The h Bar

NeuroFuzzy

12:00 AM

@barrycarter hmm... dog(barrycarter), AKA dog-ified barrycarter, sounds very strange

maybe you meant barrycarter.dog(); ?

What does human(barrycarter.dog()) look like?

kevin Tah N.

12:14 AM

hey

I am curious. Today income is a very significant component to live comfortably. Who makes more money? Theoretical Physicists or Experimental Physicists, and what traditional Physics discipline (other than Medical Physics) pays the most given similar starting and ending levels of experience?

^ @NeuroFuzzy @Qmechanic

user54412

I strongly suspect the distribution within the categories is a lot broader than the differences between the means.

user54412

@dmckee often has data for this sort of thing

Sᴋᴜʟʟ ᴘᴇᴛʀᴏʟ

12:34 AM

hi @ChrisWhite

vzn

1:29 AM

via reddit

Rediscover the Standard Model of particle physics and much more with open data from the Large Hadron Collider

dmckee

2:29 AM

@ChrisWhite AIP recently completed another physic(ist| major) employment and pay survey, but I don't think they break things down that way, and I'm not aware of another source I would consider authoritative.

3

This one breaks things down a bit by field, but not across the theory/phenomenology/computation/experiment spectrum.

kevin Tah N.

I am checking the links out now thank you

DanielSank

3:57 AM

@kevinTahN. do you mean specifically in academia or taking into account all career paths of people with physics training?

kevin Tah N.

5:06 AM

@DanielSank I suspect that taking into account all career paths might make it a bit difficult to rank by wage. In academia for instance how does it work? Also I have heard Astrophysicists have the most versatile and sought after marketable skills in the real world, how do other Physicist fair out of academia ? Is an income north of $250,000 which seems to be the number after which Americans are not considered middle class anymore a reasonable feat to achieve pursuing a Physics career?

or derivatives there of in industry?

user116211

Hmm.... is this happening to only my laptop?

user116211

user116211

Why are the MathJax not aligning properly? Is it only happening to me?

user116211

Would update more pics if found.....

Secret

5:34 AM

journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.161303

Secret

https://www.sciencedaily.com/releases/2016/04/160421133821.htm
But my pictures are incomprehensible to most, and even myself of 3 years later???

John Rennie

6:09 AM

@MAFIA36790 I'm seeing the same. If I look at this question then I see the same messed up Mathjax rendering that you see.

kevin Tah N.

It looks ok in my browser

user54412

My browser is Cthulhu-free

John Rennie

Aha! It's messed up in Chrome but not in IE11.

Danu

6:25 AM

@JohnRennie My chrome MathJax rendering is fine (atm)

John Rennie

@Danu what OS and what version? I'm on Windows 7 with v50.0.2661.87m.

Danu

Windows 10; 49.0.2623.112 m

Just updated the browser to your version---still OK MathJax

yuggib

^ Windows....scientists using windows are evil

user54412

^ Scientists? Where? ::goes back to gaming::

Danu

^ lel

John Rennie

6:37 AM

@yuggib when Windows 3.0 was first released I and all my colleagues jumped on it because for the first time we could write code not subject to the 640KB restrictions of MSDOS (640KB - that's a scary memory :-)

yuggib

@ChrisWhite the average game that I use has been published in the XXth century, so the HW+OS combination really does not matter much

John Rennie

At that time MS were bending over backwards to make it easy for us to code on Windows. They even provided free telephone support for developers.

At the same time Apple were giving a big "f*ck you" to everyone who wasn't in academia. So guess which operating system everyone in industrial research ended up using.

yuggib

I bet unix was still far better than MS

John Rennie

@yuggib at the time *nix was an unholy mixup of different incompatible versions. This was before the web, so if you wanted support you either paid a fortune to a big company or used the dialup forums.

MS enjoyed massive take up by the business community because they genuinely wanted to help - or at least that's the impression they gave. I was there at the time!

Windows 3.0 was a bit flaky, but when WfWg 3.11 was released it swept through industry like a wildfire. It was so massively better than anything we'd had access to before.

Those were really exciting times :-) I'm not sure the IT world (in industry at least) has changed so radically and so rapidly since. Though I suppose the adoption of the web has been a similar paradigm shifter.

user116211

@JohnRennie Mine is Opera.... it's always messed ;P

user116211

6:46 AM

@yuggib you use kali-Linux?

yuggib

@MAFIA36790 actually not now

user116211

oh....

yuggib

I have a mac at home

but in the unis I always use linux

John Rennie

People bitch about Microsoft, me included, but Windows enjoyed such a massive market for very good reasons. We didn't all adopt it because we were stupid or perverse.

Now, if you'll excuse me I'm struggling to come up with a good answer to:

1

Q: An explanation of Hawking Radiation

Could someone please provide an explanation for the origin of Hawking Radiation? (Ideally someone who I have been speaking with on the h-bar) Any advanced maths beyond basic calculus will most probably leave me at a loss, though I do not mind a challenge! Please assume little prior knowledge, as...

user116211

@JohnRennie why do people hate maths beyond basic calculus?

John Rennie

6:50 AM

@MAFIA36790 it's a question from someone who is still at school, and they're asking if there is an explanation that can be given using school level physics. There's no suggestion the OP hates more advanced maths, he just hasn't studied it yet.

yuggib

It's not hate, it's ignorance (not said in a bad way)

user116211

::people again taking sarcasm seriously::

John Rennie

@yuggib Indeed, none of us emerged from the womb knowing quantum field theory (with the possible exception of @ACuriousMind of course :-).

user116211

@JohnRennie Except CuriousOne also!

John Rennie

It's far from clear to me exactly what CuriousOne knows

yuggib

6:52 AM

nothing

user116211

@JohnRennie He is too bit emotional.

user54412

7:06 AM

@JohnRennie I don't know what you're going for, but I feel the simplest explanation is to Bogoliubov transform the vacuum. Actually, it's also the right explanation.

John Rennie

@ChrisWhite I was going to try to explain why the vaccum is observer dependant, though i think mentioning the Bogoliubov transformations is a step too far.

However it's worth noting that the Bogoliubov transformations/different vacuum are not on their own enough to explain Hawking radiation. They tell us why the temperature looks different for different observers, but not why there is an energy flux.

For that you have to include the horizon.

user54412

I feel the horizon is a red herring

John Rennie

The Bogoliubov transformations apply equally to any mass like a neutron star, but neutron stars don't Hawking radiate because there is no horizon. Likewise the Unruh effect, where there is a temperature difference but no energy flux.

user54412

constant acceleration relative to an observer <-> experiences a horizon as far as that observer is concerned

John Rennie

Yes, there's a Rindler horizon, but views differ about whether that would produce Unruh radiation.

user54412

7:11 AM

views differ?

John Rennie

I've been Googling this stuff trying to convince myself I understand it (I don't :-) and while everyone agrees about the Unruh effect there is lots of debate about whether it can produce a flux in the way Hawking radiation does.

user54412

also, do you mean to say that if I have a 1 g neutron star at 1.0001 Schwarzschild radii, it will sit there all day and not radiate, but if I collapse it to a black hole it will all of a sudden emit a burst of radiation?

John Rennie

@ChrisWhite correct

user54412

moreover, that any real black hole will have no Hawking radiation because real black holes never quite get to having a true horizon in finite time?

John Rennie

Well, life gets complicated when you introduce time dependence. A static 1.0001 Schwarzschild radius neutron star won't emit Hawking radiation.

Real black holes radiate because there will be a future horizon. You do the calculation by evolving the wavefunctions to $\scri^+$ in some way that I don't fully understand.

And if the horizon forms it affects the results.

I can sense the look of this is bollocks you're gving me right now, but that's what the papers on Hawking radiation say!

user54412

7:17 AM

This would seem to indicate a way of testing for true horizons...

John Rennie

@ChrisWhite hmm ...

user54412

one can measure Hawking radiation and know something about the entirety of spacetime

user54412

@JohnRennie It's a look my department (known for its tough questioning of visiting speakers) has trained me to give :)

John Rennie

@ChrisWhite :-)

Though now I think about it, the existance of Hawking radiation means black holes can't exist:

122

Q: Why does Stephen Hawking say black holes don't exist?

Recently, I read in the journal Nature that Stephen Hawking wrote a paper claiming that black holes do not exist. How is this possible? Please explain it to me because I didn't understand what he said. References: Article in Nature News: Stephen Hawking: 'There are no black holes' (Zeeya Mera...

black-holes quantum-gravity hawking-radiation event-horizon

OK, so I really don't understand what's going on here.

user54412

Of the dozens of experts I've heard say something or other about new developments with black holes and information, only one of them ever said anything intelligible. And he wasn't making any claims other than pointing out how a large number of people confused themselves with the way they were foliating spacetime.

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