Quantum mechanics, scientists, and New Age mystics

Posted by on February 21, 2012 No comments

Brian Cox — co-author with Jeff Forshaw of The Quantum Universe (And Why Anything That Can Happen, Does) (Da Capo Press, 2012) — has posted an article titled Why Quantum Theory Is So Misunderstood in the Wall Street Journal’s Speakeasy blog. There he defends his claim that according to quantum mechanics “everything is connected to everything else”, and that “this is literally true if quantum theory as currently understood is not augmented by new physics,” which for the moment (and probably for a long time to come) it isn’t. “This means that the subatomic constituents of your body are constantly shifting, albeit absolutely imperceptibly, in response to events happening an arbitrarily large distance away…”

That this statement received some well-deserved criticism in scientific circles wasn’t, according to Cox, because it is wrong but because “it sounds like woo woo, and quantum theory attracts woo-woo merde-merchants like the pronouncements of New Age mystics attract flies.”

Cox goes on to inform us (“for the record”) that “the subtle interconnectedness in quantum theory cannot be used to transmit information.” Wait a minute. Haven’t we just been told that the subatomic constituents of our bodies are constantly shifting in response to events happening an arbitrarily large distance away? If this were true, the response would depend on what happened a large distance away — otherwise we couldn’t say that it was a response to what happened there. But if what happens here depends on what happens there, then what happens here contains information about what happens there.

I am not saying that the “subtle interconnectedness in quantum theory” can be used to transmit information. It cannot. What I am saying (in agreement with the critics) is that blather about subatomic constituents constantly shifting in response to arbitrarily distant events is not the right way to illustrate the subtle interconnectedness that exists in quantum theory. Rather, it is precisely the kind of thoughtless talk that fires up the wooly masters of the New Age. Nor does saying that the constant shifting takes place “absolutely imperceptibly” explain why it cannot be used to transmit information. This qualifier is nothing but the second of two wrongs that pretend to make a right.

Cox accepts partial responsibility for the “cataclysmic tosh” purveyed by writers who cannot “possibly have the faintest idea how to use quantum theory to calculate the energy levels in a hydrogen atom” but tries to defend the use of his shifty metaphor, with scant success. Along the way he cites scientific questions — Is the climate warming and, if so, what is the cause? Is it safe to vaccinate children against disease? — whose answers “are independent of the opinion, faith or political persuasion of the individual.” I wish the tosh purveyed by those who know how to calculate the energy levels in a hydrogen atom were equally independent of their faiths or opinions. (Political persuasion may not be a factor here.)

The fact of the matter is that the mathematical formalism of quantum physics is a probability calculus. It serves to assign probabilities to the possible outcomes of measurements yet to be made, on the basis of measurement outcomes already obtained. This calculus, moreover, is the only testable part of the theory. It is all that experimental physicists need to know and most of them care to know. How, if not by way of faith or opinion, does one get from here to balderdash like the following?

“Quantum theory tells us that the universe we experience emerges from a bewildering, counterintuitive maelstrom of interactions between an infinity of recalcitrant sub-atomic particles. To understand something as simple as a rainbow, we have to allow each single particle of light to explore the entire universe on its journey through the rain.”

For a significantly more insightful discussion of quantum mechanics and its popularization I strongly recommend an article by philosopher of science Dennis Dieks, which appeared in the first issue of AntiMatters.

Quantum fuzziness and the stability of matter

Posted by on November 8, 2011 No comments

In what follows I elaborate on a couple of arguments I made in The World According To Quantum Mechanics.

Why does a typical material object occupy as much space as it does? Part of the answer is that it is “made” of atoms (as well as molecules), and that an atom occupies a space roughly a tenth of a nanometer across. So why does an atom occupy that much space, despite the fact that it is composed of a very few objects, which either (like an electron) occupy no space at all or (like a nucleus) occupy a space roughly ten femtometers across — four orders of magnitude less than the atom?

To keep the problem as simple as possible, let us consider an atom of hydrogen in its ground state. Before we can profitably do so, however, we need to clarify what it means for a quantum-physical system to be “in” a state. After all, a quantum state is a probability algorithm, and it does not make much sense to say that a quantum system is in a probability algorithm.

We may think of the ground state of a hydrogen atom as an actual state of affairs if we allow that this state of affairs is adequately described in terms of the probability distributions it defines. Specifically, we may think of the position probability distribution defined by the ground state as describing a fuzzy position, and we may think of this fuzzy position as an aspect of that state of affairs. But we need to be clear about (i) when that state of affairs obtains and (ii) how we know that it obtains.

The ground state of atomic hydrogen (qua probability algorithm) is determined by a single outcome: the lowest possible outcome of a measurement of the atom’s energy. Strictly speaking, however, the possession by the atom of a specific energy cannot be observed. What can be observed is transitions between (approximately) stationary states, including transitions to the ground state. We can observe the transition of a hydrogen atom to its ground state, and we can prevent any subsequent transition to an excited state, at least for a limited period. If we do so, we know that the ground state (qua actual state of affairs) obtains, and we know when it obtains: not at any instant of time, but during an undifferentiated time span beginning with the atom’s transition to the ground state.

So why does a hydrogen atom in its ground state occupy as much space as it does? Primarily because the electron’s position relative to the proton is fuzzy. Merely being fuzzy is not enough, though. The relative position between the two particles must also stay fuzzy. For this, the electrostatic attraction between the two particles, which (by itself) would cause their relative position to get sharper (less fuzzy), must be offset by something which (by itself) would cause their relative position to grow more fuzzy. This something is the fuzziness of their relative momentum. A mere equilibrium between these two tendencies, however, also is not enough. The equilibrium has to be stable, and for this Heisenberg’s uncertainty relation is needed. This ensures that a decrease in the fuzziness of a relative position (beyond a certain limit) causes an increase in the fuzziness of the corresponding relative momentum, and vice versa. It thereby ensures that a decrease (or increase) in one tendency causes a decrease (or increase) in the other.

The word “uncertainty”, however, is misleading. Although Heisenberg’s original term Unschärfe carries the statistical sense of this word as well as the sense of “fuzziness”, the latter is appropriate here; for what “fluffs out” atoms is not our subjective uncertainty about the values of the relative positions and momenta of the constituents of atoms but an objective fuzziness of those values.

Word Scientific Publishing Highlight for November: 30% Discount

Posted by on September 28, 2011 No comments

The World According To Quantum Mechanics

From the Publisher’s latest Newsletter:

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How the Hippies Saved Physics

Posted by on August 15, 2011 No comments

From a review by George Johnson of How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival by David Kaiser (W. W. Norton & Company, 2011). Titled What Physics Owes the Counterculture, it was published on June 17, 2011 in the NYT Sunday Book Review.

How the Hippies Saved Physics

“What the Bleep Do We Know!?,” a spaced-out concoction of quasi physics and neuroscience that appeared several years ago, promised moviegoers that they could hop between parallel universes and leap back and forth in time — if only they cast off their mental filters and experienced reality full blast. Interviews of scientists were crosscut with those of self-proclaimed mystics, and swooping in to explain the physics was Dr. Quantum, a cartoon superhero who joyfully demonstrated concepts like wave-particle duality, extra dimensions and quantum entanglement. Wiggling his eyebrows, the good doctor ominously asked, “Are we far enough down the rabbit hole yet?”…

Dr. Quantum was a cartoon rendition of Fred Alan Wolf, who resigned from the physics faculty at San Diego State College in the mid-1970s to become a New Age vaudevillian, combining motivational speaking, quantum weirdness and magic tricks in an act that opened several times for Timothy Leary. By then Wolf was running with the Fundamental Fysiks Group, a Bay Area collective driven by the notion that quantum mechanics, maybe with the help of a little LSD, could be harnessed to convey psychic powers. Concentrate hard enough and perhaps you really could levitate the Pentagon.

In “How the Hippies Saved Physics: Science, Counterculture, and the Quantum Revival,” David Kaiser, an associate professor at the Massachusetts Institute of Technology, turns to those wild days in the waning years of the Vietnam War when anything seemed possible: communal marriage, living off the land, bringing down the military with flower power Why not faster-than-light communication, in which a message arrives before it is sent, overthrowing the tyranny of that pig, Father Time?

The hippies who save physics

Members of the Fundamental Fysiks Group, circa 1975; clockwise from left: Jack Sarfatti, Saul-Paul Sirag, Nick Herbert and Fred Alan Wolf

That was the obsession of Jack Sarfatti, another member of the group. Sarfatti was Wolf’s colleague and roommate in San Diego, and in a pivotal moment in Kaiser’s tale they find themselves in the lobby of the Ritz Hotel in Paris talking to Werner Erhard, the creepy human potential movement guru, who decided to invest in their quantum ventures. Sarfatti was at least as good a salesman as he was a physicist, wooing wealthy eccentrics from his den at Caffe Trieste in the North Beach section of San Francisco.

Other, overlapping efforts like the Consciousness Theory Group and the Physics/Consciousness Research Group were part of the scene, and before long Sarfatti, Wolf and their cohort were conducting annual physics and consciousness workshops at the Esalen Institute in Big Sur.

Fritjof Capra, who made his fortune with the countercultural classic “The Tao of Physics” (1975) was part of the Fundamental Fysiks Group, as was Nick Herbert, another dropout from the establishment who dabbled in superluminal communication and wrote his own popular book, “Quantum Reality: Beyond the New Physics” (1985). Gary Zukav, a roommate of Sarfatti’s, cashed in with “The Dancing Wu Li Masters” (1979). I’d known about the quantum zeitgeist and read some of the books, but I was surprised to learn from Kaiser how closely all these people were entangled in the same web [...]

Humbling experience

Posted by on July 1, 2011 3 comments

The following is a Review by Henning Dekant (Real Name) at Amazon.com (June 29, 2011).

Richard Feynman famously stated “I think it is safe to say that no one understands Quantum Mechanics.”

This book is changing that. Although so far I have only read up to chapter 5, it looks like this unexpected treatise lives up to its preposterous subtitle.

The way Ulrich Mohrhoff introduces QM everything flows from the basic rules of calculating with probabilities and the uncertainty relation. The latter in turn is a logical requirement for stable matter and quite a misnomer in English (surprisingly the original German term “Unschaerferelation” captures its meaning significantly better).

Reading chapter 5 has been a most humbling experience. I studied physics and have always been captivated by the particle wave dualism that the classical two slit experiment embodies so beautifully. Feynman observed that this “experiment has in it the heart of quantum mechanics”. Well, I feel like eating my heart out.

The way this book covers the two slit experiment everything falls into place and makes perfect sense. There is no wave particle dualism, just the naked necessity of a probabilistic regime. It is so simple. Painfully obvious. Easy to grasp with just a minimum of mathematical rigor. It boggles the mind that QM has not been understood this way from the get go. This feels like 20/20 hindsight writ large.

To add insult to injury, this is written as a text book that’ll be easily accessible for an enterprising high school student, because it briefly introduces all necessary mathematical tools along the way. I.e. a physicist can easily skip these parts as they are cleanly separated from the chapters in which the author executes his QM program.

If you’ve been trying to make sense of QM you will hate this book. It’ll make you feel stupid for not having been able to see this all along. Time to eat some humble pie.

I’ll report back once I read the rest.