The h Bar

0celóñe7

12:10 AM

@skullpatrol What?

skullpatrol

What, what?

mtheorylord

1:16 AM

Wat?

DanielSank

2:48 AM

wut

rob

3:03 AM

Hello @DanielSank

Pythonista

Can anyone shed some light on interpretation of a conservation law for me? If I have a conservation law C = stuff here and I move to a different jet space (in different space of variables) what is the significance of C = 0 = stuff here in the new jet space? Sorry if this is a terrible question. My physics is very rudimentary.

rob

3:26 AM

@Pythonista Can you give a concrete example? I'm not familiar with the term "jet space."

Pythonista

3:54 AM

@rob

Not really unfortunately, the math is a bit beyond me. Best resource I found for my usage is the first section of this link emis.de/journals/BJGA/v15n1/B15-1-ba.pdf . More concretly, I'm considering a transformation from (x,y) to (r,s) where r and s are canonical coordinates. In these canonical coordinates the CL reduces to 0 rather than some constant V found from initial values / parameters. I'm attempting to assign a geometrical signficance to this.

From what I understand by finding the canonical coordinates (symmetry methods of ODEs) we have "straightened" the frame of the differential equation such that it represents a translation s + e, where e is a real parameter, and lends itself to being integrable. My guess is that since there are curves of constant "r" and the translation s + e then this results in V = 0.

DanielSank

4:35 AM

Hi, everybody

Secret

Why h bar seemed to be invaded by 4 dimensional objects recently?

DanielSank

Ooooh, a Pythonista. Someone with whom I can share my observer pattern library.

@Pythonista ^

Secret

I already forgot what drags Emilo into 4 dimensions in the first place

5D Cube

►

but why stop at 4?, let's head to 5

DanielSank

@0celóñe7 let's play "how many top 10 lists is Super Metroid in?"

IGN top 100 of all time: #7

Secret

actually, bad idea, I know little about the 5th dimension

DanielSank

4:43 AM

Nintendo Power's best of all time: #6

Secret

Metroid Prime 4 Teaser - E3 2017 Nintendo Spotlight Trailer

►

DanielSank

Ranker.com: #37

@Secret Yeah but I expect it to suck. The last few Metroid games were horrible. We'll see.

@0celóñe7 I'm bored of this game.

DanielSank

5:07 AM

Anyone want some low hanging fruit?

Secret

5:29 AM

I don't think it is as low hanging as it sounds like. Focusing on the system and ignoring the measurement device (that should put us in more or less copanhagen(?)). The problem is that there seemed to be no way (other than doing the interaction) to find out whether the interaction is nonunitary and projects the state into some eignestate, or is unitary and thus just transform the state to some other states

If we include the degrees of freedom and consider the interacting entity or device and the quantum system as part of a composite system, then the question will then becomes why performing a measurement entangles the device and system while photon absorption in photosynthesis can keep the two subsystems nonentangled

Secret

5:44 AM

But then, my quantum is still not very good thus I am sure there are some misconceptions somewhere in that paragraph of mine...

skullpatrol

6:28 AM

One day @Secret you'll hit an artery.

Don't pull out :P

Secret

6:52 AM

uh, I don't understand this metaphor here. what exactly is this artery that I will be hitting?

> A reliable, reproducible experiment where switching off and on the which-way data recording device triggered a change from 'particle-like' to 'wave-like' interference behaviour would be of the utmost interest and essentially warrant a Nobel prize. If and when someone performs such an experiment - trust me, you'll hear about it.

that will be essentially reversing a measurement, which is... weird

Mockingbird

7:13 AM

A metal sphere of radius R and total charge Q is cut into two equal halves. Find the force that is
necessary to hold the two parts together

Hey guys, help me with this problem!

John Rennie

13

Q: "Find the net force the southern hemisphere of a uniformly charged sphere exerts on the northern hemisphere"

This is Griffiths, Introduction to Electrodynamics, 2.43, if you have the book. The problem states Find the net force that the southern hemisphere of a uniformly charged sphere exerts on the northern hemisphere. Express your answer in terms of the radius $R$ and the total charge $Q$. Note: I...

Hmm, actually that's a uniformly charged sphere not a conducting sphere ...

Mockingbird

@JohnRennie That's the problem!

John Rennie

I'm afraid I don't know how you do the conducting sphere. That strikes me as hard because the charge will redistribute as you separate the spheres. There's probably some cunning trick involved.

Dawood ibn Kareem

@JohnRennie I don't believe the charge will redistribute. You're not adding any distance between the spheres; just measuring a force as they sit together.

Mockingbird

@JohnRennie I am concerned abiut the field created by the new charge distribution

@DawoodibnKareem Are you sure?

Dawood ibn Kareem

7:28 AM

@Mockingbird I can't think of any reason why the charge would redistribute after you cut the sphere in half, because all the charges are in the same physical location. So the force required to hold the sphere together once you've finished cutting it in half is exactly the same as the repulsive force between the two halves in the "uniformly charged" case.

John Rennie

1

Q: Force of repulsion between northern and souther hemisphere of charged sphere

A metal sphere of radius $R$ carries a total charge $Q$. What is the force of repulsion between the northern hemisphere and southern hemisphere? In this problem you consider the force per unit area on the surface of the northern hemisphere and then add it up basically: You get the average e...

homework-and-exercises forces electrostatics

Mockingbird

@DawoodibnKareem We are talking about a metal sphere. Why do you think uniformly charge distribution is the case?

Dawood ibn Kareem

Because it's perfectly symmetrical before you cut it in half. If there were uneven charges anywhere, current would flow to even them out.

Mockingbird

@DawoodibnKareem You mean uniform arial charge distribution right?

Dawood ibn Kareem

I don't know what you mean by arial. The only definition I know of for that word is Microsoft's rip-off of Helvetica.

Mockingbird

7:37 AM

@DawoodibnKareem I mean for a conducting sphere the charge will be distributeed across the outer surface of the sphere.

Dawood ibn Kareem

Oh, I see what you mean. I was thinking "hollow sphere", as opposed to "solid sphere". Obviously, for a solid sphere, there's a difference between "uniformly charged" and "conducting".

Mockingbird

@DawoodibnKareem The question isn't about hollow sphere!

Dawood ibn Kareem

Yes, that wasn't clear to me. I am a topologist, and we tend to mean "hollow sphere" when we say "sphere".

All I was doing was contradicting John's claim that we need to be concerned about the redistribution of charge. We don't - because we never actually separate the halves of the sphere.

Mockingbird

@DawoodibnKareem So you think? The charge won't redistribute? And the force will be same as before?

@DawoodibnKareem What if we do separate?

I don't think it's possible to hold two hemispheres if charges redistribute in the inner planar surface because it would need infinite amount force to keep the hemispheres in place.

Dawood ibn Kareem

If we separate the halves, then some of the charge will flow to the flat surface of each of the hemispheres. That will make the repulsive force between the two halves greater than if the charge didn't redistribute.

But so long as you're holding the hemispheres together, that's not a problem.

I believe you can find the repulsive force between the two halves by imagining that the charge on each half is centred at a certain point within each half - and you find that point the same way you'd calculate the centre of mass of a hollow hemisphere.

Mockingbird

7:47 AM

@DawoodibnKareem But if we separate for once ut's not possible to make the hemispheress stick again.

@DawoodibnKareem Yeah! I will try that

Dawood ibn Kareem

@Mockingbird The extent to which charge flows to the flat surface of each hemisphere will depend on the distance between the two hemispheres. It seems to me that the question requires you to find the force when that distance is zero. If the distance isn't zero, then the problem is difficult, just as John Rennie claims.

Mockingbird

8:19 AM

@DawoodibnKareem I agree.

@DawoodibnKareem What if I calculate it for non-conducting sphere? Will the same method work here?

I think it works.

Dawood ibn Kareem

@Mockingbird A uniformly charged non-conducting sphere? No, that won't be the same.

Mockingbird

8:44 AM

@DawoodibnKareem What would be the difference?

Dawood ibn Kareem

The centre of charge of a uniformly charged non-conducting hemisphere will be much closer to the flat surface than the centre of charge of a hemisphere with all the charge on the curved surface.

Mockingbird

O. You got me wrong. I know it's R/3 from the center. But that makes the answer 9q^2/(64*epsilon*r^2). Is it right?

@DawoodibnKareem See my message.

14

Q: "Find the net force the southern hemisphere of a uniformly charged sphere exerts on the northern hemisphere"

This is Griffiths, Introduction to Electrodynamics, 2.43, if you have the book. The problem states Find the net force that the southern hemisphere of a uniformly charged sphere exerts on the northern hemisphere. Express your answer in terms of the radius $R$ and the total charge $Q$. Note: I...

homework-and-exercises forces electrostatics electric-fields gauss-law

Dawood ibn Kareem

I don't think either of those two cases give you R/3.

Mockingbird

But this suggests otherwise?

Dawood ibn Kareem

For the solid hemisphere, it's 3R/8 from the centre. For the hollow hemisphere, (just the curved shell) it's R/2 from the centre.

Compare undergroundmathematics.org/calculus-of-powers/r5584/solution with physicsforums.com/threads/…

Mockingbird

11:12 AM

Find the potential of an uncharged metal sphere provided that a point charge q is located at a distance r from its center. The point charge is outside.

@DawoodibnKareem What do you think rhe charge distribution will be in affect of the point charge's induction?

@JohnRennie Can you help?

Secret

11:36 AM

[Rationalwiki quotes]

> Koneru Ramakrishna Rao, a past President of the Parapsychological Association, has written that the lack of any agreed-upon theory of parapsychology is one reason for the general skepticism of the scientific community regarding the existence of psi.

So... ensure you have a commonly agreed upon model and that it is falsifiable before doing anything else

djsmiley2k

lol

Secret

> This leaves no force that could possibly account for telekinesis, for example. Telepathy would require a new force much weaker than gravity that is not subject to the inverse square law, and also a detector in the brain evolved to use it for signaling. Precognition, the receipt of information transmitted back in time, would violate quantum field theory.[21][22]

What this means is that these ideas have pretty much no chance of being right even before we test them directly.

Well, one can argue there might be new forces out there that are actually strong but has so far evaded detection because we don't have the correct set of instrument to detect it, but that's a very very unlikely scenario

But yeah, if there are any evidence of nonlocal signalling, then the whole physics community will raise their eyebrows and it would take years of verification to ensure it is really valid

which meanwhile, one or many experimental errors will likely be identified and the findings falsified

> Not everything studied within parapsychology is the result of fraud or tricks. According to the scientific community, paranormal phenomena have naturalistic explanations resulting from psychological and physical factors which have sometimes given the impression of paranormal activity to some people when, in fact, where there have been none.[31]

In fact, usually the natural explanations are a lot more interesting

0celóñe7

@JohnRennie @BernardoMeurer I will buy a monitor today

Need options

Dawood ibn Kareem

Asian water monitor

Varanus salvator, commonly known as the water monitor, is a large lizard native to South and Southeast Asia. Water monitors are one of the most common monitor lizards found throughout Asia, and range from Sri Lanka and India to Indochina, the Malay Peninsula, and various islands of Indonesia, living in areas close to water. The species is known as Malayan water monitor, Asian water monitor, common water monitor, two-banded monitor, and as rice lizard, ring lizard, plain lizard and no-mark lizard, as well as simply "water monitor". == Description == The water monitor is a large species of monitor...

0celóñe7

@Kaumudi.H en.m.wikipedia.org/wiki/Charles_James_Napier#On_sati

Secret

11:56 AM

rationalwiki.org/wiki/Magical_thinking

Correlation is not equal to causation

Having said that, recent h bar discussions seemed to confuse my brains alot now

22 hours ago, by Mithrandir24601

@Secret Generally, physical laws are about correlations. That's the point of a lot of them. Especially the likes of Bell's inequality

22 hours ago, by ACuriousMind

@Secret Why do I have to write down laws in the forms of equations? Who said anything about that being a requirement for a law?

22 hours ago, by ACuriousMind

@Secret Aren't you a chemist? Isn't chemistry full of laws of the form "If you put X and Y together, Z happens."? And although one might describe that with stochiometric equations nowadays, the content of such laws is clearly not diminished by not expressing them in equations

So I guess, one way to ensure that physics laws have no overlap with the concept of woo is that most physics laws (whcih include biological and chemical ones) often don't just stop at the level of correlation, but demonstrates an actual causative link between the phenomenon and mechanisms

National Academies of Science: In science, explanations must be based on evidence drawn from examining the natural world.... Because they are not a part of nature, supernatural entities cannot be investigated by science.[8]

However, what is nature is actually quite ill defined. A place which is uuntouched by human activity, all areas with vegetations, or the ecosystem created when organisms (including humans) interact with the surrounding environment and their constructs? There is no universally agreed upon definition

The philosphy society that I am part of, conclude that nature might be used to communicate some common concept about environements, conversations, the world etc. such that it ensure everyone knows more or less what everyone is thinking

What that means is that because nature is so ill defined as a concept, we might as well say what we called the supernatural are actually part of nature, and therefore there are no supernatural entities

> Elbert Hubbard stated "To the scientist the word "supernatural" is a contradiction. Everything that is in the universe is natural; the supernatural is the natural not yet understood.

> (...) The result showed that with this mindset even the most scientifically-based technological advanced society could be portrayed as believers in magic and the supernatural:

O, and it goes further than that. Recall that I have been exploring about the concept and historical folklores of the concept magic with the Factory floor guys. Our latest suggestion is as follows:

in The Factory Floor, 22 hours ago, by Secret

In fact, using this piece of fact, we can perhaps argue that except for the class of abstract magic (to be elaborated later) all magic not only obey Clarke's 3rd Law, but in fact they are technically subsets of physics laws

in The Factory Floor, 22 hours ago, by Hannah

@Secret .. thats how i've always thought of it

in The Factory Floor, 14 hours ago, by Green

@Secret an alternative way to look at this is that abstract magic has lots of extra inputs that we can't see and can't measure. Throw in some extra nonlinear feedback loops and it's gonna be all kinds of craz

Avantgarde

12:11 PM

Hello hbar

Secret

In conclusion, at least philosophically speaking, unless you are dealing with the most useless type of magic, all notions of magic are ultimately, a subset of physics. So paraphasing Hubbard: Magic is physics we don't yet understood, and once they do, they become physics

Avantgarde

That's right

Secret

Having said that, most pseudoscience have either been unfalsifiable or had been ruled out bazillion of times in history, thus don't worry, there would not be pseudoscience in this implication

Avantgarde

It's not even wrong!

Sid

Now, how do we know something is right or wrong? Doesn't it depend on context?

Secret

12:14 PM

For science, we can only do expt to falsify models and then update our models constantly, we can never prove anything in science

It is this self correction that makes science so sucessful at modelling reality

(and of course, that unexplained coincidence why reality like to follow rules of some kind, often expressible in terms of mathematics)

Physics laws concerning entities that don't form a society are often not as context sensitive as social science phenomenon (which I think, there's a lot of emergence in play in the dynamics, thus making exact modelling complicated)

user228700

@0celóñe7 What, man?

Secret

As far I know, the major thing that limit the scope of a given physics model are things like what length and energy scales you are in

user228700

@JohnR:

user228700

How it look?

Sid

12:22 PM

That looks like a hotel room to me rather than a dormitory..

Avantgarde

It's nice

rob

@Secret I would say that most magic, especially illusions, is known physics plus very clever engineering.

Secret

@rob (the above paragraph is talking of the type of magic that appear in fiction) but yes, and there are some really good illusions/magic that even if the secret is revealed, will continue to enchant the audience because of how hard to pull it off

> They discovered the only real differences between the magical world view and science was that magic didn't have a self-correcting mechanic nor a set procedure for determining which concept best fit what was being observed.

This actually seems like an almost exact analogy on bayanesian vs frequentist

IIRC, frequentist knows the probability distributions of all events they are interested in, and that repeated experiments should corresponds to said probability distributions

This is similar to magic worldview, where all the laws are known and it is all there is, even if we don't understood them, we never need to revise anything as we go deeper

Meanwhile Bayesianist don't know or don't have the probability distribution of all events they are interested in. They first assign a prior probaility to some given question, and then each trial of an experiment or other incoming evidences will serve to update the probability distribution, so if all the evidences and experiments are not crappy and of high quality, then eventually the probability distribution will converge towards that given by the frequentists

This is similar to science, which constantly update and revise its models in face of new experiment results that don't fit the model

Under this argument, we can then understood why most (insert group of people) agree that bayaneisan is more sensible, because it updates itself constantly

and similarly, science also constantly updates. Assuming our reality is sufficiently objective and inference works, then science is the logical outcome in the way to investigate reality

This is also similar to analytic solution vs numerical solution too

analytic solution solves an equation with known methods that has no error

while most numerical schemes requires a recursive procedure to feed the answer back into the algorithm to produce an answer that might be closer to what the actual answer is

From these 3 case we can summarise two conclusions:

1. All self updating methods requires error checking, as garbage in garbage out principle applies
2. We often don't have the luxury to know everything exactly to use those exact methods nor thinking

djsmiley2k

erm

it can't be self updating, if it doesn't check if it's wrong

as there's nothing to update...?

John Rennie

12:37 PM

@Kaumudi.H That looks more like home now you have a few things in it :-)

Secret

@djsmiley2k Well, for the numerical calculation example, your algorithm gives a solution, which is then feed back into the algorithm repeatly until it stops changing (under some error bound), so the solution is constantly updating

For science, you proposed a model to explain some phenomenon, experiment then collects the data which can refine the model (e.g. stuff that deviates from the model)

user228700

@JohnRennie :-) It's better now, yep.

The Raiders of Las Vegas

When is the first day of classes?

John Rennie

@Kaumudi.H When do you actually move in?

user228700

@Sid Lol, what's ur room like?

Secret

12:40 PM

For bayanesian, IIRC, evidences are provided which then the bayes inference equation served to update the existing degrees of belief, which is your probabilty distribution of the event of interest

user228700

@JohnRennie Tomorrow. I have orientation in the morning and my family will leave in the evening.

John Rennie

Is that a window at the back of the room, behind the curtains? What's the view like?

user228700

Regular classes will start on Wednesday, I think.

The Raiders of Las Vegas

Wow, one more day!

John Rennie

@Kaumudi.H Finally, you get to start learning stuff because it's interesting and useful, rather than because you have to pass an exam! :-)

Sid

12:42 PM

@Kaumudi.H It's fine. I am surviving

user228700

@JohnRennie It is, yep, a large room-length window. The view, erm, I'm not sure. I'll update you t'row :-P

user228700

@JohnRennie Yes, YES! :-)

user228700

@Sid I see.

John Rennie

@Kaumudi.H it makes such a difference! That was what really struck me about starting at university.

Sid

The food is excellent though. I haven't eaten such a variety of food items in a long time..

The Raiders of Las Vegas

12:43 PM

There's still an exam.

John Rennie

@TheRaidersofLasVegas yes, but it's an exam on things you've studied because you want to study them.

The Raiders of Las Vegas

Absolutely

user228700

@JohnRennie Hmm? :-)

user228700

@Sid Wow, cool. What do you have?

John Rennie

@Kaumudi.H studying what you want to study instead of what you're forced to study.

user228700

12:45 PM

Right, of course. I hope my teachers are OK.

Sid

@Kaumudi.H Depends. Yesterday, we had Tandoori Chicken(Since it was Sunday). The food is still pretty good.

John Rennie

Speaking of food, I'm off to get lunch. See you all later.

The Raiders of Las Vegas

Get your A4 writing pad ready! :-)

Cya

user228700

Wow. Cool. Which college are u attending?

user228700

@JohnRennie OK, bye :-)

user228700

12:47 PM

@TheRaidersofLasVegas Lol, yep! :-)

user228700

@Avantgarde Thanks :-) My mum and I spent about 2.5 hours fixing the place.

Secret

> These men, among others, believe that while scientists are generally logical folk, they do not understand the trickery used by magicians, and can therefore be still fooled by it.

Luckily, electrons don't lie to people else the physics department will need to hire magicians/illusionists

Swapnil Das

hi

Secret

hi, long time no see

Swapnil Das

Yeah. How's is life?

Mine is sorrounded with projectiles, cosines and heavy water :P

0celóñe7

1:05 PM

@DanielSank The fact that you think the Prime games are horrible means our preferences are completely incompatible.

Of course I think Super Metroid is garbage.

@JohnRennie I don't see suggestions!

Secret

For me, still have a proposal to write, though I have read 20 key journal articles, spanning from the beginnning of the field in 1970 to 2016, so it should be complete enough

PhyMan

@Secret How much time did that end up taking?

Secret

Well due to 6 days of procrastination in maths and h bar, at least 4 months, thus yeah, sluggish reading

PhyMan

A proposal for what, may I ask?

Secret

my chemistry PhD, the PhD research department of the uni requires during the first quarter of year 1, to submit a draft proposal to check progress of PhD canditature

PhyMan

1:12 PM

Which field in chemistry?

Secret

(What makes my case more interesting is that I am from another uni applying PhD in this uni and to be admitted PhD, I already wrote another proposal thus the challenge now is to make sure it looks nothing like the old proposal)

Organometallics and computational chemistry, broad sector: catalysis

PhyMan

Nice, what exactly do you do in computational chemistry?

Secret

We have a class of piano stool metal coordination complex with an organometallic ligand called indenyl, and we do ground state and transition states geomoetry optimisations using DFT to investigate how the orientation of ligands wrt to the indenyl varies with energy

so yeah, some molecular orbitals and quantum chemistry stuff

PhyMan

I have a basic question, How did people come up with all these theories like Valence Bond Theory, CFT, LFT and all? It was taught to us by giving the basic assumptions and then lots of hand-wavery arguments

I find it difficult to believe that that was how it was actually done

Secret

Most chemistry rules you learn in undergrad are heuristic guides, similar to the rules in biology. They are empirical rules that are concluded from many decades of experiments on certain class of reactions

Since they are empirical, exceptions exists, which is why they don't seemed to hold all the time

PhyMan

1:24 PM

Oh okay, that makes sense

where are you doing your PhD?

Secret

We motivate these rules by come up with heuristic arguments such as "electron density tend to move from nucleophiles to electrophiles". They work most of the time, but they can fail

I do PhD in the University of Sydney

However, if you are a theoretical chemist or physical chemist, you can get more precise results by doing computation, which is basically numerically solve a many electron schrodinger equation

as you can imagine, they are very hard calculations, which is why you often need supercomputers to do it so they finish at reasonable times

Generally the rules, arranged in levels of sophisication is as follows:

Valence Bond Theory, CFT, LFT < Molecular Orbital Theory < Quantum chemistry

the higher up it is, the more complicated the picture is, but also the more cases where they hold

PhyMan

Wait, so quantum chemistry has such heuristic arguments? Or is it mainly maths or something else?

Secret

Quantum chemistry is mainly maths, so it is rigorous

It is just extremely hard to compute which is why we cannot teach lower years to do that

only hydrogen and hydrogen like systems have analytic solutions

Quantum chemistry does have some assumption built in, such as born oppenhenier approximation, which assumes the nucleus moves a lot slower than electrons thus they are essentially fixed in position

But more sophisticatd methods in the literature do relax these assumptions

In a sense, doing quanutm chemistry is no different from modelling stuff in physics

Semiclassical

1:43 PM

How much of it is DFT stuff? @Secret

Secret

DFT is just one half of quantum chemistry. The other is ab initio methods, which really tries to numerically solve schrodinger equation for wavefunctions instead of integrating electron densities

ab inito methods calcuation times scales with $n^{2}$ to $n^{4}$ where n is number of electrons in the system

they are very computational expensive for 20-90 atom systems that I do in my PhD

DFT is much quicker, owing to the simplifications when calculating electron density instead of the full wavefunction

Semiclassical

Right.

Secret

ab inito methods often make use of slater determinants as part of the guess solution and then this solution is recursively solved first using the hartree fock equations to obtain the wavefunction when the antisymmetry of wavefunction is considered. Electron correlations (such as columbic repulsions) is then feed into the solution depending on the model you are using, such as for MP2, you do a perturbative epxansion to the 2nd order

Semiclassical

The other thing which I imagine fits in here somewhere is the variational method.

My knowledge of numerical QM, to be clear, is limited to "oh hey eigenvalue problems in 1D"

Secret

Indeed, the first step of hartree fock is to use the variation method to minimise the energy of the wavefunction, you then feed this wavefunction back into the hartree fock equation recursively until the wavefunction stop changing within some error bound you set, this is why it is called self consistent field (SCF)

Semiclassical

1:51 PM

Right.

When I hear about solving equations self-consistently it mostly brings to mind computations involving superconductors.

Secret

not suprising cause superconductors are highly correlated systems, thus I imagine solving its wavefunction can be difficult

Semiclassical

Right.

The other big phrase you hear in this realm is Monte Carlo, not that I've done much of that myself.

Secret

yes, it is often used in molecular dynamics simulations, though exmaples where quantum effects are considered are rare because of the computational expense (and that classical could do quite well due to being high temperature or other reasons)

Semiclassical

Right.

The one conceptual issue I know about Monte Carlo is the sign problem.

Which I do find pretty interesting.

The Raiders of Las Vegas

2:32 PM

Yo @0celóñe7 wazzup?

0celóñe7

Cleaning

The Raiders of Las Vegas

What?

0celóñe7

English, ----, do you speak it?

The Raiders of Las Vegas

no

0celóñe7

Then learn it

The Raiders of Las Vegas

2:34 PM

Teach me

DanielSank

@0celóñe7 please indicate why you think I think the prime games are horrible.

I never said that.

0celóñe7

@DanielSank You said the last few games were horrible.

DanielSank

:39132138 what were the names of the last few games?

Need a hint?

The most recent was Federation Force, technically a prime game, but I doubt it's one you (or anyone else) liked.

Then before that we had Other M.

Not a prime game, and generally considered terrible.

Semiclassical

2:51 PM

To be fair, that only works if you think of a few as 'the most recent two'...but then, there just haven't been a lot of Metroid games recently beyond those two.

Federation Force wasn't great from what I heard, and Other M was...yeah.

On the other hand, if you push past those two you get stuff like the Metroid Prime trilogy and the GBA Metroid games, and those were solid.

(I've played the original Metroid Prime a ton of times)

So the Metroid franchise has had good periods. But that's not exactly recent now.

The Raiders of Las Vegas

3:08 PM

Wow @Semiclassical I would've never taken you for a semi-gamer :P

DanielSank

@Semiclassical you skipped Metroid Prime Pinball.

And Metroid Prime Hunters.

So of the last five games, one of them (Prime 3) was good.

Semiclassical

I haven't played a lot of them lately.

Ehhh. Calling Metroid Prime Pinball a Metroid game is a bit weird to me.

Hunters was also a bit of a one-off, but I think it's close enough to count. It at least had the same kind of interface as the Prime games.

John Rennie

@0celóñe7 I don't enough about gsync monitors to make any useful suggestions. If it were me I would either buy one of the better gsync monitors (at $500!!) or not buy a gsync monitor at all. Given that gsync seems to add $200 to the cost of a monitor it doesn't make sense to go for the cheap end.

The Raiders of Las Vegas

3:45 PM

@JohnRennie you may enjoy this

Secret

[Chemistry] Ok, I am fairly certain I have crawl the main branch of my research field of literature (all the way from 1969 to 2017, skipping some years which are not the main papers) 3, and not just one literature gaps have been identified.

After finishing this dam proposal again, I must quickly code the rotational matrix, if sucessful I can do 400 calculations in just 40 presses of a button!

If all goes well, this might be comprehensive enough to fill in all those annoying gaps I have seen so far

0celóñe7

4:38 PM

@JohnRennie I understand but I don't think my budget system can handle 1440p

And I don't want to downscale either

John Rennie

@0celóñe7 it's a tough call, but if it were me I'd say in that case don't buy a new monitor. Just enjoy playing games on the one you've got. Maybe revisit the issue in a years time.

0celóñe7

@JohnRennie No, I need a new monitor.

My only choice now is which one.

@JohnRennie Do you know what the Amazon return policy on monitors would be?

John Rennie

@0celóñe7 a regular good quality 24" monitor won't be much more than $100. Just buy one of those.

@0celóñe7 no idea, sorry.

0celóñe7

@JohnRennie No.

user228700

@JohnR: My roommate seemed to have absolutely no recollection of the way in which she unfriended me! Well, she didn't bring it up...

John Rennie

4:51 PM

@Kaumudi.H I'd let the matter drop :-)

0celóñe7

I got a regular good quality 24 inch monitor and was really disappointed.

user228700

:-) I feel a little safer here, actually, now that I've got all of my stuff here and have vowed not to give a crap about the loony warden.

John Rennie

@0celóñe7 the only other option is a 1080p gsync monitor, but didn't we decide they don't exist?

@Kaumudi.H good :-)

Things usually don't turn out as scary as you think they're going to be

user228700

True, true :-) I'm not in my room right now though; I'm still with my parents and will be until they leave tomorrow evening.

John Rennie

Which is just as well if you're the sort of person who thinks they are going to be ultra scary (not mentioning any names :-)

user228700

4:56 PM

@JohnRennie :-) OK, OK, I hear you.

John Rennie

Want to see what I had for my (delayed from the weekend) lunch?

user228700

Sure!

John Rennie

Pierogi!

user228700

Oh, I remember these! :-) Were they nice?

John Rennie

Yes, very good. I'd had them in the freezer for a bit and decided I really ought to get round to eating them.

user228700

5:01 PM

Cool :-)

John Rennie

Just heated with butter and a bit of garlic.

Sid

@Kaumudi.H ...duh. You are reading too much into that unfriending thing..

user228700

@JohnRennie Nice. I had lots for dinner; roti with three types of sabji. Good thing too; I hadn't had anything since 11 in the morning and I hadn't had anything before 11 either.

John Rennie

When do you get your first experience of the hostel food?

Wednesday?

user228700

No, tomorrow night! I'll let u know after :-P

John Rennie

5:05 PM

My view at college was there was no bad food.

I would eat anything I could get.

user228700

Ah :-)

user228700

We'll see. I get quite depressed if I'm denied decent food.

John Rennie

I've always had a fast metabolism and unless I eat a lot I get thin (thinner!). So my approach to college food was if it's got calories I'll eat it.

user228700

Haha :-) I get fat if I eat and if I don't, I get super thin.

Sid

Heh, 5/7 days here,we have Dal which has 5% lentils and 95% water. None of us care. We eat like there's no tomorrow.

John Rennie

5:07 PM

^

That's the right approach :-)

user228700

:-) I dunno. Again, we'll see.

user228700

I should probably get some sleep seeing as I'm still quite sick...

John Rennie

Still the tonsils? :-(

user228700

Well, they're most certainly healed but I still have a terrible throat and also body pain.

user228700

Plus, all day, I had a terrible knot in my back due to acidity; remember how I told you that I had eaten next to nothing all day?

John Rennie

5:09 PM

I bet the stress of starting at college isn't helping

user228700

Certainly not, I'm sure :-/

John Rennie

One disadvantage of college is you get to meet several thousand other students all of whom have brought along their regional variants of popular diseases.

To which being from a different region you don't have immunity!

user228700

Lol, yes.

user228700

Anyway, OK, I really must go and try to catch some sleep. I'll see u later tomorrow, goodnight! :-)

John Rennie

Goodnight

I have to go fold the laundry anyway ...

0celóñe7

5:12 PM

Apparently monitors have to be unopened to return them

John Rennie

@0celóñe7 were you thinking you'd buy a monitor from Amazon, try it, then return it if you didn't like it?

0celóñe7

@JohnRennie Yes.

You can do that at e.g. Costco.

John Rennie

Amazon must get a lot of people trying that trick :-)

vzn

5:43 PM

Mirzakhani studied billiard physics phys.org/news/2017-07-maths-genius-maryam-mirzakhani-dies.html

in theory salon, 57 mins ago, by vzn

Mirzakhani 1977-2017 / Tmachine blog

0celóñe7

6:08 PM

@JohnRennie bought a monitor and SSD

skullpatrol

7:08 PM

...and the censorship continues:

in The Periodic Table, 1 hour ago, by CowperKettle

In November, a new wave of prohibitory legislation kicks in in Russia. It will be forbidden to use proxies and VPNs. And all internet messengers will have to contain built-in features for automatically deleting messages containing "unwelcome" information.

0celóñe7

@skullpatrol only the people who have something to hide should be worried

skullpatrol

I use a VPN just because I can, pal :P

John Rennie

@0celóñe7 which monitor did you go for in the end? And what size SSD?

0celóñe7

7:32 PM

@JohnRennie a 1080 Gsync from ASUS for 400 and a 500GB 960 EVO

skullpatrol

Sounds expensive.

John Rennie

500GB is a sweet spot for SSDs right now. Big enough to be useful but not stupidly expensive.

@0celóñe7 This monitor?

skullpatrol

Yeah, a lot of stuff is still stupidly expensive.

0celóñe7

@skullpatrol So?

@JohnRennie Something like that.

John Rennie

Wow, that Asus monitor is £420 in the UK (including sales tax)

0celóñe7

7:35 PM

20?

John Rennie

:-) Oops

0celóñe7

I was about to move countries

skullpatrol

Wut

0celóñe7

@JohnRennie got free 1-day shipping on the SSD

Be prepared for panicked messages tomorrow :)

Physics Meta

8:36 PM

0

Q: Is an asker's age relevant?

In Why does Newton's Third Law actually work?, the asker states their age in the question. (They are 10 years old.) On the one hand, their age does not have anything to do with Newton's Third Law. On the other hand, it gives the answerers an idea of what age-level to answer the question at. F...

discussion questions specific-question editing

Sir Cumference

9:28 PM

@JohnRennie I've heard that if one builds a good reputation while researching in industry, they can potentially move to academia and start as a tenured professor

Not sure if that's just hearsay tho

Dawood ibn Kareem

9:48 PM

Re the question about an asker's age - I thought all the Stack Exchange sites were intended to be targeted only at adults; and the terms and conditions restricted them all to people over the age of 13. Is this no longer the case? Maybe I should be commenting on the post on meta, but I think lots of these sites would be very different if we had a whole lot of child users. I would not be in favour of this. How do others here feel?

Mithrandir24601

10:19 PM

@SirCumference I know a CS professor who did something like that

It turns out he just got a ScD last year!! :D

IanC

good evening!

Mithrandir24601

So it turns out that he didn't leave academia for industry but just took a few years out here and there to do stuff for industry

@IanC Evening!

IanC

used to lurk around reading some of the questions on physics SE, thinking about being more active here, maybe I can learn a thing or two :)

how are you folks doing this evening?

Mithrandir24601

@IanC Pretty good :) Just waiting on my tea to cool, before drinking it, then heading to bed :) Might read some more of Sourcery...

[read: 1. I'm obsessed with tea, among other things and 2. I've had a relatively relaxed evening]

IanC

nice, I think I'll make some tea before heading to work, want to substitute the coffee for it since I like both and tea is more healthy I guess, though both have a bit of opposite effects on me lol

just bought some strawberry tea

Mithrandir24601

10:34 PM

I like strawberries (quite a lot), but I'm definitely not a fan of strawberry tea :P

IanC

it will be the first time I try it

I usually drink mate tea

Mithrandir24601

Nice! I've had something similar once or twice, but it's certainly not common over here (UK)

IanC

wow, I thought it was a very common tea there

Mithrandir24601

mate? Not that I've seen...

I have seen it, but only in 1 shop (which would have been where I tried it)

Slereah

rob

10:46 PM

@DawoodibnKareem Relevant to your comment: physics.meta.stackexchange.com/q/9777/44126

Sir Cumference

@Slereah What the...?

rob

@Slereah That's the like opposite of one of Tufte's infographics: the more you study it, the worse it gets

Dawood ibn Kareem

11:04 PM

@rob I see. However, I'd like to be able to assume that the people that I'm interacting with here are at least 13. The last thing I want to do is worry that I've made a 7-year-old cry by criticising his/her answer to a physics question.

Slereah

11:43 PM

0celóñe7

@DawoodibnKareem I agree with you -- but the de facto policy of this site (physics) seems to be that children below 13 should

simply lie

Dawood ibn Kareem

@0celóñe7 OK, so how do I know, for example, that you're not 7 years old?

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