Superposition Misinterpreted

[Alan Grayson]

I've argued this before, but it's worth stating again. It's a misintepretation of superposition to claim that a system described by it, is in all the component states simultaneously. As is easily seen in ordinary vector space, an arbitrary vector has an uncountable number of different representations. Thus, to claim it is in some specific set of component states simultaneously, makes no sense. Thus evaporates a key "mystery" of quantum theory, inclusive of S's cat and Everett's many worlds. AG

[Brent Meeker]

No.  It changes the problem to the question of why there are preferred
bases.

Brent

[Philip Thrift]

On the preferred-basis problem and its possible solutions

arXiv:1008.3708 

The preferred basis problem is mentioned in the literature in connection with the measurement problem and with the Many World Interpretation. It is argued that this problem actually corresponds to two inequivalent problems: (i) the preferred-decomposition problem, i.e., what singles out a preferred decomposition of a suitable state vector of a system as the sum of a finite or countable set of vectors?, and (ii) the preferred-representation problem, i.e., what singles out a preferred representation for the Hilbert space of a system? In this paper the preferred-decomposition problem is addressed and two processes, namely decoherence and permanent spatial decomposition (PSD), are examined and compared as possible solutions to this problem. It is shown that, perhaps contrary to common belief, in realistic situations decoherence is not sufficient to solve the preferred-decomposition problem. PSD is the (hypothesized) tendency of the wave function of the universe to decompose into permanently non-overlapping wave packets. Three phases can be roughly identified as composing PSD: Microscopic decomposition, amplification, and interaction with the environment. Decoherence theory considers only the interaction with the environment and ignores the first two phases. For this reason PSD is fundamentally different from decoherence and, unlike decoherence, provides a simple and non-elusive solution to the preferred-decomposition problem.

No Quantum Process Can Explain the Existence of the Preferred Basis: Decoherence Is Not Universal

Journal of Quantum Information Science

Vol.06 No.03 (2016)

Environment induced decoherence, and other quantum processes, have been proposed in the literature to explain the apparent spontaneous selection―out of the many mathematically eligible bases―of a privileged measurement basis that corresponds to what we actually observe. This paper describes such processes, and demonstrates that―contrary to common belief―no such process can actually lead to a preferred basis in general. The key observation is that environment induced decoherence implicitly assumes a prior independence of the observed system, the observer and the environment. However, such independence cannot be guaranteed, and we show that environment induced decoherence does not succeed in establishing a preferred measurement basis in general. We conclude that the existence of the preferred basis must be postulated in quantum mechanics, and that changing the basis for a measurement is, and must be, described as an actual physical process.

@philipthrift 

[Alan Grayson]

Who chose Alive and Dead, or Awake and Sleeping for the S. cat? Wasn't it the observer? Since they had other choices, my claim stands. AG 

[Philip Thrift]

The devil cat is in the experimental details ...

Path integral approach on Schrodinger's cat

Zinkoo Yun

Department of Physics and Astronomy University of Victoria, Canada

https://arxiv.org/abs/1310.8020

"the two conditional paths in Schrodinger’s cat experiment do not interfere with each other. So there is no phase effect between them thus no quantum superposition between |dead> and |alive>"

ref: Relation between the Schrödinger's equation and the path integral formulation of quantum mechanics

https://en.wikipedia.org/wiki/Relation_between_Schr%C3%B6dinger%27s_equation_and_the_path_integral_formulation_of_quantum_mechanics

@philipthrift 

[Alan Grayson]

On Wednesday, October 9, 2019 at 12:28:38 AM UTC-6, Brent wrote:

Sean concludes there are many worlds by misapplying superposition after decoherence. What has preferred bases have to do with this? AG 

[Lawrence Crowell]

If there is a degenerate quantum state there is no preferred basis. If a field is applied, say a Zeeman effect, the degeneracy is removed and there are states with different energies. We might be quick to say the lowest energy state establishes the ladder of states. However, if we have a QED field in a perfect cavity there will then be a superposition of different energy states and photons. In effect there is no preferred basis. We have a preferred basis with deccoherence, but that only pushes the barrier back. In effect we are still left with the problem of how classical states are robust against quantum noise or decoherence so there is some reference used to define a preferred basis.

LC

On Wednesday, October 9, 2019 at 1:28:38 AM UTC-5, Brent wrote:

[Brent Meeker]

Could the observer have chosen |alive>+|dead> and |alive>-|dead> as a basis?

Brent

[Brent Meeker]

On 10/9/2019 6:26 AM, Philip Thrift wrote:

On Wednesday, October 9, 2019 at 5:52:03 AM UTC-5, Alan Grayson wrote:

On Wednesday, October 9, 2019 at 12:28:38 AM UTC-6, Brent wrote:

On 10/8/2019 9:20 PM, Alan Grayson wrote:
> I've argued this before, but it's worth stating again. It's a
> misintepretation of superposition to claim that a system described by
> it, is in all the component states simultaneously. As is easily seen
> in ordinary vector space, an arbitrary vector has an uncountable
> number of different representations. Thus, to claim it is in some
> specific set of component states simultaneously, makes no sense. Thus
> evaporates a key "mystery" of quantum theory, inclusive of S's cat and
> Everett's many worlds. AG

No.  It changes the problem to the question of why there are preferred
bases.

Brent

Who chose Alive and Dead, or Awake and Sleeping for the S. cat? Wasn't it the observer? Since they had other choices, my claim stands. AG 

The devil cat is in the experimental details ...

Path integral approach on Schrodinger's cat

Zinkoo Yun

Department of Physics and Astronomy University of Victoria, Canada

https://arxiv.org/abs/1310.8020

"the two conditional paths in Schrodinger’s cat experiment do not interfere with each other. So there is no phase effect between them thus no quantum superposition between |dead> and |alive>"

It just begs the question of basis by assuming the initial and final states.

Brent

[Brent Meeker]

Superpositions are an artifact of using a certain basis.  In principle there is always a basis in which the world is a base ray.

Brent

[Philip Thrift]

The "cat" paper by Yun seems to be the way probabilities are calculated in "real path" quantum theory.

Path Integrals and Reality

Adrian Kent

https://arxiv.org/pdf/1305.6565.pdf 

@philipthrift

[Alan Grayson]

That's a great question and the answer is No, because, as you would say, the pair (|Alive>, |Dead>), forms a "preferred" basis. We can only measure Alive or Dead. However, the other pair you have above is a perfectly valid state of the S cat system, a vector in the Hilbert Space of the system, and presumably there is an uncountable set of other valid states in Hilbert Space. This means that the interpretation of a superposition of the first pair is just as valid as the interpretation of any other pair; namely, that the system is in both components simultanously. But this is obvious nonsense given the plethora of valid bases, so the interpretation fails. THIS is my point. Am I mistaken? AG

[Brent Meeker]

The way I read what you posted above is that it would "make no sense" to say a ship on a heading of 345deg is simultaneously moving on a 270deg and 90deg heading.  I think that does make sense.   The interesting question is could it be moving on some other heading?  The answer might be no, it's in the Panama Canal.  In other words there may be something else in physics that determines  perferred basis, even thought he bare Schrodinger equation doesn't seem to.

brent

[Alan Grayson]

No, not what I meant. Rather, a ship with a heading of 345 deg, could be represented as moving on a 270deg and 90deg heading, as well as an uncountable combination of other headings.  I think this fundamental misinterpretation of superposition of states leads to the MWI and a host of other "mysteries" alleged in QM. AG 

[Alan Grayson]

IOW, you can think of the wf representing a heading of 345deg, and since the basis in Hilbert Space is not unique, you can imagine that very same wf composed of different components. Thus, if it's claimed that one set of basis components simultaneously represents the wf, one can also find another, different set of basis components to simultaneously represent the wf. It therefore makes no sense to claim that any set of basis components simultaneously represents the wf. Specifically, the quantum claim that a system can be in several component states simultaneously, is bogus, since the components are not unique. AG 

[Brent Meeker]

But my example of the ship shows that it's a commonplace that a vector can be represented as a sum of components in infinitely many ways...it's a trivial result of being a vector space.  It's just your prejudice that there has to be a unique "really, really real" representation.

Brent

[Alan Grayson]

I have no prejudice. I do not insist on a unique representation; nor do I believe that. Rather, I am saying that SINCE there is no unique representation, it's a fallacy to take, say one representation, and assert that the components in one representation, simultaneously represent the wf. So, for example, in the case of S's cat, it's a fallacy to assert that the cat is simultanously Alive and Dead. It's the lack of recognition of the NON-UNIQUENESS that is responsible for the misinterpretation of the superposition and many (not all) alleged weird interpretations of QM. AG 

[Philip Thrift]

I suppose if a ship was sent through double straits (A,B) to a linear array of docks D(x), then some angle pairs (A,D(x)), (B,D(x)) would interfere with each other and some would reinforce.

:) 

@philipthrift

[Alan Grayson]

I'm trying to make an important claim, so I don't appreciate jokes on this thread. AG 

[Philip Thrift]

It wasn't a joke.

What I call a "ship" above can be done with a 2000-atom molecule in a double slit experiment (latest news).

Now a 2000-atom molecule is not as big as ship, but it should provide what you need to know, If you think about it.

@philipthrift

[Philip Thrift]

These are oligo-tetraphenyl porphyrins enriched with fluoroalkyl-sulfanyl chains.

@philithrift 

[Brent Meeker]

On 10/11/2019 12:18 AM, Alan Grayson wrote:
> I am saying that SINCE there is no unique representation, it's a
> fallacy to take, say one representation, and assert that the
> components in one representation, simultaneously represent the wf.

But that's an invalid inference.  If there is no unique representation,
then there is more than one representation.  Some of those consist of a
linear composition of components.  You seem to infer that because there
is no unique representation then representations in terms of components
is wrong...but those two things are not only consistent, they are
logically equivalent; each one implies the other.

Brent

[Alan Grayson]

No; on the contrary, I think all the representations are valid. What's invalid

is singling out one representation and asserting the system is simultaneously

in ALL the components of THAT representation. AG 

[Alan Grayson]

I wasn't clear in one or more of my previous comments, but the latter is what I meant. 

All representations are valid; basic linear algebra. But to ascribe ontological status to 

one particular set of components, when in general there exists an uncountable set, is 

a fallacy. I thought I illustrated that point with S's cat. AG

[Brent Meeker]

Contrast the SG experiments with silver atoms.  In that case the different bases are equally real, but an atom can be in definite spin state, say UP, which is a superposition of LEFT and RIGHT.  This can be confirmed by measuring in the LEFT/RIGHT basis.  So did the LEFT/RIGHT components exist when the atom was in the UP state?  That sounds like a metaphysical or semantic question about the meaning of  "being in" a state.  But Schroedinger's cat is different because it is impossible to measure in the |LIVE>+|DEAD> and |LIVE>-|DEAD> basis.  That was Schroedinger's point that this superposition is absurd.  But why is it absurd?  The best answer seems to be Zurek's einselection, meaning it's not because there's an uncountable set of bases in the LIVE/DEAD hyperplane, but because only |LIVE> and |DEAD> are stable states against environmental interaction.

Brent

[Alan Grayson]

There may be some exceptions for my claim. I need to study the silver atom case and get back to you. But in the case of S's cat, I think the problem is with the alleged quantum states of |Live> and |Dead>. What is the operator that has those states as eigenstates? If it can't be specified, maybe the construct makes no sense. AG

[Brent Meeker]

Well none, or at least none that anyone could possibly implement as a Hermitean projection operator of some instrument.  Schrodinger just chose ALIVE/DEAD to emphasize how absurd it was to attribute superpositions to macroscopic objects.  But he didn't know why it was absurd.  He could have stuck to just the radioactive atom decaying or the geiger counter tube detecting it, but that wouldn't have been obviously absurd.

Brent

[Alan Grayson]

I agree with that! If it shows that superpositions cannot be attributed to macroscopic objects, then perhaps the idea that everything is quantum is precarious, if not false. And if he didn't need a cat, just a radioactive source, what would the consequences have been? AG 

[Alan Grayson]

Maybe Schroedinger wanted to show that superposition was inherently absurd, when interpreted as a radioactive source being decayed and undecayed simultaneously -- which is what I have been claiming on other grounds. AG

[Brent Meeker]

But that's not absurd, because it is possible to have a radioactive atom that is isolated from all environment and other degrees of freedom and so it might exist in a superposition.  This is how quantum computers gain power compared to classical computers.  Qubits exist in superpositions.  But it's hard to keep them cold enough and isolated enough for long enough to computer something.

Brent

[Alan Grayson]

But if you amplify the micro superposition and throw in a cat, you get an absurdity. Maybe Schroedinger was also trying to show that the interpretation of micro superposition is not correct. AG 

[Brent Meeker]

On 10/11/2019 6:58 PM, Alan Grayson wrote:

But that's not absurd, because it is possible to have a radioactive atom that is isolated from all environment and other degrees of freedom and so it might exist in a superposition. 

But if you amplify the micro superposition and throw in a cat, you get an absurdity. Maybe Schroedinger was also trying to show that the interpretation of micro superposition is not correct. AG 

Yes, I think he did.  But he was wrong about that.  Bohr saved the theory by declaring that there was a classical world and a quantum world,  which worked pretty well because everybody's intuition about the Heisenberg cut was about the same.

Brent

[Philip Thrift]

 Schrodinger just chose ALIVE/DEAD to emphasize how absurd it was to attribute superpositions to macroscopic objects. 

Brent

Quantum phenomena has been observed with 2000-atom sized molecules.

What counts as macroscopic?

@philipthrift 

[Alan Grayson]

I don't see how Bohr saved the theory (of superposition?) by making that declaration. Isn't there general agreement today that everything is quantum? AG

[Alan Grayson]

On Friday, October 11, 2019 at 1:50:34 PM UTC-6, Brent wrote:

On 10/11/2019 11:35 AM, Alan Grayson wrote:

On Friday, October 11, 2019 at 12:27:19 PM UTC-6, Alan Grayson wrote:

On Friday, October 11, 2019 at 12:10:27 PM UTC-6, Brent wrote:

On 10/11/2019 12:18 AM, Alan Grayson wrote:
> I am saying that SINCE there is no unique representation, it's a
> fallacy to take, say one representation, and assert that the
> components in one representation, simultaneously represent the wf.

But that's an invalid inference.  If there is no unique representation,
then there is more than one representation.  Some of those consist of a
linear composition of components.  You seem to infer that because there
is no unique representation then representations in terms of components
is wrong...but those two things are not only consistent, they are
logically equivalent; each one implies the other.

Brent

No; on the contrary, I think all the representations are valid. What's invalid

is singling out one representation and asserting the system is simultaneously

in ALL the components of THAT representation. AG 

I wasn't clear in one or more of my previous comments, but the latter is what I meant. 

All representations are valid; basic linear algebra. But to ascribe ontological status to 

one particular set of components, when in general there exists an uncountable set, is 

a fallacy. I thought I illustrated that point with S's cat. AG

Contrast the SG experiments with silver atoms.  In that case the different bases are equally real, but an atom can be in definite spin state, say UP, which is a superposition of LEFT and RIGHT.  This can be confirmed by measuring in the LEFT/RIGHT basis.  So did the LEFT/RIGHT components exist when the atom was in the UP state?  That sounds like a metaphysical or semantic question about the meaning of  "being in" a state.

FWIW, I don't think it's a metaphysical question about the meaning of "being in" a state because, for example, the superposition misinterpretation (IMO) leads to claims a particle can be in several positions simultaneously. I don't understand spin state, so I won't comment on it at this time. AG

[Brent Meeker]

Ask Schroedinger.

Brent

[Alan Grayson]

On Tuesday, October 8, 2019 at 10:20:19 PM UTC-6, Alan Grayson wrote:

I've argued this before, but it's worth stating again. It's a misintepretation of superposition to claim that a system described by it, is in all the component states simultaneously. As is easily seen in ordinary vector space, an arbitrary vector has an uncountable number of different representations. Thus, to claim it is in some specific set of component states simultaneously, makes no sense. Thus evaporates a key "mystery" of quantum theory, inclusive of S's cat and Everett's many worlds. AG

Worth a read, I think.  https://www.scientificamerican.com/article/giant-molecules-exist-in-two-places-at-once-in-unprecedented-quantum-experiment/

AG

[Alan Grayson]

I just posted the article about this. How does the existence of interference for a large molecule demonstrate that a particle can be in multiple positions simultaneously? AG 

[Philip Thrift]

I can't. He's |dead>.

@philipthrift 

[Philip Thrift]

What is your "quantum interpretation" of this:

These hefty molecules (oligotetraphenyl porphyrins enriched with fluoroalkyl-sulfanyl chains) are sent through a 2-slit screen and land on a collection array forming a diffraction pattern (just as photons do). How does the presence of the 2 slits make the interference pattern? What is interfering with what?

(Sabine Hosssenfelder says a particle - and she would have to say this molecule - is in two places at once. But she doesn't have a quantum interpretation. But what would Vic Stenger have said? I am partial to some some sort of path-integral sum-over-histories interpretation*, but it seems the world is adopting the Many World interpretation today, so it doesn't matter.)

* Sum Over Histories: Discrete Step Interpretation

   Muhammad Adeel Ajaib

   University of Delaware

   https://arxiv.org/pdf/1403.2017.pdf

Beneath the surface of our world lies a sea where quantal histories are born and die.

@philipthrift

[spudb...@aol.com]

hmm. How do we know that the sub-realm of the cosmos, a place where quantum universe (is there any other kind?) thrive and perish? Darwinian at least for the planet we know, and the rest seem lifeless, so we have no comparison that I am aware of, even as a postulated computer model. Conway's Life and all that. Also, the nice virtual particles (electrons only?) seem to pop, in and out of our laboratories, seem to be factual. This was D. Deutsches view of quantum computing, that they pop in here, pop out there. entangled here, untangle there, pop back here, and Ola' we have our qubit. 

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[Brent Meeker]

There is now, but "Shut and calculate" produced huge advancements in understanding physics, chemistry, and biology and produced the solid-state electronics revolution - without metaphysics getting in the way.

Brent

[Alan Grayson]

Where have I introduced metaphysics? If a superposition means that all components are simultaneously realizied, which I presume is Bohr's position, this is where metaphysics has been introduced, unless it can be shown valid. Does double slit interference mean all components are simultaneously realized, which is the road to MW? Why is this interpretation valid? AG 

[Philip Thrift]

The "calculate" methods (actually programs now, found in GitHub, etc.) are in-themselves interpretations of what they model, and are the only interpretation that really matter.

@philipthrift

[Alan Grayson]

On Saturday, October 12, 2019 at 11:39:04 AM UTC-6, Philip Thrift wrote:

On Saturday, October 12, 2019 at 11:16:20 AM UTC-5, Alan Grayson wrote:

On Friday, October 11, 2019 at 11:41:53 AM UTC-6, Philip Thrift wrote:

What I call a "ship" above can be done with a 2000-atom molecule in a double slit experiment (latest news).

Now a 2000-atom molecule is not as big as ship, but it should provide what you need to know, If you think about it.

@philipthrift

I just posted the article about this. How does the existence of interference for a large molecule demonstrate that a particle can be in multiple positions simultaneously? AG 

What is your "quantum interpretation" of this:

These hefty molecules (oligotetraphenyl porphyrins enriched with fluoroalkyl-sulfanyl chains) are sent through a 2-slit screen and land on a collection array forming a diffraction pattern (just as photons do). How does the presence of the 2 slits make the interference pattern? What is interfering with what?

I don't know. The size of the molecules is irrelevant. I am willing to leave it at that without grandeous interpretations.  But since you think it means all components are simultaneously realized, even if the particles are measured one at the time, with large time delays, what's the logic to this conclusion? AG

[Alan Grayson]

On Saturday, October 12, 2019 at 3:31:19 PM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:39:04 AM UTC-6, Philip Thrift wrote:

On Saturday, October 12, 2019 at 11:16:20 AM UTC-5, Alan Grayson wrote:

On Friday, October 11, 2019 at 11:41:53 AM UTC-6, Philip Thrift wrote:

What I call a "ship" above can be done with a 2000-atom molecule in a double slit experiment (latest news).

Now a 2000-atom molecule is not as big as ship, but it should provide what you need to know, If you think about it.

@philipthrift

I just posted the article about this. How does the existence of interference for a large molecule demonstrate that a particle can be in multiple positions simultaneously? AG 

What is your "quantum interpretation" of this:

These hefty molecules (oligotetraphenyl porphyrins enriched with fluoroalkyl-sulfanyl chains) are sent through a 2-slit screen and land on a collection array forming a diffraction pattern (just as photons do). How does the presence of the 2 slits make the interference pattern? What is interfering with what?

I don't know. The size of the molecules is irrelevant. I am willing to leave it at that without grandeous interpretations.  But since you think it means all components are simultaneously realized, even if the particles are measured one at the time, with large time delays, what's the logic to this conclusion? AG

 

(Sabine Hosssenfelder says a particle - and she would have to say this molecule - is in two places at once. But she doesn't have a quantum interpretation. But what would Vic Stenger have said?

Stenger found the MWI abhorrent. Don't recall what alternative he suggested, if any. AG 

[Brent Meeker]

On 10/12/2019 2:23 PM, Alan Grayson wrote:

I don't see how Bohr saved the theory (of superposition?) by making that declaration. Isn't there general agreement today that everything is quantum? AG

There is now, but "Shut and calculate" produced huge advancements in understanding physics, chemistry, and biology and produced the solid-state electronics revolution - without metaphysics getting in the way.

Brent

Where have I introduced metaphysics? If a superposition means that all components are simultaneously realizied,

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

[Brent Meeker]

On 10/12/2019 2:38 PM, Alan Grayson wrote:

What is your "quantum interpretation" of this:

These hefty molecules (oligotetraphenyl porphyrins enriched with fluoroalkyl-sulfanyl chains) are sent through a 2-slit screen and land on a collection array forming a diffraction pattern (just as photons do). How does the presence of the 2 slits make the interference pattern? What is interfering with what?

I don't know. The size of the molecules is irrelevant. I am willing to leave it at that without grandeous interpretations.  But since you think it means all components are simultaneously realized, even if the particles are measured one at the time, with large time delays, what's the logic to this conclusion? AG

 

(Sabine Hosssenfelder says a particle - and she would have to say this molecule - is in two places at once. But she doesn't have a quantum interpretation. But what would Vic Stenger have said?

Stenger found the MWI abhorrent. Don't recall what alternative he suggested, if any. AG 

Vic, liked some form of retro-causation, like Cramer's transactional QM.

Brent

[Alan Grayson]

On Saturday, October 12, 2019 at 4:49:36 PM UTC-6, Brent wrote:

On 10/12/2019 2:23 PM, Alan Grayson wrote:

I don't see how Bohr saved the theory (of superposition?) by making that declaration. Isn't there general agreement today that everything is quantum? AG

There is now, but "Shut and calculate" produced huge advancements in understanding physics, chemistry, and biology and produced the solid-state electronics revolution - without metaphysics getting in the way.

Brent

Where have I introduced metaphysics? If a superposition means that all components are simultaneously realizied,

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real? In the case of the Cat, "real" means it's alive and dead simultaneously. AG 

[Brent Meeker]

On 10/12/2019 3:57 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 4:49:36 PM UTC-6, Brent wrote:

On 10/12/2019 2:23 PM, Alan Grayson wrote:

I don't see how Bohr saved the theory (of superposition?) by making that declaration. Isn't there general agreement today that everything is quantum? AG

There is now, but "Shut and calculate" produced huge advancements in understanding physics, chemistry, and biology and produced the solid-state electronics revolution - without metaphysics getting in the way.

Brent

Where have I introduced metaphysics? If a superposition means that all components are simultaneously realizied,

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

[Alan Grayson]

On Saturday, October 12, 2019 at 5:50:53 PM UTC-6, Brent wrote:

On 10/12/2019 3:57 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 4:49:36 PM UTC-6, Brent wrote:

On 10/12/2019 2:23 PM, Alan Grayson wrote:

I don't see how Bohr saved the theory (of superposition?) by making that declaration. Isn't there general agreement today that everything is quantum? AG

There is now, but "Shut and calculate" produced huge advancements in understanding physics, chemistry, and biology and produced the solid-state electronics revolution - without metaphysics getting in the way.

Brent

Where have I introduced metaphysics? If a superposition means that all components are simultaneously realizied,

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG 

[Brent Meeker]

On 10/12/2019 5:46 PM, Alan Grayson wrote:

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG

Scan up until you see this symbol "?"

Brent

[Alan Grayson]

I explained what "realized" means by giving an example; S's cat, alive and dead simultaneously. Also, I said I would get back to you about spin superpositions when I have time to research the issue. Other than those items, I honestly have no idea what you're complaining about. Try asking me again. AG 

[Alan Grayson]

Maybe this is what you want; my definition or concept of what's "real" or "realizable". It's something that's measurable, like the fundamental particles; or in Vic's terminology, something that "kicks back".  AG

[Brent Meeker]

On 10/12/2019 7:21 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 8:07:46 PM UTC-6, Brent wrote:

On 10/12/2019 5:46 PM, Alan Grayson wrote:

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG

Scan up until you see this symbol "?"

Brent

I explained what "realized" means by giving an example; S's cat, alive and dead simultaneously.

That's a representation in the theory.  Every measurement that "realizes" its state finds it to be one or the other.  So what's the operational significance of "being realized"?  Schroedinger's whole point was that an alive and dead cat is never realized.

Brent

Also, I said I would get back to you about spin superpositions when I have time to research the issue. Other than those items, I honestly have no idea what you're complaining about. Try asking me again. AG 

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[Alan Grayson]

On Saturday, October 12, 2019 at 11:30:19 PM UTC-6, Brent wrote:

On 10/12/2019 7:21 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 8:07:46 PM UTC-6, Brent wrote:

On 10/12/2019 5:46 PM, Alan Grayson wrote:

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG

Scan up until you see this symbol "?"

Brent

I explained what "realized" means by giving an example; S's cat, alive and dead simultaneously.

That's a representation in the theory.  Every measurement that "realizes" its state finds it to be one or the other.  So what's the operational significance of "being realized"?  Schroedinger's whole point was that an alive and dead cat is never realized.

Brent

As I previously suggested, since there is no operator that has those cat states as eigenstates, S's example was probably meant to falsify the then prevailing (and continuing) interpretation of superposition, as it leads to an absurdity. It's not just about the cat! But the case of spin could be an exception to my general claim that it's a fallacy to interpret a superposition to mean the system so described, is in all component states simultaneously. AG  

Also, I said I would get back to you about spin superpositions when I have time to research the issue. Other than those items, I honestly have no idea what you're complaining about. Try asking me again. AG 

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[Alan Grayson]

On Saturday, October 12, 2019 at 11:48:33 PM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:30:19 PM UTC-6, Brent wrote:

On 10/12/2019 7:21 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 8:07:46 PM UTC-6, Brent wrote:

On 10/12/2019 5:46 PM, Alan Grayson wrote:

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG

Scan up until you see this symbol "?"

Brent

I explained what "realized" means by giving an example; S's cat, alive and dead simultaneously.

That's a representation in the theory.  Every measurement that "realizes" its state finds it to be one or the other.  So what's the operational significance of "being realized"?  Schroedinger's whole point was that an alive and dead cat is never realized.

Brent

As I previously suggested, since there is no operator that has those cat states as eigenstates, S's example was probably meant to falsify the then prevailing (and continuing) interpretation of superposition, as it leads to an absurdity. It's not just about the cat! But the case of spin could be an exception to my general claim that it's a fallacy to interpret a superposition to mean the system so described, is in all component states simultaneously. AG  

S's cat scenario was not simply about the fate of a cat. After all, we already knew a cat can't be alive and dead simultaneously. It must have been to show the fallacy of the prevailing interpretation of superposition. AG 

[Philip Thrift]

To say something is not real is also a metaphysical statement.

Even to say a formula (expression in mathematical notation) is a tool (instrument) to make predictions of a particular physical phenomenon is metaphysical in some way -- by the choice of mathematical language in which the formula is expressed,

@philipthrift

[Philip Thrift]

Vic wrote all I've done is to reify Feynman paths in the path integral.

Something like FISH (Feynman Integral Symmetry Hypothesis [Huw Price, Ken Wharton]).

@philithrift 

[Philip Thrift]

To add: To the neopragmatists [ https://en.wikipedia.org/wiki/Neopragmatism ] (and others similar), what counts as "real" vs. "useful fiction" is never quite totally separated. 

@philipthrift

@philipthrift

[Bruno Marchal]

> On 9 Oct 2019, at 08:28, 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
>
>
>
> On 10/8/2019 9:20 PM, Alan Grayson wrote:
>> I've argued this before, but it's worth stating again. It's a misintepretation of superposition to claim that a system described by it, is in all the component states simultaneously. As is easily seen in ordinary vector space, an arbitrary vector has an uncountable number of different representations. Thus, to claim it is in some specific set of component states simultaneously, makes no sense. Thus evaporates a key "mystery" of quantum theory, inclusive of S's cat and Everett's many worlds. AG
>
> No. It changes the problem to the question of why there are preferred bases.

There are no preferred base. Or, if you prefer, such base are chosen by the entities which can be conscious, or compute, relatively to such base. Then there are some explanation why such bases favour the position observable, like the analysis by Zurek of decoherence.

Bruno



>
> Brent

>
> --
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[Bruno Marchal]

On 9 Oct 2019, at 12:52, Alan Grayson <agrays...@gmail.com> wrote:

On Wednesday, October 9, 2019 at 12:28:38 AM UTC-6, Brent wrote:

On 10/8/2019 9:20 PM, Alan Grayson wrote:
> I've argued this before, but it's worth stating again. It's a
> misintepretation of superposition to claim that a system described by
> it, is in all the component states simultaneously. As is easily seen
> in ordinary vector space, an arbitrary vector has an uncountable
> number of different representations. Thus, to claim it is in some
> specific set of component states simultaneously, makes no sense. Thus
> evaporates a key "mystery" of quantum theory, inclusive of S's cat and
> Everett's many worlds. AG

No.  It changes the problem to the question of why there are preferred
bases.

Brent

Who chose Alive and Dead, or Awake and Sleeping for the S. cat? Wasn't it the observer? Since they had other choices, my claim stands. AG 

Everett showed explicitly that the relative states, and their relative statistics does not depend on the choice of the bases.

Something quite similar occur already in arithmetic, with a much general notion of "base”.

Bruno

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[Bruno Marchal]

On 10 Oct 2019, at 00:21, 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:

On 10/9/2019 3:52 AM, Alan Grayson wrote:

On Wednesday, October 9, 2019 at 12:28:38 AM UTC-6, Brent wrote:

On 10/8/2019 9:20 PM, Alan Grayson wrote:
> I've argued this before, but it's worth stating again. It's a
> misintepretation of superposition to claim that a system described by
> it, is in all the component states simultaneously. As is easily seen
> in ordinary vector space, an arbitrary vector has an uncountable
> number of different representations. Thus, to claim it is in some
> specific set of component states simultaneously, makes no sense. Thus
> evaporates a key "mystery" of quantum theory, inclusive of S's cat and
> Everett's many worlds. AG

No.  It changes the problem to the question of why there are preferred
bases.

Brent

Who chose Alive and Dead, or Awake and Sleeping for the S. cat? Wasn't it the observer?

Could the observer have chosen |alive>+|dead> and |alive>-|dead> as a basis?

In principle yes. And if you look at the cat, you are yourself described by [(seeing the cat alive )(cat alive) + (seeing the cat dead)(cat dead)]. Then I have still the choice by measuring you with a device measuring if you are seeing a cat alive, or dead, or off you are in the state 

 [(seeing the cat alive )(cat alive) + (seeing the cat dead)(cat dead)]

Or in the state

 [(seeing the cat alive )(cat alive) - (seeing the cat dead)(cat dead)]

That does not change your own statistics. 

Bruno

Brent

Since they had other choices, my claim stands. AG

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[Alan Grayson]

On Sunday, October 13, 2019 at 12:00:53 AM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:48:33 PM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:30:19 PM UTC-6, Brent wrote:

On 10/12/2019 7:21 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 8:07:46 PM UTC-6, Brent wrote:

On 10/12/2019 5:46 PM, Alan Grayson wrote:

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG

Scan up until you see this symbol "?"

Brent

I explained what "realized" means by giving an example; S's cat, alive and dead simultaneously.

That's a representation in the theory.  Every measurement that "realizes" its state finds it to be one or the other.  So what's the operational significance of "being realized"?  Schroedinger's whole point was that an alive and dead cat is never realized.

Brent

As I previously suggested, since there is no operator that has those cat states as eigenstates, S's example was probably meant to falsify the then prevailing (and continuing) interpretation of superposition, as it leads to an absurdity. It's not just about the cat! But the case of spin could be an exception to my general claim that it's a fallacy to interpret a superposition to mean the system so described, is in all component states simultaneously. AG  

S's cat scenario was not simply about the fate of a cat. After all, we already knew a cat can't be alive and dead simultaneously. It must have been to show the fallacy of the prevailing interpretation of superposition. AG 

Incidentally, as I pointed out in a previous discussion of this issue, decoherence doesn't help. Even though it is extremely rapid, say 10^(-20) sec, there is still a finite duration when, according to the standard interpretation of superposition, the cat it is alive and dead simultaneously. LC might see this as nit-picking, but it isn't. We know a cat cannot be alive and dead simultaneously regardless of the time duration, however short. So this result, when apply decoherence, doesn't avoid the superposition fallacy illustrated by S's cat. It can be traced to the interpretation of the superposition of (|decayed> + |undecayed>) of the radioactive source. AG

[Alan Grayson]

Brent is right. Stenger was a firm believer in retrocausality. I don't understand his comment, which is probably wrong, as is retrocausality.  AG 

[Alan Grayson]

On Sunday, October 13, 2019 at 7:48:29 AM UTC-6, Bruno Marchal wrote:

On 9 Oct 2019, at 12:52, Alan Grayson <agrays...@gmail.com> wrote:

On Wednesday, October 9, 2019 at 12:28:38 AM UTC-6, Brent wrote:

On 10/8/2019 9:20 PM, Alan Grayson wrote:
> I've argued this before, but it's worth stating again. It's a
> misintepretation of superposition to claim that a system described by
> it, is in all the component states simultaneously. As is easily seen
> in ordinary vector space, an arbitrary vector has an uncountable
> number of different representations. Thus, to claim it is in some
> specific set of component states simultaneously, makes no sense. Thus
> evaporates a key "mystery" of quantum theory, inclusive of S's cat and
> Everett's many worlds. AG

No.  It changes the problem to the question of why there are preferred
bases.

Brent

Who chose Alive and Dead, or Awake and Sleeping for the S. cat? Wasn't it the observer? Since they had other choices, my claim stands. AG 

Everett showed explicitly that the relative states, and their relative statistics does not depend on the choice of the bases.

Something quite similar occur already in arithmetic, with a much general notion of "base”.

Bruno

Arithmetic does not include probability theory. AG 

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[Brent Meeker]

On 10/13/2019 6:44 AM, Bruno Marchal wrote:
>> On 9 Oct 2019, at 08:28, 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
>>
>>
>>
>> On 10/8/2019 9:20 PM, Alan Grayson wrote:
>>> I've argued this before, but it's worth stating again. It's a misintepretation of superposition to claim that a system described by it, is in all the component states simultaneously. As is easily seen in ordinary vector space, an arbitrary vector has an uncountable number of different representations. Thus, to claim it is in some specific set of component states simultaneously, makes no sense. Thus evaporates a key "mystery" of quantum theory, inclusive of S's cat and Everett's many worlds. AG
>> No. It changes the problem to the question of why there are preferred bases.
> There are no preferred base. Or, if you prefer, such base are chosen by the entities which can be conscious, or compute, relatively to such base.

For someone who claims to have shown that physics is derivative from
psychology that should count as fundamentally preferred.

Brent

[Brent Meeker]

On 10/13/2019 6:48 AM, Bruno Marchal wrote:

On 9 Oct 2019, at 12:52, Alan Grayson <agrays...@gmail.com> wrote:

On Wednesday, October 9, 2019 at 12:28:38 AM UTC-6, Brent wrote:

On 10/8/2019 9:20 PM, Alan Grayson wrote:
> I've argued this before, but it's worth stating again. It's a
> misintepretation of superposition to claim that a system described by
> it, is in all the component states simultaneously. As is easily seen
> in ordinary vector space, an arbitrary vector has an uncountable
> number of different representations. Thus, to claim it is in some
> specific set of component states simultaneously, makes no sense. Thus
> evaporates a key "mystery" of quantum theory, inclusive of S's cat and
> Everett's many worlds. AG

No.  It changes the problem to the question of why there are preferred
bases.

Brent

Who chose Alive and Dead, or Awake and Sleeping for the S. cat? Wasn't it the observer? Since they had other choices, my claim stands. AG 

Everett showed explicitly that the relative states, and their relative statistics does not depend on the choice of the bases.

Something quite similar occur already in arithmetic, with a much general notion of "base”.

But he didn't explain why observations were only possible in some bases.

Brent

[Brent Meeker]

On 10/13/2019 6:52 AM, Bruno Marchal wrote:

On 10 Oct 2019, at 00:21, 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:

On 10/9/2019 3:52 AM, Alan Grayson wrote:

On Wednesday, October 9, 2019 at 12:28:38 AM UTC-6, Brent wrote:

On 10/8/2019 9:20 PM, Alan Grayson wrote:
> I've argued this before, but it's worth stating again. It's a
> misintepretation of superposition to claim that a system described by
> it, is in all the component states simultaneously. As is easily seen
> in ordinary vector space, an arbitrary vector has an uncountable
> number of different representations. Thus, to claim it is in some
> specific set of component states simultaneously, makes no sense. Thus
> evaporates a key "mystery" of quantum theory, inclusive of S's cat and
> Everett's many worlds. AG

No.  It changes the problem to the question of why there are preferred
bases.

Brent

Who chose Alive and Dead, or Awake and Sleeping for the S. cat? Wasn't it the observer?

Could the observer have chosen |alive>+|dead> and |alive>-|dead> as a basis?

In principle yes. And if you look at the cat, you are yourself described by [(seeing the cat alive )(cat alive) + (seeing the cat dead)(cat dead)]. Then I have still the choice by measuring you with a device measuring if you are seeing a cat alive, or dead, or off you are in the state

No you don't, because there is no such instrument.  Physicist, unlike metaphysicians, have the job of explaining the world as they find it...not imagining how it might be.

Brent

 [(seeing the cat alive )(cat alive) + (seeing the cat dead)(cat dead)]

Or in the state

 [(seeing the cat alive )(cat alive) - (seeing the cat dead)(cat dead)]

That does not change your own statistics. 

Bruno

Brent

Since they had other choices, my claim stands. AG

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[Brent Meeker]

On 10/13/2019 7:36 AM, Alan Grayson wrote:

On Sunday, October 13, 2019 at 12:00:53 AM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:48:33 PM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:30:19 PM UTC-6, Brent wrote:

On 10/12/2019 7:21 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 8:07:46 PM UTC-6, Brent wrote:

On 10/12/2019 5:46 PM, Alan Grayson wrote:

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG

Scan up until you see this symbol "?"

Brent

I explained what "realized" means by giving an example; S's cat, alive and dead simultaneously.

That's a representation in the theory.  Every measurement that "realizes" its state finds it to be one or the other.  So what's the operational significance of "being realized"?  Schroedinger's whole point was that an alive and dead cat is never realized.

Brent

As I previously suggested, since there is no operator that has those cat states as eigenstates, S's example was probably meant to falsify the then prevailing (and continuing) interpretation of superposition, as it leads to an absurdity. It's not just about the cat! But the case of spin could be an exception to my general claim that it's a fallacy to interpret a superposition to mean the system so described, is in all component states simultaneously. AG  

S's cat scenario was not simply about the fate of a cat. After all, we already knew a cat can't be alive and dead simultaneously. It must have been to show the fallacy of the prevailing interpretation of superposition. AG 

Incidentally, as I pointed out in a previous discussion of this issue, decoherence doesn't help. Even though it is extremely rapid, say 10^(-20) sec, there is still a finite duration when, according to the standard interpretation of superposition, the cat it is alive and dead simultaneously. LC might see this as nit-picking, but it isn't. We know a cat cannot be alive and dead simultaneously regardless of the time duration, however short.

What are you talking about?  Even when someone dies in a hospital, hooked up to all kinds of electronic recording instruments, the time of death can't be determined to the second, much less 1e-20sec.

Brent

So this result, when apply decoherence, doesn't avoid the superposition fallacy illustrated by S's cat. It can be traced to the interpretation of the superposition of (|decayed> + |undecayed>) of the radioactive source. AG

Also, I said I would get back to you about spin superpositions when I have time to research the issue. Other than those items, I honestly have no idea what you're complaining about. Try asking me again. AG 

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[Alan Grayson]

On Sunday, October 13, 2019 at 1:24:37 PM UTC-6, Brent wrote:

On 10/13/2019 7:36 AM, Alan Grayson wrote:

On Sunday, October 13, 2019 at 12:00:53 AM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:48:33 PM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:30:19 PM UTC-6, Brent wrote:

On 10/12/2019 7:21 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 8:07:46 PM UTC-6, Brent wrote:

On 10/12/2019 5:46 PM, Alan Grayson wrote:

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG

Scan up until you see this symbol "?"

Brent

I explained what "realized" means by giving an example; S's cat, alive and dead simultaneously.

That's a representation in the theory.  Every measurement that "realizes" its state finds it to be one or the other.  So what's the operational significance of "being realized"?  Schroedinger's whole point was that an alive and dead cat is never realized.

Brent

As I previously suggested, since there is no operator that has those cat states as eigenstates, S's example was probably meant to falsify the then prevailing (and continuing) interpretation of superposition, as it leads to an absurdity. It's not just about the cat! But the case of spin could be an exception to my general claim that it's a fallacy to interpret a superposition to mean the system so described, is in all component states simultaneously. AG  

S's cat scenario was not simply about the fate of a cat. After all, we already knew a cat can't be alive and dead simultaneously. It must have been to show the fallacy of the prevailing interpretation of superposition. AG 

Incidentally, as I pointed out in a previous discussion of this issue, decoherence doesn't help. Even though it is extremely rapid, say 10^(-20) sec, there is still a finite duration when, according to the standard interpretation of superposition, the cat it is alive and dead simultaneously. LC might see this as nit-picking, but it isn't. We know a cat cannot be alive and dead simultaneously regardless of the time duration, however short.

What are you talking about?  Even when someone dies in a hospital, hooked up to all kinds of electronic recording instruments, the time of death can't be determined to the second, much less 1e-20sec.

Brent

What are YOU talking about? I just made a GUESS about the decoherence time! Whatever it is, it doesn't change my conclusion. If there's a uncertainty in time, are you claiming the cat can be alive and dead during any duration?  Is this what decoherence theory offers? AG

So this result, when apply decoherence, doesn't avoid the superposition fallacy illustrated by S's cat. It can be traced to the interpretation of the superposition of (|decayed> + |undecayed>) of the radioactive source. AG

Also, I said I would get back to you about spin superpositions when I have time to research the issue. Other than those items, I honestly have no idea what you're complaining about. Try asking me again. AG 

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[Alan Grayson]

Moreover, that uncertainty wouldn't be a superposition; just some probability based on ignorance. AG 

[Brent Meeker]

On 10/13/2019 1:08 PM, Alan Grayson wrote:
> What are YOU talking about? I just made a GUESS about the decoherence
> time! Whatever it is, it doesn't change my conclusion. If there's a
> uncertainty in time, are you claiming the cat can be alive and dead
> during any duration?  Is this what decoherence theory offers? AG

Yes, part of the cat can be alive and part dead over a period seconds. 
Or looked at another way, there is a transistion period in which the cat
is both alive and dead.

But the main point is that this time had nothing to do with
Schroedinger's argument (he knew perfectly well the time of death was
vague); his argument was that Bohr's interpretation implied that the cat
was in a super-position of alive and dead from the time the box was
closed until someone looked in.

Brent

[Alan Grayson]

Agreed. Without decoherence, the cat would be in a superposition of

alive and dead from the time the box was closed until someone opened

it. With decoherence, it would be in that superposition for a very short

time, the decoherence time, when it would be in state, |decayed>|dead>

or |undecayed> |alive> before the box was opened, provided it was

opened after the decoherence time. So, as I see it, decoherence just

moves the "collapse" earlier, before the box is opened, and does not

resolve S's problem with superposition. The cause of the problem, or

paradox if you will, is the superposition interpretation of the radioactive

source. AG  

[Philip Thrift]

How would you describe the "states" of qubits in IBM's Q (quantum computer)? 

@philipthrift

[Alan Grayson]

I am not familiar with the theory on which quantum computers are based, so I 

cannot answer this question. AG 

[Brent Meeker]

True, but it resolves the problem about whether conscious observers are necessary to "collapse" the wave function (or split the world). The idea of decoherence is that, it not carefully isolated, systems are continuously "monitored" by the environment and so act classically.

Here's a good analysis which casts the Schroedinger cat story into a double slit-experiment.

https://arxiv.org/pdf/1405.7612.pdf

The cause of the problem, or

paradox if you will, is the superposition interpretation of the radioactive

source. AG 

Yes, that's the problem.  The radioactive nucleus is effectively isolated until it decays, after which it is not isolated...it has interacted with the detector.  So in the MWI the system is splitting continuously into the branch were the atom hasn't decayed and the branch where is has just decayed and interacted with the environment.  The atom is in a superposition of decayed and not decayed with amplitudes varying in time:   psi = sqrt[exp(-at)]|not decayed> +sqrt[1-expt(-at)]|decayed>  .

Brent

[Philip Thrift]

My point i really that quantum computers with actual (physical) qubits are running in labs (IBM, Google, ...) as we speak. They are real things manifesting all the basic questions about quantum phenomena being posed. So it makes more sense to answer the questions about real things than thought-experiment examples. 

In an OpenQASM program, what is happening (superpositions?, entanglements?) in the physical quantum computer when it runs?

@philipthrift

[Alan Grayson]

I think Feynman answer this question before the advent of decoherence theory. I recall reading his comments that an instrument was sufficient for observing a double slit experiment, and even destroying the interference if rigged to determine which-way. AG 

The idea of decoherence is that, it not carefully isolated, systems are continuously "monitored" by the environment and so act classically.

Here's a good analysis which casts the Schroedinger cat story into a double slit-experiment.

https://arxiv.org/pdf/1405.7612.pdf

The cause of the problem, or

paradox if you will, is the superposition interpretation of the radioactive

source. AG 

Yes, that's the problem.  The radioactive nucleus is effectively isolated until it decays, after which it is not isolated...it has interacted with the detector.  So in the MWI the system is splitting continuously into the branch were the atom hasn't decayed and the branch where is has just decayed and interacted with the environment.  The atom is in a superposition of decayed and not decayed with amplitudes varying in time:   psi = sqrt[exp(-at)]|not decayed> +sqrt[1-expt(-at)]|decayed>  .

But isn't this superposition, interpreted to mean the source is in both states simultaneously before measurement, responsible for the paradox of a cat which is alive and dead simultaneously, even if for a very short time if decoherence is considered? If so, isn't this sufficient to question the validity of said interpretation? AG 

Brent

[Alan Grayson]

The issue is whether the interpretation of superposition I object to, is somehow necessary for quantum computers to function. Is it? AG

[Philip Thrift]

On the Google quantum computer, I posted this:

The hybrid Schrödinger-Feynman algorithm (in the quantum supremacy experiment)

https://groups.google.com/d/msg/everything-list/V6MDNmcFIxs/WKV_eQm_CgAJ

The SFA (above) has whatever "interpretation" is needed, one would presume.

@philipthrift

 

[Bruno Marchal]

On 13 Oct 2019, at 16:36, Alan Grayson <agrays...@gmail.com> wrote:

On Sunday, October 13, 2019 at 12:00:53 AM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:48:33 PM UTC-6, Alan Grayson wrote:

On Saturday, October 12, 2019 at 11:30:19 PM UTC-6, Brent wrote:

On 10/12/2019 7:21 PM, Alan Grayson wrote:

On Saturday, October 12, 2019 at 8:07:46 PM UTC-6, Brent wrote:

On 10/12/2019 5:46 PM, Alan Grayson wrote:

What does "realized" mean?  made real?  Being real is a metaphysical concept.  Bohr never said anything about components of a superposition being real.  He famously said “Physics is not about how the world is, it is about what we can say about the world” and “Everything we call real is made of things that cannot be regarded as real.”

Brent

The latter comment is ridiculous. Aren't protons, neutrons and electrons real?

Ask Bohr.  You never answer my questions; why should I answer yours.

Brent

What questions haven't I answered??? AG

Scan up until you see this symbol "?"

Brent

I explained what "realized" means by giving an example; S's cat, alive and dead simultaneously.

That's a representation in the theory.  Every measurement that "realizes" its state finds it to be one or the other.  So what's the operational significance of "being realized"?  Schroedinger's whole point was that an alive and dead cat is never realized.

Brent

As I previously suggested, since there is no operator that has those cat states as eigenstates, S's example was probably meant to falsify the then prevailing (and continuing) interpretation of superposition, as it leads to an absurdity. It's not just about the cat! But the case of spin could be an exception to my general claim that it's a fallacy to interpret a superposition to mean the system so described, is in all component states simultaneously. AG  

S's cat scenario was not simply about the fate of a cat. After all, we already knew a cat can't be alive and dead simultaneously. It must have been to show the fallacy of the prevailing interpretation of superposition. AG 

Incidentally, as I pointed out in a previous discussion of this issue, decoherence doesn't help. Even though it is extremely rapid, say 10^(-20) sec, there is still a finite duration when, according to the standard interpretation of superposition, the cat it is alive and dead simultaneously.

Once the cat is "alive and dead”, it is for life! (Grin). I mean that decoherence does not “collapse” the wave. It explains only why we can’t see it. 

By the linearity of evolution and of the tensor product, Once a superposition exist, it never disappear.

LC might see this as nit-picking, but it isn't. We know a cat cannot be alive and dead simultaneously regardless of the time duration, however short.

We don’t know that. A cat is dead + Alive in the same sense that a particle is going through two slits. With mechanism, there is no contradiction, as they are in different histories/computations.

Bruno

So this result, when apply decoherence, doesn't avoid the superposition fallacy illustrated by S's cat. It can be traced to the interpretation of the superposition of (|decayed> + |undecayed>) of the radioactive source. AG

Also, I said I would get back to you about spin superpositions when I have time to research the issue. Other than those items, I honestly have no idea what you're complaining about. Try asking me again. AG 

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[Bruno Marchal]

On 13 Oct 2019, at 16:43, Alan Grayson <agrays...@gmail.com> wrote:

On Sunday, October 13, 2019 at 7:48:29 AM UTC-6, Bruno Marchal wrote:

On 9 Oct 2019, at 12:52, Alan Grayson <agrays...@gmail.com> wrote:

On Wednesday, October 9, 2019 at 12:28:38 AM UTC-6, Brent wrote:

On 10/8/2019 9:20 PM, Alan Grayson wrote:
> I've argued this before, but it's worth stating again. It's a
> misintepretation of superposition to claim that a system described by
> it, is in all the component states simultaneously. As is easily seen
> in ordinary vector space, an arbitrary vector has an uncountable
> number of different representations. Thus, to claim it is in some
> specific set of component states simultaneously, makes no sense. Thus
> evaporates a key "mystery" of quantum theory, inclusive of S's cat and
> Everett's many worlds. AG

No.  It changes the problem to the question of why there are preferred
bases.

Brent

Who chose Alive and Dead, or Awake and Sleeping for the S. cat? Wasn't it the observer? Since they had other choices, my claim stands. AG 

Everett showed explicitly that the relative states, and their relative statistics does not depend on the choice of the bases.

Something quite similar occur already in arithmetic, with a much general notion of "base”.

Bruno

Arithmetic does not include probability theory. AG 

In the arithmetical ontology? You are right.

But if we assume mechanism, it is not difficult to explain why many form of uncertainty measure appears in the phenomenology of mind and matter from the person associated to number in the computations (realised in arithmetic). This is usually what I explain in the first half on my papers on this subject. Ask me any question starting from the papers. I have not much time until the end of November to explain it here.

Bruno

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[Bruno Marchal]

> On 13 Oct 2019, at 21:17, 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
>
>
>
> On 10/13/2019 6:44 AM, Bruno Marchal wrote:
>>> On 9 Oct 2019, at 08:28, 'Brent Meeker' via Everything List <everyth...@googlegroups.com> wrote:
>>>
>>>
>>>
>>> On 10/8/2019 9:20 PM, Alan Grayson wrote:
>>>> I've argued this before, but it's worth stating again. It's a misintepretation of superposition to claim that a system described by it, is in all the component states simultaneously. As is easily seen in ordinary vector space, an arbitrary vector has an uncountable number of different representations. Thus, to claim it is in some specific set of component states simultaneously, makes no sense. Thus evaporates a key "mystery" of quantum theory, inclusive of S's cat and Everett's many worlds. AG
>>> No. It changes the problem to the question of why there are preferred bases.
>> There are no preferred base. Or, if you prefer, such base are chosen by the entities which can be conscious, or compute, relatively to such base.
>
> For someone who claims to have shown that physics is derivative from psychology that should count as fundamentally preferred.

Psychology is not a base. Then, if we assume that the brain is Turing emulable, it is necessary that physics has to be explained from psychology, or better theology. That is the first result, and the second result is that we get quantum logic at the places expected. We get three different quantum logic, all richer than the usual inferred from nature, so we will learn more with the possible futures experiences.

Bruno

>
> Brent
>
>> Then there are some explanation why such bases favour the position observable, like the analysis by Zurek of decoherence.
>>
>> Bruno
>>
>>
>>
>>> Brent
>>>
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[Bruno Marchal]

Which is something that I doubt about. Maybe this is just false. Only Zurel makes me think that the position base is more important … for us (the human), but other bases might play a similar role. For me this is an open problem.

Bruno

Brent

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[Bruno Marchal]

A quantum computer is just that, a computer that you can put in superposition state. You can put any bit in any arbitrary superposition state, like being 0 and 1 “simultaneously”. You can put the whole processor in a superposition state, even in the on/off superposition state. With a 64 quit computer, you can do 2^64 computations simultaneously, and then you can make a Fourier transform of all results, and get some information. Shor’s algorithm, to factorise large number, use such large superposition. 

David Deutsch invented it mainly to illustrate that we have to take the superposition state seriously, but of course e know this since at least Dirac.

The technical difficulty is to get those stable, but progress have shown that it is possible, notably through quantum correction code (software solution) or through topological quantum computing (by squeezing electron in some way, we can build very stable superposition, unfortunately, the “squeezing apparatus” have to be huge, and this is not for tomorrow. But like Shannon theorem showed that we can transmit information  on wires, the quantum correcting code technics refutes many impossibility statements once made in that field.  That is why so many work on this.

Bruno

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[Bruce Kellett]

On Mon, Oct 14, 2019 at 7:08 AM Alan Grayson <agrays...@gmail.com> wrote:

What are YOU talking about? I just made a GUESS about the decoherence time! Whatever it is, it doesn't change my conclusion. If there's a uncertainty in time, are you claiming the cat can be alive and dead during any duration?  Is this what decoherence theory offers? AG

 

 Maybe this is what it means for the cat to be alive and dead at the same time?

Bruce

[Alan Grayson]

On Monday, October 14, 2019 at 3:50:46 PM UTC-6, Alan Grayson wrote

Sean says the decoherence time is 10^(-20) sec. So when the box is closed, the cat is in a superposition of alive and dead during that time interval, assuming the decay hasn't happened. If that's the case, I don't see how decoherence solves the paradox, unless we can assume an initial condition where the probability of one component of the superposition, that the cat is dead, is zero. Maybe this is the solution. What do you think? AG

Brent

[Alan Grayson]

Maybe this is an easier question; after decoherence, assuming the radioactive source hasn't decayed, what is the wf of the cat?  Is the cat in a mixed state, alive or dead with some probabIlity for each? AG

Brent

[Bruno Marchal]

If the box isolates the cat, decoherence of what is in the ox will not occur. Then when the bow is opened, it will take 10^(-20) sec before you are yourself into a superposition. With the SWE, once the cat is dead + alive, in box, or out of a box, that state of superposition will never disappear.

assuming the decay hasn't happened. If that's the case, I don't see how decoherence solves the paradox, unless we can assume an initial condition where the probability of one component of the superposition, that the cat is dead, is zero. Maybe this is the solution. What do you think? AG

Decoherence never destroys any superposition. It only makes harder (quasi-impossible, impossible in practice) to get the interference back. That’s how decoherence works well in the no-collapse formulation of QM.

Bruno

Brent

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[Bruno Marchal]

Without collapse, the cat never get into a mixed state. That never happen. But the SWE explains entirely why, from the perspective of the observer (him/herself analysed with the SWE), it looks like a mixed state has occurred.

Bruno

Brent

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[Alan Grayson]

If the box isolates the cat, decoherence of what is in the box will not occur.

The box contains an environment, the air, heat, etc., so even though the box is closed, decoherence does occur. AG 

 

Then when the bow is opened, it will take 10^(-20) sec before you are yourself into a superposition. With the SWE, once the cat is dead + alive, in box, or out of a box, that state of superposition will never disappear.

assuming the decay hasn't happened. If that's the case, I don't see how decoherence solves the paradox, unless we can assume an initial condition where the probability of one component of the superposition, that the cat is dead, is zero. Maybe this is the solution. What do you think? AG

Decoherence never destroys any superposition. It only makes harder (quasi-impossible, impossible in practice) to get the interference back. That’s how decoherence works well in the no-collapse formulation of QM.

Bruno

Brent

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[Brent Meeker]

On 10/19/2019 6:56 PM, Alan Grayson wrote:

Sean says the decoherence time is 10^(-20) sec. So when the box is closed, the cat is in a superposition of alive and dead during that time interval, assuming the decay hasn't happened. If that's the case, I don't see how decoherence solves the paradox, unless we can assume an initial condition where the probability of one component of the superposition, that the cat is dead, is zero. Maybe this is the solution. What do you think? AG

Maybe this is an easier question; after decoherence, assuming the radioactive source hasn't decayed, what is the wf of the cat?  Is the cat in a mixed state, alive or dead with some probabIlity for each? AG

You can't "assume the radioactive source hasn't decayed".  The point Schroedinger's thought experiment is that when the box is closed you don't know whether or not it has decayed and so it is in a superposition of decayed and not-decayed and the cat is correlated with these states, so it is also in a superposition of dead and alive.

Brent

[Alan Grayson]

I thought you might say this. OK, then what function does decoherence have in possibly solving the apparent paradox of a cat alive and dead simultaneously. TIA, AG 

[Brent Meeker]

It doesn't necessarily solve "that problem".  Rather it shows why you can never detect such a state, assuming you buy Zurek's idea of envariance.  One way to look at it is it's the answer to Heisenberg's question: Where is the cut between the quantum and the classical?  Once envriance has acted, then the result is classical, i.e. you can ignore the other possibilities and renormalize the wave function.

Brent

[Bruce Kellett]

And if Bruno adds "But the superposition never vanishes", I would ask him to show me one situation in which this makes any difference at all. FAPP means "For All Practical Purposes". If something has no practical purpose, what actual use is it to physics? And we are doing physics here, after all. Metaphysics is "all in your mind", and I can have different things in my mind but still do physics.

Bruce

[Alan Grayson]

Woudn't you agree that if the system, in the case a cat, goes classical after 10^(-20) sec, its state must be a mixture at that point in time even if the box hasn't been opened?  AG 

[Brent Meeker]

In MWI it's only a mixture FAPP.  But if you haven't opened the box (and Schroedinger was assuming an ideal box) you don't know whether the cat has "gone classical" or not.  So your representation of its state is still a superposition.  That's the QBist interpretation.  The wf is just what you know about the system.

[Bruno Marchal]

Decoherence is just entanglement with the environment.

Imagine that the environment ion the cat in the box is just one molecule M (to simplify). M will “measure” the state of the cat by bouncing up to some position M-cat-alive (if the cat was alive) and another position  M-cat-dead if the cat was dead. By SWE, before you open the door, the environment “in the box” + the cat is described by the superposition 

   (cat-alive)(molecule at M-cat-alive) + (cat dead)(molecule at M-cat-dead)

which is still a superposition.

The same with 10^20 molecules, heat, etc. 

When you open the box, you will just get the state

(I see the cat alive)(cat alive)(molecules in the corresponding position) + (I see the cat dead)(cat dead)(molecules in the other corresponding position).

As you cannot track the behaviour of all molecules, you are unable to extract interference pattern from that superposition, and it will look like a mixed state. But without collapse of the wave, the cat, the molecules and yourself will remain in the superposition state and this forever, and whatever base is chosen to describe the wave describing you, the molecules and the cat.

The apparent collapse is only a term of a superposition seen by an observer described by some factor in that term.

Bruno

 

Then when the bow is opened, it will take 10^(-20) sec before you are yourself into a superposition. With the SWE, once the cat is dead + alive, in box, or out of a box, that state of superposition will never disappear.

assuming the decay hasn't happened. If that's the case, I don't see how decoherence solves the paradox, unless we can assume an initial condition where the probability of one component of the superposition, that the cat is dead, is zero. Maybe this is the solution. What do you think? AG

Decoherence never destroys any superposition. It only makes harder (quasi-impossible, impossible in practice) to get the interference back. That’s how decoherence works well in the no-collapse formulation of QM.

Bruno

Brent

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[Bruce Kellett]

On Mon, Oct 21, 2019 at 10:08 PM Bruno Marchal <mar...@ulb.ac.be> wrote:

As you cannot track the behaviour of all molecules, you are unable to extract interference pattern from that superposition, and it will look like a mixed state. But without collapse of the wave, the cat, the molecules and yourself will remain in the superposition state and this forever, and whatever base is chosen to describe the wave describing you, the molecules and the cat.

Hilbert space might be independent of the basis chosen to describe it. But our experience is not independent of the basis. And it is our experience that science seeks to explain. Explanation is not independent of the basis.

Bruce