Galt's Gulch

Author Assist: Power Needed for...

Posted by $ AJAshinoff 8 years, 11 months ago to Technology
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As an element of the novel I'm currently working on I need to know how much power a laser would need to change the phase of a separated quantum particle.

Would the power be detectable? Would the laser physically be to large to be contained in something the size of a refrigerator? A car? A garage?

Thanks in advance for any info provided or any link to help me find the answer for myself.

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  • Posted by ProfChuck 8 years, 11 months ago
    Actually the problem is a bit more complicated than that. The "power" of a laser is determined by two things; the photon flux and the wavelength. As it turns out a single photon of the appropriate wavelength can change the "phase" as you put it of a quantum state. The photoelectric effect is a good example of this. Photons of ultraviolet light can dislodge an electron from metal while those of infrared light fail to do so. The power of a laser is related to the product of the photon flux (the number of photons produced per unit time) and the frequency of the photons. The higher the frequency (or the shorter the wavelength) the greater the energy carried by each photon. When this energy is greater than the binding energy of an electron in the outer shell of an atom, usually a metal atom, that electron is "dislodged" and is free to flow in a conducting circuit. This is the underlying principal behind the photomultiplier tube. A blue led or hand held laser pointer produces photons of sufficient energy to stimulate quantum state changes in many materials including phosphors. This is the mechanism behind most "white light" led's.
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  • Posted by $ jlc 8 years, 11 months ago
    One of our trainers actually graduated from Cal Tech with a degree in Light Optics Physics. I posed him your questions, and he replied:

    A "separated quantum particle" sounds like one of a pair of quantum-entangled particles -- you detect the phase, but you don't change it (at least not without also changing the phase of the other). And that's not a question of power, so much as precision. The phase of a single photon can be changed by a single photon -- if it's in the right place at the right time.

    If you can provide more details, he is a bit intrigued and is willing to provide a more complete answer.

    Jan
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    • Posted by $ AJAshinoff 8 years, 11 months ago
      Thats definitely in the ballpark of the information I'm after. Yes, I understand that we can detect its phase and that any change in phase will result a change in phase to its other. But to change the phase, precision or not requires something - power of some degree large or small (a laser is light, heat increase or cold is also a degree of power absorption or release) and I need to know primarily if it (the phase changes) can be detected if instrumentation was pointing directly at the object where it was occurring.

      Thanks for casting out the net for me.
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  • Posted by $ MichaelAarethun 8 years, 11 months ago
    Just finished a book by Benioff I believe is the name of two russians working with partisans in WWII. One kept asking with all those stars emitting light all the tme and the light travels to endless distances why is it dark tonight.

    One finally answered ''because the universe is expanding."

    But if the universe is everything where does it expand to?


    Gotta love those enquiring minds. Took me a few decades to work my way around from history and political science to physics. It's a real enjoyment and no one to give me a grade.

    Thanks for the good teachers we did have.
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  • Posted by strugatsky 8 years, 11 months ago
    A laser emits photons, which are quantum particles. So, which quantum particles do you want to affect? And what do you mean by "phase"? I think that some more details are needed.
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  • Posted by $ minniepuck 8 years, 11 months ago
    Hmm...sorry I can't help answer that question, but I know when you figure it out, your story will be the better for it. I look forward to reading your work.
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  • Posted by CircuitGuy 8 years, 11 months ago
    I don't know the answer either, but it makes me curious about the story.

    Is a quantum particle a quark? I thought they didn't exist for long outside being paired up to make protons or neutrons. I'm sure they don't have a phase like regular matter has solid, liquid, gas, plasma, but there is probably some other type of phase.

    I don't know much about quantum physics, but I think authors should avoid the temptation to make it the wildcard to explain away anything.
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