The h Bar - 2015-06-29

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12:29 AM

Does the main page look kind of messed up to anyone else?

@DanielSank Er, no? How so messed up?

1:03 AM

The links in the right-hand frame were all gone.

I think it's a local problem.

Damned ISPs.

Reboot.

That happens to me sometimes

If you don't the entire page will soon disappear

1 hour later…

2:36 AM

Test

@ACuriousMind wowzers I am pink today!

2 hours later…

4:32 AM

@Qmechanic @KyleKanos @ACuriousMind please tell me why u people closed this question : physics.stackexchange.com/questions/191714/…

1 hour later…

5:51 AM

@Qmechanic please tell why the question was closed and what improvements could be made. thank you.

1 hour later…

7:00 AM

@TimKrul Whenever a question on-hold is edited, it is placed in the review queue so that the concerned 3k+ users can take a look and decide whether it is fit to be re-opened or not. Be patient.

I personally feel the question in the present state follows the site guidelines and deserves to be re-opened. I'd be interested to hear the close-voters' reason behind keeping it closed, if it is so.

7:27 AM

@KyleKanos I was congratulating you for your latest PhD, if you missed it.

How long 'till this guy is banned?

As long as it takes the mods to hunt him down...

I mean, I'd hate to see "the top scientist on Earth" banned, but you know...

Woohoo! Three stars in a row!

Yes, that would be a great setback for science :P

7:43 AM

0

Q: Should we allow questions asking for a specific perspective on something which has already been more generically explained?

Suppose we have a question Why X? and it has an accepted answer. Now suppose another user posts Why X? Specifically, what is the mathematical description of X? We might go ahead and mark the second question as a duplicate of the first. However, I'm not certain this is the best thing t...

4 hours later…

11:25 AM

@DanielSank "Charges let their momentricity flow in a loop of paired particles" today I learned a new word! (A VERY new word)

11:36 AM

@DanielSank I think most people are full of themselves. Some of them dare to be more expressive about it than others. However, I wouldn't ban them, they're just being honest about it.

1 hour later…

12:44 PM

@TimKrul I voted to close it because we are not a homework help site and don't answer "check my work" type problems, as explained in the two links of John Rennie's comment. You could reformulate it to be about the concept that is holding you back from doing the problem, but given that you've deleted the post, I suspect you're not interested in doing that anymore?

@Gaurav I did see it earlier, thank you.

1:16 PM

Hey hey

1:41 PM

Hi pal

2:13 PM

@DanielSank We don't generally take direct action against users with ... uhm ... "theories". We let the question- and answer-bans catch them. Just downvote any incorrect posts and let nature take its course.

That leaves the mods to watch out for vote fraud.

2:47 PM

@ACuriousMind Thanks again for all your help with Skyrim.

I'll try to do Morrowind on my own, but that might result in "delete local data" a few times :D

Have fun ;) Remember to play it vanilla at least a bit first, it's very different from Skyrim

Can't, that freaking font is tiny!

I'm playing it on near 1800p res.

Oh, yes, you are allowed to mod font and resolution :D

I also discovered that I can play Oblivion on battery power at 60fps!

Prepare for reading a lot regardless of font size, there's almost no voice acting.

2:50 PM

I have to seriously restrain myself to not play it on the morning commute.

@ACuriousMind Speaking of voice acting, the voice acting in Oblivion is hilarious.

Hahaha...I remember it being pretty hilaribad

They got a lot better in Skyrim.

Yeah, the voice acting is pretty much just random American people.

I lol'd when this Argonian had a sweet lady voice. The Skyrim sort of scruffy voice for the Argonians is spot on.

@Danu: Did you see Jack Lee's comment that he never uses "manifold" in the way you suggest? ;P

@ACuriousMind Doesn't a set with boundary fail the "homeomorphic to R^n" condition and is therefore not a manifold?

@0celo7 Yep.

2:55 PM

I got something right! Yay!

@ACuriousMind So is the boundary of R^n empty or something else?

My gut says "sphere at infinity", but I might be mixing that up with something else.

@0celo7 The boundary is the difference between the closure and the interior. R^n is clopen (your and Hitler's favourite thing!), so closure and interior coincide and it has no boundary.

In some applications it's indeed taken to be "sphere at infinity", but that's not technically the boundary of R^n.

So I was "not even wrong"?

Mh, "empty" is right, so your first guess was correct.

So where does the "sphere at infinity" come in?

My "No boundary" is supposed to mean "empty boundary"

@0celo7 If you think of approximating R^n by compact balls of increasing radius, and do Stokes/integration by parts on that, you get a boundary term that lives on a sphere. As you send the radius to infinity, this sphere becomes the "sphere at infinity".

...I think, never tried to make that rigorous in any way :P

3:02 PM

@ACuriousMind So when does one use that vs. just saying $\emptyset$?

@0celo7 Uh...I've seen it, but I don't know exactly where...I think it occurs for example in some treatment of gauge theories where you have to patch two solutions together to get a solution on S^4 - and the partial solutions are said to be solutions on the whole R^4, and you patch them together at the "S^3 at infinity" (the equator of the S^4).

Of course, you can avoid that by not patching R^4 solutions, but those on balls with finite radius to begin with.

@ACuriousMind Suppose we integrate a form over the sphere at infinity. Can we use Stokes' to turn that into an integral of d(form) over R^n?

...I don't think this "sphere at infinity" is such a well-defined concept that I would attempt that :D

I think the best concept is really thinking of R^n as a hemisphere of S^n, and of the "sphere at infinity" as the S^(n-1) equator. Having a "limiting behaviour" on R^n towards infinity is then the same as having a constant value on that equator.

@KyleKanos i was saying that it was completely on topic and wasnt asking to check my answer. i was just questioning about why i was getting different answers. but i deleted it as i thought i was just wasting my time editing the question which wasnt getting any +ve attention. i was going on clarifying the problem, and you people had blatantly refused to consider it on topic. i prefer it be deleted from here. thank you.

And, in this setting, you could use Stokes for a function on that equator.

@0celo7 So I retract my statement and change my answer to "Yes". :D

3:10 PM

@ACuriousMind Straumann does that in Eq. (3.209) and he's fairly rigorous.

Good that I agree with him that he can do that, then

@ACuriousMind You're the boss of mathematical rigor

@TimKrul Well if the issue is the numerics of the problem, then there are alternatives online for that. If you want the concept clarified, then you need to think about what concept of the question is giving you the trouble and ask about that.

@0celo7 Heh, try telling that to my mathematician friends :D

@ACuriousMind At least you do math with one eye open. I close both and hope for the best.

I let Jesus take the pen.

3:14 PM

@0celo7 Not sure if I always like what I see with the open eye

@ACuriousMind Minor thing: whenever I quit to desktop in Oblivion, Windows gives me a message saying "Oblivion has quit unexpectedly" and then sends an error report to Microsoft. This doesn't happen with other games. Is that something to worry about?

@0celo7 If nothing else happens, I wouldn't worry about that. Older applications sometimes can't shut down correctly on newer Windows versions, but if it has saved everything and starts up again fine, no harm is done.

@ACuriousMind Did you know that if you take the harmonic series and remove every term with a "9" in the denominator, it converges to less than 80?

@0celo7 Of course I do.

Meanwhile, I spent an hour installing and updating Linux on a USB stick, only to have the USB stick disintegrate into its improperly glued parts when I removed it from my computer. Argh!

@ACuriousMind That's where I got that too!

Crazy how that works.

3:19 PM

It's one of those "you've got to be kidding me" things

@ACuriousMind I have a nice 128GB USB 3.0 and my Win partition refuses to acknowledge it's plugged in.

I had to transfer music via an SD card from my 3DS.

Windows wasn't made for Macs, I guess :P

So sloooooow

@ACuriousMind I might have to format it. I think Mac can read Win formatting but Win can't read Mac formatting.

For some reason the SD card works fine.

What is the USB stick formatted as currently?

@ACuriousMind Literally "Mac"

3:22 PM

lol, no wonder Windows can't read it. Format it for FAT32 or something.

The hell? smbc-comics.com/index.php?id=2137

Simulating birth?

@0celo7 Yeah, probably

@ACuriousMind So is your brain fully healed now?

@0celo7 All symptoms are gone, I feel completely normal.

user image

smbc-comics.com/comics/20101109.gif I don't recognize that equation.

3:31 PM

@0celo7 That one is great. Even though it ends with the death of all quantum physicists.

@ACuriousMind You should beware!

@0celo7 If I ever begin to blather about quantum physics and free will, put me down.

Someone has posted that before.

Probably when we were talking about Penrose or Ellis and their metaphysical adventures.

@ACuriousMind I'll put you down if you ever start to support an interpretation.

I know the old you would want that. Who knows what the concussion did!

No worries, I'm still as uninterpretative as before

Reading Wald's algebraic treatment of QFT has got me thinking...how do particles work in QFT? They're not things, right? They're just artifacts of perturbation theory?

So what exactly are the particles we observe in detectors? Just modes of the fields?

3:44 PM

the particles are the states created by the modes of the free fields in the asymptotic past and future.

Alternatively, there are so-called "resonances" you can also view as particles, but I can't explain them.

Since our universe is approximately FLRW, is the concept of particle well defined for us?

Oh god, don't ask me stuff about curved space.

And no, FLRW already hasn't really a unique vacuum, there are infinitely many possible mode expansions (I think)

I just have a hard time imagining intuitively why the concept of particles is ill-defined.

@ACuriousMind I think it depends on the form of $a(t)$.

@0celo7 ...nah, I don't think so, unless it is such that we just have Minkowski space.

Is it possible for an FLRW to have timelike Killing vector?

If yes, then particles may be defined for that case.

3:48 PM

As I said, don't ask me stuff about curved space

But you just did a seminar!

Yeah...and I learned it's heaps upon heaps of vagueness

At least the way we did it

I have two books that I'm reading...they're also really vague. Wald is just too much algebra and analysis.

@0celo7 The issue is that you have to have a unique vacuum to begin with

@ACuriousMind But we are in curved space right now! If you told LHC people their particles are ill-defined they'll look at you weird.

(Unless they've studied QFTCS of course.)

@ACuriousMind There is a canonical vacuum for static spacetimes.

3:52 PM

@0celo7 Space isn't that curved here. Compared to the EM and strong/weak scales, I'd say particles on earth still pretty much think they're in minkowski space

@ACuriousMind I seem to recall particles are better defined if their wavelengths are small compared to the average curvature scale.

@0celo7 See, we did not discuss things in that generality. Don't ask me stuff about curved space ;)

@0celo7 subhorizon modes bla bla superhorizon modes particle interpretation bla ill-defined bla...I really haven't learned much.

:(

@ACuriousMind Having a timelike Killing vector allows one to create a canonical time translation operator by exponentiating the Lie derivative along the Killing field.

Now that sounds like something I would have liked to hear.

Then one can split the field expansion into positive and negative frequency parts and construct the Fock space.

@ACuriousMind Currently reading about unitary equivalence of S-matrices in stationary curved spacetime.

4:16 PM

@ACuriousMind Make that in globally hyperbolic spacetime. It is in stationary spacetimes where the S-matrix has the familiar QFT interpretation.

If that stuff interests you, Wald is for you.

4:41 PM

@ACuriousMind Wald just pulled a fast one: "That all odd n-particle amplitudes vanish follows by induction" and he didn't describe at all how that works.

Sounds like Wick's theorem to my mind that's used to flat space

lol

Got work and SE confused D:

Jun 24 at 21:06, by ACuriousMind

It's an annoying thing when people state "the general case follows by induction" but the induction step is not obvious.

That's what was supposed to happen.

Oh, I'm retarded. I thought $\psi^{ab}=\psi^{(a}\otimes\psi^{b)}$, but that's not true at all :D

This Hilbert space index notation is crazy.

5:37 PM

@ACuriousMind What if the superhorizon has supersymmetry?

@KyleKanos What if they lose the paperwork and all of the PhD committee members and your adviser vanish into the night? Then you're hosed.

@0celo7 Then a few dozen theorists have something more to be vague about, I guess :P

@0celo7 I've already been awarded the diploma itself and the online transcript has me as graduated. What hasn't come is the bound dissertation.

(which is what is processing after so long)

The h Bar seems to be considered work-appropriate. I haven't had a visit by the NSA yet.

Or maybe I have.

Oh god, what if my cat is an NSA spy??

Didn't the NSA-spying-on-Americans thing fail to be passed a few weeks ago?

My cat is not bound by the courts and legislation.

@KyleKanos So what are you doing with your time now that you are less-than-employed?

GR?

5:47 PM

@0celo7 Applying to every job I can. And also reading a few books (including the HR) & ebooks (mostly on machine learning since most of the jobs I'm applying to would require that)

@KyleKanos Human Resources sounds like an interesting read ;)

0

Q: Bug in the daily rep limit code?

Earlier today I downvoted an answer, then after the OP had edited it I retracted my downvote. In between I had hit the daily rep limit of 215 (including one accept) and now after retracting my downvote I find I have 216 rep for the day. Obviously the determined gamer's strategy should be to make...

@0celo7 Oops

@ACuriousMind Oh Lord Functional Analysis, what's the TL;DR on "trace class" operators?

6:03 PM

@0celo7 They are the operators whose trace is not infinite.

@ACuriousMind Well that's boring.

@ACuriousMind Ahh, a wild $C^*$ algebra appeared!

It used "Weyl relations"! 0celo7 is unable to derive them, it's super effective!

@ACuriousMind Whoa, I got #rekt

I bet I need the bread and soup theorem.

@0celo7 ....are you referencing Pokemon?

6:18 PM

@KyleKanos Yes

@KyleKanos I can derive it using Baker-Campbell-Hausdorff, but I have no clue how to derive that one.

Tom Baker, Bruce Campbell and Dedi Hausdorff??

@KyleKanos aka the boomstick theorem

Well it seems you recognized one of those names

@0celo7 I think it's not too bad

@Danu Yeah, I only need it to one commutator.

6:22 PM

I think some kind of induction argument works on one of the variations of the result

3

Q: Commutator algebra in exponents

Considering $X$ and $Y$ such that $[X,Y]=\lambda$, which is complex, and $\mu$ is another complex number, prove: $$e^{\mu(X+Y)}=e^{\mu X} e^{\mu Y} e^{-\mu^2\lambda/2}$$ My attempt (so far) is: Expand the exponent. $$\mu(X+Y)=\mu X+ \mu Y$$ and then split it. How can I introduce $\lambda$? Ta...

quantum-mechanics homework-and-exercises operators commutator

That's the easy case where the commutator commutes

But the general strategy is just to Taylor expand and nest commutators, as far as I remember

1 hour later…

7:41 PM

This deserves a better answer.

@DanielSank What do you find lacking in Martin's answer?

@ACuriousMind In Valter's answer here, shouldn't the $-\lambda h(\mu)$ in $h'(\mu)$ actually be $-\lambda \mu h(\mu)$?

If yes, I don't see how the result follows.

If no, I'm shit at calculus.

Not good either way :(

@ACuriousMind Ahh, (1) is incorrect.

7:56 PM

@0celo7 Yes. But the result still follows, because he also forgot a $\mu$ far earlier

I see you found it by yourself :D

I'll fix it.

Apparently, integrating the "trivial" differential equation is not trivial :P

lol

@ACuriousMind I guess you can make mistakes like that when you have a PhD

@0celo7 I make those even without one :D

@ACuriousMind At least you're not like BLT who said outright that numerical factors were of no concern to them :D

8:01 PM

Is anyone here familiar with planetary bodies, etc?

@Owatch I can point out the sun and the moon...that's about it.

I have a quick question about collisions between planet sized objects

And those aren't even planets :D

Lived 22 years of my life on one, so I'd call myself familiar with a planetary body

@ACuriousMind Second paragraph is a bit vague.

8:02 PM

@Owatch Ask away

It's a really interesting and common question so a more explicit answer might be good.

@KyleKanos Supernova != planet

@0celo7 True, but I'm supposedly an astrophysicist so I should be familiar with planets

Should != are

Well. I wanted to know if there was a way for determining what mass an object must be to destroy another object (Where objects are planet sized)

8:04 PM

@Owatch Define destroy.

I know there are differences between gaseous and terrestrial planets. But I have a very simple model

Agreed, define destroy.

Destroy as in both objects would no longer resemble a sphere. Or would be in large 'pieces'. It's hard to describe.

The moon has many craters, for example. But it still looks like a sphere.

Well, I guess either way it'd have to be a sizeable fraction of the binding energy of the planet

Eh, I guess it depends how hard they hit too.

8:06 PM

Hard hitting can be in the form of kinetic energy, if that's sufficiently large enough it could surpass the binding energy

@Owatch You're not going to get a quantitative answer.

Anyways, you'll be interested in this post:

0

Q: Properties of an object whose collision with Earth would completely disintegrate Earth

This picture got me thinking, whether such collision would be possible, and would it really look like that from the moon. What would be the properties (mass, size, velocity etc.) of an object, whose collision with Earth would completely destroy it in the manner of that picture? That is, after th...

earth collision asteroids

@0celo7 I guess there are too many variables to consider?

@Owatch Yes. Also keep in mind that these are not point particles, there are variables such as angle of impact, etc. to keep in mind.

Hell, maybe there could be planet-sized billiard.

Right. Well. Someone asked me to adjust impacts between objects in my simulator so they don't both get destroyed when they hit each other/

(Jupiter for example, would be eliminated by the moon)

So I thought maybe a % of the mass as a qualifier to destroy another object would be a good if/else test

But I see there's much more to it.

8:09 PM

What happens if you throw something into a gas planet?

Is there any solid stuff in Jupiter?

Yes.

Its core is believed to be solid

In any case, I imagine a thrown object would simply stop where the density of the gasses reached the same density as the object? Or something like that

I guess it depends on who you ask.

(Whether Jupiter has solid core)

@KyleKanos What happens if we fire a rock planet into a gas planet?

@0celo7 It is believed that the core of Jupiter is solid

@0celo7 Beyond "a collision if there's a solid core"?

I imagine there would be a lot of heat?

@KyleKanos Yes.

8:13 PM

@DanielSank Mh...if I'm bored on the weekend, I might type up something more verbose and illustrative. Right now that would be more procrastinating than my conscience can bear ;)

How about probably not much different than two (spheroidal) rocks colliding in air?

@KyleKanos What happens to the gas?

@0celo7 youtube.com/watch?v=CiLNxZbpP20

There'd probably be a slight slow down of the impactor as it traverses through the gas

@Owatch I'm talking something bigger at near light speed.

8:16 PM

Explain how a planet could be moving at near light speed?

@KyleKanos I'm unconcerned with this part of the thought experiment.

Some form of magnetism is most likely.

user image

How is that relevant to the situation? Seriously.

Because I thought we were discussing real-world physics and not fantasy

Jeez. Just imagine we have a planet-sized LHC.

Call it the BFLHC (Big Fucking Large Hadron Collider).

8:20 PM

So planet = hadron?

@0celo7 You're reading too much SMBC lately, are you? ;)

Oh, you mean planet sized...

plant-sized would be more amazing :D

@ACuriousMind (I was going to let that one slide....)

I'm not following this discussion, I just read plant-sized LHC :P

@KyleKanos Sure it is! With some other stuff thrown in, but by mass it's overwhelmingly hadronic.

<-This lump of overwhelmingly hadronic matter agrees.

8:22 PM

@ACuriousMind Ocelot wants to shoot rocky planets at relativistic speeds to collide with gaseous planets

@KyleKanos Spot on.

@Owatch Thanks for alleviating some work boredom.

@KyleKanos Sounds fun.

No problem. People keep asking for features for me to put in.

So I have to look up stuff like thi

s

I guess I will do % based.

Renormalization of the energy-momentum tensor is actually really boring.

If A is > 25% mass of B, both will be eliminated.

8:24 PM

And doing Senate work is also really boring.

@Owatch You can get your own data. Approximate planets with watermelons and potatoes of various sizes, then blast away!

> So I ... heard a single train horn blast through my neighborhood ... the closest train should be in South Central which is 9.9 miles away from where I live in car.

I think it's a typo, but they totally just admitted to living in a neighborhood in their car

"live in car"

0

Q: Mode Operators in the Virasoro Algebra

This questions concerns Exercise 2.11 in Polchinski. We are asked to compute the commutator $$L_{m}(L_{-m}|0;0\rangle) - L_{-m}(L_{m} |0;0\rangle)$$ By plugging the mode expansions, we use the definition from 2.7.6 $$L_{m}\sim \frac{1}{2}\sum_{n =-\infty}^{\infty} \alpha^{\mu}_{m-n} \alpha_{\mu n...

homework-and-exercises string-theory operators conformal-field-theory

Oh god those things are so horrible.

BLT has an appendix where they explicitly calculate the central extension of the Witt algebra using the commutation relations of the $\alpha$s. Absolutely disgusting calculation.

1 hour later…

9:35 PM

Why am I the only VTC on a blatant homework-type question?

@ACuriousMind I'm assuming you've used all of your votes?

@0celo7 If you mean the one you posted, I don't think "Why does this relation hold?" is a blatant homework question.

But it asks about a specific exercise and how to do it...

"Show me how to do X so I can do exercise Y"

@0celo7 Not really - it is about the exercise, but the question isn't "I'm stuck, what do I do?" it's "I know the steps, but I can't see why this step here is valid?" I think it's valid, and so did two others.

I wouldn't necessarily vote to reopen it if it is closed, but I won't close it.

I invoke the "I am never wrong" clause.

2

We don't need to all agree on on-topicness of every question - that's what the voting system is there for

10:20 PM

@ACuriousMind Looking forward to it.

George Smyridis

Hey guys sorry to interrupt. Have you ever regretted that you got into physics instead of engineering?

I am planning on majoring in physics next year in physics, i really want to, but my whole family insists on becoming an engineer because of the job prospects.

Did that happen to any of you?

10:40 PM

@ACuriousMind Yet, that is irrelevant because I activated my daily power (cf. e.g. racial powers in Skyrim).

@GeorgeSmyridis Depends on what type of engineering. That said, I do not regret getting my PhD in physics

@KyleKanos Since you're not getting a job in your field, will that effect your pay any?

George Smyridis

While doing your PhD, were you being payed ?

If you had gone straight computational CS, would you make more monies?

@0celo7 If it works out correctly, in a positive way :)

@GeorgeSmyridis By the University, yes.

@0celo7 Probably would have started a career sooner.

10:45 PM

@GeorgeSmyridis Well, I would say that it is increasingly true that physics skills are not going to make you directly employable if you're thinking industry as opposed to academia (KyleKanos is a physicist, now reading books on engineering). That said, the end goal for physicists is usually academia.

George Smyridis

Where are you working now?

I'd be more inclined to point Machine Learning towards CS than Eng, but the point remains: getting a pure physics PhD requires you to think more proactively during the PhD years than right afterwards

George Smyridis

So you being experienced, what would you recommend me to do? I really love physics, but i think its not worth wasting so many years for getting a PhD just to continue studying in order to work as an engineer.

I'm not aiming to be an engineer

@KyleKanos Fair enough. I suppose it depends on the book you're reading, though. For example, a lot of ML applications are in control theory, which I'd definitely put under engineering rather than CS.

10:50 PM

@GeorgeSmyridis If you want hot commodity, I'd say engineering or physics plus CS minor with emphasis on machine learning. This is big stuff for data science

@GeorgeSmyridis If you really love it, why would you call those years "wasted"?

@alarge True, ML has applications well beyond just CS, it's just that the emphasis I'm working on is more towards the data end (which is more CS oriented than not, I'd wager in my unprofessional experience)

George Smyridis

Maybe i picked my words poorly, i am not meaning wasted per say, but you know i cant be living out of my parents money for so long.
I should note that i am from Greece

Greek people have money?

George Smyridis

I'll give you a hint, the country is about to bankrupt!

10:55 PM

@GeorgeSmyridis Well, if there's no other way to finance your studies, I understand the problem

Consider bartending ;)

@ACuriousMind Are you a bartender?

@GeorgeSmyridis Do you know what it is that physicists do and who pays them, and what opportunities they have beyond academia? Similarly, how many of the engineers majoring in X do you think actually use X at their jobs?

@0celo7 No, but I know some. They make good friends :D

George Smyridis

@alarge that's the thing, i guess i am really not!

In my country you are basically supposed to work in school or, if you are extremely lucky, work for the university

That's why i am planning on leaving once i graduate. I hear there are some loans specific for students. Well, i also hear that i will be paying them back for the rest of my life. :P

@ACuriousMind As for bar tending, i am really considering it.

@GeorgeSmyridis Apart from certain professions (say, civil engineers who might have certificate requirements and the like), I think a lot of engineers, like physicists, don't actually end up using the exact thing they studied at work. At least not directly, and certainly not for the rest of their lives, as they'll likely eventually end up in a managerial position at one point or another.

I view the entire point of university not to prepare you for a certain profession, but rather to give you the tools to pursue your ambitions. If you're really passionate about physics, I'd say major in it, but as others have recommended, try to supplement your studies (i.e. minors) with more directly marketable skills. Which right now are indeed data science/machine learning etc. Those can come in handy when doing physics, too.

George Smyridis

11:06 PM

What do you do guys?

I'm currently unemployed but am looking at (1) quantitative finance, (2) data science and (3) HPC applications

George Smyridis

How are you able to work in economics? Did you take respective classes, or just applied mathematics?

Correct me, i am not familiar with the topic.

I did my PhD doing computational physics, and currently my day-to-day job is mostly coding high performance software.

George Smyridis

Really interesting, do you work in academia or in some software company?

A company.

11:18 PM

@GeorgeSmyridis One aspect of quantitative finance involves modelling portfolios with PDEs numerically; my research involved solving a set of coupled PDEs so it's not terribly different computationally, just the physical aspect is different

George Smyridis

Thank you guys you have been really helpful!

@GeorgeSmyridis Economics, finance and in particular quantitative finance are all quite distinct fields. As I suggested earlier, engineers/physicists/the like often do not directly do what they studied, but because of their quantitative backgrounds, they can often move between fields. That said, as the fields get more mature, degree programs get set up: Nowadays you can get a master's in financial engineering, or major in data science.

user54412

@GeorgeSmyridis I feel I should also point out that employability varies a lot by country. This room is dominated by North Americans, Indians, and (non-Greek) Europeans, so we may also not know entirely how careers work in your area (assuming you intend to stay in Greece).

user54412

For example, in the US all bachelor's degrees and to an ever-increasing extent PhD's are merely used to signal to employers that one is capable of being productive. The actual subject matters less than it does in many other parts of the world.

@ChrisWhite Indians?

11:25 PM

@ChrisWhite Indeed, and engineering schools in particular can also vary a lot by country. In some they are more hands-on, but in many others the undergraduate curriculum of engineers and physicists is rather similar (engineers probably won't have to take more than one course of quantum mechanics, or cover it as a part of another course)

George Smyridis

I am planning on leaving, at least i will apply to graduate schools and if i can find a job, i will stay! I would prefer US or UK mostly because of the language.
I think that i will be less that useless in Greece.

user54412

@0celo7 Hmm. Well, not today, and they were more common in the past.

@ChrisWhite Which chat members are Indian?

@ACuriousMind Why doesn't Oblivion give me helpful misc. quests? It's impossible to remember all of these rumors!

Also why am I still lvl 1? I've been gaining mad skills.

user54412

ManishEarth, Waffle's Crazy Peanut, Gowtham, Gaurav, probably more I'm forgetting right now.

user54412

At least that's what they claim.

11:29 PM

@ACuriousMind I'm gonna cheat and use uesp.net/wiki/Oblivion:Quests.

Whoops, he's not even here.

@ChrisWhite I did not know that (obviously).

George Smyridis

@ChrisWhite From what i see you are studying astrophysics in Princeton. What are you planning on doing next?

The only person whose location we really know is mine.

And @KyleKanos, once his PhD is online.

@0celo7 DC?

@KyleKanos Yes, you can vouch.

user54412

@GeorgeSmyridis I'll be applying for postdoc positions this fall I suppose, since I'm planning on trying to stay in academia. That said, there are about 10 times more PhDs in my field than academic positions, so odds are I'll end up doing something non-academic. It's not clear how astrophysics-related that would be.

11:33 PM

@0celo7 This is true, I saw some of you

@KyleKanos At the time, I thought you could see more. I was unaware the cameras were zoomed in so far.

user54412

@GeorgeSmyridis To be clear, I'm not worried about finding a job.

George Smyridis

Why is that?

@0celo7 I thought I told you how little I could see?

@KyleKanos Maybe you did. I was paying more attention to the hearing than SE.

11:35 PM

@0celo7 Who pays attention to hearings?

user image

@KyleKanos Losers like me.

George Smyridis

@ChrisWhite And why is that?

@ChrisWhite Is that you?

George Smyridis

@0celo7 Is that you?

user54412

@GeorgeSmyridis Having a PhD in science or engineering really puts you ahead of many job applicants.

11:37 PM

@GeorgeSmyridis That should be obvious in light of my question.

user54412

@0celo7 Yes... Creepy stalker

@ChrisWhite Eh, maybe against other BS/MS students, but it does nothing when competing against other PhDs.

@ChrisWhite Unless you stole someone's identity, we now have 2 confirmations.

George Smyridis

@0celo7 Guess you are right!

user54412

@KyleKanos True. But I refuse to believe all job openings are dominated by PhD applicants. Maybe the top ones, but anything that pays above minimum wage looks pretty decent to me.

11:41 PM

@ChrisWhite You'd be surprised. Assuming this chart is still accurate we're talking 30k PhDs in science & engineering per year.

user54412

That's a large figure. I always laugh when I hear politicians saying we need to train more STEM students, as though there is some shortage of STEM citizens in the workforce.

@ChrisWhite That said, you may well appear overeducated applying to BS(/MS) jobs with a PhD. Moreover, those BS/MS grads probably focused on that particular subject (whatever it may be), and will probably beat you in domain knowledge. I wouldn't worry about finding a job, but just saying that you will probably have to spend weeks or months studying for interviews and whatnot, so you're not going to just waltz in.

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