Peter Soderqvist

Quote from Heisenberg 's home side
But a basic assumption of physics since Newton has been that a "real world" exists independently of us, regardless of whether or not we observe it. (This assumption did not go unchallenged, however, by some philosophers.) Heisenberg now argued that such concepts as orbits of electrons do not exist in nature unless and until we observe them. http://www.aip.org/history/heisenberg/p08c.htm

4. The Copenhagen interpretation
Bohr understood that there was no precise way to define the exact point at which collapse occurred. Any attempt to do so would yield a different theory rather than an interpretation of the existing theory. Nonetheless he felt it was connected to conscious observation as this was the ultimate criterion by which we know a specific observation has occurred.
http://www.mtnmath.com/faq/meas-qm.html

Quotations by Werner Heisenberg: The "path" comes into existence only when we observe it. I think that modern physics has definitely decided in favor of Plato. In fact the smallest units of matter are not physical objects in the ordinary sense; they are forms, ideas which can be expressed unambiguously only in mathematical language. http://www-groups.dcs.st-and.ac.uk/~...eisenberg.html

Peter Soderqvist

Soderqvist1: even a hot noisy system is in a superposition of states, as everything else is in the universe according to Quantum Cosmology! A measuring apparatus end up in a superposition of states when it measuring a quantum system, same it happens when more apparatus are added to the chain, this chain is known as Neumann's infinite regress chain! Eugene Wigner has postulated an immaterial mind as the collapser of this infinite chain!

Consciousness and Quantum Measurement by Amit Goswami
The interpretational difficulties of quantum mechanics can be solved with the hypothesis (von Neumann, 1955; Wigner, 1962) that consciousness collapses the quantum wave function. The paradoxes raised against this hypothesis have now all been satisfactorily solved (Bass, 1971; Blood, 1993; Goswami, 1989, 1993; Stapp, 1993). http://www.swcp.com/~hswift/swc/Summ...oswami9901.htm

Soderqvist1: But David Deutsch at Oxford University circumvent the immaterial mind by assume the existence of the multiverse, there collapse of wave function doesn't exists, but decoherence do!


Minds, Machines, and the Multiverse: THE QUEST FOR THE QUANTUM COMPUTER
QUANTUM COMPUTING TAKES A QUANTUM LEAP, in the International Herald Tribune, was occasioned when researchers at MIT, IBM, Oxford University, and the University of California at Berkeley reported in 1998 that they had succeeded in building the first working computers based on quantum mechanics. Deutsch is a physicist, winner of the 1998 Paul Dirac prize for theoretical physics and a researcher at the Center for Quantum Computation at Oxford University's Clarendon Laboratory. Ever since the development of quantum theory at the beginning of the twentieth century, scientists have known that on the atomic scale matter behaves very differently from what we see on everyday scales. Particles such as electrons and atoms do not behave like the billiard balls of Newton's classical physics but seem to exhibit characteristics more in keeping with fuzzy wavelike entities. These and other properties led to a great deal of puzzlement and angst over how quantum theory should be understood as a description of reality -- or realities.

So much so that today there are a multitude of different interpretations of what goes on at the atomic level. Interpretations aside, it's long been known that at the atomic level waves can behave like particles, and particles have waves associated with them. A single entity such as an electron, for example, can travel along many different routes simultaneously as if it were really a spread-out phenomenon like a wave. The essential idea of quantum parallelism advanced by Deutsch was this: If an electron can explore many different routes simultaneously, then a computer should be able to calculate along many different pathways simultaneously too. In the early 1980s, Deutsch's proposed experiment (described more fully in Chapter 3) sounded like the stuff of science fiction. To test the existence of multiple universes, he envisaged the construction of a thinking, conscious artificial intelligence whose memory worked "at the quantum level." Such a machine, he claimed, could be asked to conduct a crucial experiment inside its own brain and report back to us whether Deutsch was indeed right to believe in the existence of parallel universes.
http://www.simonsays.com/excerpt.cfm?isbn=0684814811

Soderqvist1: I have read David Deutsch book, The Fabric of Reality, I will read this book soon!

wordsmyth

Peter,

It seems that you aren't interested in presenting an actual argument and I'm not interested in a competition of link posting. If, however, you are able to come up with an actual argument, I will be more than happy to continue the discussion. Otherwise, there really isn't anything to discuss.

Peter Soderqvist

You have not addressed the wave function in quantum cosmology, so I have posted these links, so you can read about it, and perhaps address it afterward!

Xeno

Peter - You didn't answer how actual intelligence of the observer comes into play. It is widely accepted in the Copenhagen Interpretation that observation happens upon precise measurement of the position of an electron, and it's been demonstrated that this can happen with unintelligent devices as per the double slit experiment.

Rusting Car Bumper

I have a degree in physics and never understood why Schrödinger's cat was such a big deal.

DC

Normal

I guess I'm wondering if the cat is actually in a superposition, or just theoritically in a super position.

Does our inability to observe (and thus collapse the wave function) mean that the wave function has not collapsed inside the box, as an existent in our universe?

SteveD

I guess I'll try again.

It is silly to argue whether the cat could be considered an observer. The whole point Schroedinger was trying to make was that it is absurd to attribute the uncertainties of the wave function to macroscopic objects.

I am constantly amazed that people will argue about whether the cat is actually in a superposition of states. It's ludicrous.

Steve

Peter Soderqvist

Soderqvist1: If your Copenhagen interpretation predicts that the screen collapse the wave function, in the experiment with two holes, because the screen works as a measuring apparatus, if your proposition is consistent polarization filters are measuring apparatuses too! Experiments have been made with polarization filter eraser between the two holes, and the second screen, which erases the measuring apparatus (the polarization filters in front of the two holes), and the interference pattern reappears! The difference is that the Eraser erasing information about what is going on in this quantum system, therefore the interference pattern is there, conversely, the wave function collapses when we know what is going on! Frankly, in the classical experiment with the two holes, the second screen is in a supper position of states, (a probability distribution of Eigenstates) until someone looks at the screen!

You can read about the experiment here!

Deepening the quantum mysteries by John Gribbin!
http://www.biols.susx.ac.uk/home/Joh...in/quantum.htm

The paradox can be extended to quantum cosmology, namely, what is a measuring apparatus when the whole universe is quantum system? This impasse is circumvented by most quantum physicists by adhering to MWI, when it comes to quantum cosmology, according to David Deutsch, in his book; The Fabric of Reality!

Jesse

But in a way I think Schroedinger was right for the wrong reasons--his argument didn't say anything about the phenomenon we now know as "decoherence", did it? It's now thought that decoherence is the reason we can't treat macroscopic system as being in a superposition of states, but that in theory it might be possible in unusual circumstances where the system could be sufficiently isolated from the external environment--that's the whole idea behind quantum computation. If Schroedinger was just arguing that there is something fundamentally different about macroscopic systems such that it would never be possible to have one in a superposition of states, even in principle, than most physicists today would probably disagree with this.

In the distant future perhaps we will have quantum computers large enough to simulate an entire cat, and in such a case it would be proper to treat the simulated cat as being in a superposition of states until the simulation gave us its output (which would correspond to opening the box and measuring the cat). By running the simulation over and over again from the same initial conditions it would be possible to find statistical patterns that would demonstrate interference between different parts of the superposition, although these would probably be very subtle for such a complicated entangled system.