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Roamer
Post  Post subject: Relativity & Schrödinger's Clock  |  Posted: Sun Jul 09, 2017 6:53 pm

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Pay particular attention to the alien example between 5:30 to 8:00.

Schrödinger's Clock Experiment:
Consists of a box containing box containing:
1) A microscopic clock reading (DD/MM/YYYY). This clock has a battery that can power it for thousands of years.
2) A microscopic Geiger counter.
3) A single nickel-63 atom. Wiki says nickel-63 has a half life of 100.1 years.
When the Geiger counter detects radioactivity from the Uranium-233 atom, it stops the clock.
"Dead" means the clock has stopped ticking, "Alive" means the clock is still ticking.

Tom is on Earth.
NRF : Now Reference Frame

(NRF=Alien, t=0-1) : 2 year old Tom sets up the Schrödinger's clock experiment, with the microscopic clock reading 01/01/2000.
(NRF=Alien, t=1) : The alien starts riding his bike toward earth.
(NRF=Alien, t=1.5-2) : 90 year old Tom opens the box and reads 01/01/2014 on the microscopic Clock.
(NRF=Alien, t=2) : The alien starts riding his bike away from earth.
(NRF=Alien, t=2.5-3) : 2 year old Tom is sealing a Schrödinger's clock reading 01/01/2000 into a box.
(NRF=Alien, t=3) : The alien sets his bike to move toward the earth.
(NRF=Alien, t=3.5-4) : 90 year old Tom opens the box and reads 01/01/2014 on the microscopic Clock.

Question on determinism:
Since 90 year old Tom reads 01/01/2014 on the Schrödinger's Clock when (NRF=Alien, t=2.5-3), will 01/01/2014 surely be the value Tom reads on the Schrödinger's clock when (NRF=Alien, t=3.5-4?) Why or why not?

If the answer to the previous question is yes, proceed below,

Question on wave function collapse:
(NRF=Tom, t=01/01/2060) Does it mean that the microscopic clock is in fact dead, not "simultaneously dead and alive", even though the box hasn't been opened yet?


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Olinguito
Post  Post subject:   |  Posted: Sun Jul 09, 2017 11:24 pm
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The assumption (not explicitly stated in the video) is that the motion between the alien and Tom is unaccelerated. That is, if the alien keeps moving away from Earth or keeps moving towards Earth without changing direction, then he will see the scenarios described. Changing direction involves acceleration, which will break the symmetry. See twin paradox.

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Roamer
Post  Post subject: Re: Relativity & Schrödinger's Clock  |  Posted: Mon Jul 10, 2017 8:38 am

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If I were an alien living in the Andromeda galaxy, and I knew that light needs time to travel, I would take into account the time light took to travel, and I would consider the Earth 2.5 million years older than the light I see.

The video mentioned the word consider several times when talking about what happens now.
What does the video mean by consider?
A) As in two instances of physical events took place sequentially, but the alien is uneducated and thinks that light travels instantaneously, and concludes that the event that produced the light it is seeing is from a physical event that is taking place during the alien's now?
B) As in two instances of physical events are taking place simultaneously, irrespective of whether light has reached the alien?

At first I thought that the video is talking about the consider described in B).
But then you said:
Olinguito wrote:
then he will see the scenarios described.

Do you mean the consider in the video is A)?


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Olinguito
Post  Post subject: Re: Relativity & Schrödinger's Clock  |  Posted: Mon Jul 10, 2017 4:43 pm
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Roamer wrote:
A) As in two instances of physical events took place sequentially, but the alien is uneducated and thinks that light travels instantaneously, and concludes that the event that produced the light it is seeing is from a physical event that is taking place during the alien's now?
The laws of physics hold regardless of the alien's opinion or level of intelligence: they are true whether the alien is educated or not.

Roamer wrote:
B) As in two instances of physical events are taking place simultaneously, irrespective of whether light has reached the alien?
Depends on the alien's frame of reference relative to yours. Information cannot travel faster that the speed of light. Two events perceived by one observer to be simultaneous may not be so to another observer that is in motion relative to the first observer.

Roamer wrote:
At first I thought that the video is talking about the consider described in B).
But then you said:
Olinguito wrote:
then he will see the scenarios described.

Do you mean the consider in the video is A)?

https://www.collinsdictionary.com/dicti ... h/consider

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Roamer
Post  Post subject: Re: Relativity & Schrödinger's Clock  |  Posted: Tue Jul 11, 2017 11:35 pm

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I've been doing some reading on the double slit experiment, and am wondering what constitutes observation.

But first I want to know what kind of counter is used.
The particle counter wiki page page doesn't tell me exactly what counter is used for the double slit experiment.

However, in some cases it is possible to detect photons without destroying them. Usually one uses some resonator, for example some cavity, in which photons go back and forth and prepare some atom in a very well defined spin state. Now the atom falls through the cavity perpendicular to the photons moving back and forth and the spin state of the atom after leaving the cavity will depend on the number of photons because the spin precession will be a bit faster in presence of photons. If you do this several times, you will get a nondestructive photon number measurement. However, these are so called weak measurements, so this means you do not change the photon states if you are in a photon number eigenstate already. The first measurement however might change the photon state from some undefined state to a photon number eigenstate.

What's the name of this resonator device?

What other methods can be used to detect single photons?


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Roamer
Post  Post subject: Re: Relativity & Schrödinger's Clock  |  Posted: Sat Jul 15, 2017 12:14 pm

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Let's say Harry is your best friend.
You two agree to do a coin toss in exactly 12 hours.
Harry agrees to pay you a dollar if you correctly predict the coin toss result.
You agree to pay Harry a dollar if you incorrectly predict the coin toss result.

I've create a device that (I think) can ensure that you will know the coin flip result with certainty:
Image

You immediately turn on the laser.
12 hours after the coin flip, the delay is over, and you receive the photons.
If it comes out as heads:
Place mirrors at j and k, so that it gets detected, and not erased by the quantum eraser.
The wave function collapsed, causing two blocks to appear on the interference screen 24 hours ago.

If it comes out as tails:
Don't place mirrors at j or k, leaving the quantum eraser to erase the information.
The wave function did not collapse, causing an interference pattern to appear on the interference screen 24 hours ago.

When you switch on the laser and see an interference pattern, the coin toss will turn out tails.
But, if you see two blocks appear, the coin toss will turn out heads.
You have information necessary to win the bet.

Will this experiment work?
If no, am I missing something?

P.S. Delay the beam for 24 hours by finding a way perfectly bounce it to-and-fro thousands of times between two very distant mirrors.
P.S. The thing behind that double slit is a beam slitter that splits 1 photon into 2 entangled photons.


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Roamer
Post  Post subject: Re: Relativity & Schrödinger's Clock  |  Posted: Sat Jul 15, 2017 5:32 pm

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Roamer wrote:
P.S. The thing behind that double slit is a beam slitter that splits 1 photon into 2 entangled photons.

Disambiguation: P.S. The thing behind that double slit is a Barium Borate crystal that splits 1 photon into 2 entangled photons.

Sorry for the ambiguous wording... beam splitter might mean silvered mirrors.


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Roamer
Post  Post subject: Re: Relativity & Schrödinger's Clock  |  Posted: Sun Jul 16, 2017 6:05 pm

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I'm trying to understand what counts as obscuration.

From what I know, the wave function will only collapse if which-way is known with absolute certainty.
From what I've seen, all descriptions of quantum erasers uses half silvered mirrors. Ones which has the 50% probability to reflect a photon.
But what if the mirror wasn't half (50%) silvered?

If the mirror was x% silvered, it has a (1-x)% probability of allowing photons through.
x can only be between 0 and 100.
If x is not 0 and not 100, which-way information is obscured, and the superposition of states is preserved, as the set-up does not "know" with absolute certainty which slit the particle passed through.

x could be 50.1 or 60 or 75, or even up to 99.999999999999999.
Perform the experiment many times, starting with x=51, incrementing x by 1 each time, till x=99.
Record the interference screen results each time.
Compare these results.
Would one observe a gradual change?

Using a 99.999999999999999% silvered mirror:
    Collapses the wave function. True/False?
    Obscures which-way information. True/False?
    Will produce the same results as using a 100% silvered mirror. True/False?

Does an in-between "particle pattern" and "inference pattern" make sense in quantum mechanics?
Does an in-between "information is known with absolute certainty" and "information is not known with absolute certainty" make sense at all?


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