What if....(Many worlds)
What if the "many worlds" concept is somehow proved to be true. (Before i go any further i should explain that i have zero scientific education. To be honest, i never finished high school, so forgive me if my ideas are naive). If that theory could be established as a fact what would it say about our concept of reality, in particular our viewpoints on death. For example, if other dimensions are spun up off of events which occur here does that mean that when i die here i am deceased on all planes. If not, could our search for what we think of as the "soul" be somehow related to a connection between dimensions.
Comments (105)
Interesting hypothesis. But I would like say "Supreme" figure (or God to the religious ones) instead of soul because this soul has to exist necessarily in all the connected worlds in our human bodies. Then, I guess we have to find out who or which is the ruler or host in this context.
The problem is that the many worlds scenario, in scientific rationality, would mean that any event in the entire bubble of reality that we are in, in the entire universe, can split into two possible worlds. So any sub-atomic particle in the entire universe that moves in any direction means that another world has this particle move in another direction. By just calculating this in our head, there is an infinite number of worlds where the only thing different between them is one particle, in one part of the universe, moving in another direction than our own. So to have other worlds where we live other types of lives, are alive or dead etc. are notions that are so absurdly astronomical as differences that it's impossible to really find any relevance to them. It would be impossible to find them really.
Pretty much.
No, each branch is independent. What someone does on one branch (including when they die) has no effect on any other parallel branch. [*]
Quoting Steve Leard
No, from your branch you have no connection to other parallel branches.
Everett's amoeba analogy is useful to get a sense of how Many Worlds works. As Everett put it, 'Each time an individual splits he is unaware of it, and any single individual is at all times unaware of his "other selves" with which he has no interaction from the time of splitting.'
--
[*] In principle, an isolated observer could observe another person's (or cat's) parallel branches in superposition, which would exhibit interference effects for the observer. But an individual person (or cat) can only influence their own branch. See the Schrodinger's Cat and Wigner's Friend thought experiments.
Have a read of The Multiverse Idea is Rotting Culture
About that cat, I have good news and bad news...
Quoting Wayfarer
Have you tried the Zen Anti-Interpretation of Quantum Mechanics?
Quoting The Zen Anti-Interpretation of Quantum Mechanics - Scott Aaronson
I always like this one:
[quote=Mrs Schrodinger]What did you do to the cat, Erwin, It looks half dead.[/quote]
I've heard the Sanskrit term "advaita" (nondualism) and am often tempted to use it to describe this type of thinking, but TBH I'm not confident enough in my knowledge of that area's philosophy to be sure I'd be using it right. (I'm at least familiar with the notion of "Atman is Brahman", and the veil of maya creating an illusory distinction between them, and while I don't think I agree with the usual interpretation of that, the diagram of the relationship between them that comes to me mind does remind me of a diagram I've often pictured of my own philosophy: the surface of a mirror, against which the eye of an invisible observer is pressed, and everything happening at that boundary between eye and mirror is all of phenomenal reality; the invisible observer abstracts things from those phenomena in his mind, behind his eye, but because of the mirror, he sees those things projected behind the phenomena instead; and infinitely far back into the mind recedes, forever inaccessible, the notion of some true self, which is then mirrored as and projected infinitely far into the distance as the notion of some kind of supreme being behind all of reality. If the structural similarities aren't clear: the phenomena on the surface of the eye/mirror boundary are maya, the true self imagined infinitely far back into the mind is Atman, and the supreme being imagined infinitely far behind the mirror is Brahman, which is just a reflection of Atman, which itself is just imaginary).
Yes. What I think is also needed is a reframing that doesn't depend on those dual first-person/third-person perspectives. I find Aristotle a useful resource here.
Quoting Pfhorrest
I'm not particularly familiar with Eastern non-dualism. However on Aristotle's hylomorphic view, mathematical objects are abstractions of empirically observable stuff, and not separable from that context (though they can be considered separately, as mathematicians do). I'm not sure if that really differs from your own conclusions, but perhaps a different way of getting there.
Quoting Wayfarer
:up:
Couldn't agree more. The multiverse is obscenely anti-ockhamist, it assumes a awful lot and for no good reason. The hypothesis of God is indeed far less costly... and that's an atheist talking.
Also, same question but about the existence of life on those planets instead, since that’s not a settled question yet: more parsimonious to think there is something special about Earth alone that permits life, or that there’s probably tons of life all over the place and we’re nothing special?
The principle of mediocrity is a natural theorem of the principle of parsimony, became assuming our circumstances are not unique is less complex a theory than assume something that would make us unique, even though assuming we’re not unique implies there are a lot of things like us, while if we assume we are unique then it might be just us.
Many worlds, modal realism, the multiverse, are all just the principle of mediocrity on a cosmic scale. Our universe is not special in its actuality. It’s just the one we happen to be in, and there’s lots more just like it.
Right. And many flying unicorns too.
Except for one important difference - after death, if souls are real, we're supposed to get a fresh start as babies.
THe point of the Sam Kriss article is how (pseudo)-scientific conjectures such as the many worlds interpretation filter down into popular culture. I think especially in movies, like Sliding Doors, Inception, and others of that ilk, the idea of there being an infinite number of parallel realms is naturally intriguing to us. Kriss makes that point very well.
On the other hand, imagine the kind of sobriety that would be introduced to scientific discourse if, for some reason, such ideas were suddenly declared off limits. Popular science would be obliged to be circumspect - which they claim to be, except when their formulae entail something incommensurable with their materialism, which is basically what drives the Everett interpretation (which I believe is integral to quantum computing, so let's see how that pans out).
Everett, after abandoning academic physics to work for on the design of atomic missiles during the Cold War, died at 51 of alcoholism and wrote in his will that his ashes be put in the trash. I believe he was depicted by one of the cameos in Dr Strangelove.
:gasp:
If we come across one flying unicorn (that we can confirm definitely is a flying unicorn and not some hoax or something), the most parsimonious assumption is that there is a whole species of flying unicorns that has somehow evaded detection thus far, rather than that some special circumstances brought about just this one individual. It's always most parsimonious to assume the things we encounter are normal and not unique until proven otherwise.
The simplest curve that fits to a single data point is a straight line of zero slope through that point.
Oh no need for that. You see, in the multiverse, everything that can happen does happen, LITERALLY.
At every single nano second, gazillions of worlds are created for each possible outcome of each quantum event in the multiverse. So everything that can happen does happen. Now who's to say that flying unicorns are impossible, and that a world where the skies of planet earth are dominated by winged unicorns cannot possibly happen?
This has been the stuff of science fiction for decades. Read [i]The Man Who Folded Himself[/I] by David Gerrold for a sample.
One, you (and probably others, I haven't read the entire thread) are confusing the multiverse with the many-worlds interpretation. They're two entirely separate things. And two, your statement is false. Just as you could flip a trillion coins and they all land on heads, there are things that might not happen even in the multiverse (which again, is NOT the many-worlds interpretation).
Okay so, are you going to tell us the difference between the many-worlds and the multiverse, or are you going to keep it for yourself?
I never said otherwise. I said "in the multiverse, everything that can happen does happen".
I'll keep it between me and Wikipedia.
Quoting Olivier5
How do you know? And who decides what "can" happen in order to make your claim true?
Okay, the many-worlds interpretation. Multiverse is another sci-fi scenario, fair enough.
Quoting fishfry
The Schrödinger equation ?
Ok.
Quoting Olivier5
Is that a question? Make your case that "whatever can happen, will happen." If I flip infinitely many fair coins, it's possible that I never get a tail. Unlikely, but possible. The multiverse (which is what we're talking about in this case) might do something unlikely like that. And since it's a perfectly unfalsifiable notion, it's not science. You already agreed that multiverse theory is sci-fi, yet you claim to be able to make predictions about it. How do you square those two things?
Actually, I'm talking of the many-worlds interpretation of quantum physics. You were fiscal enough to point at the difference with the multiverse, so now you're stuck with it.
I just apply the definition of the oh-so-many-worlds scenario. It is a scenario that exhausts all quantum possibilities, by definition. So, assuming for the sake of the argument that tossing a coin is quantic, in the many-worlds interpretation there is one world where you get "head" and another world where you get "tail". If you toss the coin one million times, one of the world "created" by your tossing will have you get 1 million times "head" in a row, and in another world, another version of yourself got 1 million times "tail" in a row. And all the possible combinations in between those two extremes would also see the light of day in their own world.
Just spit balling here and its off topic i know. If there is a multiverse there would have to be an original "verse", as it were. And if this is true, going a step further, what if changes in the original verse is also the only dimension that can generate spin offs because it is imbued with the magic sauce that is required for this to happen. And could that sauce be the existence of quantum mechanics.
"fiscal: relating to government revenue, especially taxes."
Hokay!
Quoting Olivier5
Alright!
Quoting Olivier5
Sounds like I win either way!
Quoting Olivier5
Whateva.
You're right. For multiverse, it's not necessarily true that whatever can happen does happen. But for many-worlds, it does seem to be the case that the universe splits into every possible outcome. It's a pretty nutty idea. Sean Carroll is a big believer. For my part I'm holding out for better physics in the future. Maybe someone will eventually sort this out.
When they describe many-worlds they always talk about binary choices. The car turns left or the car turns right, the cat is dead or alive. But they never consider continuous choices. If the car is in the middle of an open field, it can turn in any direction. That's a continuous range of choices. Is there a world for each of these choices, uncountably many of them? Or perhaps only a finite collection for each Planck-length sized angle the car can turn? I don't know what the MWers say about that.
I think this is misguided. The MWI doesn't add any assumptions; in fact, its appeal is that it takes assumptions away.
The apparent premise here is that MWI is adding an unnecessary premise that there are many worlds. The problem with this is that MWI doesn't add this assumption; QM realism does. In the double slit experiment, the particle somehow goes through both slits... that's where the many worlds come from, and it's already there. What MWI does, versus the traditional interpretation, is remove an assumption... namely, it removes the assumption that there's a privileged viewpoint where collapse is "real"; we can loosely call this classical realism.
Take Schrodinger's cat experiment as an example. Before Schrodinger opens the box, Schrodinger is already compelled to model its contents as a superposition between two worlds. In one world, a cat observed a lump of material decay; that's the dead cat. In that world, the decay was detected, the detector broke a vial of poison, and the poison is what killed the cat. In the other world, a cat observed a lump of material not decay; that the living cat. In that world, no decay was detected, the vial contained the poison, and the cat just lived. From the point of view of the dead cat, the radioactive material is not in a superposition between decaying and not decaying; it has already collapsed into decaying. Similarly, from the point of view of the living cat, the radioactive material has already collapsed into not decaying. But Schrodinger's model has both of these terms in it; so the cats' points-of-view collapses are not "real" collapses. They are instead just entanglements; the cat's state is entangled with the state of decay of the material. So if the living cat's sees apparent collapse, what makes Schrodinger special when he opens the box? How come Schrodinger's collapse is ontic when the cat's collapse is just perspective?
So to emphasize, MWI doesn't add the assumption of multiple worlds; the assumption leading to multiple worlds is already there. The traditional interpretation has a world with a dead cat and a living cat in it; those are worlds. MWI instead removes the assumption that some collapses are ontic whereas others are just apparent.
Quoting fishfry
Same response to fishfry... answering this question from an MWI point of view is easy. Don't look at the many worlds, because that's not the assumption; the worlds are just perspectives. They're descriptions to classical beings like us. The worlds are emergent; it's the wavefunction that's real.
So just look at the wavefunction. Is there continuity there? If so, since the universal wavefunction is ontic (under MWI; that is the assumption), then they must be real. If you're looking at a human choosing to steer, it's not entirely clear that correlates to a wavefunction continuous along all paths... the math leading up to that could get insanely complicated. But there are continuities in the wavefunction; if you start with the double slit, but you cut "infinite slits" into the barrier, then the photon goes everywhere. In that case, that wavefunction being ontic (under an MWI perspective), all of those are real (so long as you can come up with "worlds" based on each of those, each such world would be real).
You can't understand something in this one world, so you need to assume gazillions of worlds.
Why are we classic? Isn't that a contradiction to MWI, where everything is quantum mechanical?
I don't know either, but I just had this thought that whenever I dribble a bit when peeing, I create a few thousands universes (each with all these galaxies and black holes and stuff in it) just to account for where the drops of my urine may or may not fall. I feel like Zeus with thunder in my hand now.
So you're not against MWI, but QM?
Quoting SolarWind
No, it's in the wavefunction. When Schrodinger models the state of the box, he would model a superposition between two classical states. There's a cat that died, because the vial broke, because a detector detected decay, because there was decay. And there's a cat that didn't die, because the vial didn't break, because the detector didn't detect decay, because there wasn't any. The cat's states are entangled with the state of radioactive decay. And when Schrodinger opens the box, Schrodinger's states become entangled with the radioactive decay.
LOL. Now I can't unsee that.
I did some Googling around (ie "research") and found this interesting thread.
https://physics.stackexchange.com/questions/536522/how-does-many-worlds-interpretation-work-for-non-50-50-probabilities
This was in response to someone asking if there can be uncountably many branches. So the either/or binary choices are just a popularization. The hard core many-worlders are perfectly fine with uncountably infinite branching at every instant.
QM is science. I am pro science, always. The MWI is an attempt to stick to the metaphysics of Galileo and Newton, i.e. to strict determinism, in an era where this idea is obsolete precisely because of QM.
I am pro QM, but anti MWI. I don't buy the observer's magical powers to collapse a wave function either. My interpretation is that interactions with stuff collapse or at least restrict the wave function, allowing stable, predictable macrostructures to emerge from highly unstable and unpredictable micro elements.
Thales said that all things were made of water. This was his way to say that the world was not made of several elements (fire, water, earth, air for instance) as people believed in his time but made of just ONE substance. QM is telling us that this universal substance -- the water of Thales -- is in fact a probability wave.
I don't understand a word, can't it be more detailed?
As I said, in this interpretation, everything that can happen does happen. Including flying unicorns, I think.
The MWI is just an interpretation. It embraces quantum realism, giving up classical realism. It hasn't been demonstrated true.
All I'm arguing is that it's naive to argue that MWI is making more assumptions; the core of MWI, explained in terms of Schrodinger's cat, is that there's nothing privileged about Schrodinger opening the box versus the cat.
ETA:
Quoting Olivier5
MWI just gets rid of that collapse (at least ontically, in the sense that the other terms disappear from the universal wavefunction and "become unreal"). The apparent collapse is explained by observers themselves entangling with quantum systems. That explanation isn't new; it's how Schrodinger would explain the cat. MWI is just saying as with the cat, so with Schrodinger.
Quoting SolarWind
See edit.
I cannot see myself as a quantum object. What determines in which of the many worlds I am? It makes a difference to me whether I win the jackpot or one of my many copies.
A fun novel exploring MWI here, in case you were interested...
MWI says that there are infinite worlds, while Schrödinger assumes his cat can't be dead and alive at the same time. Can you spot which assumes less and which assumes more?
I think that gets outside of MWI proper and into philosophy of identity. Personally, I think personal identity constructed anyway.
Let's say S1 is Schrodinger before opening the box, SA2 is Schrodinger who opens the box seeing a living cat; SB2 is Schrodinger who opens the box seeing a dead cat. Then neither SA2 or SB2 are the "genuine" Schrodinger; they both have equal claims of being the same as S1. But SA2 and SB2 do not affect each other; those "terms" in the wavefunction are now decohered. So SA2 and SB2 are different from each other.
Quoting SolarWind
Given the model above, there's no genuine version of Schrodinger to ask about.
There's a problem with your phrasing. "Schrodinger's cat" isn't an interpretation of QM; it's a thought experiment in it. What you're comparing is something akin to MWI and a traditional interpretation.
The traditional interpretation assumes there are two fundamental processes; Schrodinger's equation and Born Rule. MWI sees the assumption of the Born Rule as a fundamental process as unnecessary, so doesn't assume it. Since one is less than two, MWI is making fewer assumptions. MWI is saying there are an infinite number of worlds because it makes less assumptions; getting rid of those worlds requires more assumptions than MWI makes (that BR is fundamental).
I am actually talking of Erwin Schrödinger's own interpretation of QM, which he tried to argue for in his famous thought experiment about a cat in a box. In his view, the cat had to be either alive or dead, hence the Copenhagen interpretation was impossible to hold. Read about the history of the thought experiment.
Okay, history. Regarding the history of Schrodinger's cat per se, that was introduced in 1935 by Schrodinger's "Die gegenwärtige Situation in der Quantenmechanik". I don't speak German, but there are translations of "The Present Situation in Quantum Mechanics" in English. In this paper, Schrodinger introduced the cat thought experiment, and discussed his ideas on quantum mechanics. I have no idea what you're referring to here in particular that's any different from what I have said, but I have an English translation, so if you want to refer to parts of this paper go ahead.
But regarding the history of what I'm discussing, MWI was introduced in 1956 by Hugh Everett's thesis, "The Theory of the Universal Wavefunction". In this paper's introduction, Hugh discussed the two processes I'm talking about and discusses problems with the consistency of entertaining both processes. In that introduction, wavefunction collapse via the Born Rule is what Everett calls Process 1. The evolution of the wavefunction is what Everett calls Process 2. The particular inconsistency Everett points out is the inconsistency between Process 1 and Process 2; the way it's supposed to work, you use Process 2 until you observe, then you take out Process 1 and use that. Everett discusses in particular the inconsistency that is introduced when one observer (B) tries to describe an observer (A) as part of a quantum system (S); in that case, B is supposed to use process 2 to model A+S, but A uses Process 1 to model S. Everett then discusses five alternatives for how to resolve this: (1) A solipsist approach (e.g., B gets to apply Process 1, A is wrong to apply Process 2), (2) A "realms" (my term) approach, where QM is simply held invalid to any observer or macroscopic system, (3) An "isolationist" (my term) approach, where we suppose that B cannot posses a model A+S for some reason, (4) An incompleteness approach, where we surmise that there's some other hidden theory explaining QM, (5) A universal approach, where we simply discard Process 1. Everett's theory presumes alternative 5; he is discarding Process 1 as being real.
My use of Schrodinger's cat is as a device to talk about Everett's model... alternative 5. In this device, Schrodinger is B, the cat is A, and the quantum system S is the radioactive material.
So all of that is before you. Now, what different thing than I said are you talking about?
I'm talking of Erwin Schrödinger's interpretation of QM.
Okay, I'll try this way. What about it?
This may be true if the probability is 0.5 vs 0.5. What if we wait shorter for the radioactive element to decay and the ratio is 0.58 (living cat) vs 0.42 (dead cat)? How many SA2 and SB2 are there then?
Still two, or many. It depends on how you resolve the fact that the BR appears to work in MWI, and that's something I'm not sure how to do... possibly that's a good reason not to buy into it, or maybe it's just something beyond my scope.
In the mathematical formulation of quantum mechanics there are usually six postulates, listed here.
However it is possible to simplify the formulation by omitting (at least) the collapse postulate - postulate V in the link. That is the sense in which MWI requires less assumptions (read: formal postulates) than other interpretations.
The consequence is that every physical event is described by the Schrödinger equation - measurement is not singled out for special treatment.
It does assume an infinity of worlds.
Another consequence is that, everytime I pee, I create thousands of universes, just to account for where the droplets may fall.
Sean Carroll says nobody knows if MWI requires infinitely many worlds or not.
Yep. As David Wallace puts it, the alternatives are to change the physics or to change the philosophy.
Quoting Interview with David Wallace
Quoting Interview with David Wallace
In the classic physics era, massive objects were supposed to attract one another at a distance, without any physical chanel of interaction between them, as by magic. Even Newton thought this was a problem, that the world could not possibly be that way, with actions at a distance. And yet the likes of Wallace were for two centuries quite happy to see Newtonian gravity as "the way the world was like"...
A scientific theory makes predictions about how the world behaves in quantitative terms. It doesn't tell you "what it's like" ontologically or qualitatively, never did, never will.
The only philosophy that needs to change here is that of strict determinism. Remove this assumption and you are left with a probabilistic interpretation of the wave function. You just need one world for that, but one open to surprises.
It's even worse. The MWI supporters claim the world divides when the states are decohered. But decoherence is an exponentially decreasing process that is theoretically never complete. Therefore already the basic assumption is wrong and the MWI can be thrown into the garbage can.
https://www.youtube.com/watch?v=kTXTPe3wahc
Most of the video is so-so, nothing new if you've seen the material before although I did pick up a new insight or two. Sean Carroll comes on at 12:30, and his part is definitely worth watching. At 14:25 he says: "Does it happen infinitely often, we don't know," and then says the number is "gigumongous."
I think the difference between infinite and gigumongous is rather technical.
Interestingly, the conservation of mass and energy would seem gigumongously violated by this constant burgeoning of a gigumongous number of new universes.
You're still counting the wrong thing. Believing that France exists is not making 67 million assumptions. Also, if those worlds are a problem with MWI, you should have a problem with them in QM.
Quoting Olivier5
Something is majorly broken with this argument. If your wavefunction has A+B in it, and you have applied a force to a mass in A, does A then move twice as fast? Assuming it did, if we entertain collapse into A, did we lose mass to B going away?
Quoting SolarWind
That does not follow.
There's just one world in most QM interpretations.
I don't think you grasp what a world is. If you have a wavefunction expressed as A+B, you have two worlds. If you have a superposition, you have multiple worlds.
What does not follow from what?
I don't think superposition of states is a good way to think about QM.
Everything you have after "Therefore" does not follow from what you have before "Therefore".
Can I guess? Are you perhaps suggesting MWI requires worlds be fully decohered? If that's the case, you just have a misconception of MWI. MWI isn't proposing that anything different happens with wavefunctions than that they evolve in accordance with Schrodinger's Equation. It's simply, more or less, the idea that measurement is entanglement; that when a device (or observer) measures something in superposition, the device (or observer) is entangling with those states.
Oh sorry. I actually thought "many worlds" had something to do with many worlds. And in every book about MWI it says that they divide at a measurement. But maybe you are talking about something completely different.
It does, but you're attacking a straw man. A "world" is not an entire decohered universe.
That's correct, but that division is an entanglement.
Radioactive-lump system evolves into a superposition (ignoring amplitudes):
|decayed> + |undecayed>
Cat-system measures this; that entangles the cat with these states:
|decayed>|dead cat> + |undecayed>|living cat>
Schrodinger measures this; that entangles Schrodinger with these states:
|Schrodinger-sees-dead-cat>|decayed>|dead cat>
+ |Schrodinger-sees-living-cat>|undecayed>|living cat>
There are now two worlds. We do not have to wait until Alice, or Andromeda, are decohered... the "Schrodinger-sees-dead-cat" no longer interacts with that living cat. Nothing is being added to the equation here; no partitions that aren't there already... we simply do this instead of collapsing when Schrodinger measures the cat-radioactive material system.
https://www.preposterousuniverse.com/blog/2021/01/28/energy-conservation-and-non-conservation-in-quantum-mechanics/
That article is well worth reading. It's a thorough layman-level discussion of conservation of energy in quantum physics. "Today I learned," actually last night when I read this piece, that energy isn't even conserved in our own slice of the universe. In quantum theory, energy is merely conserved "on average" and not necessarily all the time. How do you rescue true conservation of energy? With many-worlds! Sean Carroll is a hell of an expositor.
That would be an instrumentalist view of science, but Wallace takes a realist view, i.e., that a theory represents the structure of the world.
Newton thought that the "action at a distance" aspect of his gravitational law was a problem because he was also a realist. As are and were many scientists, including Einstein.
Wallace again:
Quoting Interview with David Wallace
Quoting Olivier5
Superposition is a fundamental principle of quantum mechanics, regardless of interpretation. What alternative would you suggest?
Just to reiterate @fishfry's point with a simple example. In MWI, the total energy of the universe is the weighted average of the energies of each branch. Suppose that there is only a single branch and the total energy is E. Now suppose that the universe splits into two branches such that:
[math]|\psi\rangle = \sqrt{\frac{1}{2}} |Branch 1\rangle + \sqrt{\frac{1}{2}}|Branch 2\rangle[/math]
When an observer measures the energy, they will measure (approximately) E. So, from the observer's point-of-view, energy has been conserved on their branch. To calculate the total energy of the universe, it is necessary to square the amplitude of each branch and multiply by their respective energies. So:
[math]Total\space energy = \frac{1}{2}E + \frac{1}{2}E = E[/math]
So the total energy of the universe has also been conserved.
Why the average and not the sum? What is the argument here?
That is not what a scientific theory ever does. Science is not religion.
He could not figure out e.g. how come the star Syrius would exert a physical force on him (and him on Syrius) over such a vast distance, without any intermediary between them. My point was that, beyond Newton himself, very few people actually cared for this element of magic in the classic Newtonian theory of gravity. Most were content with this magical representation of the world.
So if you assess Newton's theory against your criteria of realism, he fails miserably. But if you assess his theory against the quality of the predictions it allowed, then Newton scored big time.
Quoting Andrew M
No, it's not. You don't seem to know much about QM. Have you watched enough youtube videos yet?
Because that reflects the contribution of each branch to the wave function.
Quoting Olivier5
You're mistaken. From Paul Dirac's classic textbook:
Quoting The Principles of Quantum Mechanics, Ch.1: The Principle Of Superposition, p4 - Paul Dirac
Also you haven't said what your alternative way of thinking about QM is. For example, how would you describe the double-slit experiment without assuming superposition?
Quoting Andrew M
I would assume that the photon behaves as a wave until it interacts with something, at which point somehow it behaves as a particle.
That is childish. An interaction always exists: The Van der Waals forces from the laboratory, the natural radioactivity and the gravity of the earth.
Van der Waals forces are inter molecular. Gravity does not affect light.
Matter is an antenna for electromagnetic waves via displacement of charge distribution (Van der Waals) and partially absorbs the EM waves.
With gravitation the deflection of light is known.
OK, we're on the same page then. You seemed to be saying you could think about QM without that.
Quoting Olivier5
Without detectors at the slits, the photon still interacts with the apparatus at the slits. Yet an interference pattern is still observed.
For an even simpler example, when a photon interacts with a beam splitter, the interaction is described by a wave function (i.e., there is amplitude for both the photon transmitting and reflecting). This is exploited by Mach-Zehnder interferometers, for example.
So your assumption can't be correct.
Not the photons passing the slits.
And what about the many neutrinos that are flowing through the earth, and what about the virtual particles?
Those photons as well. Amplitude for every possible path through the apparatus contribute to the observed interference pattern - including when the photons are emitted one by one. The characteristics of the apparatus (such as the positions and widths of the slits) determine the paths the photon can take and thus the specific interference pattern.
Even with photon detectors at the slits, the resulting photon position information can be erased, restoring the interference pattern.
The issue can be simplified by considering a Mach-Zehnder interferometer where there are only two possible paths. Photons sent one at a time through an MZI will exhibit wave interference even though they interact with components of the MZI itself (such as beam splitters, mirrors and sample liquid on the paths).
Quoting InPitzotl
Quoting InPitzotl
Ok, so a photon still behaves as a wave when it is reflected by a mirror. Fair enough. That doesn't make for an infinite number of universes, though.
So at every branching, the total energy of the universe is divided by 2? And likewise with its mass, I suppose. Since there is a gigamongous number of branching per nanosecond, it follows that if the MWI was true, our universe would become empty of all matter and energy quite rapidly, like in a few seconds.
You have a cake with a weight of 1 pound. You divide the cake in two pieces. Now you have two half cakes, each with a weight of 1/2 pound. Global weight is conserved. The universe has some amount of energy, and it's divided among the worlds. The sum of the energy of all the worlds is always the same.
I do share your concern that if the total energy of the universe (universe being all the worlds taken together) is finite, then this places a limit on how many worlds there can be; because as the number of worlds increases, the amount of energy in each world gets smaller. I don't know how Sean Carroll handles this problem.
Here's a possible way to think about it.
Consider a superimposed photo. The number of times that the photo is superimposed doesn't change the amount of material in the photo. There is still only one photo, but it can be described from different points of view. Further, a filter could potentially be applied such that you see one definite picture (or slice).
This idea reflects the math of superposition. Suppose I have a vector (which can be visualized as an arrow) that points north-east. It's just one thing. But I can also consider it as a linear combination of one vector pointing north and another vector pointing east. Now there are two things. But nothing has really changed. I'm just describing the original vector in a different way.
Now suppose that you have a quantum coin that is in a superposition of heads and tails. In MWI, whether it is one coin (like the north-east vector) or two coins (like the north vector and east vector) is just a matter of how you want to describe it.
What MWI says is that you, the observer, are a quantum system just like the quantum coin. From an isolated observer's viewpoint (see Wigner's Friend), you become entangled with the quantum coin when you measure it. The universe still contains the same energy that it did before, but it now looks different from your point of view compared to the isolated observer's point of view (where they describe you as in a superposition of measuring heads and measuring tails).
Thought experiments mean very little, especially when poorly thought through.
E.g. what Schrödinger forgot in his famous mind experiment is that the cat is just as valid an observer as his master. And the Schrödinger equation of the Schrödinger cat (or of any other cat) remains unknown so even if we assume that the cat can be described with QM formalism, we have no idea how.
A cat, or a human being for that matter, is not just an observer. She is also a biological system. Nobody has ever solved the Schrödinger equation for biological systems, it's far too complicated. We can barely compute it for simple molecules, like water. If you want to apply QM to life, you got a lot of very very hard "shut up and calculate" to do.
So before you can speak of me getting "entangled" with my coin, you would have to show that QM applies to me, as a whole, and that my holistic Schrödinger equation accepts such a possibility.
I'm pretty sure Schrödinger and Wigner had carefully thought their ideas through. What is relevant are the implications of those thought experiments for differentiating and testing various interpretations and theories.
Quoting Olivier5
Perhaps Schrodinger's Bacterium?
Quoting 'Schrödinger's Bacterium' Could Be a Quantum Biology Milestone
How come Schrödinger did not see that his cat was just as good an observer as he was, pray tell?
I'm sure he did. But the thought experiment is not about what the cat observes, it's about where the line is drawn (if at all) for when a system stops being in a superposition of states.
The line is my consciousness at the latest, because I experience only one world.
Sorry, I'm not sure what you're saying. Can you clarify?
Quoting SolarWind
OK, so consciousness causes collapse, on your view? Or something else?
The Schrödinger cat thought experiment was conceived in order to refute the Copenhagen interpretation, specifically the idea that the act of "observation" or "measurement" reduces or "collapses" the wavefunction. I am sympathetic to the attempt, I don't believe in the magic of observation either. But to me, it seems Schrödinger forgot a tiny little detail, which is that his cat was an observer too and therefore (according to said Copenhagen interpretation) could collapse the wavefunction inside his box, all by himself.
Edit: I've read your "Schrödinger bacterium" article. As often the case, the title widely overstates the finding that
"Our models show that this phenomenon being recorded is a signature of entanglement between light and certain degrees of freedom inside the bacteria,”.
Namely, the analysis points to a quantic interaction between photons and the bacterium's chlorophyll. What happens when a photon is "captured" by a chlorophyll molecule has been the subject of countless studies and many of them call upon QM to explain how photosynthesis works. For instance, chlorophyll is known to be fluorescent. It releases photons in a certain precise wave length (red). You can see it for yourself here, or you can just put a nice green solution of chlorophyll under the sun, and you will notice like a faint red light shimmering inside the green liquid.
Now, fluorescence is considered a quantic phenomenon, so this finding above that chlorophyll can "entangle" with photons doesn't seem so new to me.
"Latest" I wrote. But the truth is a combination of Bohmian Mechanics and the Schrödinger–Newton equation causing the collaps. It depends in the mass of the measuring apparatus. The cat is heavy enough.
OK, but the basic point of Schrodinger's thought experiment was that if it doesn't make sense to imagine macroscopic phenomena being indeterminate, then it shouldn't make sense to imagine atomic phenomena being indeterminate either. After presenting his thought experiment, Schrödinger says:
Quoting The Present Situation in Quantum Mechanics - Erwin Schrödinger, 1935
...
Quoting Olivier5
From the article, "According to study co-author Tristan Farrow, also of Oxford, this is the first time such an effect has been glimpsed in a living organism."
And regarding future experiments, "Several research groups, including those led by Gröblacher and Farrow, are hoping to take these ideas even further. Gröblacher has designed an experiment that could place a tiny aquatic animal called a tardigrade in superposition—a proposition much more difficult than entangling bacteria with light owing to a tardigrade’s hundreds-fold–larger size."
Fair enough. Is that different to the Penrose interpretation?
Not really. The scales of reality are a view of the mind. Nature is one. The basic point Schrödinger was trying to make is that observers are not magic; they don't collapse wave functions just by "observing".
About your paper, it may indeed be the first time such an effect is evidence in vivo, as opposed to in vitro. But they haven't "entangled" a whole bacterium yet, only its chlorophyll.
Note that in the double slit experiment, you can replace photons by whole molecules, and it will still work. You will get interferences... So molecules behave as waves too, including medium size molecules such as chlorophyll. But I don't think the double slit experiment works with entire bacteria.
As I understand it, via Sean Carroll's work, if you die here, you may well be alive in many other universes, but that would not matter in the sense that you are closed off from causal interaction with the other "you's". The problem with Many Worlds, is that, there is no evidence that could be gathered that offers proof of its validity. It's a speculation based on a scientific equation that seeks to establish determinacy. It could be false, in that the universe may be indeterminate deep down.
Yes. The Bohm-Schrödinger-Newton interpretation does not need the general relativity. The particles move according to Bohm, entangle with the measuring apparatus, this localizes itself over its own gravity and acts back over the entanglement, which causes the collapse. At 10^10 atomic mass units, the transition is quantum mechanical-classical according to SN equation.