Here I am, awoken once against in this long night.
Many things are to be said, or that is my desire, though the need of my sleep will confine me to
fewer words, it will indeed not be
lesser words.
Some kind of recap is now needed. Even though no posts of mine were seen in these recent discussions, none of them were unread, or not deeply considered in the mind. However, as I stated in a PM Claudio, my task would require a lot of focus to be successful and complete. As the focus was not there, I decided not to post, because it is my intent to contribute and express complete information and not lacking, to the extent it is possible. There were several posts in which I could rebut as misunderstandings, though the repeated use of ad hominem and condescending language mainly used by BrandonHedberg seemed to suggest that what could initially seem as short-term progress would most likely become long-term negativity if engaged in a attempted rationale discussions back and forth. Nevertheless, I thank Brandon among others who helped create this situation, because of this simple thing:
A theory and model should indeed be engaged with critically, because that which is either the weak link or
appear to be the weak link will be revealed by the involved inquiry. The model will either as a result be weakened or strengthened by removing the weak link, whether it was really a problem or a problem of
expression and communication. Because of this inquiry, proponents of the model (those in favour of MBT) are forced to either succumb to the opposition (ignoring it is the same) or step up to it and resolve the problem.
A quick remark about a potential problem with QM physicists, their assumptions and worldview. A problem with QM is it's far reaching implications of reality, which is often said by physicists to be the ball game of philosophers. In addition to this, there exists literally dozens of
interpretations of QM, each with their underlying metaphysical assumptions. What is not always cognizant to the physicist, is that his personal belief about reality dominates to a large degree which interpretation he will align himself to. How such physicist will react to evidence within the QM field will again rely on his approach to new information, and how rooted the metaphysical assumptions really is. Maybe you are thinking about how MWI relates to beliefs, it actually shows my point by trying so hard to maintain its assumptions that reality is realist, deterministic and even locale. It is result by forcing an objective reality upon an probabilistic reality, thereby it maintains some twisted truth (how universes [reality frames] branch out probabilistically, but objectively instead of in a probabilistic database consisting of information, in MWI every probablity actualizes while in MBT it doesn't) but maintains the belief in an objective reality. My point is that one must see the state of physics (its development) in relation to the nature of paradigm shifts, which is a crucial thing to understand if one wants to go beyond dogma and mainstream and push the boundaries of science.
First a short note on Realism in physics, from
http://en.wikipedia.org/wiki/Philosophi ... in_physicsQuote:
"Realism in physics refers to the fact that any physical system must have its property defined, whether or not it is measured (or observed or not). However, some interpretations of quantum mechanics hold that a system lacks an actualized property until it is measured. This implies that quantum systems exhibit a non-local behaviour. Bell's theorem proved that every quantum theory must either violate local realism or counterfactual definiteness. Physics up to the 19th century was always implicitly and sometimes explicitly taken to be based on philosophical realism. With the advent of quantum mechanics in the 20th century, it was noted that it is no longer possible to adhere to local realism — that is, to both the principle of locality (that distant objects cannot affect local objects), and counterfactual definiteness, a form of ontological realism implicit in classical physics. This has given rise to a contentious debate of the interpretation of quantum mechanics. Although locality and 'realism' in the sense of counterfactual definiteness, are jointly false, it is possible to retain one of them. The majority of working physicists discard counterfactual definiteness in favor of locality, since non-locality is held to be contrary to relativity. The implications of this stance are rarely discussed outside of the microscopic domain. See, however, Schrödinger's cat for an illustration of the difficulties presented. It can also be argued that the counterfactual definiteness 'realism' of physics is a much more specific notion than general philosophical realism."
Now with this in mind, let us proceed.
All the big fuzz about Tom giving false information is simply not true.
Yes, it may very well have been too general and vague as presented in the lecture, but it is indeed true my friends :)
The problem came when Tom used the double split experiment as example, in a very non-technical way, which lead to Brandon thinking it was false, because Brandon did not consider the
all the variants of the experiment. Tom did in fact in describe the
Wheeler's delayed choice experiment, or the result of it, with the metaphor of the traditional double slit experiment as example. This have caused some of the confusion.
What is this mysterious experiment which you couldn't find?
It was initially a thought experiment, made by the known physicist John Wheeler. In 2007 (and 2000) it was realized as an experiment.
Here is the intro from the wiki article:
Quote:
"Wheeler's delayed choice experiment is a thought experiment proposed by John Archibald Wheeler in 1978. Wheeler proposed a variation of the famous double-slit experiment of quantum physics, one in which the method of detection can be changed after the photon passes the double slit, so as to delay the choice of whether to detect the path of the particle, or detect its interference with itself. Since the measurement itself seems to determine how the particle passes through the double slits, and thus its state as a wave or particle, Wheeler's thought experiment has been useful in trying to understand certain strange properties of quantum particles. An implementation of the experiment in 2007 showed that the act of observation ultimately decides whether the photon will behave as a particle or wave, verifying the unintuitive results of the thought experiment."
Quite amazing I must say.
Here are some excerpts from the real paper:
Quote:
“Thus one decides the photon
shall have come by one route or by
both routes after it has already done its
travel”
"Our realization of Wheeler’s delayedchoice
GedankenExperiment demonstrates
beyond any doubt that the behavior
of the photon in the interferometer
depends on the choice of the observable
which is measured, even when that
choice is made at a position and a time
such that it is separated from the entrance
of the photon in the interferometer by a
space-like interval. In Wheeler’s words,
since no signal traveling at a velocity less
than that of light can connect these two
events, “we have a strange inversion of
the normal order of time. We, now, by
moving the mirror in or out have an unavoidable
effect on what we have a right
to say about the already past history of
that photon”"
"Once more, we find
that Nature behaves in agreement with
the predictions of Quantum Mechanics
even in surprising situations where a ten-
sion with Relativity seems to appear"
The full paper can be read here:
http://arxiv.org/PS_cache/quant-ph/pdf/ ... 0241v1.pdfSimilar experiment, Random Delayed-Choice Quantum Eraser via Two-PhotonImaging:
http://arxiv.org/PS_cache/quant-ph/pdf/ ... 2207v2.pdfI should mention, quantum astronomy, as it is relevant in the next part of my post:
http://www.seti-inst.edu/news/features/ ... -scale.phpNow read
viewtopic.php?f=9&t=5333 and it should start to make sense.
-------
The Reality TestThis is such a great article, which really gives some new insight into the whole affair.
http://www.quantum.at/fileadmin/quantum ... _Tests.pdfSome excerpts:
Quote:
"For more than 70 years, innumerable physicists have tried to disentangle the meaning of quantum mechanics through
debate. Now Zeilinger and his collaborators have performed a series of experiments that, while neatly agreeing with the
theory’s predictions, are reinvigorating these historical dialogues. In Vienna experiments are testing whether quantum
mechanics permits a fundamental physical reality. A new way of understanding an already powerful theory is beginning to
take shape, one that could change the way we understand the world around us. Do we create what we observe through the act of our observations?"
"Most of us would agree that there exists a world outside our minds. At the classical level of our perceptions, this belief is
almost certainly correct. If your couch is blue, you will observe it as such whether drunk, in high spirits, or depressed; the color is surely independent of the majority of your mental states. If you discovered your couch were suddenly red, you could be sure there was a cause. The classical world is real, and not only in your head. Solipsism hasn’t really been a viable philosophical doctrine for decades, if not centuries. But none of us perceives the world as it exists fundamentally.
We do not observe the tiniest bits of matter, nor the forces that move them, individually through our senses. We evolved to experience the world in bulk, our faculties registering the net effect of trillions upon trillions of particles or atoms moving in concert. We are crude measurers. So divorced are we from the activity beneath our experience that physicists became relatively assured of the existence of atoms only about a century ago. Physicists attribute a fundamental reality to what they do not directly perceive. Particles and atoms have observable effects that are well described by theories like quantum mechanics. Single atoms have been “seen” in measurements and presumably exist whether or not we observe them individually."
"Gröblacher walked me through the tabletop obstacle course: The laser light passes through a series of polarizers and filters,
hits the crystal, and splits into two beams of single-file photons. Detectors in both beams measure the polarization of each
photon, which are related to one another. The data is tested against two theories: one that preserved realism but allowed
strange effects from anywhere out there in the universe, and quantum mechanics."
"It took them months to reach their tentative conclusion: If quantum mechanics described the data, then the lights’ polarizations didn’t exist before being measured. Realism in quantum mechanics would be untenable."
"Without hesitation, he said sending humans into space as detectors to test the theory. In space there is enough distance to exclude communication between the detectors (humans), and the lack of other particles should allow most entangled photons to reach the detectors unimpeded. Plus, each person can decide independently which photon polarizations to
measure. If Leggett’s model were contradicted in space, he might believe. When I mentioned this to Prof. Zeilinger he said, “That will happen someday. There is no doubt in my mind. It is just aquestion of technology.” Alessandro Fedrizzi had already shown me a prototype of a realism experiment he is hoping to send up in a satellite. It’s a heavy, metallic slab the size of a dinner plate."
"Zeilinger’s group, which has tested decoherence, does not believe there is a fundamental limit on the size of an object to observe superposition. Superpositions should exist even for objects we see, similar to the infamous example of Schrödinger’s cat. In fact, Gröblacher now spends his nights testing larger-scale quantum mechanics in which a small mirror is humanely substituted for a cat. Brukner and Kofler had a simple idea. They wanted to find out what would happen if they assumed that a reality similar to the one we experience is true—every large object has only one value for each measurable property that does not change. In other words, you know your couch is blue, and you don’t expect to be able to alter it just by looking. This form of realism, “macrorealism,” was first posited by Leggett in the 1980s. Late last year Brukner and Kofler showed that it does not matter how many particles are around, or how large an object is, quantum mechanics always holds true. The reason we see our world as we do is because of what we use to observe it. The human body is a just barely adequate measuring device. Quantum mechanics does not always wash itself out, but to observe its effects for larger and larger objects we would need more and more accurate measurement devices. We just do not have the sensitivity to observe the quantum effects around us. In essence we do create the classical world we perceive, and as Brukner said, “There could be other classical worlds completely different from ours.” Zeilinger and his group have only just begun to consider the grand implications of all their work for reality and our world."
I asked Dr. Zeilinger about this as I was about to leave his office. “In the history of physics, we have learned that there are
distinctions that we really should not make, such as between space and time… It could very well be that the distinction we
make between information and reality is wrong. This is not saying that everything is just information. But it is saying that
we need a new concept that encompasses or includes both.” Zeilinger smiled as he finished: “I throw this out as a challenge
to our philosophy friends.” A few weeks later I was looking around on the IQOQI website when I noticed a job posting for a one-year fellowship at the institute. They were looking for a philosopher to collaborate with the group.
They have published many papers, this is one I found:
Quote:
"In conclusion, we violated Bell’s inequality by more than 16 standard devia-tions, in an experiment simultaneously closing both the locality and the freedom-of-choice loopholes. This represents the most conclusive falsification of local realism to date. A completely loophole-free Bell test will have to both exclude these two loop-holes and simultaneously close the fair-sampling loophole by ensuring that, in the limit of no background noise, at least 44.5% of all generated particle pairs are detected18. We believe that such an experiment is possible."[/b]
From Violation of local realism with freedom of choice -
http://www.univie.ac.at/qfp/publication ... 008-33.pdfIt would then seem that the next stage of these kind of experiments should take place in space, an interesting turn I think.
It is of my hope that people will now get a clearer picture, and be less confused.
Out of time, goodnigth.. I will sleep for many hours. Zzzz :-)
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