I always get confused with the sign conventions. Chemistry had a different one

Verify it

So

dU=-dW

Now dW=-pdV

dW=pdV

Also pv is directly proportional to T from pv=nrt

So dU should be directly proportional to T

@ACuriousMind I ran out of letters on my fluids homework and named a point $M$

12:26 PM

@tatan So a straight line

@Avantgarde am i correct in my reasoning?

@Avantgarde In my uni, our chemistry uses $dU=\delta Q-\delta W$

@tatan Seems to be so yeah

@Secret I gave up long ago trying to memorize which sign went in where.

12:55 PM

I don't remember signs, but the convention we are taught is that work done by the system will reduce the internal energy of the system

Interestingly, regardless of conventions, we both use $dU=TdS-pdV$

1:37 PM

@ACuriousMind I need a legitimate GR expert. Whom do I talk to

1:50 PM

@0ßelö7 I don't know many GR people. Is it a question you could ask on the main site?

Q: Should close notices be more specific?

2:06 PM

@ACuriousMind Probably, as long as I don't reveal my true intentions

Physics Meta

0

Recently I've asked an off-topic question: How to plot forcing oscillation with damping correctly?. The close notice has only one line of instruction: This question does not appear to be about physics within the scope defined in the help center. I agree that this is not about physics, but t...

feature-request closed-questions close-reasons

@ACuriousMind but I infinitely prefer a discussion to the Stack Exchange format

2:20 PM

in Mathematics, 19 secs ago, by FuzzyPixelz

Quantum mechanics would be interesting, and by that I mean counter-intuitive and mind blowing :)

2:40 PM

hey everybody , a good day to you all
Here I came across conflict ,
A problem is given:

That a conductor(rod) is hung through to wires
and a magnetic field is perpendicular to the plane of conductor, now we have to calculate the direction and magnitude of current so that the
wies holding the rod are relieved of tension, everything seems sweet and simple
The bone of contention is
according to right hand rule direction of the current should be from left to right( in +x axis)
so that force is upward ( +j) to relieve tension

Anonymous

@tatan $U=nC_vT$ for ideal gases. You can usually take $U_o=0$ at $T=0 K$. So the graph would be of the form $y=mx$

Anonymous

But then T is constant

Anonymous

So it would just be a point

Anonymous

2:59 PM

@Xasel What do you mean by plane of conductor(rod)? Also, please use MathJax for asking questions and add diagrams if possible.

Anonymous

. physics.stackexchange.com/questions/350789/…

Anonymous

. physics.stackexchange.com/questions/350804/…

Anonymous

. physics.stackexchange.com/questions/351105/…

Anonymous

. physics.stackexchange.com/questions/351142/…

Q: Terminology surrounding superconductors and the Meissner-Ochsenfeld effect

SPAAAAAM

Anonymous

3:10 PM

@EmilioPisanty There were several good questions (having the condensed matter tag) which went unanswered last month

Anonymous

Some more examples:

Anonymous

1

As stated in (Annett, 2004;pg 55) not all materials whose resistances vanishes exhibit the Meissner-Ochsenfeld effect (MOE). Which of these is therefore the defining property of a superconductor (if either)? And... If it is the vanishing resistance - is there a specific name given to supercondu...

condensed-matter terminology superconductivity

Anonymous

<https://physics.stackexchange.com/questions/352147/how-do-i-determine-the-ferro‌magnetic-exchange-stiffness-from-magnetisation-measu>, <https://physics.stackexchange.com/questions/352153/london-equations-what-is-the‌-mass-is-present>, <https://physics.stackexchange.com/questions/352282/effect-of-electric-field-on-‌graphene-in-2d-reciprocal-space>

Anonymous

<https://physics.stackexchange.com/questions/352634/can-magnons-exist-at-t-0-wit‌h-a-inhomogeneous-magnetic-field>, <https://physics.stackexchange.com/questions/352916/effective-hamiltonian-of-pho‌sphorus-with-spin-orbit-coupling>

Anonymous

<https://physics.stackexchange.com/questions/353313/ionized-impurities-in-semico‌nductors-under-room-and-incerasingly-high-temperatur>

Anonymous

3:13 PM

@EmilioPisanty I could show atleast 10 more good questions with this tag which went unanswered last month

Holy spam

Anonymous

I'm not trying to pick up a fight but there is surely less answerers for condensed matter compared to ~~some~~ many other tags

yeah well, for now I flagged all your messages for spamming

your account will be suspended and deleted

and your pet will die

Anonymous

@EmilioPisanty Do let me know your point of view. I suppose the examples I gave are examples of good (atleast not bad) questions

Sid

...whoa

Anonymous

3:19 PM

If we consider a tag like special relativity (physics.stackexchange.com/questions/tagged/…) on the other hand, much less good questions went unanswered.

Anonymous

This is strange because in the real world there are obviously more physicists working on condensed matter than on relativity.

Anonymous

@AccidentalFourierTransform Phew :P

Anonymous

I think I'm done for now

well, every physicist that works on CMP knows SR, but not vice-versa, right?

Anonymous

@AccidentalFourierTransform Every physicist who works on CMP wouldn't bother to answer SR questions instead of CMP questions...

Anonymous

3:22 PM

They might answer a few

Anonymous

But still it doesn't sound right

I mean, who cares? it's CMP, that's barely physics...

:-P

Anonymous

@AccidentalFourierTransform If CMP isn't physics then GR is math. :P

Anonymous

And yet GR tag exists on this site. lol

CMP?

@Blue what?

Anonymous

3:29 PM

@0ßelö7 Condensed matter

@Blue You keep talking about monthly statistics like they're meaningful

and you keep talking about the unanswered stats of individual tags like they're meaningful

Your original claim was that condensed-matter routinely has more unanswered questions than other comparable tags

None of the evidence you've put forth so far gets even close to supporting that claim

Sure, you can cherry-pick plenty of good questions from that tag that are unanswered. But you can do exactly the same for any tag that's big enough.

Anonymous

@EmilioPisanty If monthly statistics are not meaningful then what is?

Anonymous

Yearly?

@Blue I'd put the bar at six months

but yearly is probably better

or, if you want, six-month averages of monthly statistics

Anonymous

IMO last 6 months should be fine to tell us the story

Anonymous

3:35 PM

We don't need to check before that

If you haven't realized just how jumpy the statistics are, and how susceptible they are to monthly and weekly variations in rates, then you haven't been looking at those stats for long enough.

Anonymous

Sure, I'll can collect all the good questions which went unanswered in CMP in the last 6 months

@Blue Is that opinion grounded in any evidence, or did you just pull that number out of a hat?

@Blue sigh. No, that's not the point.

@Blue The key phrase in your claim is comparable tags

If your stats are not a comparison of unanswered rates vs other tags, coupled with metrics that show that the tags are comparable, your stats are meaningless.

Anonymous

@EmilioPisanty We are talking about the current situation of the site. It doesn't make much sense to dig into history before 6 months or 1 year

@Blue ::facepalm::

here's one concept that's relevant to condensed matter:

Anonymous

3:37 PM

@EmilioPisanty So, in your opinion what makes two tags comparable?

fluctuations

@Blue question rate

Anonymous

@EmilioPisanty Ok. So in that case the you'd like to know (No. of good unanswered questions in the last 6 months/1 year for a particular tag)/(No. of good questions asked in that particular tag in the last 6 months/1 year)

Anonymous

It shouldn't be tough to find that ratio

Anonymous

For two different tags

3:40 PM

@Blue Yes. Luckily enough, I already went and dug out those numbers for you.

@blue: this is what I meant

And, as I said before, CM does not particularly stand out as unduly underanswered.

according to Right Hand rule, the answer should be current is in the direction from left to right (+ x,axis)

Anonymous

@EmilioPisanty The numbers you had dug out earlier included all questions (including downvoted questions)

@Blue please don't make false claims

3:41 PM

where B is into plane of the conductor( B = B (-k)

and putting the value s into the equations yields vector in the direction -y or (-j)

rather than the upward direction as desired (+j)

since i x (-k) = (-j)

Anonymous

data.stackexchange.com/physics/query/719064/…

Anonymous

Oh, the code checks for score>0

@Blue in case the SQL wasn't transparent enough

 Post.Score >= 0

Does anyone have the book "Solid State Physics" by Hook&Hall digitally?

Anonymous

That should have been mentioned in the title :P Anyway, so CMP stands at around 29%

3:45 PM

I thought it would be easy to find, but so far I'm only getting weird books that seem like a bunch of lectures together

@ShaVuklia does libgen not have it?

let me try

oh I had forgotten about that site

@Blue Not strange at all when you consider that SR is something people simply interested in physics might pick up, but significant CM expertise will be rather rare outside of actual physicists actually working on it.

@Blue sigh. Yes. And perturbation-theory is at 33%, but I don't see you rising a stink about getting more people to answer those questions.

ditto with CFT, topology and computational-physics

Anonymous

@EmilioPisanty Alright, sorry for that. But well, CMP does lie among the top 10 unanswered tags. Should we not do anything about it? Or let it be as it is?

3:48 PM

@Blue You keep trotting out phrases like "top 10 unanswered tags", without specifying the relevant metric, like they mean something

they don't

well, I have intuition that the if current considered the actual flow of electron(negative charge) then it will yield finally (+j) but I doubt that that HS books use Benjamin's convention ?

@Emilio as far as I can see, they don't have it either:(

and, if what really worries you is the top 10 of that query, why aren't you tearing out your clothes over perturbation-theory?

@ShaVuklia yeah, that's a bad sign, then

Anonymous

@EmilioPisanty Well, it's because I'm more interested in CMP. I didn't look at the perturabation-theory questions as such.

@Blue confirmation bias, much?

3:50 PM

@ShaVuklia : Law of Ebooks states that if a kindle version of the book exist then surely a digital manifestation of it exist , you only need to think creatively to find it !

Anonymous

Anyhow, if no one feels there's a problem of less answerers for certain tags, then I'm fine. It just seemed from my experience in the past 2-3 months (since I started learning this subject) that CMP questions don't get answered much.

Anonymous

The past 1 year statistics seem to tell a slightly different story

Anonymous

Well, it might just be fluctuations as you said @EmilioPisanty

But anyways, to do some of your homework for you: yes, condensed-matter does stand out from that list in that, even though there is a rough continuum of unanswered rates going from the 20%s to roughly 40%, once you take a reasonable definition of that rate, CM is a good deal larger than the rest of the tags on that list.

i.e. the only other question to top 400qs/yr on that list is solid-state physics

(though then again QFT isn't that far behind, at 22% over 1yr, and that one is much larger)

The important thing to note is that those statistics have some reasonable measure of tag size, and they provide differentials over comparable tags. If you want to argue that CM deserves special attention, it needs to be on those grounds.

@Blue I think phrasing it as a "problem" might be the wrong way to think about it. We have several areas where it would be nice if we had more knowledgable people contributing. Nevertheless, the site mostly still works in these tags - I'd not say there is an urgent problem