2:02 AM
4648

if not a: print("List is empty") Using the implicit booleanness of the empty list is quite pythonic.

Why the hell

2:24 AM
Definitely not how I would opt to check for an empty list
But to each their own I suppose

I do that all the time :D

Until somebody makes a list-like object that does something weird because who would think to do that...

nah, it won't happen

3:02 AM
Lists and booleans should be different things...

nope

where is the rigor

don't need no rigor
but I mean, I probably wouldn't use python to code a sprawling 300k line code base that builds some application...(I wouldn't, I'm a data scientist, not a software eng, maybe some would)

4 hours later…
6:47 AM
morning

bonjour

7:05 AM
Hey @RyanUnger

2 hours later…
8:37 AM
$$r'_g h = \frac12 \Delta_L h - \delta^*_g(\delta_g h) - \frac12 D_g d(\operatorname{tr}_gh)$$
Jesus
not terribly easy to parse

8:56 AM
That FTL causality question is still gathering answers... physics.stackexchange.com/questions/486806/…

9:09 AM
HWGA
Here We Go Again

9:45 AM
I have read a paper that talked about FTL using MIND POWERS once
by our old friend Eric Davies
Wormhole papers are kind of on a scale, rly
from papers by Hawking to whatever is on Vixra
Many nuances
look at this glorious MS Word
Although I'm not sure I would call Hawking's view on wormholes at the most reasonable on the scale
He actually wrote that any decent theory of quantum gravity should have wormholes
Bit cocky if I may say

he was known to be cocky
so they say

I'm afraid I never met the man
and it may be a little late for it
I always thought that if I met him I could ask him to autograph HE, but then immediatly after I realized it may be complicated

10:02 AM
yeah, I think the last thing he signed was his professorship acceptance

I can just put the pen in his hand and sign for him
What is he gonna do
Hell I could probably do it now
Just need a shovel

he's ashes

even better
sign with the ashes

beside Darwin's ashes

More importantly
Did they find Hawking's paper on wormhole pair production
He said he was working on it in 92 but I don't think he ever published it

10:10 AM
perhaps, penrose would know?

10:20 AM
mb

writing to old physicist tends to be a fairly random business

you'll never know, if you don't try

Equation 47 in particular

When did the Simons foundation start their support?

10:46 AM
Are spectral triples just an algebra formulation of a geometry with spin structure?

What's a spectral triple

'Last week messed around and got a [spectral] triple double. Freakin brothers everyway like M.J. I can't believe, today was a good day.'

lol

@bolbteppa ntlab and Wikipedia says it's a Hilbert space, an operator and Dirac operator on a manifold with spin structure. I don't quite understand what they describe. I guess it's just an algebra formulation of a geometry with spin structure.

10:57 AM
In noncommutative geometry and related branches of mathematics and mathematical physics, a spectral triple is a set of data which encodes a geometric phenomenon in an analytic way. The definition typically involves a Hilbert space, an algebra of operators on it and an unbounded self-adjoint operator, endowed with supplemental structures. It was conceived by Alain Connes who was motivated by the Atiyah-Singer index theorem and sought its extension to 'noncommutative' spaces. Some authors refer to this notion as unbounded K-cycles or as unbounded Fredholm modules. == Motivation == A motivating...
'noncommutative geometry'

sorry it's nLab not atlab, but I don't really know what that lab is though I often consult information there.

Where is the non-associative geometry if we're going buck wild
28

At the end of a conference given by Alain Connes in 2000 (here is a video in French), a member of the audience asked a question. I transcribed and translated it for you below: Audience: You showed that noncommutative geometry greatly simplifies the physics in a very elegant way, by actually lo...

11:12 AM
I don't even get how so many of the vixra people don't use latex
Some of them seem to have some basic knowledge of math and physics
and latex is fairly common with online communities for physics

I guess, some people are just plain old fashioned

11:30 AM
Microsoft Word isn't old fashioned
It's more recent than Latex

I would guess they simply have no idea what it is or a vague sense it exists and think it's like learning programming and too complicated
Or are trying to get as close as they can to be writing with feathers on parchments :p

Hell I'd rather see it done with a quill than with MS Words
5

Some of these are not bad

well anyone can post to vixra
there's the occasional decent author
But that is a bit of a risky thing rly
tarnish your fine reputation by being a vixra poster
"Levi-Civita Rhymes with Lolita"
Oh no

The latest string post on vix haha

11:35 AM
pretty short article

That Levi-Civita one is not bad either

awful title, tho

'Kaluza-Klein for Kids' is snazzier

The ol' KKK

12:00 PM
at least this paper is in latex

12:57 PM
@bolbteppa I think learning programming is like learning a language; it requires some guidance (teacher, mentor or video program) to start but once the learning is started, it may not be too difficult to continue.

1 hour later…
2:01 PM
0

There are many possible types of singularities which can occur, even under such benign conditions. Beyond the extremal Nordstrom metric, let's consider : Minkowski space with the line $\{ (t, 0, 0, 0) | t \in \mathbb{R} \}$ removed. This is a regular boundary point, which is technically a singu...

Quite possibly the dumbest spacetime I've devised
It is quite possibly dumb enough to warrant a blog post
Although I should try to check for horizons, too
Hell wait, maybe I can just do a Weyl transformed Minkowski space
With conformal factor $\sin(1/r)$

Slereah u have a blog?

Kind of

All things are a bit unfinished

only 2 topics in physics :(
Im guessing its a new blog
?

2:10 PM
oh there's plenty of topics
Most of them are drafts, though

oh ... Also I dont see a comment section

Feel free to comment right here

I think its better when u engage with ur audience

Not sure I have an audience
Well, outside of this chat

ohk ... havent read an post with it's entirety

2:12 PM
also it's all handcoded
So I'd have to code the comments

wow! u can web design too (apart from physics)

Well a man's gotta eat
more moneys in websites than in metric

Yea ... thats gonna b my story too ..
to get a 1st
so Im gonna go into big data
and do physics on the side

@Slereah you don't build websites by repeatedly piling in more javascript libraries?!

@danielunderwood well not personally
But for work, I'm afraid there is a lot of the javascript

2:17 PM
Slereah are there any other blogs u'd recommend me? I read no even wrong and back reaction ..

Terry Tao's blog is alright

ah yea ... I infrequently visit his from time to time
and also Scott Arasons
(if i got his name right)
How often do u get the arguement terry makes?
(in his posts) ... personally I seldom get the details (not have enough of a math background :( (somethin I regret))

@MoreAnonymous 4 gravitons is good.
2
I stopped reading Backreaction as I felt it was more about Hossenfelder's views on collider proposals than physics.

read that too ... but he doesnt post as frequently as woit and Sabine ... Also there used to b 4 gravitons (/people behind the blog on a wide range of topics) ... Now I think theres only one (I might b wrong since I dont visit that one freqquently)

Also remember to read the reference frame
By our lord and saviour

2:23 PM
Ugh ...
I hate name calling and languagge in that one

I actually started the blogsphere with his blog ... But it was sooo bad I thought if all sting theoroists are like this god save us!
@JohnRennie ... But I think Sabine does a variety of posts ... Not just "why more massive colliders are a bad idea"
Also Slereah ... u shd b careful about such memes (not everyone esp Lubos I guess) would approve

Bad Astronomy is fun but not much science.
@MoreAnonymous there was a period of several weeks when she just went on and on about it, and that put me off her blog. If she has finally got fed up of complaining about other physicists I might give her blog another try.

Can I complain about other physicists not hiring me on my blog
I have names!

havent heard of that one (Bad Astronomy) ...
@Slereah man ... ur in super troll mode today arent u?
@JohnRennie I also like physics posts over physics-activism posts ... But I can sympathise with her frustrations .. Like I'm not sure if physics-activism has a better outlet than the internet

2:33 PM

troll level is over a 1000
!
Also theres a new Sabine post labelled: "No, a next larger particle collider will not tell us anything about the creation of the universe"
:P

I mean probably not but she don't know!

@MoreAnonymous So she is still banging on about colliders then?
Perhaps I shall continue to look elsewhere.

Yea .. I guess there are 2 camps both being equally aggressive ... One says SUSY/(new physics) is a collider away ... The other one says of course not nothing will be found ... I feel bad for the common man who doesnt know which camp to believe ... My personal take is u mught get lucky who knows

You know
There was a song in the 40's about how building big accelerators was not a good idea

2:41 PM
@MoreAnonymous it's not that I've taken sides in the argument, it just gets boring when Hossenfelder goes on and on about it.

yea .. I agree ... unfortunately the blogosphere does not work as please see the arguments I made previously ... My advise to her would write a book about it perhaps ... Like thats super-effective learn something from WOit and Smolin :P
@JohnRennie I just skip tthose posts I mean the title does give it away
Maybe I should actually advise her to do that on her blog :P

If you get brain damage, can they withdraw a degree

I doubt it

Risky
Surgeon could have a degree and have forgotten all about surgery!

2:55 PM
I don't think they withdraw degrees if you suddenly convince yourself of pseudoscience; I don't see why they would take it away for brain damage. Seems like a slippery slope when ones work should stand on it's own merits anyways

they can only strip away a degree if they prove you cheated

@Slereah A degree doesn't let a surgeon operate in a professional capacity, there is licensing boards for that which should be ensuring that any licensed surgeon is still capable of doing the job.

I never cheated on any exams
And here I am now
In this awful job

If you think thats bad ... I never memorised previous exam questions for mine
(even though they'd repeat)

3:12 PM
@MoreAnonymous hi, she (SH) did just write a book, she cites it repeatedly on her blog, recommend it, + cf extensive discussions in here on it (ofc rather controversial, even a "lightning rod"... but very funny in places... shes like a science comedienne/ court jester at times). amazon.com/Lost-Math-Beauty-Physics-Astray/dp/0465094252

Fuck I think my example doesn't actually work
Forgot to invert the metric for the Ricci scalar
I'll have to Investigate
Wait no it's probably fine
since it's in an exponential

3:39 PM

What we need is a collider on the Moon, right around its equator. ;)

@vzn ... I havent read the book ... But it's good to know its amazon reviewers are pleased
Do u thnk her book has had had a massive impact like IWoits and Smolins ??

@MoreAnonymous I've read Hossenfelder's book and I enjoyed it. It is well written and entertaining.
But it is written to support her own view. I'm not necessarily saying she's wrong, just that she went into writing it already confident of what she would find.

@MoreAnonymous meant to mention the book is quite similar to woit + smolin, it can all be read as a sort of trifecta & doubt that any of them have had much major "impact" on scientific directions/ public povs etc... think all are worthwhile to read/ consider seriously. its also nice that 2/3 are prolific bloggers. so what is your edu bkg? re JRs point on SH, she has copious research backing her admittedly strong pov.

3:54 PM
I have 2 masters ... one in theoretical physics the other mathematical physics ... but despite this I dont think Ive mastered GR or QFT :/
Like I cant think of them as I think of QM
Which I think I understand better

@MoreAnonymous Mscs from what country? what was your undergrad, physics? did you do theses? what are the titles? are they available online? was re-noticing an old question you had comparing universe to fluid... was wondering about it physics.stackexchange.com/questions/461224/…

@RyanUnger I'm no witch

UK ... yea undergrad was physics as well ... I have done 2 thesis as part of my masters.. lemme check (they arent well written tbh ... Not really good at writing my results)
yea ... I wasn't sure ... the relation between pressure and volume is an off-shell relationship
didnt get what they were going on about though

@MoreAnonymous are you familiar with "dimensional analysis"? think there must be some-to-many worthwhile analogies between fluid dynamics and unverse cosmology, largely unexplored so far.
@MoreAnonymous are you talking about the Tenev + Horstemeyer ref?

I dont remember the content of that comment ... Like I remember clickin on it but I forget my opinion

4:01 PM
Im glad this OP decided to write this Doppler question; I'd noticed a few odd components to some of their answers on relativity questions. But it looks like they are having problems accepting what they're being told.

@MoreAnonymous encourage you to look into BM & try to articulate what you dont like about it in particular.

BM = bohemian mechanics? I'm not aware of it being compaitble with QFT

@MoreAnonymous its a work in progress. theres a lot of literature at this point. its tying into some new research directions in hydrodynamic models. (Couder-Fort-Bush) and theres new experimental support etc

@JohnRennie any recommendation for summer reading in GR before lectures start next year?

I honestly m not an expert on the interpretations of QM ... But the whole subject sometimes turns me off because at the end of the they all(/most) of them have the same equations ... though I'm curious what u think about quantum computation? I mean that doesn't make sense on a classical level

4:07 PM
@JakeRose Carroll seems popular

@MoreAnonymous you are in the majority in this chat room wrt that pov, many have said similar things about interpretations. agree that it has a going-in-circles feeling at times. its a very old debate, close to over a century now. but think the gridlock/ stalemate shows signs of finallly breaking in medium term future. huge fan of QC myself & also think it may yield new ways of looking at QM foundations, see research in that direction.

@JohnRennie short enough to get through over summer?
Mostly I just want some usage of tensor beyond the maths course we did

I've never studied GR rigorously and the book I used (Bernard Schutz) isn't one I'd recommend if you're going to be studying GR in any depth. Carroll's book is gnerally popular and I think you could at least work through the first few chapters.

Carroll and Wald and Poisson and Weinberg

@vzn I think I'm with Pete Shor on this one
122

Deterministic models. Clarification of the question: The problem with these blogs is that people are inclined to start yelling at each other. (I admit, I got infected and it's difficult not to raise one's electronic voice.) I want to ask my question without an entourage of polemics. My recent p...

4:11 PM
Many such things!

@Slereah Wald's book Gravitation? If so that's a mammoth tome.

It is

Not really a summer study book.

Most GR books are fairly thick

Though not even that rules not BM:

https://physics.stackexchange.com/questions/34588/shors-algorithm-and-bohmian-mechanics
@vzn

4:17 PM
@MoreAnonymous a gem of a Q/A on this site for a variety of reasons incl the two individuals GTH/ PS. note over ½ decade old already. they both argue their povs authoritatively. have a different pov on this.

@MoreAnonymous I suspect that Peter Shor has spent some time thinking deeply about quantum computation. ;)

Also If u like QC u might like what I call QFT-computation :P ... The result is so crazy I think it has to be wrong: physics.stackexchange.com/questions/433329/…
@PM2Ring Hooft isn't an intellectual opponent I'd like to take on personally ... But yea Shor does him justice

@MoreAnonymous can you say what country/ school you got your Mscs at?

I got my MScs in the United Kingdom
Durham University
and University of Nottingham

@MoreAnonymous am interested in at least the titles, + pdfs if available

4:23 PM
I tried to google them (the thesis) .. I cant find them
Like the first one was about twistors and spinors which I did in durham uni

lol ok

Of course giving away that information would make you Less Anonymous :-)

haha ... yea
the second one is basically done under Alexender Schekel in nottingham uni
@vzn I'm not academically briliiant (I dont score well in exams) ... but i think i ask sometime insightful questions :P

@MoreAnonymous aschenkel.eu

yea that dude ...
really clever guy

4:27 PM
@MoreAnonymous some humility there. Mscs are not to be taken lightly and put you ahead of most surrounding this site. and there are many with degrees who arent much interested in research. etc

yea ... but Im sure everyone on stackexchange loves physics
expect for those homework question ppl
:P

@MoreAnonymous so, big data? several around here delving into it also. are you working right now?

just doing an online course ... and cursing my life
(the dream was to make it as a physicist)
:'(

@MoreAnonymous have heard much about this over the years, it seems to be untenable for many talented/ hardworking ppl... you can find some support group around here at times...

yea ... but there's always the Einstein route .. which did work for Einstein atleast

4:37 PM
@MoreAnonymous einstein was singular in many ways.

haha true
But yea ... I did have Phd offers in physics
just not in quantum greavity
so I was like ...

@MoreAnonymous really! wow. you turned them down as not subjs you wanted to commit to? what were the subjs?

yea ... was too narrow

@MoreAnonymous the world of academia was rather different a century ago :P

one was condensed matter (density funcitonal theory)

4:39 PM
@MoreAnonymous which course are you doing?

not an expert on it but yea attended some lectures
the big data one? I think its called great learning its suppose to b part time
the other was actually in quantum computing but I didnt fancy the topic

it;s not a great one ... but I think it's recognised in Inida
afk
back
@ACuriousMind I'm not sure what's the point u were making by"the world of academia was rather different a century ago :P"
Anyone reads any online physics magazines like Quanta (I'm wondering if there are more of that caliber which Im not aware of)

I'm not sure either ;), but there are several factors that come to mind: Physics was much less specialized (consider e.g. how little was known about quantum theory, and how many subfields there are today), academia as a whole seemed less competitive for the few tenured positions,... A figure like Einstein is today much less likely than it was back then.

@MoreAnonymous quanta is really great, read/ cite it avidly, its unusually high quality for free. there are paid options. eg physics world, new science, etc

4:50 PM
I think Einstein was definitely an anomaly ... But to be fair Plank did recognise his genius which hepled I guess accelerated his rise

@MoreAnonymous yes physics is much different, a simple metric is total # of physicists graduating per year, its gone up very substantially. it was a very specialized/ more neighborhood-like field in einsteins time. but note even einstein in his time had difficulty getting his 1st academic positions. hence the swiss patent office.

A hundred years ago amateur scientists could still make a useful contribution i.e. like Einstein you could do science in your spare space. These days that's simply not possible. The frontiers have moved so far it takes years of full time study just to get to the starting line.
The same has happened in mathematics. In fact I suspect it happened earlier in maths than it did in physics.

Yea ... master's alone are not enough to get u to research level (I think Phd is required) ... I advocate extending the master's number of years in physics
though not everyone would like that

I think the masters is well positioned as it is. If you plan to do research the masters is just a year to find out if you really want to do a PhD.
I don't see how extending a masters to two or three years would achieve anything.

It would allow myself to be upto speed with GR and QFT research level :P

4:55 PM
That's what the PhD is for.
You aren't going to be doing research without a PhD, so there's no advantage to in effect just moving some of your PhD years backwards into a masters course.

I guess ...
I only wish I'd struggled more at the time of my masters ... rather than trying to be creative and asking insightful questions
Like I think u have to switch off certain parts of understandin to do it in the time frame
thats my main frustration with the masters
Sometimes I think I should just do a third masters .... But I might be peculiar but im not yet crazy ... and i think a 3rd masters is kinda crazy

5:12 PM
If you aren't going to stay in academia then I'd start looking for a job now.
2
You can always work for two to three years then look again at going back to do a PhD, though most people I know who started work after their PhD quickly lost interest in the academic world.

yea ... im kinda doing the same ... though my situation is a bit more constrained

you fool

it's not :P

I'm living it and I want out

6:16 PM
@JakeRose try watching these and if you're following along use his book with them
@MoreAnonymous if you want it you need to fight harder, the level of competitiveness is astounding

6:29 PM
@bolbteppa true that ... I wonder though would u say it's necessary to risk your health as well?
for it? Like Ive been in a situation like that before ... In India when I studied for IIT- JEE ..

6:44 PM
@MoreAnonymous no of course not but need to fight for it like nothing else, the second-last one here is still open apparently
The kappa one might be ok as well

7:07 PM
Thanks ... I agree about the giving up to some extent ... Im not sure if its practical but I was thinking of returning after doing a job for some time ... I dont know if this is practical .. But it is what it is

7:24 PM
@JohnRennie And you can go back much later. My Dad started his PhD around the time he turned 50. It has been very useful in his "I'm done working for other people but I'm not actually ready to quit working" consultancy.
2

8:05 PM
this question: physics.stackexchange.com/questions/479486/… is one of the best questions of PSE. I wish it was massively more upvoted, like 5k votes.
none of the answers are correct so far and the asker has done more research than any of the people who answered (I feel guilty for upvoting one of them now!)
oh lol nice he edited his answer i could remove the upvote

@thermomagneticcondensedboson The question itself seems way too technical to surpass the 100 upvotes mark. Not that it's a bad question; just that to be a highly upvoted question it has to be very accessible to a broad audience. This generally means it has to address something in pop-sci or everyday experience. The nitty-gritty of magnets isn't that pop-sci. As a famous clown-poet once said, "***** magnets, how do they work?"

yeah I agree @JMac, unfortunately!
Honestly, I feel I do not vote much on PSE. However I am generally in the top of voters.... which seems to suggest to me that most votes on PSE come from the popular questions that get to be seen on the other stack exchange websites.
all the other questions have generally a very low vote count. not many people vote
and that's where the most interesting and deep physics questions are asked
2

3 hours later…
11:43 PM
@dmckee seriously, 50 years old? when did he get his undergrad degree...