Confessions of a researchaholic

October 24, 2009

Schrödinger’s cat

Filed under: Imaginary,Real — liyiwei @ 4:06 pm

When I was a kid I have been deeply fascinated by theoretical physics (to the point that I was propelled to pick up college level calculus and physics around age 15), and a recent article in Economist reminded me of one of the questions I had in my mind a long time ago.

Here it is. If someone opens the box containing Schordinger’s cat without my knowledge, what will the cat’s existence to me? Is it still a quantum superposition (i.e. the cat is dead and alive simultaneously), or it will collapse into a definite probabilistic state (i.e. the cat is either dead or alive with a certain probability, but not both)?

I never ended up pursuing theoretical physics because I opted for a more practical major in college that would allow me to “hack” things, so I still do not know the answer to that old question. But now I think for all practical reasons, the cat (or any macroscopic object) is very unlikely to be in a true quantum superposition for a very simple reason: it is simply too macroscopic to be devoid of quantum disturbances that act as probes to collapse the quantum states. Thus, for all practical purposes, the intriguing situation is unlikely to exist; the cat is either dead or alive, but not both.

Growing old does not necessarily make one wiser, but likely more pragmatic.

1 Comment »

  1. I think the Schrodinger’s cat is more like a metaphor than a reality experiments.
    If you want to do such a experiments, you need to control the environment e.g. the only quantum effects in the box is just the trigger itself, which is not possible by current experimental physics technologies.

    Comment by Allen — October 25, 2009 @ 3:40 am | Reply

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