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My diabolical scheme for Quantum Immortality

by physics.x2010
Tags: quantum mechanics, schrodinger cat
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physics.x2010
#1
Mar6-12, 02:04 PM
P: 6
Hello all!!

This is my first post here. I must have been living in a cave to not be here earlier, but such is life. Anyhoo, onwards!!

I place myself inside a large Schrodinger's Box and launch myself into space, immediately after which the whole of earth is wiped out in a freak accident. If there is no one around to observe the collapse of my wave function, does this mean I will be (theoretically) immortal? Or at least both dead and alive simultaneously ? At least till intelligent life elsewhere in the universe is aware of my presence???

I am basing this off my (limited) understanding of the Copenhagen Interpretation of QM and Counsciousness -caused- collapse.

Thanks in advance!
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StevieTNZ
#2
Mar6-12, 02:06 PM
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What exactly is with all these new people joining within days of each other, and posting these kind of questions (references to the teleportation thread yesterday)?
physics.x2010
#3
Mar6-12, 02:26 PM
P: 6
Quote Quote by StevieTNZ View Post
What exactly is with all these new people joining within days of each other, and posting these kind of questions (references to the teleportation thread yesterday)?

I am a lone wolf, I assure you. Or we are all from the future here to warn you about Skynet.

Stupid jokes aside, I really believe I have a fair question. Renninger negative-result experiment tells us that we dont need 'detection', as long as we have an 'observation'. If by 'observation' consciousness is implied, then is my question not reasonable? (within the realm of QM anyways)

Thanks!

The_Duck
#4
Mar6-12, 02:47 PM
P: 843
My diabolical scheme for Quantum Immortality

Consciousness has nothing to do with wave-function collapse, regardless of the misleading connotations of the term "observation." The universe functioned identically to how it currently does long before humanity evolved.
Mukilab
#5
Mar6-12, 02:57 PM
P: 73
Quote Quote by The_Duck View Post
Consciousness has nothing to do with wave-function collapse, regardless of the misleading connotations of the term "observation." The universe functioned identically to how it currently does long before humanity evolved.
So what does it mean by observation? Interacted with?
lugita15
#6
Mar6-12, 03:04 PM
P: 1,583
Quote Quote by physics.x2010 View Post
Stupid jokes aside, I really believe I have a fair question. Renninger negative-result experiment tells us that we dont need 'detection', as long as we have an 'observation'. If by 'observation' consciousness is implied, then is my question not reasonable? (within the realm of QM anyways)
Look at this book (page 161) to see how Renninger negative-result experiments can be explained without reference to conscious observation.
StevieTNZ
#7
Mar6-12, 03:27 PM
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Quote Quote by lugita15 View Post
Look at this book (page 161) to see how Renninger negative-result experiments can be explained without reference to conscious observation.
I fail to see how that is the case. How do we know no collapse has occurred prior to knowing what the spin is?
lugita15
#8
Mar6-12, 03:31 PM
P: 1,583
Quote Quote by StevieTNZ View Post
I fail to see how that is the case. How do we know no collapse has occurred prior to knowing what the spin is?
I wasn't saying that a consciousness-causes-collapse explanation is ruled out. But people often assume that unlike other phenomena in quantum mechanics, the Renninger negative-result experiment cannot be explained without conscious observation. I was just pointing out that even Renninger experiments can be explained via decoherence.
StevieTNZ
#9
Mar6-12, 03:37 PM
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Quote Quote by lugita15 View Post
I wasn't saying that a consciousness-causes-collapse explanation is ruled out. But people often assume that unlike other phenomena in quantum mechanics, the Renninger negative-result experiment cannot be explained without conscious observation. I was just pointing out that even Renninger experiments can be explained via decoherence.
I don't see any explanation of decoherence in that experiment on page 161.
lugita15
#10
Mar6-12, 03:52 PM
P: 1,583
Quote Quote by StevieTNZ View Post
I don't see any explanation of decoherence in that experiment on page 161.
Quoting from the text:
An x-polarized particle leads to an entangled state... Because the detector states are orthogonal, we find an apparent collapse of the spin states (provided the detector states are macroscopic).
In other words, for a Renninger negative result the particle still gets entangled with the detector, and then we can explain the appearance of wavefunction collapse in the usual decoherence way.
physics.x2010
#11
Mar6-12, 04:30 PM
P: 6
Quote Quote by lugita15 View Post
Quoting from the text: In other words, for a Renninger negative result the particle still gets entangled with the detector, and then we can explain the appearance of wavefunction collapse in the usual decoherence way.
Thanks.

So essentially, consciousness is not really necessary for wave function to collapse? Nice. That clears up a few cobwebs in my brain.

So what would constitute an 'observation' in my case?
StevieTNZ
#12
Mar6-12, 04:36 PM
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Quote Quote by physics.x2010 View Post
Thanks.

So essentially, consciousness is not really necessary for wave function to collapse? Nice. That clears up a few cobwebs in my brain.

So what would constitute an 'observation' in my case?
Ah I see. decoherence as in with the apparatus, not environment (I associate decoherence with interaction with environment).

Yes, that is an explanation, but part of many that try to solve the measurement problem. Of course, if the macroscopic object is quantum mechanical, then you have issues. If you modify the Schrodinger equation, you don't generally have an issue (except it doesn't get completely localised into one definite state - as far as I've read).
lugita15
#13
Mar6-12, 04:43 PM
P: 1,583
Quote Quote by physics.x2010 View Post
Thanks.

So essentially, consciousness is not really necessary for wave function to collapse? Nice. That clears up a few cobwebs in my brain.

So what would constitute an 'observation' in my case?
Decoherence is about how when you have large numbers of particles interating, so that the interference effects becomes smeared out and you get the appearance of wavefunction collapse. But decoherence does not explain genuine wavefunction collapse if such a thing exists.
lugita15
#14
Mar6-12, 04:48 PM
P: 1,583
Quote Quote by StevieTNZ View Post
Ah I see. decoherence as in with the apparatus, not environment (I associate decoherence with interaction with environment).
We are talking about decoherence with the environment. The whole reason why the pointer basis of the detector arises is because of environmental decoherence. See here for an explanation of the pointer basis.
lugita15
#15
Mar6-12, 05:12 PM
P: 1,583
physics.x2010, here's a post of mine from another thread that you might find interesting:
Quote Quote by lugita15 View Post
The reason there is still disagreement as to what constitutes measurement is that it makes no experimental difference according to quantum mechanics. The way QM works under the Copenhagen interpretation is that you have to split the world into two parts, the “observer” or measurement device, and the “observed” or the particles you’re measuring.

The measurement device is assumed to behave classically. The particles in the observed system are in a superposition of states described by the wave function which keeps evolving until it interacts with the classical measurement device. The question is where to draw the line. You could consider a photon to be the observed system and an atom to be the measuring device, but you can also consider the photon-and-atom system as in a superposition of states, and take a Geiger counter to be the measurement device. So there is this von-Neumann chain, going from elementary particles to Geiger counters to human beings, and we have to decide where to cut it off.

Von Neumann proved in his famous "Bible" of QM that regardless of where you cut the chain, you would get the same experimental results. But he argued that wherever you cut the chain you have things made out of particles on each side of the cut, so there’s no principled way to place the cut in the middle. So he decided that you should place the cut between the human mind and the human body, because he believed that the mind is non-physical. Hence "consciousness causes collapse" was born. Nowadays, the most popular view is decoherence, where there is no real collapse, it's just that when you have a large number of particles in the environment interacting with the system, the wave function becomes smeared out and looks like it has collapsed. So decoherence gives us a reasonable place to cut the chain, when the number of particles involved reaches a critical number so that interference effect become negligible.
DaveC426913
#16
Mar6-12, 05:41 PM
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Quote Quote by physics.x2010 View Post
If there is no one around to observe the collapse of my wave function, does this mean I will be (theoretically) immortal?
While you may or may not be both dead and alive simultaneously, in the "alive" box your life will continue as normal and, optimistically, you will die of old age.

After 100 years, you will be dead in both boxes. One wavefunction will represent a guy who's been dead a few years and one will represent a guy who's been dead for many decades.

Sorry to disappoint.
questionpost
#17
Mar6-12, 09:04 PM
P: 198
All the molecules in your body are constantly being measured or interacted with by each other and random forces, and I also don't think you understand these wave mechanics. Debroglie only proposed the Cat-in-a-box thing because he demonstrated that that was NOT how quantum mechanics works on the macroscopic scale. Your body doesn't have a single wave function because it's not a single particle, it's many small particles whos probability density is practically 0 at visible distances and the phenomena of superposition is not to state multiple realities are happening at once, but that the location is undefined or does not exist at a specific localized point, much like a classical wave. Your cells will age, and that's about it, chances are your going to die, though you'll probably run out of fuel and freeze or run out of O2 before you die of old age.
physics.x2010
#18
Mar7-12, 03:14 AM
P: 6
Thank you for your response everyone !!

I was having problems trying to resolve QM in the macroscopic scale. It is nice to be here, and hopefully I will learn enough, soon enough to help contribute to fruitful discussions soon.

Thanks !!


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