"Thanks Basil for this clarification. It is true that Bohm's original motivation was a realist (as opposed to instrumentalist, Bohrian interpretation). I should have been more clear about that. But it rather quickly became a path to resolving the measurement problem -- if not for its original author(s), certainly for those who have championed it since then.
Also, regarding the quote ["What I felt to be particularly unsatisfactory was the fact that the quantum theory had no place in it for an adequate notion of an independent actuality-i.e. of an actual movement or activity by which one physical state could pass over into another".] This is a key component of the measurement problem. Also, let me take the opportunity to note that it is not necessary to identify a 'realist' view of qm with the existence of 'hidden variables'. I have been proposing a realist view that does not involve hidden variables -- but it does involve an expansion of what we normally like to think of as 'real'. The usual tacit assumption is that
'real' = 'existing within spacetime' (and that of course requires 'hidden variables' that tell us 'where' the entity lives in spacetime, or at least identifies some property compatible with spacetime existence)" (end-quote)
Me: We all seem to agree that the idea that "real" must be "local in spacetime" is false. Q is real, but it is generally not a local BIT field in 3D + 1 spacetime when there is entanglement. Oddly enough the macro-quantum coherent signal Q in spontaneous breakdown of ground state symmetry is local in 3D+1 but it is generally coupled to nonlocal micro-quantum "noise."
Ruth "In contrast, I think PTI provides us with a realist concept of an independent actuality -- a "movement or activity by which one physical state could pass over into another". "
Me: So does Bohm's ontological interpretation.
Ruth: "But that 'actuality' is rooted in potentiality, which is a natural view given the mathematical properties of quantum objects."
Me: Seems to me you are playing with nouns replacing one vague metaphysical notion with another. What is "potentiality"? Mathematically it's Bohm's Q - perhaps extended to Yakir Aharonov's weak measurements with advanced Wheeler-Feynman back from the future post selection in a post quantum theory with Antony Valentini's "signal nonlocality". Some think that violates the Second Law of Thermodynamics. However, since it only obtains in open systems that is not so. Furthermore our actual universe, the causal diamond bounded by both the past and future horizons is an open system out of thermal equilibrium.
Ruth: "So one can give a realist, physical account, but it is indeterministic -- involving a kind of spontaneous symmetry breaking. Given that we already have spontaneous symmetry breaking elsewhere in physics, I think we should allow for it in QM.
Thanks again for the clarification --"
David Bohm, Albert Einstein, Louis De Broglie, Wolfgang Pauli, Richard Feynman
Jack Sarfatti On Jun 26, 2013, at 2:26 AM, Basil Hiley wrote:
Ruth, may I make a correction to what you wrote below. Bohm '52 work was not 'originally undertaken to solve the measurement problem.' He had a different motive. I asked him to clarify, in writing, w...See MoreThis paper is dedicated to three great thinkers who have insisted that the world is not quite the straightforward affair that our successes in describing it mathematically may have seemed to suggest: Niels Bohr, whose analyses of the problem of explaining life play a central role in the following di...
"I don't rule out that some deeper theory might eventually be found, that could help answer ultimate questions in more specific terms. But it hasn't been demonstrated, to my knowledge, that one has to have violations of Born Rule in order to explain life." (end quote)
To the contrary, it has been demonstrated in my opinion. First start with Brian's paper "On the biological utilization of nonlocality" with the Greek physicist whose name escapes me for the moment.
Second: Lecture 8 of http://www.tcm.phy.cam.ac.uk/~mdt26/pilot_waves.html
Specifically, how the Born rule depends on violation of the generalized action-reaction (relativity) principle that Q has no sources. Q pilots matter without direct back-reaction of matter on Q.
In other words, orthodox quantum theory treats matter beables as test particles! - clearly an approximation.
Obviously signal nonlocality violating no-signaling theorems has a Darwinian advantage. Indeed, without it, entanglement appears as static noise locally. Imagine that Alice and Bob's minds are represented each by a giant macroscopic coherent entangled quantum potential Q(A,B). It would obviously be a survival advantage for Alice and Bob to directly send messages to each other at a distance like the Austraiian aborigines do in the Outback. Now use scale invariance. It's obviously an advantage for separate nerve cells in our brains to do so. Also in terms of morphological development of the organisim - signal nonlocality is an obvious plus, which I think is part of Brian Josephson's message in that paper.
Subquantum Information and Computation
(Submitted on 11 Mar 2002 (v1), last revised 12 Apr 2002 (this version, v2))
It is argued that immense physical resources - for nonlocal communication, espionage, and exponentially-fast computation - are hidden from us by quantum noise, and that this noise is not fundamental but merely a property of an equilibrium state in which the universe happens to be at the present time. It is suggested that 'non-quantum' or nonequilibrium matter might exist today in the form of relic particles from the early universe. We describe how such matter could be detected and put to practical use. Nonequilibrium matter could be used to send instantaneous signals, to violate the uncertainty principle, to distinguish non-orthogonal quantum states without disturbing them, to eavesdrop on quantum key distribution, and to outpace quantum computation (solving NP-complete problems in polynomial time).
Comments: 10 pages, Latex, no figures. To appear in 'Proceedings of the Second Winter Institute on Foundations of Quantum Theory and Quantum Optics: Quantum Information Processing', ed. R. Ghosh (Indian Academy of Science, Bangalore, 2002). Second version: shortened at editor's request; extra material on outpacing quantum computation (solving NP-complete problems in polynomial time)
Subjects: Quantum Physics (quant-ph)
Journal reference: Pramana - J. Phys. 59 (2002) 269-277
Report number: Imperial/TP/1-02/15
Cite as: arXiv:quant-ph/0203049
(or arXiv:quant-ph/0203049v2 for this version)