Quantum physics is one of those fields which has a reputation for being obstruse and complex, not merely in that it requires deep foundations of knowledge and advanced mathematical tools to plumb, but in that its claims are inherently confusing, even contradictory. The confusion in the popular understanding of what quantum physics really is, and what its implications are, is not helped by some of the exotic interpretations thrown around by both legitimate physicists and by journalists attempting to communicate them (usually with far too much “hype,” as is definitely the case around quantum computers). However, even researchers in the field are susceptible to some of these contradictions, as the field has wrestled for its entire century of existence with how to interpret quantum results in a classical reality, and especially how to reconcile the seeming contradictions between the quantum and classical scales and experiences of reality.
In a recent essay from Quanta Magazine, “Are the Mysteries of Quantum Mechanics Beginning to Dissolve,” Ball argues for a resolution to these seeming contradictions proposed by Zurek in a recent book called Decoherence and Quantum Darwinism. I’ve not read it yet (I may at some point), but Ball’s description of the central arguments in the essay is lucid and reasonably compelling. Rather than invoking the many worlds theory to explain a lack of wave collapse, or introducing some exotic and mysterious mechanism by which wave collapse can be induced, Zurek’s claim is that wave collapse is a natural result of the inevitable interactions a wave function has with its environment and the entanglements which result.
Wave collapse is a problem for quantum physics because it seems to require an observer, putting some ungrounded notion of philosophical “consciousness” at the heart of what is supposed to be a fundamental description of the universe. In the famous two-slit experiment, the result is different depending on whether or not the experiment is observed. The mechanism by which observation affects the wave functions that become the particles and macroscopic effects with which we interact is elusive, and arguably spookier in some interpretations than any supposed action at a distance. The latter refers, of course, to entanglement, which was famously referred to as “spooky action at a distance” for how it seems to require communication between two distinct entities at instantaneous speeds, in violation of the light speed limitations of relativity. In truth, entanglement is not quite so spooky, and no cosmic speed limits are broken in the process. Rather, in entanglement, what began as two particles in effect become a single entity, described by a single mathematical function. By far the most readily approachable representation of entanglement I’ve found, although the analogy is not perfect, is to a pair of gloves. If you have a pair of gloves, and you blindly grab one of them before travelling a thousand miles away, you will instantly know to which hand the left-behind glove belongs when you pull out the one you brought with you. Quantum entanglement is similar.
Entanglement is a pervasive feature of quantum interactions, arising in some respect from almost any interaction that can occur. Zurek proposes that these entangling interactions, in their vast multiplicity, are the mechanism by which the wave functions collapse and a seemingly classical reality emerges (Ball refers to this as entanglement “dilution” of the object’s “quantumness”). No infinite worlds, no spooky action at a distance, no arbitrary dividing line between the quantum and classical realms, just a natural and inevitable wave collapse mechanism arising from another attested principle of the same theory. It is elegant, it doesn’t introduce anything novel, and it makes concrete claims which can be tested (and are being tested now) in existing laboratory environments.
It also happens to align with what I’ve long thought to be the case, that the minute interactions which must take place for any observation or measurement of any kind to occur might represent the mechanism by which wave collapse is induced. So, the proposal appeals to me, for what that’s worth. I’m not a quantum physicist, although I like to consider myself reasonably well informed on the subject, and I dabble a bit deeper in the math when it comes to electromagnetism and some sensing technologies. We’ll discuss all these concepts in much more detail if I get around to reading and reviewing Decoherence and Quantum Darwinism in the future, or Waves in an Impossible Sea, which is also on my reading list and broadly considered a core entry in the quantum physics genre. For now, I encourage you to give Ball’s Qualia essay a read. If nothing else, it might help make quantum physics seem a little less like magic.
IGC Publishing 