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Cows
Cows
1:12 AM
Let me spend some time thinking about this QED thing today
Actually, I don't want to do this yet
let me just look for something cute so I can practice scattering amplitudes and differential cross sections first
Then I would try to explore QED a bit
Should be interesting
Let me see if I can make this cross section etc stuff natural in my head (hehe ) . . . will be intermittently learning this while playing with pieces of paper tonight.
 
 
2 hours later…
Cows
Cows
3:29 AM
Not so random question
0
Q: Gamma functions integral identity

bianchiraIn Srednicki's QFT book, eq. $14.27$ is a result used over and over again for computing loop correction. It is the following integral evaluated in terms of gamma functions: $$ \int d^dq \frac{(q^2)^a}{(q^2+D)^b} = \frac {\Gamma (b-a-\frac{1}{2}d)\Gamma (a+\frac{1}{2}d)} {(4\pi)^{d/2}\Gamma(b)\G...

quantum-field-theory integration
Is there an insight gained by using the integral identities?
. . . .*** Physics insight i.e
just curious
I probed harder and found these
the plots . ..
any physical meaning in this context?
Or is it mathematics and nothing else?
ping me . . .
Heading back probe some trivial things on paper
 
 
2 hours later…
Jack Clerk
Jack Clerk
5:58 AM
Hi, good evening/morning/night for everyone!
Well, I'm a undergraduate student and I indend to write my Bachelor tesis in a not so distant future.
So, I really interested on Classical/Quantum Field Theory, Special and General Relativity.
I think that the research on Semiclassical Gravity is quite quite interesting but I love the classical gravity too.
I would like to write something that "blend together" All the black holes solutions, exotic solutions of EFE,GW and astrophysics and of course Quantum Field Theory.
 
John Rennie
John Rennie
6:10 AM
That seems ambitious for an undergrad dissertation ...
 
Jack Clerk
Jack Clerk
Well, I agree. But QFT GR and Black Holes, "must" to be in my future thesis.
I have these two articles here: https://arxiv.org/pdf/0710.4474.pdf and
https://arxiv.org/pdf/gr-qc/0009013.pdf
There are other that covers more exotic solutions?
 
Anonymous
6:24 AM
@JackClerk What does '"must" to be' mean though? I can't comprehend that sentence :P
 
Jack Clerk
Jack Clerk
It's just that I want to write about what I said and QFT, GR and Black Holes are the topics that cannot be left out of my thesis.
 
Cows
Cows
7:13 AM
Is anyone here? I have some trivial questions about correlation functions of a certain type
 
Cows
Cows
7:28 AM
hmm , I'm not excited about what people are saying about correlation functions . . . . at any rate. . what do I know
 
Slereah
Slereah
7:41 AM
turns out the Rindler observer on a Penrose diagram involves the Gudermannian function :
Gudermannian function
The Gudermannian function, named after Christoph Gudermann (1798–1852), relates the circular functions and hyperbolic functions without explicitly using complex numbers. It is defined for all x by gd ⁡ x = ∫ 0 x 1 cosh ⁡ t d t . {\displaystyle \operatorname {gd} x=\int _{0}^{x}{\frac {1...
or something close to it
 
Anonymous
@Slereah Just out of naive curiosity: Does there exist any mathematically valid model of a completely "classical universe" (non-relavistic and non-quantum mechanical)? (A discussion with Mithrandir in the QC chat got me a bit interested in the implications of this)
 
Anonymous
25
A: What situations in classical physics are non-deterministic?

SlereahThere are two famous cases in classical mechanics that fail to be deterministic. The first, and most famous, is Norton's Dome, which corresponds to a system with a force of the form $$F = \sqrt{r} $$ There are more details on the Wikipedia article (it's usually described as the result of a rea...

 
Anonymous
I was wondering about the possibility of the Space Invaders example you gave for non-determinism
 
student
student
the ideal of a purely Newtonian universe vanished long ago
 
Anonymous
@student Why?
 
student
student
7:54 AM
Einstein
and
The Evidence
 
John Rennie
John Rennie
I think you're missing the point. Blue knows perfectly well that the universe is not Newtonian, but he is asking about non-determinism in a hypothetical purely Newtonian universe. A perfectly Newtonian universe is a valid construction - it just doesn't describe the real universe.
 
Slereah
Slereah
@Blue I mean sure?
Although Newtonian cosmology is plagued with problems
 
Anonymous
@Slereah Any standard examples of such models? (I'd just like to have a read although probably I won't understand much)
 
student
student
that's why i added "The Evidence" :-)
 
Slereah
Slereah
I think Earman wrote a paper on it
MORE PROBLEMS
Is that really what you want
 
Anonymous
8:03 AM
Hehe :P Thanks, I'll read it
 
Slereah
Slereah
and of course, Newtonian cosmology suffers from the Olbers paradox
unless you use some weird fractal universe
 
student
student
perhaps, an ether wind?
 
Slereah
Slereah
@JackClerk if you want some QFT with weird spacetimes try to compute the propagator on a wormhole solution :p
it's a fairly unpleasant solution because it's a Mathieu function outside its regime of pleasantness
 
Mithrandir24601
Mithrandir24601
8:19 AM
Anyone fancy answering this or this, now that we're on the topic of alternative universes?
 
Slereah
Slereah
@Mithrandir24601 I don't think it's a good idea to go FTL even in a Newtonian universe
really weird shit happens
because the EM potential will lag behind
 
Mithrandir24601
Mithrandir24601
@Slereah That's why it's so fun from a WB perspective!
 
Slereah
Slereah
I'm not sure what happens to atoms when you go faster than light and their EM field starts lagging behind
also of course
Cherenkov radiation
 
Mithrandir24601
Mithrandir24601
@Slereah Well, this is an observed thing, at least
 
Slereah
Slereah
Well not quite
Because this is Cherenkov radiation in a Newtonian context
As seen in that weird 1890's paper
About particles going FTL and radiating Cherenkov radiation because of this
 
Mithrandir24601
Mithrandir24601
8:24 AM
@Slereah All the better for WB :P
 
Slereah
Slereah
FTL communication would probably be doable in a Newtonian universe, but I dunno about FTL travel
Fuck what was that paper
that may be it
 
 
3 hours later…
Physics Meta
Physics Meta
11:43 AM
-1
Q: Why my question "How good currently is superstring theory in explaining what Standard Models can't explain?" is being put on hold?

GravitonRefer to my question here on "How good currently is superstring theory in explaining what Standard Models can't explain?" It has been closed by being "too broad", and I can't understand why. As stated in the title, the question is asking about "How good currently is superstring theory in explain...

discussion support
 
Emilio Pisanty
Emilio Pisanty
12:26 PM
Hey @ACuriousMind, my sockpuppet smoke-alarm just beeped (see maths.se thread linked above).
 
Anonymous
@EmilioPisanty lol
 
Novalium Company
Novalium Company
1:02 PM
@Blue I have a question about the article you sent me to read. I'm reading it but you know the senario where you have a closed vacuum container with water in it and soon enough the vapor will come into thermodynamic equilibrium with the water. (Their pressures are the same). So the vapor pressure is the pressure of that vapor when in equilibrium. My question is: won't the water start boiling at the beginning, since it's a vacuum, and would that mess up the process?
 
 
1 hour later…
Anonymous
2:05 PM
@NovaliumCompany Ah, that's a bit subtle. In such cases you'll have some of the water molecules from the surface quickly escape into the space above the liquid and already start exerting the "vapour pressure", no? You wouldn't really observe boiling in a closed container like that
 
Novalium Company
Novalium Company
Then how should I observe it?
As the equilibrium is already done? I shouldn't imagine the beginning, just the final result?
 
Novalium Company
Novalium Company
2:22 PM
The link you sent me doesn't explain how I should view it, so I'm sorry for asking ;\
 
Anonymous
@NovaliumCompany The equilibrium establishes really quickly
 
Novalium Company
Novalium Company
Does it? Why? Maybe because the space above the water is vacuum and the reaction process will be faster and since there is no pressure to push on the surface of the water, the molecules can escape and turn into vapor for seconds?
 
Anonymous
Tbh boiling and evaporation are very complex topics in statistical physics. So we are considering only what happens at equilibrium, at your level.
 
Novalium Company
Novalium Company
Ok understood. Thanks. I'll continue the reading.
 
Anonymous
Anyhow did you understand why boiling occurs ?
 
Anonymous
2:25 PM
And when ?
 
Anonymous
That's the more important part
 
Novalium Company
Novalium Company
When the vapor pressure (in equlibrium) is equal to the pressure of the air. (Although I have a few questions about this)
 
Anonymous
In closed containers boiling doesn't occur unless you add heat fast enough
 
Anonymous
Or the volume of container is too large
 
Anonymous
There was a good answer on this...wait a bit
 
Anonymous
2:35 PM
1
A: Why boiling can't take place in closed containers

oceandevil24You can understand this well by thinking about why a liquid boils in the first place. Imagine you have a pot of water, and it's just sitting there in your kitchen. Intermolecular forces (specifically hydrogen bonding for H20 molecules) keep the water in liquid state. The air molecules zipping ...

 
Anonymous
@NovaliumCompany ^
 
Novalium Company
Novalium Company
Google: "Boiling occurs when the vapor pressure of the liquid is equal to the atmospheric pressure exerted on the liquid". My question: The vapor pressure in equilibrium? Also I thought there was no air in the closed container? And also why does boiling occur in an open system, where vapor pressure can't be established because equilibrium between the water and the vapor is impossible, since the vapor cannot establish pressure to oppose the presssure of the water.
Ok I'll check it out.
What, water doesn't boil in a closed container. Then how do pressure cookers work?
Nvm, I'll google it sorry :D
Well, I read the comment but I don't know if I know what I should know.
 
Anonymous
@NovaliumCompany I don't think the statement "boiling occurs when VP=AP" is particularly intuitive, at least for beginners. I prefer to think in terms of kinetic energy of molecules as presented in that answer.
 
Novalium Company
Novalium Company
Yep, it makes no sense to me too.
So if I have an open system with water, boiling will occur when the water has enough KE to spread it's molecules and form bubbles inside the whole liquid?
 
Anonymous
But remember this:
 
Anonymous
2:49 PM
"The pressure exhibited by vapor present above a liquid surface is known as vapor pressure. As the temperature of a liquid increases, the kinetic energy of its molecules also increases. As the kinetic energy of the molecules increases, the number of molecules transitioning into a vapor also increases, thereby increasing the vapor pressure."
 
Anonymous
(from Wiki)
 
Anonymous
@NovaliumCompany Sort of, yes
 
Novalium Company
Novalium Company
Yep, I know that. So vapor pressure can be just defined as the pressure of the vapor acting on the surface of the liquid?
Instead of the whole vacuum closed container case?
 
Anonymous
@NovaliumCompany The point is: "which vapour"?
 
Novalium Company
Novalium Company
The one created by the water?
from the constant evaporation?
when the molecules on the surface have high enough energy to bypass the air's energy and become part of it?
 
Anonymous
2:52 PM
In open containers you'll have considerable air present too....so you can't really define vapour pressure directly there
 
Anonymous
@NovaliumCompany Statistically speaking, some molecules on the surface will always have sufficient energy to become part of air
 
Novalium Company
Novalium Company
That's exactly why evaporation constantly happens?
 
Anonymous
@NovaliumCompany Exactly
 
Novalium Company
Novalium Company
Yay.
I actually know something :D
Anything else I should know about boiling? For know I know that it happens when the molecules of the water have enough energy to spread and form a bubble, which will rise to the top, but that is a very simple explanation and doesn't satisfy me enough.
 
Anonymous
Now can you explain boiling in open containers using this kinetic energy logic ?
 
Novalium Company
Novalium Company
2:57 PM
Ok, give me a minute.
 
bolbteppa
bolbteppa
Why does one do normal ordering
 
Anonymous
Remember that for open containers you have the surrounding air whose net temperature and pressure remains practically unchanged
 
bolbteppa
bolbteppa
There is a ******* insane justification in terms of the Dirac sea
 
Anonymous
Also the kinetic energy of the air molecules remain practically unchanged
 
Novalium Company
Novalium Company
In an open container, water and air are present. If we add heat to the water and reach the boiling temperature, evaporation will occur in the whole liquid and bubbles will form because they have enough energy to spread. That is a very simple explanation and doesn't satisfy me enough ;\
 
bolbteppa
bolbteppa
3:02 PM
From $\langle 0 |\nabla \cdot \mathbf{E} |0 \rangle = e_0 \langle 0| \psi^{\dagger}(x) \psi(x) |0 \rangle = e_0 \sum_n \langle 0 | \psi^{\dagger} |n \rangle \langle n | \psi(x) |0 \rangle = e_0 \sum_n |\langle 0 |\psi^{\dagger}(x)|n \rangle|^2$ the vacuum has an infinite charge density, which is the infinite electrostatic charge of the Dirac sea, and so you modify your entire theory by subtracting off this charge density, the result being normal ordering
 
Novalium Company
Novalium Company
@Blue I don't think I did well...
 
Semiclassical
Semiclassical
@bolbteppa gotta pick a vacuum somehow
 
Anonymous
@NovaliumCompany You are glossing over the "Why will vaporization occur throughout the liquid in the first place?"
 
bolbteppa
bolbteppa
It's weird how a ton of things make a ton of sense by using the Dirac sea
 
Novalium Company
Novalium Company
I actually don't know what boiling is at all, I know it's like evaporation but in the whole liquid.
 
Semiclassical
Semiclassical
3:06 PM
@bolbteppa hence why solid state people love talking about the Fermi level :P
it's a lot easier to just say "states are filled up to this point, and then some perturbative stuff happens"
 
Anonymous
@NovaliumCompany Uh....internolecular bonds start breaking throughout the bulk ? The subtle point is why temperature doesn't change during boiling even if you keep adding heat
 
Sir Cumference
Sir Cumference
Morning
 
Novalium Company
Novalium Company
@Blue Because things need heat to boil, and you constantly need to provide it. I don't know, maybe something is dragging the temperature of the water down. Maybe as the water evaporates, heat is lost to the room, and that means that the water temp. has fallen down below the boiling point and needs a little bit of more heat to start again?
 
bolbteppa
bolbteppa
Apparently there are real problems with this when you apply it to bosons so idk how to make sense of all this
 
Anonymous
@NovaliumCompany See, if you keep hearing a liquid at some point the intermolecular bonds will start breaking. Before that you'd just have evaporation from surface since some surface molecules always have sufficient kinetic energy to escape.
 
Anonymous
3:11 PM
Is that part clear ?
 
Novalium Company
Novalium Company
Yep.
 
bolbteppa
bolbteppa
'This is how the 'negative energy sea' was eliminated. There is nothing incorrect about it, other than that the true content of QFT, i.e. renormalization, reaffirms the S-matrix point of view, 2).'
1
A: Why is normal ordering a valid operation?

ZardosAs other answers mention, it was originally (in QED) about getting a neutral vacuum. It is useful to go back to Schwinger's old version of QED, before Dyson's approach became accepted. See Pauli: Selected topics in field quantization. Pauli presents both ways of looking at it: 1) define the ele...

 
Anonymous
@NovaliumCompany Now when the intermolecular bonds start breaking, if you look microscopically, obviously locally kinetic energy (temperature) might increase in some locations but for a bulk the energy is used up to break the internolecular bonds instead
 
Anonymous
Temperature is actually defined for a bulk of substance. It isn't meaningful for a few molecules only
 
bolbteppa
bolbteppa
Normal order
In quantum field theory a product of quantum fields, or equivalently their creation and annihilation operators, is usually said to be normal ordered (also called Wick order) when all creation operators are to the left of all annihilation operators in the product. The process of putting a product into normal order is called normal ordering (also called Wick ordering). The terms antinormal order and antinormal ordering are analogously defined, where the annihilation operators are placed to the left of the creation operators. Normal ordering of a product quantum fields or creation and annihilation...
 
Novalium Company
Novalium Company
3:17 PM
What do you mean by a bulk?
 
Anonymous
@NovaliumCompany A large number of molecules
 
bolbteppa
bolbteppa
It's just defined in qft so that $\langle 0 | \hat{O} | 0 \rangle = 0$ always holds, which it doesn't without including $: \, :$
 
Novalium Company
Novalium Company
Ok so?
 
Anonymous
Of the order of Avogadro's number say
 
Anonymous
@NovaliumCompany So the point is temperature (which is a bulk property) doesn't rise even if you keep adding heat while boiling
 
Novalium Company
Novalium Company
3:20 PM
It rises but it drops back again, because some of it is used to break the bonds?
 
Anonymous
@NovaliumCompany No
 
Anonymous
Read what I wrote again
 
Novalium Company
Novalium Company
So in boiling, it doesn't rise because it is used to break the bonds?
 
Anonymous
It's deeper than that. I'm trying to explain what temperature really means in this context.
 
Novalium Company
Novalium Company
Temp. is just the average kinetic energy between a bulk?
 
Anonymous
3:27 PM
@NovaliumCompany You're close. I'd just say "proportional to"
 
Anonymous
The word "average" is really significant here
 
Anonymous
There might be chaotic behaviour locally in a liquid but unless the whole liquid starts showing that chaotic behaviour, that is, turned to a gas, it hasn't boiled completely but rather is in the process of boiling.
 
Novalium Company
Novalium Company
So am I right about what temperature is?
 
Anonymous
@NovaliumCompany "Temperature is a proportional measure of the average kinetic energy of the random motions of the constituent microscopic particles in a system (such as electrons, atoms, and molecules)"...in this sense, yes
 
Novalium Company
Novalium Company
And boiling is basically when the intermolecular bonds start breaking, and while they break, the temperature will stay constant (if you keep supplying heat), because it is used to break the remaining bonds?
 
Anonymous
3:33 PM
What you've written is fine, but I don't know if it makes intuitive sense to you yet.
 
Novalium Company
Novalium Company
Well, ask me, anything.
 
Anonymous
I don't need to. You just need to ask yourself if you're feeling satisfied. ;)
 
Anonymous
Maybe just read the conversation a few more times otherwise.
 
Novalium Company
Novalium Company
I want to know what is the relation between boiling and the atmospheric pressure. I know that at high atm pressure, water boils at a lower temp, maybe because the molecules of the water don't need that much KE to break the pressure of the less-dense air?
(The molecules of the water can more easily break through the pressure of the air, because it is lower than the average (1 atm))
Is that a good way to view it?
 
Anonymous
@NovaliumCompany Think about it. We'll discuss it tomorrow again. Okay ? I got some work now
 
Novalium Company
Novalium Company
3:38 PM
Ok, then, see you :) and thanks.
 
enumaris
enumaris
4:07 PM
You have the relation backwards. At high pressure, water boils at higher temp.
 
Novalium Company
Novalium Company
yep, sorry, I mean at high altitude.
where the pressure is lower and air is less-dense.
 
Novalium Company
Novalium Company
4:28 PM
Oh god, I just realised what was wrong with my understandings about boiling. Now I started looking at vapor pressure as the pressure inside the bubbles. When bubbles form they make the water expand and that pushes against the atmospheric pressure. That means that for bubbles to appear, they need to have high enough internal vapor pressure to fight against the atmospheric one. Tell me if I'm misunderstanding something.
For example, this video shows it that way: youtube.com/watch?v=ffBusZO-TO0
Also the last comment here, says the same: physicsforums.com/threads/…
 
heather
heather
If anyone has a little time, if they could look at this question of mine over on math.SE on a modified simpson's rule, I'd really appreciate it. No one seems to have looked at it yet.
 
Novalium Company
Novalium Company
@heather I am not smart enough for that, sorry ;\
 
heather
heather
@NovaliumCompany no problem; i was just seeing if anyone was interested.
 
Novalium Company
Novalium Company
4:42 PM
Guys, nevermind, please ignore my comment about the boiling, it is wrong.
 
enumaris
enumaris
0
Q: Relativity : Energy - Mass Equivalence Thoughts

Hasan HammoudThe relativistic energy is equation is the following : $$E=\frac{1}{2}mu^2 + mc^2$$ Assume that a body is at rest $u=0 $ then the relativistic energy equation reduces to Einstein's Famous Equation: $$E=mc^2$$ Now assume this body emits 10 MJ does energy mass equivalence say that since it "lost...

energy relativity
how does this "question" have answers...it doesn't even have a question...
 
Golokopitenko
Golokopitenko
5:01 PM
how good are you guys at kinematics?
because I've been given a seemingly impossible exercise to solve
 
enumaris
enumaris
Depends
 
Golokopitenko
Golokopitenko
it is extremely simple
 
enumaris
enumaris
on my patience
extremely simple but seemingly impossible to solve?
 
Golokopitenko
Golokopitenko
man crouches 0.5 meters (relative to his chest while standing), then jumps 1 meter in the air (relative to his chest while standing, again)
find acceleration
no time, no speed, nothing.
so basically, this guy has jumped 1.5 meters and we have to find the acceleration it took for him to get there
again, without time, or initial speed or nona that
 
enumaris
enumaris
well supposidly initial speed is 0
 
Golokopitenko
Golokopitenko
5:05 PM
yeah
and there's g, which is -9.81 m·s-1
 
enumaris
enumaris
yep
 
Golokopitenko
Golokopitenko
and that's about it
without time or initial speed there's no way to solve this
 
enumaris
enumaris
you mean m*s^-2 btw
 
Golokopitenko
Golokopitenko
oh yeah, I meant that
 
enumaris
enumaris
I think
the 0.5 meters is a clue
and initial speed is 0
 
Golokopitenko
Golokopitenko
5:08 PM
hmm
final speed would also be zero
 
enumaris
enumaris
final speed at the top of his jump is 0 yeah
 
Golokopitenko
Golokopitenko
since his maximal height is when he stops right before falling
v^2=v0^2+2a(x-x0) hmmm
which yields a wrong result
 
enumaris
enumaris
I think that what the question is trying to ask is, this guy accelerates up (starting from 0 speed) with some acceleration a for 0.5 meters. At the end of this 0.5 meters he's going some speed. This speed is being decelerated by gravity such that he only reaches 1 meter into the air above "chest level". Find what "a" has to be.
this is solvable
 
Golokopitenko
Golokopitenko
so he... loses all his acceleration past the 0.5m point?
 
enumaris
enumaris
Find what speed going up yields a jump of 1m, then find how much acceleration will be needed to reach that speed in a span of 0.5m.
That appears to be why the 0.5m figure is included in this question.
 
Golokopitenko
Golokopitenko
5:11 PM
hmm actually they ask for his legs' acceleration
 
enumaris
enumaris
The question is not really explicit though...
Try figuring out my much simplified question first, that's probably the answer they are looking for.
 
Golokopitenko
Golokopitenko
but again, I'm missing time, so I can't find speed anyway
 
enumaris
enumaris
you don't need time
 
Golokopitenko
Golokopitenko
alright, lemme try it
 
enumaris
enumaris
sounds good :)
 
Golokopitenko
Golokopitenko
5:18 PM
aaaaaaaaand solved
you really did put me in the right track @enumaris
 
enumaris
enumaris
:D
Glad to help
 
Golokopitenko
Golokopitenko
separating the problem into two halves was really smart
 
enumaris
enumaris
to be fair, the problem is phrased a bit ambiguously
but if you just do a ton of these problems, you sort of get an understanding of what they expect from you lol
 
Golokopitenko
Golokopitenko
yeah, and you have to solve part b (which asks for the initial speed) to find part a (acceleration)
I hate it when they do that
 
enumaris
enumaris
yeah that part will just come with experience
 
Secret
Secret
5:20 PM
post quantum models
either no unitarity or noncausal
 
Golokopitenko
Golokopitenko
philosophy incoming: what if our physical capabilities are just not enough to understand the universe through a unified theory?
 
enumaris
enumaris
what does it mean for a super theory to decohere to quantum theory
 
Secret
Secret
Probably that will mean somehow causality or unitary is emergent from its dynamics
 
enumaris
enumaris
"We ask whether there exists an operationallydefined
theory superseding quantum theory, but which reduces to it via a decoherence-like
mechanism. " wtf does this mean lol
 
Secret
Secret
Think of it like eh... after decoherence, it becomes a superposition of states, but again I have not read into it in detail yet
 
enumaris
enumaris
5:25 PM
how does a theory experience decoherence...
are they talking about decoherence as a way to go form quantum to classical behavior...or...
I find physics papers to be essentially unreadable
 
Secret
Secret
5:42 PM
Ok I have read a little bit more into it. Basically we define a bunch of processes, and part of the information get lost and discarded into the environement, and the remaining stuff obeys quantum, thus we have hyperdecoherence
I need more time to digest the details though
 
Novalium Company
Novalium Company
Guys, I'll ask a very stupid question. We know that in our brain, billions of electrical charges are passed and processed. Theoretically speaking, what if we could hook up a potential difference source (a battery) in our brain, woudn't that trigger some weird stuff to happen with our brain? Can that technology be used to display images in our eyes, just like when we dream?
 
enumaris
enumaris
hmmm
Not that specific
But people have used Magnetic fields on brains to induce some sensations
but not like...specific images or dreams
 
Novalium Company
Novalium Company
That's really interesting.
Yep, of course not.
How would they know where to place the battery and when...
 
Golokopitenko
Golokopitenko
didn't some guy invent some sort of magnetic diadem which allegedly made people focus
 
Novalium Company
Novalium Company
If humanity achieves that type of technology, we could basically create a cheaper htc vive.
 
Golokopitenko
Golokopitenko
5:55 PM
what makes you think it'd be cheaper lol
 
Novalium Company
Novalium Company
You are right, but I guess, maybe not :D
But for sure, it will be more realistic.
 
CooperCape
CooperCape
@BalarkaSen Officially never have to look at anything with a C or H in it ever again, and I could not be more pleased.
Even if I fail, idc.
never.
again.
 
enumaris
enumaris
with a C or H?
Calvin and Hobbes?
You have a problem with comics?
 
Golokopitenko
Golokopitenko
Carbon and Hydrogen
he has a problem with organic chemistry
 
Novalium Company
Novalium Company
xDD
 
CooperCape
CooperCape
5:57 PM
@enumaris Yeah, they suck
jk
 
enumaris
enumaris
@CooperCape blasphemy
 
Cows
Cows
hello peeps :D
 
CooperCape
CooperCape
Used to be a beano addict if that means anything to anyone.
 
Novalium Company
Novalium Company
@Cows Sup
 
CooperCape
CooperCape
Back in the day.
 
Cows
Cows
5:57 PM
just hanging out watching tv and stuff :P relaxing today
 
Novalium Company
Novalium Company
For the past 3 days all I did in my free time was to try to understand how boiling and vapor pressure relations work... but I think I finally got it done or at least I made some sense of it.
 
CooperCape
CooperCape
All I done today past 11:45 was go to a pub and nap.
Could not be better.
 
Sid
Sid
@CooperCape You have wasted your time. Don't you feel guilty? :P
 
CooperCape
CooperCape
@Sid Second to last exam today, and last one is ez maths, so if I'm honest the only thing I feel guilty of is not napping more.
 
Novalium Company
Novalium Company
Btw, every year, our english teacher makes us read 1 book during the summer break and they are mostly like crime, stuff like this. We had like 20 books to choose from and each of them was in a limited amount. You won't believe what I got my hands on and there was only 1 copy of it, so I was the only one owning it, I'm lucky.
 
enumaris
enumaris
6:02 PM
crime and punishment?
 
Novalium Company
Novalium Company
I got my hands on the 'Double Helix'. It's about the discovery of DNA and genes. Finally something interesting.
 
enumaris
enumaris
wasn't there a woman who essentially discovered DNA
but they gave the credit to Watson and Crick because they are dudes
 
Novalium Company
Novalium Company
Donno
 
Cows
Cows
@enumaris really?
 
bolbteppa
bolbteppa
Rosalind Franklin
 
enumaris
enumaris
6:07 PM
I vaguely remember reading something about that
 
CooperCape
CooperCape
I recall that yeah
 
Cows
Cows
I thought it was Watson and Crick
hmm
 
bolbteppa
bolbteppa
Wasn't alive, she did most of the imaging work leading up to it
 
Cows
Cows
wow
 
bolbteppa
bolbteppa
Also the other guy
 
Cows
Cows
6:08 PM
wow! Just reading about her now on wikipedia
 
enumaris
enumaris
hmmm
 
bolbteppa
bolbteppa
'The power politics of professional rivalries and alliances were also in play. The key image that revealed the double helix structure of DNA, known as “Photograph 51”, was taken by Franklin and her PhD student Raymond Gosling at King’s College London in May 1952. Her King’s colleague Maurice Wilkins then showed this iconic image to Watson at Cambridge without Franklin’s knowledge or consent. Watson and Crick also gained access to a King’s report that Franklin had helped prepare,
which contained extra experimental information that Crick crucially recognised as the final piece of the puzzle. The fact that Franklin moved from King’s to the less well regarded Birkbeck College in 1953 probably didn’t help her cause either.'
Also Linus Pauling, the master of Chemistry and only person with two Nobel prizes I think, could have discovered it theoretically before all of them, but got his chemistry wrong :p
 
Mithrandir24601
Mithrandir24601
@bolbteppa bahahahaha!! Although t'Hooft also has 2 Nobel prizes I think(?)
 
Cows
Cows
lol this was some next level academic content shuffling. So basically her student infiltrated sensitive data and gave it to the opposition camp damn. hard core man
lol
 
Mithrandir24601
Mithrandir24601
Nope - I'm totally wrong on that
 
bolbteppa
bolbteppa
6:12 PM
But Watson and Crick were on the right track without her work and were looking for it and were literally looking for the right model and knew where to look etc
 
Mithrandir24601
Mithrandir24601
Apparently: Marie Curie, Linus Pauling, John Bardeen and Frederick Sanger have 2 nobel prizes each
 
bolbteppa
bolbteppa
Ah
 
Mithrandir24601
Mithrandir24601
@bolbteppa How can an institute get multiple nobel prizes?
 
Cows
Cows
hehe
 
bolbteppa
bolbteppa
Opposing barbarism :p
 
Cows
Cows
6:17 PM
I wonder what the next Nobel prize in physics could be about. . . probably some neutrino thing
 
enumaris
enumaris
maybe my neutrino thing
(not really)
 
Mithrandir24601
Mithrandir24601
@Cows Neutrino oscillations were 2015, so probably not again so shortly after that
 
Cows
Cows
hmm yeah, . . but if it's not neutrinos then may be it will be some condensed matter cool thing hehe
@enumaris :P I had no idea you were a neutrino person too hehe. Someday I want to know how neutrinos work too
 
enumaris
enumaris
I don't know how neutrinos work
my thesis was on neutrinos tho
 
Cows
Cows
oh nice
yeah lately (~ last 2 weeks ) I've been seeing articles about neutrinos and a possible new force, particle and how the standard model has been broken. I think the articles are cool, but I don't know enough about any of the topics to be excited like everyone else hehe
 
enumaris
enumaris
6:27 PM
you can talk to vzn
he will make you excited
even if you don't want to be
 
Novalium Company
Novalium Company
Guys, what is the science that studies the brain, like what parts is it made of, each part what it does...
 
Cows
Cows
hehehehe
 
Mithrandir24601
Mithrandir24601
@NovaliumCompany neuroscience
 
Cows
Cows
someday. . .
someday, I hope to wake up and be able to know what these plots mean lol
they look really cool though
 
enumaris
enumaris
that's MiniBooNE
 
Cows
Cows
6:31 PM
yeah, I've been hearing about them a lot lately
What did they do?
 
enumaris
enumaris
they found an excess of neutrinos that's not easily explainable using the current 3-flavor model of neutrino physics
 
Cows
Cows
nice
 
enumaris
enumaris
But AFAIK there's still concerns about "background effects" (i.e. systematic errors)
But if their results hold up, apparently it would mean that there are multiple sterile neutrino species
(big jump from the current model of 0 sterile neutrino species)
 
bolbteppa
bolbteppa
 
enumaris
enumaris
my sources (imaginary neutrino friends) tell me they are awaiting microBooNE results to confirm
before jumping to add sterile neutrinos
 
Cows
Cows
6:37 PM
yeah this will be huge
I wonder how one goes from qft(model that is put together) or standard model to building and testing? I guess someone calculates some probability for observing some number of particles at some detector or something, and then it is measured as charge and energy detection somehow? maybe . . I am pretty impressed this is possible lolz
Especially with neutrinos
 
enumaris
enumaris
pretty much
you use QFT to get scattering amplitudes
 
Novalium Company
Novalium Company
Guys, are there any more related to brain sciences exepct neuroscience?
 
enumaris
enumaris
then you calculate from those scattering amplitudes what kind of counts (of some event) you are expecting
then you do the experiment to see if those counts match up
many sciences are related to the brain
cognitive science, psychology, psychiatry...
 
Cows
Cows
ah, then if you find excess or less you are in trouble as long as you do it within the right sigma hehe
 
bolbteppa
bolbteppa
 
enumaris
enumaris
6:42 PM
neuroscience is the most "structures based" one that is more about looking at how the brain (and more generally your nervous system) sends signals at a basic level and stuff like that
 
bolbteppa
bolbteppa
Didn't a bunch of people come up with FTL theories to justify the FTL experiment that turned out to be faulty wiring a few years ago
 
Novalium Company
Novalium Company
Hmm, ok then, I shall read a book on it, because it seem interesting.
 
Semiclassical
Semiclassical
@bolbteppa The joy of OPERA
 
enumaris
enumaris
"A sterile neutrino would be a fourth type that would be even more elusive because it wouldn't directly interact with other matter at all." I think he means 4th, 5th, or more type. At least according to my sources.
cus the new results should be pointing to multiple sterile neutrino species
So if MiniBooNE researchers underestimated their background, Dorigo explains, then they may have essentially mistaken background events for a signal.
but this part seems legit
that's why people are waiting for MicroBooNE
 
bolbteppa
bolbteppa
'However, in April 2017, physicists with the Daya Bay Reactor Neutrino Experiment near Shenzhen, China, reported that the entire deficit could be explained if theorists had simply overestimated the number of antineutrinos produced by one component of the complex fuel'
 
Semiclassical
Semiclassical
6:46 PM
It is sorta funny to me that QFT experiments largely boil down to “stuff goes in, stuff comes out”
That doesn’t make it any less effective tho
 
bolbteppa
bolbteppa
I just find it shocking that you can think of a Dirac sea and explain anti-particles and charge renormalization and vacuum infinities with this crazy picture and see it e.g. in the Lamb shift
 
vzn
vzn
@JackClerk hi, ambitious indeed! reminds me of another very ambitious undergrad working on his sr thesis who used to hang out in here for years... re GR try tenev + horstemeyer + many other refs here incl black holes etc vzn1.wordpress.com/2018/05/25/fluid-paradigm-shift-2018
@bolbteppa + still convinced the sea is not fluid? :P
 
Semiclassical
Semiclassical
Yes.
Dirac sea is not a sea in real space.
 
bolbteppa
bolbteppa
Well actually it is a 'sea' of anti-particles in real space, and the electrostatic repulsion of any given electron from the sea causes the bare charge to change to the observed charge
Which is nuts
@vzn your blog says "hi all. what if research into the interpretation of QM leads to a QM + GR path/ direction for unification?" have you ever looked into the Fermi theory of beta decay and how it was non-renormalizable and how a renormalizable version of this theory led to the standard model, and how the problem of unifying Gravity with particle physics comes from the exact same problem?
 
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