12:38 AM
@heather working on a reading list
@heather or not, I just blew a fuse and lost all the work
@JohnRennie wonder how much current my fan draws
I turned it on and tripped the breaker

1:19 AM

1 hour later…
2:20 AM
@ACuriousMind I am trying to estimate $\det (A^*A)$ using $||A||$. Any ideas?

2:38 AM
Last night dream: The spherical projectiles themselves appeared in last night dream in the form of rolling steel balls in a lava canyon place
It does seemed Guillotine is (insert word) enough to probably have suppressed any contents from the movie Oldboy form becoming dream elements for now

2:53 AM
@ACuriousMind Ah, $|\det (A^*A)|=||\wedge_k A^*A||\le ||A^*A||^k\le ||A^*||^k||A||^k=||A||^{2k}$.

Hi, everybody.

@DanielSank hi

3:23 AM
I heard that weak interaction is often between hadrons like (proton/neutron) but it interacts with leptons like electrons and neutrinos
however if the weak interaction only works on tiny distances how would a electron/neutrino ever come close enough to a proton/neutron for this force to even be significant in day-to-day

@DanielSank does this look like a good book? link.springer.com/book/10.1007%2F978-3-319-31089-3

@0celóñe7 Page taking too long to load,
so I dunno

@Slereah maybe if that physicist is Einstein or Feynman
or the astro popsci guy

the black science man

3:35 AM
I hadn't noticed his skin color

Are you trying to learn economics @0celóñe7
For the GDP

@Slereah I am trying to invest money
I need to buy another SSD and am low on cash

@Downgoat particles aren't little balls and their interactions aren't like tiny billiard balls colliding. Particles don't have precisely defined positions. An analogy often used is that the particle is like a fuzzy cloud.

If you have to learn about stochastic calculus before investing you're gonna have to wait a bit before investing
might take a while to learn enough to wisely invest

@Downgoat So a particle scattering event is like two clouds overlapping. As long as some bit of one cloud overlaps some bit of the other cloud there is a probability of the particles interacting, though (especially for the weak force) that probability may be very low.

3:52 AM
I have to put it in twice?

Maybe they originally planned on asking cellphone + landline but didn't write it down properly

4:07 AM
@Slereah for the 1% of college students who have a landline

just put your cell number twice

I did

4:37 AM
@JohnRennie ok thanks, this makes sense
I was wondering why we don't see neutrons and protons changing into each other all the time

Well an isolated neutron does turn into a proton (though it takes about 15 minutes)
In nuclei neutrons are stabilised by the presence of the other nucleons.

5:01 AM
One more question: in the strong force between quarks. Are the gluons carrying color charge virtual? If not, where does the energy come from for QCD to take place or am I significantly misunderstanding how it works

You need to be careful about taking the concept of virtual particles too seriously.
Virtual particles don't really exist. They are a computational device - a way of breaking down a very complicated calculation of the interaction between particles into manageable chunks.

I thought virtual particles are real particles but within energy uncertainty?

No, I'm afraid the popular science press has done a great disservice to mankind by misrepresenting the reality of virtual particles.

@ACuriousMind rick and morty isn't on netflix
guess I won't watch it

@JohnRennie back to reading then... :P

5:07 AM
@Downgoat there are some useful questions on the Physics Stack Exchange

5:17 AM
7 hours ago, by Mithrandir24601
@ACuriousMind it's continuous in one direction (time), but discrete in another (different brains) - as such, some $I_j\left( t_1\right)$s are closer to $I_i\left( t_1\right)$ than $I_i\left( t_2\right)$
That is one interesting take on the philosophy of identity
0

What I am saying doesn't probably make any sense. But, what if we take space time and add in each point a random generator, or a white noise, or any other stochastic process. Would it help to connect quantum mechanics and relativity? What about adding a fluctuation term? For example one option...

That $S$ might only add a stochastic element to the metric, rather than adding actual quantum stuff to it
Actually... can spacetime metrics be stochastic...?
Interestingly, google search on that did brought up a lot of stochastic interpretation of quantum mechanics material
But I don't see without noncommutativity, how can one introduce quantum effects in the curvature of spacetime
Perhaps that might means I need to give this interpretation a read some day...
In particular I should read up how this interpretation introduce nonlocality

if i understand correctly. virtual particles don't 'exist' in the typical sense but you can observe their interactions (e.g. virtual photons with electrons)?

Virtual particles are, if I understood correctly, contributions of the quantum field when it is expressed perturbatively
They probably don't exists in non perturbative treatments of QFT I think...

5:38 AM
@Downgoat no. You can observe interactions, and those interactions can be calculated as a perturbative expansion. And the terms in the expansion can be represented as Feynman diagrams.
But those Feynman diagrams do not represent particles, virtual or otherwise, even though they look like the interactions of particles. The Feynman diagrams represent an integral called the propagator.
So the interaction is certainly real, but the virtual particles used to calculate it are not real.

so when you say 'real' do you mean observable or do you mean 'virtual particles' are merely a way of representing interactions (i.e. don't exist)

Real = observable
But I also mean 'virtual particles' are merely a way of representing interactions (i.e. don't exist)
Technically, a real particle is any particle in a Feynman diagram that comes in from infinity and/or goes out to infinity.

Particles also aren't real
Only fields are real!

Any particle whose trajectory starts and ends in the diagram just represents the propagator.

But @JohnRennie

5:52 AM
I haven't seen a field in the night sky and neither have you

Does that mean that no photon is real
Since any photon that we detect has interacted with a detector
And hence is just a propagator in a diagram

@Downgoat slereah's comment has some justification behind it but is probably more confusing than helpful at this stage :-)
@Slereah every particle started somewhere, i.e. no earlier than the Big Bang, and given time every particle will interact somewhere. So you can argue this means all particles are virtual, but whether this is useful is debatable.

I never found the whole "Is X real" to be a useful question in general
Since there isn't really any good criterion for realness

@Slereah I thought particle roughly = point source emitting a wave/perturbations in field?

'Fraid not
@Downgoat I had a go at explaining this here:
40

There is lots of experimental evidence that the electromagnetic field exchanges energy with atoms in discrete chunks, and if we call these chunks photons then photons exist. Which is all very well, but my guess is that you’re really interested to know if the photon exists as a little ball of ligh...

You might be interested to have a read ...

5:59 AM
what does it mean for a number to exist
constructible numbers might exist
why should $\Gamma(\pi+e)$ exist

6:12 AM
I'm giving a seminar on superconducting qubits tomorrow at 10:00 PST over the internet.
Everyone is invited.

What even is a number in the most abstract algebraic context is not clear

7:06 AM
@Phase yes, if you gave the colliding neutrons enough energy they would form black hole, and yes if you gave them more energy they would form a bigger black hole.

Actually, what will happen if a black hole can reach the size of a galaxy...

not much
black holes of any size have the same behaviour, at least for the GR part

I am also suspecting they will also behave similarly in QG as being so big, quantum effects might be negligible
[Random GR scenario]
Orbiting around a CTC but not moving along it
probably the space around the CTC should be pretty normal...

1 hour later…
8:53 AM
$\ce{H20}$
$\require{mhchem} \ce{H2O}$

that doesn't seem easy to achieve
though I guess you could form that with van der waals forces

It works :-)

Oh can we import libraries now?

$\require{mhchem}$ Have a nice drink of $\ce{H2O}$
$\ce{H2O}$

$$\require{halloweenmath} \xrightwitchonbroom$$

8:57 AM
It looks as if you only require one \require{mhchem} on the page, which makes sense.

Aw
Doesn't seem to work
or at least not with all packages

1 hour later…
10:10 AM
This is getting ridiculous

Maybe stop being awful at answering

20k rep via answering, and I'm awful. That hurts :(

Sic transit gloria!

1 hour later…
11:33 AM
@KyleKanos I guess the serial downvoting will be reversed, though the question is who is doing it and why. Presumably the community mods will be able to identify the offending account.

yesterday, by ACuriousMind
@KyleKanos Looking into it.

11:57 AM
@JohnR: Check Gchat! :-)

@Kaumudi.H These messages confuse me: Does Gchat not have notifications on its own? :P

@ACuriousMind :-P I'm sorry. It does, but John uses the Desktop version of the app and doesn't check it very often.
...it would seem.

Hi @MathematicsAminPhysics

user84215
@skullpatrol Hello

How's it going?

user84215
12:10 PM
Good

user84215
My idea has been also designed for theoretical physics. Please visit Planning MSE University

12:37 PM
There's also a Computer Science Education.SE site that maybe interested in your idea.

12:57 PM
$\require{mhchem}$
$\ce{CH3COOH}$

choo choo

1:12 PM
@ACuriousMind so where is RM

@0celóñe7 Who or what is 'RM'?

Rohm Muffield?

Rick
Marty

If you mean Rick&Morty, then I still don't know what you mean by "where"
Usually they are hopping all over the universe
@Slereah wat

(john duffield)

1:18 PM
(and Ron Maimon(?))

Quite strange dream

hmm, did @DanielSank post the link to the seminar he was giving? I can't seem to find it.

0celo: details?

@ACuriousMind so where the hell do I watch it
@Secret nope
I need to psychoanalyze it myself

lol ok

1:26 PM
@ACuriousMind well? You said it was on nextflix

@0celóñe7 It is on Netflix.
At least in Germany

So how was the total solar eclipse experience for the fellow Americans here?

where i was at, we saw about 95% totality - it was pretty amazing.
nearly didn't work out - it was rainy/cloudy monday morning.

@ACuriousMind god, why is TV so horrible

of course, it cleared up right after the eclipse =P

1:29 PM
A guy on Puzzling put out a picture for us. It was good.

The video of the eclipse posted by Veritasium was pretty amazing. Did anyone watch it?

I watched multiple youtube live streams yesterday (since we aussie don't see any eclipse)

I don't want to sound racist but all eclipses look the same

Imagine what it is like to watch 4 totality at the same place one after the other

@Secret It's like watching the same video on repeat 4 times, i.e. boring? :P

1:36 PM
Watching new york, and then vancover, and then somewhere else (forgot)

I saw a total eclipse 17 years ago
It was alright
but nothing special

The corona is not very visible at totality though in the life streams

1:49 PM
I don't quite understand how to do a problem I am working on:
> An airplane is flying horizontally with speed 1000 km/h (280 m/s) when an engine falls off. Neglecting air resistance, assume it takes 30 s for the engine to hit the ground. (a) How high is the airplane?

h = (1/2)*g*t^2.
the horizontal velocity component won't have any effect on the vertical height

oh...
right, that makes sense. ::facepalms::
thank you =)

I was waiting for heather to articulate her confusion but I guess just giving the answer works too :P

:-)

Pretty sure there should be a second part to that problem. Else, why would they give that velocity?

1:54 PM
that's why Heather wrote "(a)" XD

Oh... duh.

(b) How far horizontally does the engine travel while it falls?

which should be 8.4km.

yup.

2:02 PM
why did he turn a baby anyway
Do ice zombies grow up?
or is he just gonna be a zombie baby forever
that doesn't sound very useful

I presume it grows up

otherwise you'll just have a toothless baby gumming your ankles

@Slereah Put it into a catapult, throw into besieged city to terrorize the population?

I have a nuclear spoiler image
@ACuriousMind are you caught up yet?

@0celóñe7 No.

2:08 PM
Spoiler : the ice king was made of asparagus the whole time

you mean the night king?

sure whatever
ice darth maul

@ACuriousMind I'm sad to say you're not missing much

funnily asparagus has sugar backwards and a snake in its first 3 letters..

sugarapsa

2:14 PM
Don't ask me to remember the names of everyone on GoT
I know maybe 6 names

what kind of ping is that

2:50 PM
1ms ping response time seems suspiciously fast ...

3:06 PM
@heather will do when it starts

ah, okay. thank you.

@ACuriousMind Why doesn't one mathrm the $C$ in $C^k$?
$\mathrm C^k(\Omega)$

3:18 PM
@0celóñe7 ::shrug::

@heather We're also going to try to record it - I'm not sure how well it'll work, but it's worth a shot

@Mithrandir24601 what is happening?

Daniel Sank is giving a seminar on superconducting qubits over the internet
see starboard

I don't know what that means or any details

3:26 PM
@0celóñe7 A while back, I asked DS to give a talk on superconducting qubits online and he kindly agreed, so it's happening in about an hour
and a half

how and where?

Hey all, I'm pretty sure I will be missing the chat session today, just FYI

@DavidZ :'(
:P

3:44 PM
this is the last day of summer for me...i dunno how it went by so fast.

Does anyone know an advanced geometry book ???

3:58 PM
@0celóñe7 to not confuse it with the complex numbers

@Черенки Many
what are you looking for
@Slereah that is $\Bbb C$

i know single variable calculus
and i am a highschool student

@Slereah I need to write a book on the Correct Notation for things

it would be nice