Cramer's Transactional Interpretation.

[hyksos]

Okay we have a thread on CTI now.

My purpose for starting up a thread on the Transactional Interpretation of Quantum Mechanics -- mostly for purposes of criticizing and critique. Some random observations ...

1.
CTI claims to resolve retrocausality. (In particular the retrocausal paradoxes of QM) However does so by invoking copious amounts of retrocausal phenomena with backwards-in-time moving waves. I'm not completely sure you can resolve retrocausality by embracing retrocausality in everything.

2.
CTI bends the word determinism to its breaking point. We know what a mathematician means when he says

X uniquely determines Y.

The determination is not meant to unfold mechanically in space and time, like a calculation, but instead means something like "there exists a functional association between" X and Y in a world of deduction. Saying that a future event "determines" a physical event in the present, doesn't really mean "determine" in the sense of Laplace. Not the kind of gear-A-turns-gear-B determinism we normally associate with matter/substance.

3.
CTI might be argumentum ad mysterium. It might be approaching the measurement problem and not addressing it head on. I worry (this is my opinion of course) that CTI is moving the measurement problem to a backburner. While we seem to have found a source of determinism for a present spacetime event, the mystery is "outsourced" to a fuzzy future state which is seductively mysterious enough to be believably undetermined.

Your thoughts?

[hyksos]

4.
CTI definitively asserts that the future definitely physically exists. Anything argument about the future "not yet manifest" cannot exist in CTI. Blustering over that topic seems either unwise or unscrupulous. Whole multipage threads on this forum have been spilt on that topic alone. Seems hasty to just accept it as easily as we would change into a different pair of socks.

[bangstrom]

4.
CTI definitively asserts that the future definitely physically exists. Anything argument about the future "not yet manifest" cannot exist in CTI. Blustering over that topic seems either unwise or unscrupulous. Whole multipage threads on this forum have been spilt on that topic alone. Seems hasty to just accept it as easily as we would change into a different pair of socks.

My understanding of CTI is that particles in our local surroundings can interact non-locally in a wavelike manner with particles at remote distances which is what we observe with the retrocausal paradoxes of QM. So anything distant from us lies in our future, and from the other perspective, we are a part of the future for the material world that lies at a distance from us.

This means that interacting particles are in direct quantum contact despite their observational separation so that, at the quantum level, there is no such thing as distance. What we see as “distance” is a statistical readout of instantaneous non-local events separated by space and time. As the old saying goes, time is Nature’s way of keeping everything from happening at once and space is Nature’s way of keeping everything from happening in the same place.

I think of retrocausality in CTI as limited to particles but not necessarily “everything” above the particle level. And the “future” as limited to those particles remote from our own rather than something “not yet manifest” since our local particles are what interact non-locally (instantly) with the rest of the physical universe and vice versa.

[TheVat]

This means that interacting particles are in direct quantum contact despite their observational separation so that, at the quantum level, there is no such thing as distance. What we see as “distance” is a statistical readout of instantaneous non-local events separated by space and time. As the old saying goes, time is Nature’s way of keeping everything from happening at once and space is Nature’s way of keeping everything from happening in the same place.

Good ol' Wheeler, right? Man had a way with words. I still find it confusing to say there's no such thing as distance at a certain "level." If events are separated by space, then they are at a distance from each other. That is what "distance" means. If observation is to mean anything, it means that we are observing distances. IF someone wants to say that, at the "quantum level," the photosphere of the Sun is in their living room, that's all very poetic but it doesn't do much to make sense of quantum theory.

[bangstrom]

Good ol' Wheeler, right? Man had a way with words. I still find it confusing to say there's no such thing as distance at a certain "level." If events are separated by space, then they are at a distance from each other. That is what "distance" means. If observation is to mean anything, it means that we are observing distances. IF someone wants to say that, at the "quantum level," the photosphere of the Sun is in their living room, that's all very poetic but it doesn't do much to make sense of quantum theory.

Observations at the macro level do not necessarily apply at the quantum particle level because macro objects are massive collections of quantum particles so what we observe are the collective averages of particles and not necessarily what may be happening with every individual particle. This is collectively known as quantum wierdness.

We may observe distances between objects at the macro level, but at the quantum level, separation is not a persistent phenomenon and widely separated particles can momentarily interact as if they are parts of a single whole. Non-local interaction where distance no longer matters is one example of this wierdness.

[hyksos]

My understanding of CTI is that particles in our local surroundings can interact non-locally in a wavelike manner with particles at remote distances

That is not CTI. You just described regular entanglement.

So anything distant from us lies in our future, and from the other perspective, we are a part of the future for the material world that lies at a distance from us.

\hat you are attempting to describe with distant spacetime points being "in our future" is just the normal phenomenon of a wave approaching us from the distance place in the regular expand-out manner. Stuffy grad students call it the "future lightcone".

Secondly, it is definitely not CTI. CTI explicitly has waves that move backwards in time, and to a normal human observer, these A-waves would look like an explosion in reverse. They begin spread out over the environment, then coalesce to a point. This is a specific ontological commitment in CTI.

This means that interacting particles are in direct quantum contact despite their observational separation so that, at the quantum level, there is no such thing as distance.

That doesn't follow from CTI at all. I have never in my life seen "Direct quantum contact" mentioned in any article on Interpretations of QM in my entire life. The only place I've ever seen that phrase used is in Faradave's posts on this forum.

Your description of "no space" can be demonstrated false in simple lab experiment. When a quantum system is measured, it gives us actual values every time. When engineers are trying to build a quantum computer, this problem is called decoherence, and it annoys the hell out of them. The entangled qubits will "collapse" into their own little deterministic states if any kind of heat or disturbance sneaks into the computer. Once collapsed they can no longer leverage the non-local interactions that give them the special powers to compute.

Decoherence is the reason numero uno that we don't have quantum computers in our living rooms.

What we see as “distance” is a statistical readout of instantaneous non-local events separated by space and time. As the old saying goes, time is Nature’s way of keeping everything from happening at once and space is Nature’s way of keeping everything from happening in the same place.

I don't see how this applies. What you are describing is true of the unitary wave evolution -- that strange moment when nobody looks at matter. But this universe has measurement, wherein unitary wave evolution is suddenly stopped by measurement, and genuine particle properties are observed.

There are many different reasons for engaging with Interpretations of QM. (I'm not going to list them.) One of them is to resolve the Measurement Problem. It seems to me from all I have read that CTI is an attempt to resolve the Measurement Problem.

The question was posed in the narrative about the physics professor at Princeton in his office. A photon at a shallow angle to the glass window can reflect or transmit at a 50/50 chance. What in the universe causes the decision?

I agree wholeheartedly with non-local interactions, but those are insufficient at explaining why we physically observed that particular outcome.

I think of retrocausality in CTI as limited to particles but not necessarily “everything” above the particle level.

We are perfectly satisfied when we have uncovered what looks like a deterministic cause for the photon's decision at the glass window surface. But CTI is suggesting its cause was the emission of an A-wave in the future from an electron in the ceiling of the office. But what then caused the emission of that A-wave in the future?

This is what I was (fuzzily) saying about CTI moving the question to the back-burner and not addressing it head on. It has out-sourced the indetermism in the present to indeterministic events in the future. I then sneared at it as argumentum ad mysterium

https://en.wikipedia.org/wiki/Measurement_problem

[bangstrom]

My understanding of CTI is that particles in our local surroundings can interact non-locally in a wavelike manner with particles at remote distances

That is not CTI. You just described regular entanglement.

CTI is regular entanglement expressed in Cramer's way which is a bit more visual and teleological than the usual. Other than that, what is the difference?

This means that interacting particles are in direct quantum contact despite their observational separation so that, at the quantum level, there is no such thing as distance.

That doesn't follow from CTI at all. I have never in my life seen "Direct quantum contact" mentioned in any article on Interpretations of QM in my entire life. The only place I've ever seen that phrase used is in Faradave's posts on this forum.

Cramer’s quantum handshake completing a transaction is just another way of saying direct quantum contact, non-local interaction, entanglement, quantum superposition or other phrases for the same type of phenomenon.

If you want to be picky about semantics, the acronym for John Cramer’s Transactional Interpretation of Quantum Mechanics is TIQM. I have never in my life seen "TIQM" mentioned in any article on Interpretations of QM as “CTI” in my entire life. The only place I've ever seen that phrase used is in your posts on this forum.

Your description of "no space" can be demonstrated false in simple lab experiment.

Bell and Aspect in the early sixties were the first to demonstrate non-local “no space” interaction in the laboratory and it has repeatedly been demonstrated ever since.

The question was posed in the narrative about the physics professor at Princeton in his office. A photon at a shallow angle to the glass window can reflect or transmit at a 50/50 chance. What in the universe causes the decision?

The primary cause for this 50/ 50 decision going one way or the other is the distance to the backside of the glass and wavelength of the light. Feynman has a detailed explanation of this in his QED and the Wheeler-Feynman Absorber Theory has an explanation that is no different from Cramer’s except that Cramer explains this as a wave phenomenon rather than with photon particles moving forward and backwards in time. Cramer's TIQM is essentially the old W-F Absorber theory with waves instead of particles preceding an EM interaction and the change over is an enormous improvement over Wheeler and Feynman.

[hyksos]

CTI is regular entanglement expressed in Cramer's way which is a bit more visual and teleological than the usual. Other than that, what is the difference?

CTI (pardon me, TIQM) has an A-wave, which is something you are avoiding talking about.

Bell and Aspect in the early sixties were the first to demonstrate non-local “no space” interaction in the laboratory and it has repeatedly been demonstrated ever since.

Yes there are dozens upon dozens of physical phenomena observed in labs that must be explained as non-local interactions. I'm not denying any of those. But this non-locality is destroyed upon measurement--- giving rise to something called the MEASUREMENT PROBLEM. I claimed explicitly in my post that this is what TIQM is trying to resolve. You skipped over that primary claim in my post, entirely.

https://plato.stanford.edu/entries/qt-issues/#MeasProb

https://en.wikipedia.org/wiki/Measurement_problem

http://www.pitt.edu/~jdnorton/teaching/ ... asurement/

https://www.britannica.com/topic/philos ... nt-problem

The primary cause for this 50/ 50 decision going one way or the other is the distance to the backside of the glass and wavelength of the light. Feynman has a detailed explanation of this in his QED

This is factually false. There is nothing in QED that resolves the measurement problem.

Yes QED contains a detailed explanation for why this shallow-angle probability is 50/50. But it pointedly and explicitly does NOT EXPLAIN why a particular outcome is observed.

The book QED is a "gentle introduction to field theory" for the layperson. You may have noticed that it contains zero equations. Like, zero. It is not a textbook.

To explain why a particular outcome is observed and not the other, we have to address the Measurement Problem. It my strong and bald claim: Cramer, in positing TIQM was primarily concerned with the Measurement Problem. If you respond to this post and you do not address that claim, then you and I are not having a "conversation".

Cramer's TIQM is essentially the old W-F Absorber theory with waves instead of particles preceding an EM interaction and the change over is an enormous improvement over Wheeler and Feynman.

It's not an improvement. I already typed up a bullet point list showing why it's not.

[bangstrom]

But this non-locality is destroyed upon measurement--- giving rise to something called the MEASUREMENT PROBLEM. I claimed explicitly in my post that this is what TIQM is trying to resolve. You skipped over that primary claim in my post, entirely.

In TICM, the non-local events preceding our observation of light are time symmetric or atemporal and take place outside spacetime and are therefore not observable. Cramer’s retarded waves moving backward in time are nullified by his advance waves moving forward in time leaving behind a completed transaction that an observer interprets as a single photon exchange of energy traveling from a signal source to a receiver.

The observation of an energy exchange takes place AFTER the the non-local events are complete so measurement does not destroy non-locality. This is probably why Cramer has little or nothing to say about the measurement problem.

The primary cause for this 50/ 50 decision going one way or the other is the distance to the backside of the glass and wavelength of the light. Feynman has a detailed explanation of this in his QED

This is factually false. There is nothing in QED that resolves the measurement problem.

Yes QED contains a detailed explanation for why this shallow-angle probability is 50/50. But it pointedly and explicitly does NOT EXPLAIN why a particular outcome is observed.

The chance of light entering or being reflected by a glass surface is not 50/50 but it ranges from nearly 0 to 100 percent and it is predictable given just the wavelength of the light and depth of the glass and Feynman explained why in simple terms in QED.

In QED Feynman’s field of photons moving backwards in time is absorbed into his field of photons moving forward in time leaving a single photon path that can be detected AFTER the non-local events have transpired so, in this case also, detection does not destroy non-locality so there is no measurement problem here either. The measurement problem is addressed in other theories where the question arises as to whether or not local “reality” can exist without observation.

[hyksos]

In TICM, the non-local events preceding our observation of light are time symmetric or atemporal and take place outside spacetime and are therefore not observable. Cramer’s retarded waves moving backward in time are nullified by his advance waves moving forward in time leaving behind a completed transaction that an observer interprets as a single photon exchange of energy traveling from a signal source to a receiver.

"time symmetric or atemporal and take place outside spacetime and are therefore not observable."
(* citation needed)

The observation of an energy exchange takes place AFTER the the non-local events are complete so measurement does not destroy non-locality. This is probably why Cramer has little or nothing to say about the measurement problem.

Once again, I assert in plain text : Cramer's entire motivation for TIQM was to address the measurement problem.

There are many interps of QM out there of different flavors. They each have a different motivation, and sometimes their motivations overlap. For example, DeBroglie-Bohm Guiding Wave was an attempt to bring trajectories back into QM.

Cramer's TIQM has a specific ontological commitment, namely that a photon's decision to reflect or transmit is not an acausal event... (what Einstein called "God throwing dice.") but is in fact totally determined by an Advanced Wave emitted from the absorber in the future. Therefore I assert ---> TIQM is an attempt to address the Measurement Problem.

The chance of light entering or being reflected by a glass surface is not 50/50 but it ranges from nearly 0 to 100 percent and it is predictable given just the wavelength of the light and depth of the glass and Feynman explained why in simple terms in QED.

You already said this, and I already addressed it. Now you are saying it again and we are going in circles. This statement is not just "wrong" , it exhibits a profound lack of understanding of even the context of what you are reading. My job on this forum is not to give you a free education in modern physics, and so every minute I waste in my life correcting you is making me increasingly frustrated.

But let's try this.

+ QED is a wonderful book that. everyone should have it on their shelf {heap additional praise and other info about why it was written and Feynman as a science teacher blah blah blah}.

+ It's fun and other should have fun with it. I read it when I was 17.

+ QED is not NOT NOT Feynman's interpretation of Quantum Mechanics.

+ QED is NOT a textbook. It is a "gentle introduction" to Quantum Field theory of the electromagnetic force, written and targeted at a lay audience. It has no equations in it. Look at your copy of it. Zero equations. When Feynman says we "add all the arrows together" he is actually referring to a path integral. But laypersons have not sat in upper level university courses on Lagrangian mechanics and the calculus of variations : so he writes "add all the arrows". Get it?

https://en.wikipedia.org/wiki/Path_integral_formulation

https://en.wikipedia.org/wiki/Lagrangian_mechanics

https://en.wikipedia.org/wiki/Calculus_of_variations



+ QED explains how the 50/50 probability of the photon is calculated simple terms. Yes.

+ QED most assuredly DOES NOT tell you what causal mechanism determines how a photon behaves upon measurement. If Feynman spent a single sentence describing what CAUSES that decision, he would have been writing an interpretations of QM. But QED is not not NOT NOT an interpretation of QM.

This non-locality that you keep blabbering about is a feature of the orthodox 1939 version of QM and most of us called it "entanglement".

1.) Entanglement is not guaranteed to happen,

2.) Entanglement does not always happen maximally,

3.) Human observers can destroy non-local entanglement anytime we want by measuring a system explicitly.

4.) We have no quantum computers in our living rooms. Why? Because a noisy warm environment can destroy the fragile non-local interactions of qubits. This is not a every-once-in-a-while thing. Decoherence is the bane of all quantum computers. Even the ones they build in cryogenic labs.

These 4 items are perfectly described and explicitly predicted by the formalism. They derive from the fact that the (states of a) Schroedinger wave is expressed in a Hilbert space, and that these things called observables will either commute or not commute in that space. When two observables are totally orthogonal you get so-called "maximal" entanglement. YOu can also have "weakly" entangled systems. Long-story short : we don't need a theory of entanglement from you nor Faradave. We already have a theory.

There is unitary evolution where long-separated pieces of the same wave function affect each other across large distances. Then there is this thing variously called decoherence, or the "Collapse of the wave function" where these formally entangled pieces of a wave function become distinct, deterministic and local particles.

Why does this occur? Does it occur at all? <----- This is the Measurement Problem.

We don't have access to Richard Feynman on this forum. But very much in the manner of Susskind, I woudl presume that Feynman was averse to interps-of-QM. One of those guys who would probably say "We don't need them". This idea that we don't need interps-of-QM at all in the first place : this ideas is a sentiment that is widely shared by many people today. I'm sorry that this forum does not have any such people to come here and chime in.

Feynman had become very comfortable -- philosophically and intellectually comfortable -- in living in a universe where totally non-determined physical events happen. He was comfortable with non-local entanglement happening. He no longer felt any inner emotional need to probe deeper and find some completely deterministic mechanism "underlying" the large-scale features of the theory.

John Cramer is different. He is one of those guys feeling something is missing from the picture. He added these Advanced Waves to the formalism , which are not in the formalism. At the very least, we know he added these backwards-in-time A-waves in order to help undergrads visualize quantum processes.

[bangstrom]

"time symmetric or atemporal and take place outside spacetime and are therefore not observable."
(* citation needed)

http://www-users.york.ac.uk/~mijp1/tran ... TI_30.html
"3.7 Collapse and Nonlocality in the Transactional Interpretation
In the TI the collapse of the state vector is interpreted as the completion of the transaction started by the OW and the CW exchanged between emitter and absorber. The emergence of the transaction from the SV does not occur at some particular location in space or at some particular instant of time, but rather forms along the entire four-vector which connects the emission locus with the absorption locus (or loci in the case of multiple correlated particles). The transaction employs both retarded and advanced waves which propagate, respectively, along positive and negative lightlike (or timelike) four-vectors. Since the sum of these four-vectors can span spacelike and negative timelike or lightlike intervals, the "influence" of the transaction in enforcing the correlations of the quantum event is explicitly both nonlocal and atemporal."

OW is an offer wave, CW is a confirmation wave. These are the advanced and retarded waves of the W-F Absorber theory. SV is the state vector of a quantum particle. It is the position, momentum, time, energy, spin and isospin and other variables that give a quantum particle its identity.[/i]

Once again, I assert in plain text : Cramer's entire motivation for TIQM was to address the measurement problem.

Cramer's TIQM has a specific ontological commitment, namely that a photon's decision to reflect or transmit is not an acausal event... (what Einstein called "God throwing dice.") but is in fact totally determined by an Advanced Wave emitted from the absorber in the future. Therefore I assert ---> TIQM is an attempt to address the Measurement Problem.

Assertions are meaningless without support. You may be entirely right so go ahead and explain why.

+ QED explains how the 50/50 probability of the photon is calculated simple terms. Yes.

Are you saying the calculated probability is 50/50 and not 0 to 100?
That is the one part I don't understand because the probability is rarely 50/50.

3.) Human observers can destroy non-local entanglement anytime we want by measuring a system explicitly.

The question remains as to whether entanglement was lost before the observation or if the measurement caused entanglement to be lost. The latter posibility is the measurement problem.

There is unitary evolution where long-separated pieces of the same wave function affect each other across large distances. Then there is this thing variously called decoherence, or the "Collapse of the wave function" where these formally entangled pieces of a wave function become distinct, deterministic and local particles.

Why does this occur? Does it occur at all? <----- This is the Measurement Problem.

We know entanglement and and decoherence occur. If they happen spontaneously without observation, then there is no Measurement Problem. If measurement is the cause of decoherence, then we have a measurement problem with the question of whether or not our awareness (consciousness) is an active participant in the nature of what we call reality. That is how I see the measurement problem.

Feynman had become very comfortable -- philosophically and intellectually comfortable -- in living in a universe where totally non-determined physical events happen. He was comfortable with non-local entanglement happening. He no longer felt any inner emotional need to probe deeper and find some completely deterministic mechanism "underlying" the large-scale features of the theory.

John Cramer is different. He is one of those guys feeling something is missing from the picture. He added these Advanced Waves to the formalism , which are not in the formalism. At the very least, we know he added these backwards-in-time A-waves in order to help undergrads visualize quantum processes.

The Wheeler-Feynman Absorber theory and QED both include forward and retarded signaling the same as Cramer’s TIQM.

http://www-users.york.ac.uk/~mijp1/tran ... TI_30.html

"3.1 Advanced Waves and Wheeler-Feynman Absorber Theory
The basic element of the transactional interpretation is an emitter-absorber transaction through the exchange of advanced and retarded waves, as first described by Wheeler and Feynman (1945, 1949) [see also (Feynman, 1967b)]. Advanced waves are solutions of the electromagnetic wave equation and other similar wave equations which contain only the second time derivative. Advanced waves have characteristic eigenvalues of negative energy and frequency, and they propagate in the negative time direction."