The h Bar

However, most mythology are filled with stories and imagination that the information that is encoded in them about observations in nature are hard to filter out

Not to mention, you need to understand the symbolisms of the culture to successfully decode them in modern language

(The next 3 paragraphs are about the zodiac and theology, which unfortunately is so outdated compared to modern experimental results that I have nothing coherent to say about them)

"Saturn had a rival, however, in the visually much brighter planet, Jupiter, and Jupiter could regularly be seen to catch up to and pass Saturn in the Zodiac due to his faster speed. This rivalry and periodic close proximity seems to have led to some interesting results for timekeeping in the way the ancients used natural cycles to set up a system for studying time and space. "

Periodic motions in the orbit of planets, give a way to define a date system for ancient civillasations

Nowadays, we still rely on periodic phenomenon to define a second, but we go microscopic into the world of atoms

"Is it because Jupiter takes 12 years to move around the Zodiac that there are 12 constellations instead of... and the fool was paraded as mock king."

That played a role in defining the Gregorian calendar. However there are a lot of other details, and the calendar's development is a gradual process shaped by many civilisations.

"The story of Hamlet was adapted by Shakespeare from the Icelandic and Norwegian myth of Amlodhi or, in a later version of the name, Amleth, which became Hamlet. It is a Norse retelling of the Monomyth. And Amlodhi was associated with a mill and the planet Saturn, hence "Hamlet's Mill." "

(No specific comment)

"These celebrations went on year after year for centuries and precise astronomical records were also kept in many of the high civilizations of antiquity. After only a ... that the ancients not only knew about the phenomenon but were virtually obsessed by it. "

"This is not to say that precession was understood in the terms we know today, involving a torque or force on the spinning planet from the gravitational pull principally of the Sun and Moon acting upon the uneven distribution of the planetary mass. It only means that they were well capable of observing its long-term effects"

Indeed, our ancient ancestors are very good at documenting long term phenomenon

Nowadays, we just give this laborious work to computers to crunch the data for us

The development of computers help make modelling phenomenon subjected to some prescribed assumption more efficient reproducible and predictive. This is a huge step forward for us humanity in understanding nature

Jan Hirschner

11:31 AM

Just a [random] comment: In my limited perspective, great deal of mythology is a meta-cognitive analogy to own thought patterns. Syntax and vocabulary abuse might also be considered a socio-political game for determination of the human power structure by means evaluation of capability of concealing information. This ability is based on quasi-logical linguistic reasoning and the scope of the memory of the individuals. Metaphoric and loose usage of the subjects and objects in spoken word is the norm in fictional literature.

@Danu It's exactly what I was about to read today after I didn't get around it during the weekend ;)

user228700

@JohnR: Afternoon :-)

user228700

I plan on making that coffee again this evening, with the "biscuit" and all!

@JanHirschner indeed. And the rigidity of the use of terms in science make it easy to communicate the observation with minimal background thus facilitate understanding of it among different parties and reproducibility of the result. Whereas for mythology, the mindset being used in using metaphors kinda helps in training a more holistic thinking, thus facilitate creative combinations of ideas and experiments to produce unanticipated and novel results in scientific investigations (IMO)

LegionMammal978

Just curious, is there somewhere that gives fission product probabilities for most elements? I've only been really able to find data for some actinides

11:49 AM

@Kaumudi.H Hi :-) Coffee?

user228700

@JohnRennie Yep. Although, I've forgotten the recipe-I'm going to have to wing it and hope for the best.

user228700

Dear Sir, have u ever had sewage water gush out of ur taps?

@Kaumudi.H Ugh! No!!

user228700

Happened to us just this morning. Somehow, the pipes leaked into one another.

Is that a regular occurrence in Chennai?

user228700

11:54 AM

No, this is only the second time that it's happened in my 18 year-long stay in Chennai.

user228700

To be clear, it wasn't exactly dirty slush, just that the water (still remarkably clear somehow) smelled excessively of...sewage.

Ugh^2 :-)

user228700

:-P I gots to find a good recipe for this chocolate coffee I plan on making hmm...

I guess you'll be boiling the water for the next few days then!

user228700

No, we drained out all that dirty water, and cleaned the tank. Now it's all clean :-)

user228700

11:57 AM

Still, we're boiling the water used for drinking just for good measure.

Jan Hirschner

Please do not burn yourself.

user228700

Burn myself? Why would I do such a thing?

user228700

Aw man, 4 cups of chocolate?! I'm going to have to settle for something a little less fancy...

Geez, 82 pages. Well, I guess I wasn't doing anything else today...

user228700

foxnews.com/food-drink/recipes/2011/12/24/…

user228700

12:02 PM

I'm suspicious of websites that don't show pictures of the end-result, at the very least.

user228700

1. Mix all the ingredients above in sauce pan
2. Heat until bubbling
3. Serve in mugs with whipped cream

user228700

^ This is the sort of recipe for me! x'D

Well the end result is just going to be a brown fluid - not unlike what was coming out of your taps this morning :-)

user228700

@JohnRennie >.< Like I said, the water was remarkably clear, not brown!

@Kaumudi.H I was taking liberties with the truth in order to make a silly joke :-)

user228700

12:06 PM

:-) OK.

user228700

I remember having mentioned that recipe here before, let me have a look...

user228700

Jan 29 at 8:45, by Kaumudi. H

It contained coffee, milk, a pastry (sort of), and some melted chocolate. I mixed them in the mixer and it was divine.

user228700

@JohnR: I have a box of cocoa powder, that will do, no? (For the chocolate)

"They are also the very people to have �prophesied� (actually predicted by calculation) the beginning of a World Age. Their priesthood would have observed the precession over the centuries and known how to use the conjunctions of Jupiter and Saturn to uniquely select a precise starting date. They... but incorporating the symbols of the new constellation rising before the Sun on the Vernal Equinox. "

@Kaumudi.H Yes, for hot chocolate type drinks we normally use cocoa.

12:11 PM

Really, metaphors are a really bad way to code information. It is useful for facilitating out of the box thinking, though

Putting in actual chocolate makes the drink very fatty because of all the cocoa butter.

user228700

Alright then. I still want it to be a bit frothy, so I'm going to go buy those pastries to add! (Don't cringe :-P)

user228700

And instead of mixing by hand/boiling, I'll add them all into my mixer along with some ice cubes and mix the crap out of it. I'll tell u how it turns out...

tea > coffee. but of course all the dudes drowned them on the boston harbor

user228700

Say, @JohnR: I haven't worked with cocoa powder before, how much dyou reckon I need to put in for a cup?

Bernardo Meurer

12:15 PM

@JohnRennie Starway to Heaven guitar solo in 3

2

I don't know. It's a long time since I've made hot chocolate. Doesn't that recipe you found give the quantities?

Bernardo Meurer

1

@BernardoMeurer :-)

user228700

@JohnRennie No, I'm making my own...

Q: How can current flow in an ideal wire if all of its points are at the same potential?

0

If I have an ideal wire and I connect a battery to it, then the potential drop is zero along the wire, right? So, all its points must be at the same potential. Well, that means charges ( which are initially assumed to be at rest) will not go from one point to another in the wire. There's one more...

12:16 PM

@Kaumudi.H Yes, but you can look at existing recipes to get a guideline as to how coca powder you need ...

@ACuriousMind The OP wants the question to be unmarked as duplicate.

user228700

None of the existing recipes give a good idea. Sigh, I'm definitely going to mess this up. No problemo, I'm just gonna wing it.

@YashasSamaga That's...an odd situation but how are the questions not duplicate?

The OP asked...

Also, raise mod flags instead of pinging me in chat, everyone!

2

12:19 PM

I marked it as duplicate and the OP accepted it which makes the bot automatically mark it as duplicate.

the woes of being a moderator

Now he wants it to be undone.

Unless it's really urgent and I'm currently here, the flag is the better way to go

Sorry

@YashasSamaga No worries, just noticed a trend lately (not just from you)

12:20 PM

Is the flag on this still outstanding or did it get rejected?

Maybe we should think of making an "office" chat room like the math mods :P

@JohnRennie You should be able to see that by looking at your flag history

Remind me where I find that ...

(I.e. clicking on your "helpful flags" on your meta profile)

There should be a list of all your flags and whether they are pending, helpful, disputed or declined

Aha, thanks. Pending - though I didn't think it was an especially controversial flag

@JohnRennie I'm afraid I will decline to comment on that for the moment, but rest assured we're not ignoring it.

12:27 PM

Consider 12 face diagonal of a cubical block . How many pairs of them are skew lines .

I think it should be 24 as each diagonal has 4 skew lines

But the answer given as 30

Can anybody help me in this

What does "being skew lines" mean?

Probably that they don't belong to a common plane.

no

Skew lines are lines which do not intersect but are also not parallel.

Skew lines

In three-dimensional geometry, skew lines are two lines that do not intersect and are not parallel. A simple example of a pair of skew lines is the pair of lines through opposite edges of a regular tetrahedron. Two lines that both lie in the same plane must either cross each other or be parallel, so skew lines can exist only in three or more dimensions. Two lines are skew if and only if they are not coplanar. == General position == If four points are chosen at random uniformly within a unit cube, they will almost surely define a pair of skew lines. After the first three points have been chosen...

Ah

Right

Sorta nice question. To each diagonal there are 5 lines skew to it though, no?

12:30 PM

How

@BalarkaSen There are 10 for each diagonal but you'll probably double count few times.

@SirCumference because fire is a plasma

Look at the image in wiki. Think about the diagonal AB1. Then BC1, A1D, A1C1, BD, D1C are all skew to it

@Yasha 10? How?

I think you're counting parallel ones.

@ACuriousMind if you're still around, when the question quality ban was introduced were the moderators of the sites consulted?

@BalarkaSen is D1C is not parrallel

12:34 PM

@JohnRennie You mean this?

No! AB1 and D1C are in skew position

@ACuriousMind Yes

@BalarkaSen why it is not parrallel

Then what is parrallel to AB1

DC1 is parallel to it.

Not D1C

Skew lines to AD are B1D1, D1C, AB1, AC, BC1

hmm I think there are just 5

but when you count for B1D1, you will count AD again

so that won't be a new pair

to get an answer as 30, you need to have 6 pairs per diagonal

12:37 PM

AD is not a diagonal...

@JohnRennie Then the answer is "sort-of", we did know a bit beforehand it was coming.

@BalarkaSen The OP said " 12 face diagonal "

@BalarkaSen Oh, I meant A1D not AD

@YashasSamaga no it should be 5 per diagonal to get 30

You will double count @user123733

A1D and B1D1 are a pair.

No you won't, @Yashas. There are 12 face diagonals, so you count 5 * 12.

Then you divide by 2

12:38 PM

You will count it once when you count for A1D and once again when you count for B1D1.

(5)(12)/2=30

@ACuriousMind I ask because if there was any form of consultation the obvious extension would be to implement a similar ban for consistently poor answerers, and I was curious to know if that was mentioned. But it sounds as if you were told rather than consulted.

So 5*6 = 30

Ah.

Thanks @BalarkaSen

@YashasSamaga

12:40 PM

I took the number of diagonals as 10 for some reason lol

@JohnRennie I think SE-wide poor answers that are not VLQ or spam are a far smaller problem than poor questions, so that's probably not on the team's radar.

Koolman

Hi @Kenshin

We could ask, though, if you think there's broad support for activating such a ban here.

hi @koolman

Or you could do it as a feature-request on mother meta (or our meta, depending on whether you're thinking SE wide here or not) yourself

Koolman

12:42 PM

How was your japan trip @Kenshin

@Koolman na i haven't been on it yet

Koolman

Then

it's in a few months

@ACuriousMind well, as I'm sure you're aware, it would be a loaded issue at least as far as I'm concerned as there are some rather obvious targets for such a ban. Personally I would be strongly in favour, but whether there would be broad support I have no idea.

@JohnRennie who are the "obvious targets"?

12:47 PM

@Kenshin, really? asking for names like that is unnecessary.

@heather how so?

@JohnRennie I'd certainly be in favor.

@Kenshin it's like talking about someone behind their back, something along those lines. It's unnecessary and kind of rude to the person you're talking about.

(perhaps I'm wrong, but I don't think it seems quite right to ask a question like that.)

@heather you'd rather the new rule be implemented and have them banned without the public knowing who was banned and why?

I prefer transperancy

@JohnRennie Sure I'm aware. But we'd need to hash this out in some form of meta discussion so that we could show the CMs that our community actually wants it.

@ACuriousMind well I could raise it at the chat session tomorrow, but I won't do so if you think it would be unnecessarily provocative. In any case I suspect there is little chance of it happening.

12:50 PM

@Kenshin I'd want to know who was banned but why ask who someone suspects of anything? You're talking about two different issues now.

@Kenshin The automatic low quality bans are deliberately intransparent so that people cannot game the algorithms, and they are also deliberately conservative so that they don't ban users who are just having a bad day. That is, even if John thinks he has identified "obvious targets" there is no guarantee at all those targets specifically will be affected.

@heather well I personally don't think we need the ban so i'd be curious to know who John thinks should be banned in case it changes my opinion

Perhaps I'll see the posts of these suspect users and realize we do need the ban

or perhaps I will think John is too harsh

but either way I gain valuable information useful in forming my opinion on whether the ban is useful or not

@ACuriousMind I don't think we should be banning anyone based on algorithms

@JohnRennie Follow your conscience. If you think that "provocation" is necessary then go ahead - I'm not the one to tell you what you should or should not discuss with regards to site policy.

@Kenshin ahahahahahahaha...if we didn't sit behind algorithmic bans every SE site would be positively flooded with spam.

^

@heather Nope. Fire is a chemical reaction, plasma is a state of matter :)

12:56 PM

@ACuriousMind so if we already have this in place then what is the debate?

I know we have restrictions on posts that don't meet the required quality

@Kenshin ...did you not read the mother meta post about turning on comprehensive quality bans?

but I didn't know that we had algorithmic bans already for pooor quality posts

@SirCumference i've been lied too!

@ACuriousMind yeah I thought it was only on 8 sites, but you're telling me it has always been in place on all sites?

There are, essentially, two steps - the spam filters and the LQ filters. The latter was cranked up considerably in its power recently on an SE wide scale for questions, and JohnRennie was asking whether one could/should also do that for answers.

12:57 PM

@heather a flame contains very few if any ions.

@Kenshin There have always been LQ filters but they restricted users for a few days at maximum

Now they can hobble accounts with a long history of negative contributions for months, if not indefinitely

@heather Plasma is ionized gas (gas whose electrons have been stripped from the atoms)

Like in the Sun, or through the gases that lightning travels through (I think)

It's all on mother meta somewhere but I'm too lazy to search for it :P

ok

@SirCumference to be fair most lab plasmas are not fully ionised. But a flame has a very, very low concentration of ions.

1:00 PM

@JohnRennie I'm giving the chemistry-textbook definition I remember from high school :P

it's hard to form an opinion on the bans when there is so little transparancy on what it takes to be banned

I think 6 months seems like a long time for a low quality ban, but if the algorithm has a low false positive rate then it it's probably fine

@ACuriousMind did you see my question?

@SirCumference no, I know what a plasma is...my dad just always told me that fire is a plasma and I never questioned it.

@heather Yeah, I just wonder why the two are often associated

thermodynamics heat visible-light photons everyday-life

3

Q: Confused about fire?

Im confused about fire. The way I see it : Heat creates (kinetic) energy in mass and this creates stronger vibrations of atoms. When those vibrations are strong enough the electrons interact stronger due to electromagnetic forces. This causes the electrons to fly away. This is the creation of a...

1:02 PM

Why are you people here? Don't you have school

Most people think the Sun is made of fire, when it's really plasma

@0celo7 i have 7 minutes before heading out to the bus (it's just after 7 where I'm at)

@heather If your interested, fire is really just a chemical reaction that takes place if you have oxygen, a fuel source, and lots of heat.

Those are the three main requirements.

@0celo7 Yes, but I never know whether you resolve these questions later on or not so I wait till you ask me again ;P I think the "by analyticity" should just be "by continuity"

@SirCumference is it really a gas, basically, then?

@SirCumference well, the classic description is "a big burning ball of gas" which makes people think of fire, I suppose.

1:06 PM

@heather Admittedly, that description falls flat since it's not actually fire. But it is a decent analogy for nuclear fusion (which "powers" the star like fuel), even though fusion isn't related to fire

well it's pretty darn hot so whatever

it's all semantics

they're both exothermic reactions that produce heat and radiation

@heather Well, it's more like a chemical reaction, in the same way that...uh...

I'm tired, I need an example

@SirCumference What do the Jews have to do with this?! :P

@ACuriousMind Oh goddammit...

I was confused as hell until I reread my post XD

user228700

1:08 PM

@JohnR: Divine indeed.

One of the funnier typos I've seen recently :D

hi @Kaumudi.H

@Kenshin Plasma is a reaction?

user228700

Hey :-)

user228700

1:09 PM

@Kaumudi.H aha, so your guesswork was on target then :-)

@SirCumference the light and heat from the sun is due to nuclear fusion, an exothermic reaction

this is the part that is described to be like fire

@Kenshin Oooooh

Yeah, but that's too darn general

adios, have to head for school =)

user228700

@JohnRennie Yep! Pastries, coffee powder, cocoa powder, ice cubes, sugar...

Pastries?

user228700

1:09 PM

Also, milk of course.

What pastries? You didn't mention pastries! :-)

@heather Oh, I know! Whatever the hell is happening here would be a chemical reaction, but it's merely caused by how the atoms are trading electrons (or in some cases, protons)

nice drink

user228700

@JohnRennie Lotte Choco pie--three of 'em. I made for my sisters as well.

States of matter are caused by the motions of the atoms and their constituents

user228700

1:10 PM

Holy crap, I can't believe I made a drink so delicious! :-o

Ah yes, I remember now - we discussed what to put in the drink several days ago.

user228700

Yep, we did.

@Kaumudi.H young lady!!!!

2

user228700

:-P What Sir?

Language!!

user228700

1:11 PM

:-P Lol, OK.

watch the fing language

@BalarkaSen *effing

whatever man.

Holey shirt!
My shirt has a hole in it.

user228700

U're trying too hard (:-P)

1:13 PM

https://en.wikipedia.org/wiki/Astrological_age
Ok... this "clock" is extremely inaccurate in the very long term. That means, whatever said by Terry Alden in his web article on how the precession of the vernel equinox coincide with the star of bethdem may not hold water at all

Shrug. You win some you lose some :-)

Oh well. I have to go into town. See everyone later.

user228700

Bye :-)

Bye :)

Howdy @Danu

https://www.sciencedaily.com/releases/2016/12/161201112550.htm
O, if Terry Alden wrote his web article in the 1991, does that means he realise this result way before Grant Matthew...?

Danu

@ACuriousMind I was hoping it'd apply to answers too

:(

1:19 PM

@ACuriousMind you think those n-tuples are dense in R2n?

@ACuriousMind Makes sense, the condition $zX\wedge yX\ne 0$ is just that they're not collinear

@0celo7 Yup.

@ACuriousMind I think you can also write the power series, set it equal to the power series, then cancel terms using the symmetries of the tensor. At least, that's what sleeping Ryan thought.

"It is this point of intersection, this zero reference point, which is precessing slowly along the Ecliptic in the reverse direction through the Zodiac as the Earth's axis wobbles. It might be visualized as if, in Figure 1, the Zodiacal constellations (i.e., the whole sky of stars) were to be slowly moving upward and to the left along the slanted Ecliptic while the Equinox point remained stationary.
Fortunately the precessional motion is extremely slow or the Vernal Point would not be much good as a stable reference point. The movement is about 50 seconds of arc per year, less than 1/60th o…

Claim: Extremely rare natural phenomenon with extremely long periods + insane amount of obsfucation, metaphor, fiction, hyperbole and stuff records as traditions, written or other forms-> mythology

Conclusion: Science is MUCH better at comminucation of observations of natural phenomenon

My opinion on astrology: I don't think rare astronomical phenomenon causes great changes to happen. Technically yes, it does affect us to some extent (but perhaps not more than "Wow, this phenomenon is rare and very cool, mysterious", and then people is then motivated by that awe to do some action. If something big happens afterwards, it is most likely a concidence, rather than the rare astronomical event causes people to act that way)

Rather the picture is more like: There are some astronomical phenomenon with a very long period, and that is useful for some kind of timekeeping, provided it is sufficiently accurate

"Recognizing that mythology and religion may be overly interpreted as historical rather than as transcendent or spiritual truth, the safest thing to say is that these persons certainly could have existed but that the Monomyth is primary and does not require the physical existence of human avatars even though it may be written as a story about exactly that. It exists as a universal instruction or guide in its own right with or without human embodiments.

It seems that the lives of certain individuals may fall into the Monomyth pattern, however, and become associated with it. "

I am glad in the 21 st century, we don't use that many myths to encode information, otherwise it is very easily distorted. But a deeper question arise. How will our far future descendants interpret our archive of knowledge of the whole humanity, given that context changes with time and culture slowly

"There is no problem, however, in determining the exact time of the end of the Age of Pisces and the beginning of the New Age of Aquarius. It is necessary, however, to first determine, as before, the correct "window of opportunity." "

No, we scientist don't allow such imprecise error bounds

"We can assume that the World Monomyth will need another revision but will tell the same eternal story in a new updated way, somehow utilizing the symbols associated with the constellations of the Water Carrier and its opposite, Leo, the Lion. Perhaps the hero of this Age will be born of or raised by a lion and have a career in water conservation. "

I wonder how will the monomyth adapt when in the year 2400, the constellation of picasis and taurus overlap thus the vernal equinox will be located in both constellations, hence in astrological terms will probably mean two ages overlapping each other...?

Either it means this supposingly periodic phenomenon is not quite periodic enough to serve its timekeeping role, or it means a new interpretation is needed

But I guess more relevantly, 2400 years is such a long time away. Given the rapid changes in our society, it is unsure if humanlity can survive that far, or would have already wipe itself out due to some major conflicts earlier. There's also the possibility that jupiter and saturn might be knocked out into new orbits by some event, rendering the whole system of celestial sphere (as we currently understood) useless

1:54 PM

@ACuriousMind How does one know if a Lie group is a matrix group or not?

Akoben

Does anyone think it's worth me putting a bounty on physics.stackexchange.com/questions/312585/…

Because if it's not likely to get answered either way i'd rather not waste the rep :)

Q: When is a finite dimensional real or complex Lie Group not a matrix group

18

I have a smattering of knowledge and disconnected facts about this question, so I would like to clarify the following discussion, and I also seek references and citations supporting this knowledge. Please see my specific questions at the end, after "discussion". Discussion and Background In ...

lie-groups lie-algebras rt.representation-theory

@Akoben One would have to read the paper you link in order to try and decipher what the authors mean by that (cf. the comment, which makes no sense at all if one doesn't know the content of the paper); such questions generally don't fare well here because many are not inclined to read/skim an unknown paper to potentially answer a question.

2:13 PM

How can I do the photon-clock thought experiment if the clock is moving faster than light?

I have been thinking since last two hours. I can't find a solution where photon travels at the speed of light in two frames of reference (static point and the clock itself).

2:24 PM

@ACuriousMind You helped me before with a question I had on gluons - I have another and just wondered if you could answer/pass comments on it? It is here physics.stackexchange.com/questions/313411/…

@CAF Generally, whenever the color analogy seems to contradict what you get by explicit calculation of the amplitude/color factors, then you've just found a case where the analogy breaks down. Have you got a non-video reference for that single-gluon diagram vanishing?

Akoben

@ACuriousMind I figured that might be the case, i'll leave it. Cheers!

2:39 PM

Hello

@YashasSamaga

@Ramanujan Hi, what is your question?

@YashasSamaga.

What are your thoughts about it?

I won't give away the answer. I'll make you find the answer.

What is heat capacity?

Specific heat capacity is inversely proportional to change in temperature

@ACuriousMind I'll try find one - I think it's a common sentiment that to have an interaction between a colourless initial and final state, one must go to a two gluon exchange. How would one see that the one gluon exchange diagram between two protons cannot happen on a group theoretic level (ie on a formal level and not using colour analogies) ?

2:45 PM

@Ramanujan I did not ask that. "What" is heat capacity?

@YashasSamaga, the amount of heat required to change the temperature of substance by 1

degree Celsius

@CAF ...by computing the amplitude of the diagram. I can't remember what exactly the group-theoretical factors attached to the vertices are so I can't say for sure.

@Ramanujan or degree Kelvin

@YashasSamaga, with Kelvin I think it is not necessary to mention degree

@Ramanujan If you have an object A with heat capacity of 10 and object B with heat capacity of 20, which object will take more heat to increase its temperature by one degree?

@Ramanujan Yes, it is not necessary to mention the degree but unfortunately I am used to it.

2:48 PM

Object B

So higher heat capacity = more heat is required to increase the temperature

so now tell me the answer for question A

Object C gains maximum temperature @YashasSamaga

@ACuriousMind The vertex factors would be $t^a_{ij} t^b_{kl} \delta^{ab} = t^a_{ij} t^a_{kl}$ where $i,j,k$ and $l$ are the colour labels of the quarks. So somehow this must vanish in the case of considering colour singlet initial and final states.

@ACuriousMind So...no easy answer?

@Ramanujan Yay! You solved the question A yourself. Now try to answer question B.

2:51 PM

@CAF Aren't they anti-symmetric in the lower indices and $i=j$ and $k=l$ if your quarks are the same color before and after?

@0celo7 Yup

@YashasSamaga

, I guess A

Why guess? Explain your reasoning.

@ACuriousMind I don't think they're antisymmetric but putting in i=j and k=l I would get t^a_{ii} t^a_{kk}. I think this does not mean a sum on i and k, but if indeed it was a sum then I would have Tr t^a which indeed vanishes. So, why is it a sum on i and k? At the level of the amplitude I believe there is only a sum on the adjoint rep index a?

@YashasSamaga, I don't know reason

Think! Try! Read the question again.

2:58 PM

@YashasSamaga, for cooling purpose --->bcoz it can absorb more amount of heat with itself being heated..

@YashasSamaga, I don't know the reason for heating one

@Ramanujan You got close but your reasoning isn't complete.