Monthly Archives: December 2009
(Last Update: 2011/01/23 – Text Corrections & Clarifications)
One of the most commonly used means of supporting belief in various sorts of New Age and mystical/psychic woo is the invocation of that popular and notoriously poorly understood icon of modern physics, Quantum Mechanics: Wouldn’t it be ducky if everything in the Universe were intimately connected to everything else, every particle bound to every other through the phenomenon of quantum entanglement, all of reality in holistic unity; a holographic universe in which nothing was truly separate from anything else, all existing as a single zero-dimensional point in which all possibilities are realized, our notions of objective reality an illusion? Wouldn’t it be wonderful if All were One? That instant communication with anyone in the universe, regardless of apparent distance or time by reading the quantum oscillation of entangled atoms across the universe, including particles in our own brains so bound to those of others, was possible? Doesn’t this sound just a little too convenient? Well, unfortunately it is. It’s bullshit, and here’s why:
The phenomenon of entanglement, or the Einstein-Podolsky-Rosen (EPR) effect, is a property in which two or more particles, though separated by distance, perhaps even at opposite sides of the universe, can show a sort of ‘spooky action at a distance’ through the action of quantum non-locality, and a thing which we have experimentally confirmed through our tests of quantum teleportation, instantaneously transmitting the quantum properties of one particle to an entangled counterpart at theoretically any distance.
This entanglement allows the instant exchange of quantum states, such as, say, the property of spin, between the bound particles, even as far apart as the other side of the Galaxy, simultaneously. Where one particle would be, say, spin up at any instant, its twin would simultaneously be spin down. And any change in one particle’s quantum state would instantly result in change to that of the other. The problem is that Einstein’s theory of Special relativity still holds at astronomical distances, so that nothing, no energy, and thus no information that could be carried by that energy, may travel faster than light, much less instantly.
It should be noted, however, that there is some controversy among physicists as to the exact operative definition of the term Instant.
The act of ‘observing,’ really just physical interaction, and having nothing to do with any human notions of ‘consciousness’ since one is merely interacting with the particles in order to read them by bouncing other particles of radiation of some form or another off of them, thus changing their quantum state, and this would cause the entangled particles to exchange their quantum properties between each other randomly.
This, and the limits on the speed of energy transfer imposed by Special relativity ensure that only random noise would be obtained from such non-local ‘communication.’ No meaningful data may thus be instantaneously transferred.
Our current understanding, and laboratory observations thus far indicate that quantum cryptography, the transfer of data in a way that seems to disallow any possible eavesdropping, at the speed of light by way of entangled photons, is possible, but the ansible, while interesting in principle, from the Ender’s Game science-fiction series is not.
Another problem presents itself during the observation of these particles, an issue not taken into account by some ‘Oneness’ models of cosmology derived from quantum mechanics: that of quantum decoherence, a phenomenon caused by entanglement itself, the new bonding resulting from the interaction of any one or more of a set of entangled particles with any other particles in the universe, causing an overriding of the original entangled state of the particles, thus scribbling over any older non-local connections with new ones, whatever particles they have most recently interacted with.
Quantum entities tend to be promiscuous when it comes to entanglement, interacting and entangling with any new random particles they come in contact with, the very source of their own decoherence.
This is why alleged phenomena such as psi are untenable quantum mechanically as we currently understand physical laws to operate. Even if any particles in one person’s brain could somehow be entangled with those in another brain, thus supposedly allowing non-local exchange of information by paranormal means, the fact that these same particles are interacting with any other particles in either of the two linked brains, means that any entanglement existing would be scribbled over almost as quickly as it began.
Human beings alone are composed of a staggering number of particles, all of them interacting with each other and foreign particles originating from outside the body, reaching us from other parts of the universe, especially from our immediate environs and from other regions within our own bodies.
For objects as large as humans, even our brains alone have such a large de Broglie wavelength, such a high quantum number, that the decoherence caused by the continuous entanglement of the particles making it up with each other and indeed all other surrounding particles bombarding them, that for any noticeable quantum effects to occur, one would have to wait longer than the lifespan of the universe to see them.
To quote Robert Novella, ‘human beings are walking bags of decoherence.’ Such quantum intimacy seemingly granted by entanglement is denied us on any meaningful timescale, for it is overcome almost immediately in the event that it does happen by its own indiscriminate nature. It seems that, as far as current understanding of quantum theory is concerned, I’m sorry to say that science really doesn’t support the mystics after all…
- Universe’s Quantum Weirdness Limits Its Weirdness (wired.com)
- Can I build an ansible to communicate across the cosmos? [Ask A Physicist] (io9.com)
- Quantum networks closer with Alberta discovery (cbc.ca)
- Quantum entanglement, meet Heisenberg (arstechnica.com)