/sci/ - Science & Math

[Anonymous No.1821004]

>myfacewhen relativity is wrong

[Anonymous No.1821009]

Sooner or later these trolls will have elevated themselves to posting pics about theories that are worth arguing about. I hope.

[Anonymous No.1821010]

>>1821004
too complicated, couldn't you just use a magnet?

[Anonymous No.1821015]

agreeed. however, there's still the matter of getting the information over to the other person faster than the speed of light.

[Anonymous No.1821021]

>>1821009
The next logical step is to post real physics.

[Anonymous No.1821027]

>>1821015
That doesn't matter, the point is that information at another point in space is CONTAINED within the event at one of the slits.

[Anonymous No.1821043]

Welcome to more than 50 years ago?

[Anonymous No.1821046]

The two photons are caused by the same event and as the photons are related to each other they both carry the same 'information' about the event. Therefore you know the outcome of the event at the speed of light.

[Anonymous No.1821053]

You're assuming that both photons still exist when one is measured, but the other one could have undergone any number of interactions. On an instantaneous quantum level, you can't have a real vacuum.

[Anonymous No.1821054]

>>1821021
Didn't I just say that?

[Anonymous No.1821057]

HAY OP IM HOLDING A HOTDOG IN MY HAND.

THAT IS ONE BIT OF INFORMATION I KNOW

HOWEVER, BECAUSE THE HOTDOG IS IN MY HAND, THAT MEANS IT CANNOT ALSO BE IN THE HAND OF ALIENS LIVING IN ALPHA CENTURI

BUT WAIT....THAT SECOND BIT OF INFORMATION REGARDING WHAT THE ALIENS IN ALPHA CENTURI ARE NOT HOLDING GOT TO ME INSTANTLY AS AN ENTAILMENT OF THE FIRST BIT OF INFORMATION. THAT MEANS I GOT INFORMATION FIFTY BILLION TIMES FASTER THAN THE SPEED OF LIGHT.

HI FIVE WE BOTH PROVED RELATIVITY FALSE FUCK YEA LETS HAVE A BLOWJOB PARTY

[Anonymous No.1821065]

>>1821057

supersymmetry

[Anonymous No.1821072]

I don't know why people use this quantum example to illustrate this fallacy.

Two people each decide to pick a secret number that only they know, person A picks 1 and person B, 0. Only they know what the other has, but another person (C) knows that between them they have 0 and 1.

A and B move to opposite sides of the world, C follows A and tortures him, finding out he has the number 1 and INSTANTANEOUSLY knows B must have 0.

Shame no information is transmitted this way and relativity doesn't give a shit.

[Anonymous No.1821075]

>>1821072
It has to do with what people actually mean by "information." That's why you can't use that example.

[Anonymous No.1821077]

>>1821075
No it's exactly the same, no information is transmitted in this example or in quantum entanglement.

[Anonymous No.1821084]

What now sciencefags?

[Anonymous No.1821105]

that information was carried in photon 1, not in photon 2. so actually you gained information at the speed of light. not faster.

[Anonymous No.1821124]

There's a /sci/ FAQ going around somewhere, but for some reason quantum entanglement / FTL information transfer isn't mentioned on it.

There's a couple of posts ITT alluding verbally to why no information is transferred (let alone instantaneously transferred), but here's a proof for the mathematically inclined:

Suppose Herp and Derp share a mixed quantum state: <div class="math"> \rho_{HD} = \sum_{i,j} p_{i,j} | \psi_i^H \rangle \otimes | \phi_j^D \rangle </div>
Now suppose Herp performs some kind of derpy operation on his system, using the measurement operators <span class="math"> M_i[/spoiler] where <span class="math">\sum_i M_i = I[/spoiler]

Can Herp influence Derp's system, sending him information without interacting with him?
Let's have a look shall we?

The state of Derp's system after Herp's measurement is given by the durptastic

<div class="math"> \rho_D^{\times} = tr_H \left( \sum_k ( M_k \otimes I) \rho_{HD} ( M_k^{\dagger} \otimes I ) \right) </div>

<div class="math"> = tr_H \left( \sum_{i,j,k} p_{i,j} M_k | \psi_i^H \rangle M_k^{\dagger} \otimes | \phi_j^D \rangle \right) </div>
<div class="math"> = tr \left( p_{i,j} M_k | \psi_i^H \rangle M_k^{\dagger} \right) </div>
<div class="math"> = \sum_i tr_H \left( ( M_i \otimes I ) \rho_{HD} (M_i^{\dagger} \otimes I ) \right) </div>
<div class="math"> =\sum_i tr_H \left( ( M_i M_i^{\dagger} \otimes I ) \rho_{HD} \right) </div>
<div class="math"> = tr_H (\rho_{HD} ) </div>
<div class="math"> = \rho_D </div>


See that? Derp's derpy state stays exactly as it was before herp does their herpy measurement. Therefore NO information is transferred, let alone instantaneously / FTL. The only way to actually transfer INFORMATION would be by using a clasical information channel.

inb4 latex erros, latex errors everywhere

[Anonymous No.1821127]

There's a /sci/ FAQ going around somewhere, but for some reason quantum entanglement / FTL information transfer isn't mentioned on it.

There's a couple of posts ITT alluding verbally to why no information is transferred (let alone instantaneously transferred), but here's a proof for the mathematically inclined:

Suppose Herp and Derp share a mixed quantum state: <div class="math"> \rho_{HD} = \sum_{i,j} p_{i,j} | \psi_i^H \rangle \otimes | \phi_j^D \rangle </div>
Now suppose Herp performs some kind of derpy operation on his system, using the measurement operators <span class="math"> M_i[/spoiler] where <span class="math">\sum_i M_i = I[/spoiler]

Can Herp influence Derp's system, sending him information without interacting with him?
Let's have a look shall we?

The state of Derp's system after Herp's measurement is given by the durptastic

<div class="math"> \rho_D^{\times} = tr_H \left( \sum_k ( M_k \otimes I) \rho_{HD} ( M_k^{\dagger} \otimes I ) \right) </div>

<div class="math"> = tr_H \left( \sum_{i,j,k} p_{i,j} M_k | \psi_i^H \rangle M_k^{\dagger} \otimes | \phi_j^D \rangle \right) </div>
<div class="math"> = tr \left( p_{i,j} M_k | \psi_i^H \rangle M_k^{\dagger} \right) </div>
<div class="math"> = \sum_i tr_H \left( ( M_i \otimes I ) \rho_{HD} (M_i^{\dagger} \otimes I ) \right) </div>
<div class="math"> =\sum_i tr_H \left( ( M_i M_i^{\dagger} \otimes I ) \rho_{HD} \right) </div>
<div class="math"> = tr_H (\rho_{HD} ) </div>
<div class="math"> = \rho_D </div>


See that? Derp's derpy state stays exactly as it was before herp does their herpy measurement. Therefore NO information is transferred, let alone instantaneously / FTL. The only way to actually transfer INFORMATION would be by using a clasical information channel.

inb4 latex erros, latex errors everywhere

[Adrian !wf/oOO.fjg No.1821157]

>>1821127
to bad the only people who will understand that already know that no information is transferred.

[Anonymous No.1821159]

>>1821157
You're probably right.
Although anyone who done a pure mathematics degree and done lots of delicious linear algebra/functional analysis will understand it mathematically but not necessarily know of it as a physical interpretation.

[Anonymous No.1821178]

>>1821127
cool, thanks. I've seen similar arguments before and thus falls in the category of people who already knew about info-transfer, but this derivation is nice and derpy.

[Anonymous No.1821235]

This is the EPR paradox, the point of it is was the wavefunction of two entangled particles can collapse across the universe instantly, so it's sort of like a magical signal is being sent faster than light, but it still isn't possible to send information using this.

[Anonymous No.1821239]

>>1821127
>implying any of the mouth-breathers who dwell /sci/ will understand this

[Josef !!nUf2NflSAyw No.1821242]

quantum entanglement in herpderp language, awesome ;)

[Anonymous No.1821244]

>>1821239
>implying the person who posted it doesn't understand it

[Anonymous No.1821247]

This shit is like saying "HURR I HAVE TWO BOXES, I'LL PUT A STONE IN ONE AND LEAVE THE OTHER ONE EMPTY; I'LL GET THEM ONE LIGHT-YEAR APART, AND WHEN I OPEN ONE, I KNOW WHAT'S IN THE OTHER, DURR"

[Anonymous No.1821342]

>>1821127
shiiit nigga that is some tight QM.
I only got a masters degree so at first I was like herp, and then i derped.
I wanna get it though man...
What read?

[Anonymous No.1821355]

>>1821342
What's your masters in? If it's mathematics then I recommend

Introduction to Quantum Theory - Keith Hannabuss

http://www.amazon.co.uk/Introduction-Quantum-Theory-Graduate-Mathematics/dp/0198537948

It's a good mathematical approach that doesn't forget its physics, doesn't actually go into quantum information stuff, but gives you all the tools you'd need to understand that proof above.

This is pretty decent too:

http://www.amazon.co.uk/Quantum-Computer-Science-David-Mermin/dp/0521876583/ref=sr_1_1?s=books&i
e=UTF8&qid=1285775738&sr=1-1

[Anonymous No.1821362]

>>1821247
Yes, but as a means of randomly selecting an option it has some nice properties. Like no possibility of eavesdropping. Given n entangled particles we can select among <span class="math">2^n[/spoiler] possibilities without anyone knowing in advance which will be selected.

[Anonymous No.1821412]

>>1821355
maths/physics but I don't use the physics at all these days - seems like a shame. Thanks for the book recommendation man, I'll pick up the Hannabuss one some time.

[Anonymous No.1821448]

[Anonymous No.1821453]

[Anonymous No.1821457]

[Anonymous No.1822916]

[Anonymous No.1822936]

But there are things faster than light anyway?

Cherenkov radiation is created because of this

[Anonymous No.1822950]

>>1821448
That could actually work.

[Anonymous No.1822951]

>>1822936
Faster than speed of light IN A MEDIUM. Not actually faster than light.

captcha: klitcam much?