Quickfire Quantum Qs

Tom,

"Rob claims 1 bit of information recovered from each measurement" No. I claim that there is only 1 bit of information that can ever be recovered from ANY set of measurements, that obeys the limiting case of the Heisenberg Uncertainty principle; that is why both position and momentum cannot be measured.

Also, in Bell tests, no "interval of time" is required: both observers can perform their individual measurement, on their individual member of an entangled pair, simultaneously.

Rob McEachern

Rob,

I stand corrected.

So far as Bell tests, with two independent observers, there absolutely is an interval of time between them. Entanglement is a convenient fiction.

Colin,

The determination of the "heads vs. tails" of an ordinary coin is a 3-D problem. I deliberately made the simulation a 2-D simulation of polarity, to greatly reduce computing requirements and to make it directly analogous to polarity measurements made on photons.

I have been working on a "slideshow" to explain how the misinterpretation of quantum theory began (with de Broglie's "association" of a wave with a particle) and why it persists. I have not finished it, but your post inspired me to post it on vixra so we could discuss it; the file is too large to post here. I'll let you know, when it appears.

If you do not already have a copy of David Bohm's book, "Quantum Theory", I would urge you to get one; I am using it to provide context for my own reinterpretation of QM.

Rob McEachern

Hi Tom,

When it comes down to it, the projection of the coin (or vector) onto Alice's or Bob's rotated instrument reduces each measurement to a single dimension, which is determined by Alice or Bob when they set the angle on their instruments. This measurement is then compared to a fixed threshold to determine whether the polarity is positive, negative, or undetectable.

What I had in mind is that modeling electron spin requires quantum probabilities and, as you say, qubits to determine the state of electron spin. But the decision process ought to be similar, comparing a probability to a threshold to make a decision on the state of polarity.

Colin

Colin,

Here is a link to the slideshow: What is wrong with interpretations of Quantum Theory?

Rob McEachern

From your slideshow: "Quantized Observations result from observations having: a small Information content not a small physical size of the object being observed!" You make an important point. Observations of quantum processes are not about small scale, but limited information. In a previous FQXi contest essay, I argued that the cosmological redshift is compatible with tired light under the assumption that quantum uncertainty extends to cosmological scale, with a complementary relationship between distant time dilation at the source of light, and energy lost in transit noted at the local light receptor. Hopefully, that assumption seems a little less outrageous now.

Your discussion of Maxwell's demon is also relevant. Gravity is an obvious suspect: it is the force that makes hot air rise to the ceiling of a room, and cold fall to the floor, without a partition between the hot and cold regions.

There seems to be a typo at the top of page 30. "Shannon discovered the *maximum* number of bits of information, required to perfectly reconstruct an arbitrary curve" should be *minimum*.

Fisher's measure of information looks like it was made for hidden variable problems. Wikipedia says it is "the amount of information that an observable random variable X carries about an unknown parameter of a distribution that models X."

Bohm's "Quantum Theory", published in 1951, sounds like a classic and I could use an introduction to his work. I will get that book. I wonder how it compares to "The Undivided Universe" (1993) written with Hiley and published four decades later.

Colin

In regards to the "minimum" versus the "maximum" on page 30, they become equal at the limit, which is why I "put it another way" in the middle of the page. I can see that the language is a bit ambiguous. The point I was trying to make is that additional measurements, of supposed, additional components, will not yield more information - the maximum amount has already been attained by the previous measurements; consequently all subsequent measurements must be correlated with the first.

Maxwell's demon is precisely a pre-quantum-theory example of a "decision making" process, like "calling" a coin, that is being misinterpreted in quantum theory as "wave-function collapse." It is all related, to Shannon's insights into the nature of information.

Bohm's book is more than just a classic, it is a treasure trove of insights into what is really going on in the quantum world (he seems to have written it, as an attempt to understand the theory himself, as much as to explain it to others), and in particular, from a particle scattering, rather than physical wave propagation, point-of view. Here is an interesting quote from the Wikipedia article on Bohm, regarding his Ph.D research:

"the scattering calculations (of collisions of protons and deuterons) that he had completed proved useful to the Manhattan Project and were immediately classified. Without security clearance, Bohm was denied access to his own work; not only would he be barred from defending his thesis, he was not even allowed to write his own thesis in the first place!"

What I find interesting about his ideas on particle scattering, are in connection to things like the double-slit experiment. He showed that (section 21.23) potentials with sharp edges will produce oscillatory scattering cross-sections: AKA interference patterns.

The one thing that he could not figure out, is why quantum scattering, unlike classical scattering, is such that "the deflection process is described as a single indivisible transition", rather than like the continuous deflection, of a mass in a gravitational field. He remarks upon this fact in several places.

The missing answer is an information-mediated decision process, like Maxwell's Demon: if the field cannot "detect" a particle (recover a single bit of information) and the particle cannot detect the field (think of the symmetric interaction of identical particles), then there can never be any interaction whatsoever, except at the points at which it *is* possible to recover such a bit. So quantum particles scatter off ripple's in the field within the slits, just like bullets scattering off one specific point on a rippled, steel plate, thereby producing an "interference" pattern - with no wave propagation required.

Rob McEachern

Thanks for explaining the significance of a decision process being involved in quantum scattering, as opposed to the gravitational analogy. An example like that really helps to put what you are getting at in context.

I recall one of my high school teachers demonstrating the double slit experiment using microscope slides spray-painted black, with the two slits etched onto one of the slides using a pair of back-to-back razor blades. The separation between the slits was just right for the light that was used.

Had to chuckle - "not even allowed to write his own thesis in the first place!"

Colin

New experiment confirms that Information and Decision-making-processes are key to understanding Maxwell's Demon

Rob McEachern

As usual, the decrease in system entropy is balanced by an increase in the demon's entropy from storing information about the system. (But this raises the question: could a demon built in to fundamental physical processes use information about physics, as opposed to temporary information about the state of the system, to maintain a state of low entropy? That seems more like what happens with hot air rising, and cold air falling.)

Anyway, it really looks like an elegant experiment in quantum thermodynamics.

Hi Olivier,

I'll take a look at your paper.

You might find my comment about Bell Tests, Schrödinger's coin, and One-Time Pads interesting in this context.

Also, note that all Bell-type theorems and experiments only deal with the EPR-B paradox rather than the much more general, original EPR paradox. In other words, Bell only deals with David Bohm's version of the paradox, that is restricted to observables with only two observed states, like spin-up and spin-down. But the original EPR paradox deals with the Heisenberg Uncertain Principle. Why can't CONTINUOUS variables (like position and momentum), that can take on any value in the classical realm, be simultaneous measured in the quantum realm? The fact that Shannon's Capacity, when evaluated at number-of-bits-of-information=1 turns out to be identical to the Heisenberg Uncertainty Principle, provides the answer, as to why that happens in general, and not just in the resticted Bohm version of the paradox.

Rob McEachern

Consilience does not appear to be a topic of interest on this site.

Is that the case and, if so, why not?

(I am inquiring primarily about E.O. Wilson's volume titled Consilience: The Unity of Knowledge. There has been some subsequent activity but not much progress that I can detect.)

This would recommend that.. What we are seeing as quantumness is essentially nature's truncation (or its inability to speak to or potentially spread) the higher sounds of the (Classical) variational waveform through microscale flow.

All the Best,

Alka

Tell me what you think of this thought experiment:

How significant are our decisions? Are they meaningless, as in they are determined, and we are just objects set in motion with no control of our destiny. Or are the decisions we make ours and we are therefore in control of our own destiny? One such area in physics which might set light on this is quantum mechanics, and in particular the double slit experiment. The double slit experiment is an experiment, in which either electrons or photons are fired towards a two slit assembly, resulting in an interference pattern emerging. This experiment has been performed on all sorts of objects, such as molecules, atoms, and even carbon bucky balls. However the experiment has never been performed on living organisms. Imagine a scenario in which we take a small airborne bacteria, or even a non airborne bacteria and place it in a double slit experiment situation. This experiment would differ considerably in that the experiment is probing whether the decision of the microbe was quantum mechanical or not. The experiment works by placing microbes in a box with a two slit assembly one at a time on one side of the box, while on the other side of the two slit assembly there is a detector screen with food in order to attract the microbes over. Rather than being fired across the microbes will make the decision to travel towards the food on the detector screen. They will not be set in motion. It has been proven that single cellular organisms are capable of making basic decisions. One of these decisions is the ability to travel towards food molecules and they can in fact sense molecule gradients as small as one molecular per micron in a background of just 1000 molecules per cell volume. The first possible outcome of this experiment is that an interference pattern of these microbes forms, which suggests that our actual decisions are quantum mechanical, which is derived from the fact that the bacteria made the decision to travel through either one of the slits to a particular piece of food. This therefore means that if an interference pattern forms the decision of the microbe to travel to the detector screen was as a result of random wave function collapse and therefore effectively the bacteria under those circumstances were not making those decisions because the end result was just an emergence of the property of random wave function collapse. One could therefore draw the philosophical conclusion that our actions are therefore insignificant. However there is a second outcome, which is that no interference pattern forms, which tells us that our decisions are not quantum mechanical because the microbes, would in this scenario be able to evade random wave function collapse. In addition this experiment could shed light on the role of the observer in quantum mechanics, as to whether consciousness plays a role in wave function collapse. This might be implied if an interference pattern isn't formed because the microbe was able to observe itself and the wave function therefore collapsed. Although this experiment is not complete at this stage it is about the principle, and there are many questions left to solve such as how such a small interference pattern. The De Broglie( length of a bacteria traveling at 80km/h with a mass of 2e-17kg is 1.49e-9nm, and therefore does not have a large wavelength so the interference will be negligible. Another point which needs development is an exact experimental technique to carry this out, which is currently being worked on.

For some further insights into the nature of "Quantum Weirdness", see my "Socratic Dialog" with Tim Maudlin

Rob McEachern