The h Bar

12:00 AM

...and to continue that thought, possibly some other more plausible/ convincing implicate order (fully mathematically consistent) can be found at some pt... seems he was attempting to recruit adherents/ investigators/ contributors to a longrunning research program... but was largely unsuccessful...

bolbteppa

It used one theory that contradicts special relativity to find links to another theory that contradicts special relativity lol http://motls.blogspot.ie/2004/10/objections-to-loop-quantum-gravity.html
and ended up disprobving general relativity haha

It can't be that simple, I have to be misinterpreting all this lol

ACuriousMind

@vzn Have you ever heard anyone using the "concepts" of implicate and explicate order except Bohm?

(and his disciples, that is)

vzn

AC he admittedly has few disciples. just said that.

agreed they are not mainstream physics concepts. however "implicate" is a rough short hand for what also goes by name "hidden variable theories".

did you say above that bohmian mechanics is local or nonlocal?

ACuriousMind

@vzn I'm not sure what I said, but it is explicitly non-local

Which is how it circumvents von Neumann's and also Bell's no-go theorems for hidden variable theories

vzn

you seemed to assert bohmian mechanics had some )( redeeming qualities & studying it has some )( value. (looking...)

2 hours ago, by ACuriousMind

@tpg2114 It is a valid, equivalent formulation of quantum mechanics, and it is very instructive to see that a non-local hidden variable theory can be the same as a local probabilistic theory

but wasnt able to follow that exactly.

in that is BM the "non LHVT"? then what is the "local probabilistic theory"?

ACuriousMind

12:09 AM

BM is the non-local HVT, yes, and normal QM is the local probabilistic theory

vzn

ok thought that was the idea but find it strange to see QM referred to as a "local probabilistic theory".

ACuriousMind

The former is non-local, but realist, and the latter is local, but non-realist, therefore both conforming to Bell's theorem that quantum theories cannot be both realist and local.

@vzn Yeah, "probabilistic" should read "non-realist" for precision.

vzn

QM is not regarded as "local" by almost anyone....?

ever since Bell it has been proven to be nonlocal....?

bolbteppa

Do you still hold that view @ACuriousMind that it "is a valid, equivalent formulation of quantum mechanics", despite the fact it denies spin is an independent variable, contradicts Heisenberg uncertainty principle (as stated in Landau "there is no concept of the path of a particle"), has to basically invoke Bohr's quantization rule ad-hoc, and does not allow a relativistic generalization?

ACuriousMind

I am very sorry, but I have to go, urgently. I'll try to return tomorrow

vzn

12:16 AM

bol agreed with AC in that BM was intentionally "engineered" to align with QM predictions. it can be seen as a sort of mathematical transform.

iiuc it attempts to derive a "field" (or field-like construction) that would underly any QM prediction & shows this can be done in general (mathematically).

motl displays those "field" configurations graphically eg for the 2slit experiment etc. in the cited blog

bolbteppa

Yeah it is constructed to agree with experiment, and it does look like a nice theory, but when I compare it to the QM in something like Landau it's kind of obvious that Bohm can't make sense, those 4 points I listed above are just humongous issues, so you can't call it a mathematical transform because the internal logic of Bohm doesn't exist, a mathematical transform would imply QM has issues with spin etc... :) That Heisenberg issue is the foundation on which Landau constructs QM tbh

vzn

agreed it has "big issues" but think its critics miss some of the major point of the construction (not exactly intended the same as a complete theory)... ie think it was offered by bohm somewhat provisionally

bolbteppa

Yeah apparently DeBroglie offered it in 1927 or so but it was ignored, QM wasn't fully formed then anyway, then Bohm picked it up in the 50's or so, I can vaguely remember this being linked to Nelson's mechanics

vzn

btw when you say "does not allow a relativistic generalization" that is subtle, presumably nobody has actually proved its impossible, that can be taken to really say nobody has come up with one which is quite different than mathematically/ theoretically impossible.

yes it builds on some of debroglies ideas.

you know like microsoft likes to say embrace and extend lol... (ah full disclosure they used to say that about java & then got sued by sun for millions $$$, and lost)

in short bohmian mechanics is an attempted mathematical refutation of the copenhagen interpretation that "no deeper theory" can underly QM and does advance physics understanding in the area, albeit more abstractly at times. it is both partially successful in that aim and not fully fleshed out.

dmckee

1:19 AM

It's been a good day: I did something sciency.

9

user54412

1:39 AM

@dmckee What did you do. And more importantly did you look like this:

user54412

3

dmckee

Not quite like that but lasers were involved ...

Well, one laser.

And no sharks.

Kyle Kanos

Lasing is nice

dmckee

3

A: Possibility of making an experiment in a classroom to simulate DNA diffraction

With one change this should work. For a transmission experiment you'd probably be better printing on a transparency. I haven't tried this, mind you, but laser printers can achieve the necessary scale quite easily. You might be able to get it to work in reflection mode printed to paper, but you...

The question was from December and I finally got back to try it out with sufficient equipment.

Come to think of it, my students would probably find that guy's hair to be a good representation of my own.

Any how, laser printers are very cool, high precision tools that we've come to take for granted. Today I made them spiffy again. At least for myself.

vzn

+1 (who was it just defending the site as allowing applied Q/A but not emphasizing it?!)

anyway one last notable pt/ factoid re bohmian mechanics (occurred to me) before the topic disappears into cyber chat oblivion. bell is on record as stating it inspired his own impressive/ pivotal work. this is not widely reported/ acknowledged.

a perhaps key phrase to keep in mind wrt bohmian mechanics: work in progress...

user54412

1:55 AM

@dmckee Now I'm wondering if by stacking slightly different transparencies one can see 3D diffraction effects, whatever those happen to be

vzn

bohm & his mechanics & other theories are definitely a black sheep of physics, and of "even more" than that (re mccarthyism), and in some weird ways it all got mixed up together.

dmckee

@ChrisWhite Interesting question. I've no idea how I would hold them in the proper relationship to one another. I was going to try the OP's professor's idea of printing periodic function on the plane first.

I'd really like to be able to do a "x-ray diffraction" lab.

Even without the actual x-rays.

vzn

CW fyi your image bears a lot of resemblance to dr doofenshmirtz :)

user54412

well, it's not my image, it's on wikimedia

user54412

apparently it was picture of the day on English Wikipedia

dmckee

1:59 AM

I guess I could create the offset with the printer and just stack them neatly.

Might be worth a try.

vzn

the world just cant have too many mad scientists =D

user54412

@dmckee That's what I was thinking. But the periodic functions might be more fruitful.

dmckee

Speaking of mad scientists: smbc-comics.com/?id=3445

vzn

lol yeah great someone posted that not too long ago

dmckee

Hmmm ... might have been me actually. I'm repeating myself.

vzn

2:02 AM

lol oh yeah but worth repeating... 3 stars last time :)

do you teach?

ok right your profile says that. undergrad?

dmckee

2:17 AM

@vzn Yeah. The school has had "university" on the gate for a few years now because we got a graduate nursing program, but the sciences are strictly undergrad.

Any way, I am encouraged to do all the research I can with no money, no equipment, no space, no release time and no assistance, so I would really like to finish my Death Ray Grant Application.

vzn

dmc not exactly following. sounds like youre "doing more with less," as is the general theme/ spirit these days everywhere (both in academia & industry)... however, would you have any interest in a very novel acoustic experiment that draws parallels to QM? :)

Alfred Centauri

3:11 AM

@ACuriousMind but I have to go, urgently. I'll try to return tomorrow ... IBS?

vzn

5:13 AM

8 hours ago, by ACuriousMind

But they literally give no argument for that - they say, Bohmian mechanics is equivalent to normal QM, and so classical geodesics must be replaced by Bohmiann trajectories

from physorg summary

> In cosmological terms, the scientists explain that the quantum corrections can be thought of as a cosmological constant term (without the need for dark energy) and a radiation term. These terms keep the universe at a finite size, and therefore give it an infinite age. The terms also make predictions that agree closely with current observations of the cosmological constant and density of the universe.

it sounds like they presenting/ arguing mathematical simplicity/ elegance of the theory (maybe less complexity compared to alternative models aka Occam's razor!), & some agreement with empirical observations, & some other connections.

> In a related paper, Das and another collaborator, Rajat Bhaduri of McMaster University, Canada, have lent further credence to this model. They show that gravitons can form a Bose-Einstein condensate (named after Einstein and another Indian physicist, Satyendranath Bose) at temperatures that were present in the universe at all epochs.

> "It is satisfying to note that such straightforward corrections can potentially resolve so many issues at once," Das said.

> In physical terms, the model describes the universe as being filled with a quantum fluid. The scientists propose that this fluid might be composed of gravitons—hypothetical massless particles that mediate the force of gravity. If they exist, gravitons are thought to play a key role in a theory of quantum gravity.

cybersynchronicity, sounds like solitons to me =D

S S

8:49 AM

Transformers Robots in the Sky..

(drumroll)

academia.edu/t/a-JVa9mwX-U0zMD/10527918/…

Opinions?

How the hell can an electron be charged photon?

tpg2114

1:11 PM

Sigh... I have to write a Poisson solver for a class project. I have spent 2x longer trying to plot the line with a slope of -2 in semi-log scale than I spent writing and verifying the solver.

Not sure why a 2nd order PDE is easier to solve than a simple line. Sad, sad times.

ACuriousMind

1:43 PM

@vzn The summary really leaves out the most important part - how they justify these quantum corrections.

@dmckee Most mad scientists are actually mad engineers ;)

3

bolbteppa

2:28 PM

Guys can we give intuitive pictorial interpretations to groups like $SO(2)$ (connected with Fourier series), $SU(2)$ (connected with Legendre polynomials), $SL(R,2)$ (connected with Hypergeometric functions)? For Bessel functions you can interpret the related group as the group of motions of the plane, for example

There is a cool way to look at representation theory that kind of unifies the special functions

ACuriousMind

@bolbteppa SO(2) is rotations of the plane, SU(2) is (double cover of) rotations in space, SL(2,R) is (double cover of) Möbius transformations.

bolbteppa

Well $SU(2)$ comes from decomposing a matrix $A$ into $A = U^{-1}AU$ and then decomposing the $U$ rotations into the product of reflections right? So can we intuitively say $SU(2)$ is a group of reflections?

My intuitive understanding is that spinors naturally arise when you change basis and then represent the rotations in this change of basis in terms of reflections

That explains the double-cover nature since you can replace $U$ by $-U$ and get the same results, so it looks to me like reflections are the real intuition, what do you think? :)

ACuriousMind

Yes, because $SU(2)/\{\pm Id\} = SO(3)$.

The double cover nature is precisely because the 3D rotations are the quotient of SU(2) by the reflection

You can also think of the three-sphere $S^3$, or unit quaternions

SU(2) has many different ways to look at it

bolbteppa

Well I find it odd to think of them as reflections, because this group gives rise to Legendre polynomials, which are associated with spheres right, but it's probably what's really going on, these polynomials represent the group of reflections somehow

ACuriousMind

@bolbteppa The group of reflections? What do you understand under a reflection? For me, the only reflection is $-Id$, so that'd be a two-element group.

bolbteppa

2:45 PM

Hmm I must be confused, I guess I'm thinking about reflections in the plane that generate the symmetric group, it looks like $SU(2)$ is a group of rotations where you attach a sign to them, maybe like rotating clockwise vs. anti-clockwise?

ACuriousMind

@bolbteppa Symmetric group? You don't mean the permutation groups of sets, right? Ah, but I know now what you mean - in even dimensions, every rotation is decomposable as even number of reflections on d-1 hyperplanes

bolbteppa

Yeah, silly haha What I'm really trying to do is to interpret a big list of functions as representing some specific group (which is true) and learn how to think of them with pictures, it's some weird form of representation theory allowing you to use geometric intuition, all the equations of math physics & the pde's are unified this way but it's tough

1) additive group of real no.s = exponential function, 2) multiplicative group of positive reals = power function $t^a = e^{a \ln t}$, 3) additive group of complex no.s = $e^z$, 4) multiplicative group of non-zero complex numbers = polar form, 5) Circular plane rotation group = trigonometric function, 6) hyperbolic plane rotation group = hyperbolic functions, 7) plane motions = Bessel functions, 8) signed rotations on a sphere (???) = Legendre functions ($SU(2)$)

dmckee

@ACuriousMind Well, the serious money, the hordes of minions, the groupies, and above all else the respect is all on the applied side. Once the get out of mad grad school they realize that and try to shift their focus.

bolbteppa

9) the gamma function is a group representation of the group of linear transformations of the real line in this view!

ACuriousMind

@dmckee That makes sense

@bolbteppa Why do you say Legendre functions are SU(2) and not SO(3)? AFAIK, the Legendre polynomials are of integer degrees, which would be exactly the reps of SU(2) which are also ones of SO(3)

bolbteppa

3:10 PM

I'm not sure, I'm checking that point now, very interesting

Sofia

3:55 PM

@ACuriousMind where are you? Anyway, I copy here your comment : "you mean the structure of the classical phase space, which in turn is the cotangent bundle of the configuration space (any manifold, basically) charted by the coordinates x_ j ? And we are doing some variant of geometric quantization? (. . . one must recall Darboux' theorem, heuristically indicating that no "local" effects can be seen since, locally, there is just one symplectic geometry)"

@ACuriousMind all the concepts that I marked with boldface, will "they" understand? You don't explain to yourself, do you? You explain to a beginner, see the level of the question.

ACuriousMind

@Sofia I'm right here :) What about that comment?

Sofia

@ACuriousMind , my dear one, to whom you explain? Is a beginner.

ACuriousMind

@Sofia If they do not understnad these concepts, they should not be asking the question. You can't just barge in and ask questions about how the classical geometry affects the quantization process if you have not understood what the classical geometry actually is.

vzn

AC. agreed with your point that ideally physical eqns are derived. however some very low-level/ fundamental eqns cannot exactly be derived. eg schroedingers eqn. then there is some aspect of whether the formula fits the known data, and then "reverse engineering" eqns that way. the same was done for planks derivation of quanta & planks constant. such cases are admittedly rare in physics, but not nonexistent.

ACuriousMind

In particular, if you do not use the concept of Hamiltonian mechanics/symplectic geometry, it is wholly unclear what you even mean by the geometry of the classical space

Sofia

3:59 PM

@ACuriousMind Show some heart! Even I don't know what is the cotangent bundle. But I have other means, s.t. I understood your comment and I liked it.

ACuriousMind

@vzn The equation of motion of the Heisenberg picture actually arises very naturally just by sending the classical Poisson bracket to the quantum commutor, hence the Schrödinger equation is actually not as ad hoc as it may seem, since it is equivalent to the Heisenberg equation of motion. But you are of course correct that some things simply have to be assumed/fitted to empirical input

bolbteppa

@vzn Schrodinger's equation is derived in Landau by the quasi-classical approximation

vzn

some of the more straightfwd or intuitive derivations of the schoedinger eqn were only discovered after schroedinger came up with it. there are multiple ways to "derive" it.

later derivations do not exactly match his own original "justifications".

ACuriousMind

@Sofia I really didn't mean to come across as mean with that comment, I rather wanted to show how subtle the question is when one tries to phrase it properly. It's really borderline unclear how to answer the question without these clarifications

@vzn That the inventors/initiators of a new subset of physics lacked the understanding (and rigorous derivations) we have of their work hundred years later is really a common theme in physics, is it not?

BTW, it's OFFICIAL chat session. ;) Anything particular to talk about, room?

Jim

No

ManishEarth

4:07 PM

food

vzn

yes exactly AC. so if there is a ("halfway plausible") new model for birth of the universe it could take decades of analysis by many researchers to truly sort out!

its the birth of a new meme/ model for birth of the universe :)

Jim

And like in the beginning of the universe, millions of new memes will be created in the first few fractions of a second

ACuriousMind

I think the creation of million of memes in fractions of a second rather describes the current state of the internet than anything else :P

Kyle Kanos

One thing to discuss was Sabretooth's (now deleted) meta post.

I put a bit of work into that answer

And it's gone :(

vzn

its the old indian adage of blind men & the elephant...

Jim

4:10 PM

@ACuriousMind It's the beginning of the internet universe

vzn

& the "ultimate elephant"... "mother of all elephants"

ofc its "half baked" just like .... bohmian mechanics lol

now staggering 4270 upvotes, 3881 comments on reddit/ & counting...

ACuriousMind

@KyleKanos That nobody has reposted a similar question would indicate people don't think it needs to be discussed, wouldn't it?

Kyle Kanos

Or voted to undelete it

vzn

sabretooth the surly one announced in another chat room he had enough & was leaving this site.

ACuriousMind

@vzn His account has already been removed

vzn

4:15 PM

did he remove it? is that possible?

ACuriousMind

You can ask the SE team to delete your account

Kyle Kanos

Yes, you can delete accounts

ACuriousMind

And they usually comply quite quickly

vzn

RIP lol

Kyle Kanos

I don't think it's all that funny

infinitesimal

4:16 PM

:(

Kyle Kanos

It's kinda sad that certain people drove him away

vzn

why not? he seemed maladjusted to me

argumentative, picking fights etc

imho, this is one of the friendliest rooms to "newbs" have come across on se.

infinitesimal

true

vzn

but there is also a strong no BS "not suffering fools gladly" vibe ... feature, not a bug ... :)

but, didnt witness all the interactions with him, only some of them.

Kyle Kanos

I'm not sure about you, but I take my work pretty seriously

If someone came along and insulted it, I'd probably take it a little personally

If that happened multiple times from different people, I'd want to leave too

infinitesimal

4:23 PM

don't leave yourself vunerable

Kyle Kanos

That doesn't even make sense as a rebuttal

Thomas Klimpel

@KyleKanos You should have enough reputation to still have access to both his questions and you answer.

Kyle Kanos

@ThomasKlimpel I can see it, if I so choose to. But others won't.

infinitesimal

don't talk about things you are sensitive about

Kyle Kanos

That also doesn't make sense

infinitesimal

4:25 PM

nvm

Kyle Kanos

If you are sensitive about your work and you join a site that is about your work, how can you not discuss it?

vzn

?!? KK almost for sure it was sabretooth who flagged you re breaking bad ref right?

Kyle Kanos

Or why would you not discuss it?

@vzn Yes, I do believe it was him.

vzn

wrt his style, he is likely going to have a difficult time in more than merely an internet chat room.

science is sometimes ("seemingly") no holds barred

infinitesimal

that whole ordeal was my fault, and i apologise

Kyle Kanos

4:28 PM

I'm not blaming you alone, but I do think you were a contributing factor. A few other people were rather demeaning to him

Apparently myself included, given my "meme" posts the other day

vzn

the memes were hilarious. they werent directed at him. it was "burning off steam". like unrestrained chat rooms.

Kyle Kanos

They weren't directed at anyone really

vzn

maybe we just all have too much time to burn/ kill in here lol

should all be doing something productive wink

infinitesimal

true

vzn

look at how much power a newbie has over a chat regular eg via flagging, its "asymmetric"

Kyle Kanos

4:31 PM

I'm a computationalist, so I can be working whilst logged in

vzn

lol good excuse/ rationalization there... me too lol :)

infinitesimal

me three

vzn

this room seems unusually busy/ lively lately, last few wks

has a lot of energy

thats not too common in se chat rooms.

infinitesimal

try the math room

ACuriousMind

@vzn The MO chat regularly freezes :D

vzn

4:34 PM

MO is great/ awesome, another se "outlier"

it depends on the room. the MO number theory room is uneven. (hey inf liked your zhang/ number theory refs)

on other hand, a massive science area in real life, the se CS rooms are rather comatose lately. :(

re, if anyone wants a look at "real life no-holds-barred science/ physics", take a look at aaronsons blog.

Sofia

@ACuriousMind : first of all I answered him at his level. Next, for God's sake, be kind with people weaker than you. You are a gifted person, others are less, and they apply to you.

vzn

answered who?

teadawg1337

The MSE (Mathematics Stack Exchange) chatroom is boring to me sometimes. Usually not intellectually stimulating enough for me. I'm a bit hesitant to try MO, as I'm only a first-year undergrad...

I'm starting to lean more towards physics lately, though

vzn

tea, MO site is very intimidating/ challenging but the se chat rooms are usually very open/ friendly. good place to start.

ACuriousMind

@vzn Context is this question

vzn

4:49 PM

"weaker" lol sounds like (mud?) wrestling

KK/ CW wondering if you ever do any "discretionary" stuff with the clusters/ grids, ie personally motivated stuff, speaking of mad scientists/ engineers, have (long had) a ("wild-n-crazy") idea ... :)

Kyle Kanos

I've not used Stampede for personal things, but I've used my University's cluster for personal things

vzn

ok so do tell like what kinda "personal things"... physics? not?

Jim

Physicists are like Unix Administrators. You ask them a question and you get AN answer, but it often is not to the one you asked....

Kyle Kanos

Both physics and not

vzn

what is not physics? games? doom? ;)

bitcoin mining? :p

Kyle Kanos

5:01 PM

Naw, you can't do that on there

(games or bitcoining)

vzn

yeah actually heard story/ legend/ folklore (?) about someone getting in trouble for bitcoining once

Kyle Kanos

Mostly it was testing MPI vs OpenMP

vzn

ok.

Kyle Kanos

It wasn't a physics problem I was doing, but I suppose it's somewhat related

I also tested some Hadoop

ACuriousMind

@vzn smbc-comics.com/?id=2158

vzn

5:02 PM

nice

doom running on MPI vs OpenMP :p

Jim

Oops, ;)

Kyle Kanos

You need graphics cards for those

I don't know that the clusters I use have them...

vzn

hey, just use all those dormant nvidia GPU cards lying around wink

Kyle Kanos

Lol...I can imagine the request I need 3 hours on the node for testing Doom

Jim

I thought bit mining was ~dead at this point, due to increased computation needed. (Compared with hardware and elec. needed.) Some limit was passed about 1-2 years ago.

vzn

5:09 PM

J its an interesting area, just wrote on it. there was a cool NYT article on industrial mining. its industrial scale now/ corporatized. its not dead, its quite alive, its just now out of reach of (aka not profitable for) "mom & pop shops"

alarge

@Jim By this I suppose you mean that people turned to ASICs rather than general purpose machines? Not that I have really followed what's going on in mining, but at least at some point people were into those things.

vzn

yes once GPUs were viable (a "window") but now its all custom/ highly optimized ASICs.

fyi this is an interesting room

mempool

A place to chat about the Bitcoin Stackexchange, Bitcoin in ge...

1

infinitesimal

some sports betting sites are using bitcoin

vzn

yep. it is growing. just heard in bitcoin movie about remarkable site that uses cryptographic protocols to prove fair betting to participants (but it was game gambling in that case). iiuc they moved out US due to "regulatory pressure".

infinitesimal

5:24 PM

The US is shutting down gambling web sites.

vzn

the nature of bitcoin mining is that over time, "emergent equilibrium", it becomes commoditized & everybody doing it, even with great hardware, only makes nickels and dimes so to speak, enough just to pay for the costs.

there was an earlier window where one could seemingly get rich with bitcoin mining, but in retrospect it was more bitcoin ownership early in the game (with rising value).

Jim

5:57 PM

@alarge Last I heard, even the ASIC miners were not cost-effective. The complexity is rising faster than the tech speed ups.

Physics Meta

0

Q: Can this question about ice be re-opened?

Can ice freeze? I think this question is about explaining physical laws and physical chemistry and also related to "Accepted and/or actively researched theories" which are on-topic. I believe I gave enough details also. It was put on hold after a long time and after I got a good answer that I ...

vzn

J there will always be cost effective (but not nec highly profitable) bitcoin systems based on its design. ASIC is the current technology but its industrialized, ie en masse, in clusters/ rackmounted, large datacenters, near cheap energy sources, etc

user54412

@vzn always? Computation is expensive in terms of power, there's no getting around that.

vzn

CW yes... havent yet found paper/ descr on this, but basically its a supply/ demand price equilibrium that gets established. the mining "supply" matches "demand" (transactions). in addition to revenue from mining, there is a per-transaction fee that works somewhat like a ask/ bid spread. basically every miner on the network is competing for transaction volume/ revenue/ fees which pushes transaction overhead down, but also increases mining supply if there is any small )( incremental profit in it.

ie per transaction charges (not fixed, but stable) always pay for the accounting computation.

quick poking around, some (scientific) analysis here Near Zero Bitcoin Transaction Fees Cannot Last Forever / Kerem Kaşkaloğlu. there are interesting parallels to econophysics not yet explored.

alarge

6:19 PM

@vzn I see absolutely nothing related to econophysics here, it's standard economics.

vzn

re our earlier exchange, standard economics has significant physics aspects, a viewpoint not (yet) widely appreciated :)

Jim

I don't see how the technology cost curve (what if electricity suddenly became free?) is necessarily tied to the complexity curve. The value of the bitcoin itself would have to play a role. (Something which it isn't doing very well.) At the end of the day, bitcoiners don't seem to realize the value/power (for good or ill) of monetary policy.

vzn

...relating to "energy" associated w price/ supply/ demand equilibriums etc.

in fact bitcoin increases the energy-money connection more directly (via "computational energy"...)

the value of bitcoin is actually fairly/ increasingly stable last ~½ yr compared to historic levels. compared to other fiat currencies (with maybe even millions of times or more the "market cap" / "user base") ofc it is quite volatile.

alarge

@Jim My understanding is that if nobody mines, there are no transactions. Thus people would start paying transaction fees until mining is again profitable.

user54412

But if transaction costs become high enough, you still give up you bitcoin assets as sunk costs that cannot be recovered

vzn

6:28 PM

"bitcoin assets"? are you talking about mining rigs/ equipment?

alarge that is correct, mining is tied/ coupled to transactions.

user54412

No, the value of bitcoins I own.

Jim

There's a hysteresis lag/issue with whether to commence mining again. New hardware has to be designed and built. Not a quick reacting influence.

user54412

If my bank charges $1,000 for me to withdraw $10 from my account, then I essentially have lost that $10.

vzn

yes. but that is very similar to other commodities eg oil supply/ demand. in fact bitcoin mining is a very fast-reacting commodity supply system because the mining is entirely computational. it may be one of the most fast-reacting commodity supply systems in existence in some senses.

Jim

My ATM charge me $3 to withdraw $3 from it.... ;)

vzn

6:30 PM

BTC transaction charges are negligible now and will be negligible long into the future, basically forever, as long as the currency doesnt eventually crash (which now seems highly unlikely). competition will keep prices down. the bigger issue with bitcoin is volatility due to demand/ supply of the currency which is not really related to mining. its related to user uptake/ acceptance.

Jim

The hardware isn't. You need to have physical hardware. And state of the art stuff too. Anything less is not worthwhile. No one is bitcoining with farms of TRS-80s.

vzn

did anyone notice? banks have massive expensive mainframes. they spend millions on their accounting systems. bitcoin is no different. except that in some ways its superior :)

in bitcoin he efficiency of cost of money moved per transaction is possibly orders of magnitude superior to the existing banking system but for now admittedly thats an apples vs oranges comparison.

alarge

@Jim Suppose you have old mining machines. You turn them off when you don't get profits, which in turn makes transaction costs go up, making mining once again more profitable. New hardware on the other hand give you an edge over the competition allowing you to mine when others have stopped (which eventually drives down transaction costs as everyone acquires the next gen miners).

vzn

note that a major cost of mining is electricity. so turning off machines, you dont pay for electricity. its quite similar to oil sitting in reserves. again, bitcoin mining/ transaction processing is like a commodity (with supply/ demand dynamics, response etc) in this pov.

alarge

@ChrisWhite I think you have the same issues with traditional currency: If dollar depreciated so much that the price of gas to drive to the ATM was more than you could withdraw, you wouldn't do that, either.

Sofia

6:44 PM

This is a letter to everybody. There is an ugly custom to give minuses to people and run away without explaining the reason of the minus. The consequence is that the person that got the minus won't know what was wrong and will repeat the mistake. It especially goes with homeworks solved. Not everybody is aware that it's forbidden to solve such questions completely, and even if people know, they don't know up to which extent it's allowed to help. Please leave explanation about the minuses

Kyle Kanos

> I'm a software engineer with no background in physics...I'm just interested in these kinds of questions because I have many theories, yet little practical math knowledge

Jim

If you don't have state of the art hardware, it makes no sense to bitmine. The complexity rises 10x or so quite quickly. So it's no time at all that old hardware runs at 1% or less compared to new stuff. Even with free electricity, it's not worth it. Just look at all the discontinued models for specialized bit hardware. They are worthless. No one wants them. At any price.

alarge

@Sofia Well the minuses ought to help you judge as to what extent it is permissible to help. People will have different opinions, of course, so some might give a minus while others might not. I usually explain my downvotes, but not always; especially when it should be apparent to all why I did so. Would you also advocate the same policy for upvotes; Why the asymmetry?

Kyle Kanos

sigh those are always the people that do that too

@Sofia I feel zero obligation or compulsion to leave any comment on any post I vote on, up or down

alarge

@Jim Right; That's why you get new hardware if you want to mine. It's not like people let you just take free money. Maybe I missed your point.

vzn

6:50 PM

Jim there was a window when individual hobbyists could profitably mine, but that will never return. remember it fondly. eg like the dotcom bubble. silicon valley bumper sticker: "plz god just one more bubble" :\

this also reminds me of an old yogi berra saying.

> that restaurant is too popular, nobody eats there any more.

Jim

I guess what I am saying/implying is that if you turn off your bitmining hardware, it probably never makes sense to ever turn it on again. Ever.

vzn

did you ever mine? you can use it for doom now :)

large bitcoin operations probably have some offline capacity at times depending on demand, not sure.

Jim

@vzn That was also a Alaska Oil Boom Bumper Sticker. I guess they are printing them in ND now....

David Z

@Sofia of course it's never required to leave a comment to explain your vote. But it is generally considered polite to do so.

Sofia

7:10 PM

@KyleKanos I am a responsible person. I don't hide after leaving a minus. To the contrary, I mention what was the mistake, and if it is corrected, I am glad to remove the minus. To get minus upsets people. Is someone pleased by upsetting people? But I leave this to the conscience and responsibility of everyone.

Kyle Kanos

Leaving it to the conscience and responsibility of everyone, yet demanding, Please leave explanation about the minuses seems rather contradictory.

vzn

sof, re downvoting without comments, sympathize but its at discretion of voters, voters are under no obligation. just part of life on se. try reading some of these povs from a totally different group.

15

Q: About some criticisms against down-votes without explanations

I am worried about the attitude of some people who claim that down-voters must always explain the reason for down-voting or who criticize the users who vote down posts without explanations. (Here is an example of such a criticism.) On the Stack Exchange system, voting is anonymous: users have t...

discussion down-votes

ACuriousMind

Has also been discussed to death on mother meta:

599

Q: Encouraging people to explain downvotes

I used to get "upset" (though that is too strong a term) when I got downvoted without comment. If my answer isn't good enough then I'd like to know why. Not only does it improve the answer for the OP but it improves my knowledge too. Where the down-vote has been explained I've found it useful & ...

feature-request status-completed voting down-votes comments

Kyle Kanos

I also disagree with the notion that it's irresponsible to not comment about your downvote

vzn

the majority opinion is clear across multiple metas. add to those this on Mathematics

Kyle Kanos

7:15 PM

I also believe that anyone who takes a -1 to heart has some growing up to do. The rep is actually quite meaningless. You do not get prizes for having any amount of rep, be it 1 or 1,000,000

vzn

.... years ago se did announce some token prizes to top users (se tshirts), & hoped this program would gain more momentum, but alas that died with their swag store. :( ... did anyone try suggesting reviving this on meta? worth a shot. ("cant get hung for trying"...) they do have a nice program of donating money (tens of thousands of dollars) to charities chosen by mods.

ACuriousMind

@Sofia Note that the downvote text for questions says: "This question does not show any reasearch effort; it is unclear or not useful" I downvote many questions (at least in comparison to the average voter here), not because I like to give -1, but because there simply are many questions that do not show research effort, and that are plainly not useful. These questions do not contain mistakes, so the only comment I could leave would be to repeat the downvote text, which is superfluous.

Sofia

@KyleKanos I am grown up, enough. You cannot know what is in the minds of people. I found other people too that are upset by minuses. Leaving minuses at whim devoides of meaning the minuses and pluses. But, I repeat, nobody can read other people's minds.

Kyle Kanos

Leaving minuses at whim devoides of meaning the minuses and pluses. suggests that there is meaning to reputation when, in reality, there isn't

David Z

@Sofia well what do you mean by "at whim"?

vzn

7:22 PM

@Sofia -1 :p

Sofia

@ACuriousMind to whom you speak? I flag questions that are below the level of this site. Maybe I am even more severe than you. But not this is the issue. Many people are not aware of the rules. They get a minus without knowing what they did wrong, and they will continue to do mistakes. That's the major issue.

vzn

ouch

Sofia

@KyleKanos points give privileges. And people want them.

ACuriousMind

@Sofia I am not talking about questions that are off-topic. (I also run out of close votes nearly every day, but that's a different story) I responded to your plea that people leave comments pointing out what is wrong with the observation that there need not be anything wrong in a question for it to deserve a downvote.

Kyle Kanos

@Sofia Privileges that also do not have any intrinsic value.

innisfree

7:29 PM

@kyle Are there any studies about SE users' attitudes to points? I like the scoring system because a high score indicates that a user might be a trustworthy source of information, but I'm not motivated by earning points.

Sofia

@ACuriousMind Whaaat? It's a law that says that if "you" (i.e. someone) are not pleased with an answer that doesn't mean that the answer is wrong. So, think what you do when you vote.

vzn

"the gamification" / atwood re se rep pt design etc

Kyle Kanos

@innisfree Professional studies or Meta.SE "studies" of it?

innisfree

That said, I wouldn't enjoy the site if other people felt my contributions were worthless or detracted from the site.

Sofia

@KyleKanos we have to do here mostly with students. They see a minus and believe that the answer is wrong. And, by the way, it may be the best of all answers. But the beginners don't have the means to decide. They rely on this site's voting.

ACuriousMind

7:32 PM

@Sofia I really can only repreat the downvote text. If I downvote a question, it means: "This question does not show any research effort; it is unclear or not useful" Nothing more and nothing less.

Kyle Kanos

@innisfree: Thinking more on it, over at SO, rep can matter for those wanting to get into the industry. Having a sizable rep can influence employers into thinking you know what you're talking about

Sofia

@ACuriousMind you argue with me on something on which I agree with you. The problem is not this.

@innisfree : I understand nothing of what you said.

Kyle Kanos

@Sofia That is a more reasonable argument than invoking emotions

If the answer is indeed the correct one, the downvotes will be washed out by the upvotes, in due time

Sofia

@KyleKanos did it happen to you to stay 6 hours with someone for making him understand how to solve an issue that his teachers didn't explain, and for which he found no explanation, nowhere?

@KyleKanos are you aware of teachers teaching wrongly? And people are really confused?

Kyle Kanos

No, I've not spent 6 solid hours helping someone--they probably need someone actually with them if they need that much help.

I am aware of teachers teaching the wrong things

Sofia

7:40 PM

@KyleKanos then ,is it possible not to help? From such things come emotions.

innisfree

That's an interesting link re gamification, though I'm sceptical about the claim that users participate in SE because it resembles a game. My hunch is that regular physics SE users have something in common besides a strong interest in physics; that regular users share some values or beliefs.

Kyle Kanos

And I'm aware that people do get confused

And we do our best to help straighten them

vzn

innis yeah like the link too. se, its gamification + niche topics etc ofc.

Kyle Kanos

@Sofia I cannot say if it's not possible to help someone. But I'm not about to give up my family life to help Random Internet Stranger.

vzn

sof ofc there is a teaching aspect but there is also a "sink or swim" aspect of se. have you heard of that expression?

Sofia

7:43 PM

@KyleKanos I also won't neglect my family for such a situation. But effort, good will, comes with some sense of correctness and hence, emotions.

vzn

se & voting/ rep system is a case of collective intelligence & wrt science, not well/ widely publicized/ understood

Danu

Hi people

Kyle Kanos

I help people on this site because (a) I can, (b) I enjoy it. I have no actual emotional attachment to it.

vzn

but you do have emotional connection to chat right? :p

Danu

I have some emotional connection to my fake internet points!

hi @KyleKanos, @ACuriousMind, @DavidZ and others

Kyle Kanos

7:47 PM

Hi @Danu!

Danu

Yay, a response

Kyle Kanos

@vzn Nope, sorry. You people are nice, but you could be AI, for all I know

Danu

I spend too little time in here right now

ACuriousMind

@Danu You're alive!

Danu

@KyleKanos come on Kyle, you know you love me!

@ACuriousMind alive and kicking

vzn

7:48 PM

← defn an AI :p

Danu

Exams are over, life is good

Sofia

@KyleKanos I also enjoy. But I saw so many revolting stories of what goes in schools, of how irresponsible teachers can be, that I indeed feel the need to repair as my possibilities permit, the situation. I may seem a Don Quichote. I don't care.

Kyle Kanos

@Danu In the sense that I love all mankind, sure. In the sense of familial or something else, no.

Danu

Ugh

vzn

sofia quichote! viva la seniorita

Danu

7:49 PM

Hate you too

Kyle Kanos

Sorry

:D

Sofia

@vzn I am also good at jokes, you stay away from me!

vzn

lol still looking for that :p

seriously, you are quite serious :|

Sofia

@vzn If I'll "bestow" on you some jokes, you'll not be pleased. So, keep distance!

Danu

@ACuriousMind and my physics grades are turning out better than the math ones

Also trying to get into some algebra

started reading Vinberg - A Course in Algebra

vzn

7:52 PM

isnt the pt of jokes to be pleased? :p l8r (& plz feel free to "bestow" anytime) :)

Kyle Kanos

@Sofia I'm also well aware of people who know how to play people. That is, they tell you a sad story to make you feel bad and help them. I don't fall for that stuff.

ACuriousMind

@Danu Algebra is fun :D But, given your complaints about your math lectures so far, I'm not surprised you did better at physics

Sofia

@KyleKanos, @ACuriousMind, @innisfree, and all the other friends, I still believe that this discussion had some effect! And now, I have other things to do. Bye everybody!

Danu

@ACuriousMind working on it :)

Emilio Pisanty

8:10 PM

0

A: Community Promotion Ads - 2015

Danu

lol the physics overflow one at +18/-18 votes is hilarious

Kyle Kanos

@Danu Kinda sad that there are 18 people who think it's worth the upvote :shrug:

Danu

I don't know, I think the site has value.

I personally didn't vote on it

David Z

8:26 PM

Well, the question of whether it has value is not necessarily the same as whether we should promote it

user54412

8

Q: Why are professor's websites so ugly?

I can't help but notice that even in CS, professor's websites are almost always difficult to navigate, poorly-organized, and just generally hard to look at (poorly-tiled backgrounds, inconsistent fonts, etc.). Why is this? Is it expected of academics? I'll be applying to graduate programs in the...

graduate-admissions graduate-school website

2

user54412

Good. Question.

Danu

lol

@DavidZ Yeah, fair enough.

user54412

8:44 PM

Speaking of academia, am I way off-base here?

user54412

We clearly live in different worlds. Every PhD recruiting event I've ever heard of makes sure to leave the prospective students alone with the current grad students for some time precisely because it gives the current students a chance to speak openly about the department. A culture of "thou shalt not say bad things about us" seems repressive, to say the least. — Chris White 2 mins ago

user54412

Are there really departments where professors openly admit to thinking less of students who express their honest opinions about the departments' shortcomings?

Kyle Kanos

Our department leaves prospective students in the care of the grad students

user54412

Same here.

Kyle Kanos

Most prospective students I've talked with already know the faculty (via their own searches) and are interested in the area

I tell them straight up that there is lots of hiking areas within 5 minutes, but if you want commercial things you're going to spend 45 minutes getting to the nearest city

Nearest (useful) airport is Charlotte, about 2 hours away

innisfree

9:06 PM

That is a good question about profs' webpages. So many profs' webpages look like they were designed in the 90s and/or have pictures of them that look like they were taken in the 90s.

Also, they often design them with themselves in mind. e.g. they include pages of links that serve as a their favourites in a web browser.

And they seem to think that web bots crawling the web for internet addresses haven't twigged that name at domain dot com is an email address that should be read as name@domain.com

Kyle Kanos

@DanielSank: I think this is perfect for you ;)

DanielSank

9:50 PM

@KyleKanos It's true. The males become senescent after mating and die. The females guard the eggs in their den for months, cleaning them, blowing fresh water over them, preventing algae build-up, etc. When the eggs are ready (for some species) she blows them out of the den. A group of pedatory fish eat many of them. The ones which aren't eaten produce planktonic octopuses.

As plankton the octopuses grow extremely fast. Once they're large enough they settle to the bottom and become the creatures we're used to seeing.

The females become senescent and die after the eggs are released.

Kyle Kanos

Octopuses have 8 arms. That's like the extent of my octopus knowledge

DanielSank

Dude, they are fascinating. I recently read a great book about their physiology, habits, etc.

They (at least some species) go into cardiac arrest while swimming. They have to stop and breath after a while.

They have three hearts.

Kyle Kanos

Yeah, they just don't seem to entice me any

DanielSank

The blue ringed octopus is so poisonous that a bit can kill an untreated human in minutes.

@KyleKanos: Who "drove" SabreTooth away?

Kyle Kanos

I can think of three people who were at least part of it

But since he's lurking, you could ask him

DanielSank

9:55 PM

IMHO, if people are driving away enthusiastic users, that should be handled in some way. In the very least telling people that their actions are counterproductive and explaining how to improve is usually more useful that semi-silent grumblings.

2

At least, in my case, if I act like an ass I prefer someone point it out so I can improve.

Put another way, if the perpetrator isn't informed nobody has any reason to expect improvement of the situation :)

@SabreTooth: I love you. Come back.

mempool

Transcript for