Quantum Entanglement

by Ira Mark Egdall

Nature is not only stranger than we imagine, it is stranger than we can imagine.
– J. B. S. Haldane

You want wild and crazy? Forget jumping out of an airplane or going out with that nose-pierced, body tattooed delinquent with the multi-colored hair your mother hates. Just look at reality.

I’m talking about the reality revealed by so-called quantum entanglement, where two particles — no matter how far apart — are intimately and instantly connected.

Take two entangled photons moving in different directions. Per conservation laws, if one is vertically polarized, the other must be horizontally polarized, and vice-versa. So when you measure the polarization of one photon, you instantly know the polarization of the other.

So what’s the big deal? Einstein and his colleagues Podolsky and Rosen (EPR) argued each photon had a certain polarization before you measured it. All the measurement did was reveal what that polarization was all along. And once you measured the first photon, you knew what the second photon’s polarization was.

But quantum theory says a photon’s polarization, like its other variable attributes, is in a kind of limbo. Its polarization is undetermined until it is measured. In other words, a particle’s attributes like polarization are not programmed in advance. They exist only after measurement.

Physicists have since conducted a number of tests to find out whether this is true. These Bell experiments show quantum theory is right. A particle’s variable attributes are not pre-programmed. They are random — determined in the act of observation itself.

So in the above experiment, the polarizations of both photons start out indeterminate, in quantum limbo. The act of measuring the first photon sets its polarization — and the polarization of the second photon. Instantly. Across space. No matter how far apart the two particles are. Something here can and does influence something way over there. In zero time. The universe is “non-local”.

This quantum reasoning also applies to a particle’s location. As Rosenblum and Kuttner wrote in their book, Quantum Enigma, a particle “was not there before you found it there. Your happening to find it there caused it to be there.”

Whoa. Our universe is wilder than we can imagine.

Caveat: Arguments against the completeness of quantum theory and the interpretation of Bell experiments remain topics of ongoing physics discussion and research. David Bohm’s so-called Causal Interpretation of quantum mechanics is the most famous non-local hidden variable theory (there are a number of others). Bohm’s theory reproduces the predictions of quantum mechanics without resorting to probabilities. In Bohm’s clever but convoluted construct, a particle’s attributes are pre-programmed, known before measurement. Based on an idea from Louis de Broglie, a hidden “guiding wave” traveling faster than light governs the motion of a particle. However, the theory remains non-local.

What do you think? I welcome all comments — pro and con.

My website: marksmodernphysics.com
You can also follow me on Twitter@IMEgdall

15 thoughts on “Quantum Entanglement”

  1. I think this is among the most vital information for me. And i’m glad reading your article. But should remark on some general things, The web site style is wonderful, the articles is really excellent : D. Good job, cheers

  2. Great post. I was checking constantly this blog and I’m impressed! Very useful info specifically the last part 🙂 I care for such information a lot. I was seeking this particular information for a long time. Thank you and best of luck.

  3. You really make it seem so easy with your presentation but I find this matter to be really something that I think I would never understand. It seems too complicated and very broad for me. I’m looking forward for your next post, Iíll try to get the hang of it!

  4. Udaybhanu and PeterJ, you have perfectly illustrated the problem with modern physics. Quantum theory is stranger than we can know or understand, but it is not stranger than we can imagine. Various versions of the pilot-wave and dynamical collapse interpretations, and even combinations of these, can offer quite non-strange speculations about quantum theory.

    However, it’s become unacceptable to include speculation in serious physics. Unfortunately, quantum theory is incomplete, and must for explanatory purposes be supplemented with something speculative. Refusing to do this results in exactly these two alternatives.

    1. Leaving gaps that people like Udaybhanu can fill with their gods.

    2. Using snarl words like “reify”, as PeterJ did, to delegitimate the complete theory quest itself.

    We’ll never have all the answers, and we’ll never be able to verify all the answers we have. But we do have darn good guesses, and we need to stop being afraid of how different and apparently incompatible they are, and simply get them out there. We don’t have to agree. We don’t have to understand. But we have to explain, so the next generation can bring new thoughts to bear on our musings.

  5. Aka Spooky Action at a Distance, or Instantnaiety of Action at a Distance, etc…

    1) action inherently is defined as a phyiscal/energy, cause and effect, ergo, an action here causes a predetermined setting to exist elsewhere, or even and action elsewere.

    2) action here occurs at some speed beyond that of speed-of-radiation, ergo such FTRadiation speeds, appear to us a instaneous, for whatever unknown reason,

    3) the action of choice, of a prexisting probability oa quantified yes or no resoultion , at point A, is preprogrammed into point B, i.e. the quantification at point A, is intimatly predetermined by all processes of Universe, ergo, choice at point A is predetermined, ergo point B attributes are predertined.

    I like both #2 and #3 above and believe both are involved, too whatever degree, and to whatever degree of overlap of those two.


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