The h Bar

Captain Bohemian

00:41

Whatever unbelievable thing may happen: a MSc thesis in biotechnology at the Durban University of Technology is transformed into a PhD thesis.

danielunderwood

01:20

@enumaris you got me to look at pytorch and I ended up here...I think I've found my weekend reading material arxiv.org/pdf/1611.08097.pdf

enumaris

02:09

@danielunderwood I typically prefer pytorch

Secret

03:15

0

Q: Why do quantum tunneling consume energy, if not then why it must pay back borrowed energy quickly?

I understand that quantum tunneling is a pure example of the uncertainty principle but clearly transistor had to be powered to work properly, anyhow I like to know if it is true that particle must borrow energy to quantum tunnel then quickly pay it back? I thought this is supposed to be probabili...

gating

Secret

03:37

annualreviews.org/doi/full/10.1146/…

> In other words, the pattern of interactions should define the geometry. If a system has many nonlocal connections, then it could be that no geometrical interpretation is possible.

Sir Cumference

04:29

Argh why do degrees even exist

My calculator was on that mode during my exam

Why the hell am i even supposed to use a calculator for these exams

sigh...

Bernardo Meurer

06:54

@JohnRennie Up yet?

John Rennie

@BernardoMeurer Always :-)

Bernardo Meurer

@JohnRennie Morning!

John Rennie

You're up very late (or very early :-)

Bernardo Meurer

It's not even midnight yet!

I got new headphones :)

John Rennie

@BernardoMeurer ah, of course, you're on the west side. The farthest west I ever got was Minnesota so I tend to think of EST when I think of US time

Bernardo Meurer

06:57

@JohnRennie Minnesota is too cold for me!

John Rennie

@BernardoMeurer I was there in Autumn and the guy I was meeting with said sometimes the temperature doesn't get above zero in winter. I immediately thought: that's not so cold - sometimes it doesn't get above zero in the UK.

Then I realised he meant Fahrenheit :-)

Bernardo Meurer

Then you realized it was F?

Yep, lol

mrspeakers.com/headphones-22/aeon.html

New cans

John Rennie

@BernardoMeurer Cool :-)

Woah! 800 dollars!

Bernardo Meurer

I got'em used :)

John Rennie

But then I'm sure you can spend a lot more than that on headphones :-)

Bernardo Meurer

07:00

Paid half that

Had 40h on them, pretty much brand new

John Rennie

I've run out of things to buy, which is kind of sad really :-)

Bernardo Meurer

Get more audio stuff!

I saw these reaaaaaaally nice amps today

John Rennie

The thing is that I really like the sound of my current hifi. It's the same amp I sent you and I think that amp has a perfect sound for rock/metal.

Bernardo Meurer

I agree

That amp is awesome

I need to fix the volume servo on mine

John Rennie

Likewise the speakers, which are Heybrook HB2s that are older than you are :-)

Bernardo Meurer

07:03

It's not hard to be older than me! :P

What about a nice DAC?

John Rennie

@BernardoMeurer it's not the best amp ever by a long way, but for rock I think it just gets the balance right. You don't want too clean a sound for rock - you want it a bit punchy.

Bernardo Meurer

Black Sabbath on that amp and with my Elac Uni-fi's is baller

The first track from their first album, those storm sounds

Pinned me to the wall :P

John Rennie

@BernardoMeurer my favourite album EVER! :-)

Bernardo Meurer

That album is the bomb

John Rennie

They recorded the whole album in one day!

Bernardo Meurer

07:05

So good

I know! It's nuts!

John Rennie

I think that's part of what makes it so good. They didn't spend months in the studio messing around with it. They just rocked out and got it on tape :-)

Bernardo Meurer

The recording is awesome, and that first track is so damn good

Back when Ozzy wasn't completely nuts :P

John Rennie

@BernardoMeurer I use a Mac Mini as the audio source and the built in DAC is pretty good. I did try a DragonFly (I forget which) but I couldn't hear any difference.

Bernardo Meurer

I just got a Schiit Fulla 2 for my birthday

I like it, tiny dac/amp combo

John Rennie

I've been toying with the idea of getting a wireless DAC of some form since I use the phone for music a lot more now. But it's not on my urgent list.

Bernardo Meurer

07:07

I want to get an amsandsound amp now

All wireless DAC's suck because of aptX, etc

I used to use Plex

So I controlled the playing with my phone

John Rennie

@BernardoMeurer Yes, that's why I haven't done anything about it yet

I use Kodi running on the Mac Mini and a programmable remote

Bernardo Meurer

That's also good :)

Kodi FKA. XBMC, right?

Also I dropped that Dell you gave me while moving the other day

John Rennie

I'm still in theory on the Kodi team though I haven't submitted any pull requests for about a decade. Life just got too busy.

Bernardo Meurer

Now my hardwood floor has a huge dent

Laptop was unscathed

John Rennie

@BernardoMeurer :-)

Bernardo Meurer

07:11

That thing is indestructible

John Rennie

I'd be inclined to retire the laptop and look for something like a Dell 3020m or a Lenovo m93p if you want a compact compute unit.

Bernardo Meurer

I use it as a distcc box and VPS

My daily driver is a ThinkPad P1

John Rennie

In theory they only accept low TDP CPUs, but I'm using one with a i7-4790T and that shows no sign of throttling.

Bernardo Meurer

Which is meh

I've been thinking about getting one of those Intel NUCs

John Rennie

Kind of pricey ...

And I don't think they take the top end CPUs.

Bernardo Meurer

07:14

Yeah, unfortunately

I might just build something myself with a Mini ITX mobo

John Rennie

This sort of thing

Use liquid metal and you could probaby get an i7-4770 to run without throttling.

Bernardo Meurer

Oh yeah, those ThinkCenters are awesome

Liquid metal scares me

It corrodes the PCH

John Rennie

And it's tiny - about the same size as a NUC or Mac Mini

@BernardoMeurer only if it's aluminium

Bernardo Meurer

It does nothing to copper?

John Rennie

Perfectly safe with copper

Though you'll only need it if you're going to go right over the top. An i7-4790T is a 45W CPU and is nearly as fast as a fully blown 4770

Bernardo Meurer

07:18

Hmmmmmm

I want one of those new AMD ones

:P

Have you seen the perf on the Threadrippers and Epyc SKUs?

It's nuts!

And they have like 8000 PCIe lanes

John Rennie

It depends what you need. For distcc I'm not sure the top end AMDs have any special advantage other than sheer horsepower.

Bernardo Meurer

More threads

More success

John Rennie

The big Threadrippers seem to be popular with video applications: rendering and 4K video processing.

Bernardo Meurer

They have so many threads

I want one at work

John Rennie

Yes for distcc you get more files being compiled at the same time. But since you don't need to handle huge amounts of video data I'm not sure the increased PCI bandwidth is much of an issue.

Bernardo Meurer

07:22

I do at work!

John Rennie

Are Threadrippers that expensive?

Bernardo Meurer

I work with 4K streams for AI

No, but Epycs are

John Rennie

Ah OK :-)

Bernardo Meurer

Still cheaper than Xeons

:P

John Rennie

Vision processing?

Bernardo Meurer

07:23

Yeah, I do a lot of data preparation

I'm giving a talk in Italy in June about some of it :)

rustlab.it

John Rennie

Cool :-) I spent a month in Italy when I was PhD student and really loved it. Mind you Italy has probably changed in the four decades since then :-)

Anyhow. I need to get back to work.

Bernardo Meurer

And I to sleep!

Catch you later John!

John Rennie

Bye :-)

Tapi

@JohnRennie When will you be back, Sir?

John Rennie

08:21

@Tapi I'm back now ...

Tapi

Can you explain that capacitor problem?

John Rennie

@Tapi let's move to the problem solving room

Novalium Company

08:44

An entangled pair of photons means that both of their wavefunctions will collapse to the same polarization angle when one of them is measured?

Secret

09:39

annualreviews.org/doi/full/10.1146/…

While the idea on how spacetime is basically weaved by how information are correlated between quantum states forming an intricate network is good, there's always one thing that really bugs me about it:

If gravity is none other than the mutual information and entropy shared by a network of entangled states, then given how complex we expect the network to be in general, why we seemed to fail to perturb at least part of this network in a small region as every interaction at atomic levels should be constantly performing joint measurements on parts of the network

and that should be visible as a varying strength or other properties of gravity in that region

Unless, said perturbation is already done in the form described by the Einstein field equation, meaning that the stress energy tensor and the curvature tensor is really the classical limit of all these quantum interactions and measurements at subsets of this underlying network

The idea that entanglement makes spacetime to emerge from it also seemed to suggest it has close relationship with the entropic gravity models

7

Q: Since pretty much everything is decohered, why we can even made superpositions in the lab at all?

We knew that one reason why most quantum mechanical experiments have to be done in a low temperature and isolated from environment condition is to preserve the coherence required for quantum states to be in superposition and entanglement, as the environment, via einselection, will entangle some o...

quantum-mechanics thermodynamics superposition

Meanwhile, the answer to this question suggests we can actually do little to the already existing tensor networks where gravity is emerged from, and all we can do is to set up boundary conditions so that the solutions set up another tensor network to simulate gravity on top of it

And finally, as the very end of that article suggests, there seemed to be more than just entropy to explain spacetime

user351417

14:15

@EmilioPisanty Hehe was there a bit of a mix-up with the leftmost pair of columns in meta.stackexchange.com/a/307973?

Emilio Pisanty

14:35

@Rishi I have no idea

I just cut and pasted from a whole lot of sprite sheets

I don't have any of them around any more, and it's unlikely that they still exist publicly

You're right that the leftmost column has inconsistent button placement

Akash. B

hi

Emilio Pisanty

It's entirely possible that the sprite sheet for that site, whichever it was, was ordered differently than the rest

This isn't necessarily a problem - it would've been matched by a corresponding change in how the html positions and crops the sprite to make the buttons

But it's also possible that I caused it on my end

No idea

But do look into how sprite sheets work

They're a fascinating piece of black magic

If you want a structured challenge - see if you can use your browser's dev tools (ctrl shift I on chrome) to find the graphics asset that creates the upvote button on the site

Akash. B

@JohnRennie you there?

Novalium Company

Is everything we taste just the product of the 5 tongue senses and the texture of the food?

Akash. B

14:51

hmm

ACuriousMind

15:05

@NovaliumCompany No, a lot of "taste" also comes from aromatic compounds that we perceive with the nose rather than the tongue. It's why some stuff suddenly tastes bland if you have a cold

Semiclassical

Also, the notion of there being a correspondence between regions of the tongue and different tastes is BS

Akash. B

is this physics room?

Semiclassical

room description seems to say so

Akash. B

can we reach on the other side of earth if we drill a hole through its centre?

ACuriousMind

...where else could you end up?

Akash. B

15:11

@ACuriousMind it would be the fastest means of transport

ha ha

Semiclassical

if

Akash. B

@Semiclassical but the chat does not seems to say so

Scáthach

Maybe aliens hid teleporters for themselves and we go to their planet

Akash. B

@Scáthach ?

Scáthach

I am jk. Ignore mexD

Semiclassical

15:13

@Akash.B how bizarre, that people occasionally talk about subjects other than physics

ACuriousMind

@Akash.B You would probably run into problems such as your vehicles getting incinerated by the molten core :P

Akash. B

@Scáthach too much imagination

@Semiclassical no matter just said

@ACuriousMind It recurs me about a scene in a movie

Semiclassical

The Core?

Loong

Well to Hell hoax

The "Well to Hell" is an urban legend regarding a putative borehole in Russia which was purportedly drilled so deep that it broke through into Hell. This urban legend has been circulating on the Internet since at least 1995. It is first attested in English as a 1989 broadcast by a U.S. domestic religion-based TV broadcaster, Trinity Broadcasting Network. == Legend and basis == The legend holds that a team of Russian engineers purportedly led by an individual named "Mr. Azakov" in an unnamed place in Siberia had drilled a hole that was 14.4 kilometres (8.9 mi) deep before breaking through ...

Akash. B

@ACuriousMind when a train coming at tremendous speed hits a fuel truck, the fuel trucks explodes leaving the train harmless

is it possible

Semiclassical

15:17

tbf, the Darvasa gas crater looks like a gate to hell: en.wikipedia.org/wiki/Darvaza_gas_crater#/media/…

ACuriousMind

@Akash.B why're you asking me?

Akash. B

@ACuriousMind yeah

Loong

@Akash.B but when a train coming at tremendous speed hits a nuclear waste container, the train explodes leaving the container harmless

Spectacular 100mph Train Crash

►

Akash. B

@Loong ?

Chris

@Akash.B Unless you can go thousands of kilometers an hour through the molten core, it's still going to be slower than taking a rocket around the long way. ;)

Akash. B

15:22

@Chris hmm

@ACuriousMind what can't i ask you?

ACuriousMind

@Akash.B I was just wondering why you pinged me specifically with that question

Akash. B

@ACuriousMind no such intentions as you think

ACuriousMind

In that case, please don't randomly ping people.

Akash. B

@ACuriousMind okay

then how can i grab the attention of the people

ACuriousMind

You...don't? If people find whatever you post interesting enough to engage with, they will do so on their own

5

@Semiclassical "it is thought to have been burning continuously since 1971" Yeah, sounds like a gate to hell alright

John Rennie

15:50

@Akash.B you're welcome to ping me, but in general pinging people just to ask them a question is viewed as a bit rude. Just ask the question, and if people want to answer it they will.

Novalium Company

16:49

What will happen if I put plasma lighter under water?

Also plasma is just ionized air that conducts electricity and shoots photons. (have a lot of energy)?

vzn

17:50

@CaptainBohemian interesting/ remarkable/ very rare & relevant to the academic pov of this room. reminds me somewhat of (also rare) "honorary phds"... it would be interesting to see a list of those....

Physics Meta

21:52

2

Q: What are the rules of chat when it is used to extend a discussion initiated with comments?

When there are too many comments in a question, I am offered to move things to chat. That makes perfect sense, or at least I guess it does. Anyway, after I accepted the automatic suggestion to create a chat based on the comments, I have recently been accused of making people wait for too long (t...

support

Bernardo Meurer

22:35

@JohnRennie Got the headphones

They are awesome :)

Jake Rose

23:20

I’m always surprised when I come in here and see some random person asking a billion questions, never waiting to discuss an answer to it before blasting off to the next one. Then once everybody stops engaging with said person because of how the discussions play out, they get really annoyed that nobody will answer there questions.

strange world we live in.

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