Measuring Quantum Fluctuations on the Human scale:

Discussion in 'Physics & Math' started by paddoboy, Jul 14, 2020.

  1. paddoboy Valued Senior Member

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    https://www.ligo.caltech.edu/news/ligo20200701

    Quantum fluctuations can jiggle objects on the human scale
    Feature Story • July 1, 2020

    The universe, as seen through the lens of quantum mechanics, is a noisy, crackling space where particles blink constantly in and out of existence, creating a layer of background quantum noise whose effects are normally far too subtle to detect in everyday objects.

    Now for the first time, a team led by researchers at MIT LIGO Laboratory has measured the effects of quantum fluctuations on objects at the human scale. In a paper published today in Nature, the researchers report observing that quantum fluctuations, tiny as they may be, can nonetheless “kick” an object as large 40-kilogram mirrors of the Laser Interferometer Gravitational-wave Observatory (LIGO), causing them to move by a tiny degree, which the team was able to measure.

    It turns out the quantum noise in LIGO’s detectors is enough to move the large mirrors by 10-20 meters — a displacement that was predicted for an object of this size by quantum mechanics, but had never before been measured.

    “A hydrogen atom is 10-10 meters, so this displacement of the mirrors is to a hydrogen atom what a hydrogen atom is to us — and we measured that,” says Lee McCuller, a research scientist at MIT’s Kavli Institute for Astrophysics and Space Research.

    The researchers used a special instrument that they designed, called a quantum squeezer, to “manipulate the detector’s quantum noise and reduce its kicks to the mirrors, in a way that could ultimately improve LIGO’s sensitivity in detecting gravitational waves,” explains Haocun Yu, a physics graduate student at MIT.

    “What’s special about this experiment is we’ve seen quantum effects on something as large as a human,” says Nergis Mavalvala, the Marble Professor and associate head of physics at MIT. “We too, every nanosecond of our existence, are being kicked around, buffeted by these quantum fluctuations. It’s just that the jitter of our existence, our thermal energy, is too large for these quantum vacuum fluctuations to affect our motion measurably. With LIGO’s mirrors, we’ve done all this work to isolate them so that they are now sensitive enough to be kicked around by quantum fluctuations, and this spooky popcorn of the universe.”

    Yu, Mavalvala, and McCuller are co-authors of the new paper, along with graduate student Maggie Tse and Principal Research Scientist Lisa Barsotti at MIT, along with other members of the LIGO Scientific Collaboration.

    more at link..................
     
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  3. DaveC426913 Valued Senior Member

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    Ten to twenty metres! That's a heck of a kick!

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  5. paddoboy Valued Senior Member

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    Damn!

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    10 to the minus 20th mtr
     
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  7. Xelasnave.1947 Valued Senior Member

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    It is difficult to see solid objects as they must be...almost like clouds of mist really.
    Alex
     
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  8. DaveC426913 Valued Senior Member

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    Yeah. Did a double-take before I realized it what it was supposed to be.
    It's just a copy-paste artifact. It's printed correctly in the article.
     
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  9. Vociferous Valued Senior Member

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    That's usually written as 10^-20 meters. I've shown you that before.
     
  10. paddoboy Valued Senior Member

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    No not at all...In fact I don't believe you have posted anywhere in the sciences, instead wallowing in your myths and pretense.

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    You take it easy, OK?
     
  11. paddoboy Valued Senior Member

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    Seems its fooled at least one!

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  12. Xelasnave.1947 Valued Senior Member

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    You take the time to help and he just does not listen but that's what you get with Aussies.
    Nice new avatar ... It is so you.
    It's a very nice monkey you have there.
    Alex
     
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  13. Vociferous Valued Senior Member

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    I don't have to go looking for your ignorance when you display it everywhere you post:
    I really thought you'd correct your error without me having to explicitly point it out to you. Even in this thread, you seem ignorant of how to write it:
    Not to mention all these other times you failed to write it correctly:
    Hell, there's too many to link. Here's the search results:
    200 results!
    Except I obviously knew what you meant earlier, even though you had no clue how to write it. At least now you finally know. And knowing is half the battle.
     
    Last edited: Jul 19, 2020
  14. Michael 345 New year. PRESENT is 71 years old Valued Senior Member

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    Who said devolution does not happen?

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  15. Xelasnave.1947 Valued Senior Member

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    I thought I would get pulled up calling it a monkey but I guess he thinks that is a monkey.
    Are you home yet?
    Alex
     
  16. Michael 345 New year. PRESENT is 71 years old Valued Senior Member

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    I only got to see it because it shows up on occasion with the message - You are ignoring this member

    No, but we, 3,000 stranded tourist, apparently are being kicked out with 30 days notice (7 days ago) with NO flights

    Looks like going to be a long swim

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  17. Xelasnave.1947 Valued Senior Member

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    Go the other way.
    Alex
     
  18. Vociferous Valued Senior Member

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    Couldn't happen to a better guy.
     
  19. Q-reeus Valued Senior Member

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    A cursory reading of the unpaywalled version https://arxiv.org/abs/2002.01519v1 makes it clear the first highlighted line is completely divorced from the next two.
    In whatever sense the 40Kg mirrors supposedly move as a whole owing to 'quantum jiggling', the actual 'jiggling' is owing to laser intensity fluctuations, NOT 'virtual particles/zero-point vacuum fluctuations'. Once again, this classic article effectively puts paid to the notion of 'zero-point vacuum fluctuations' as the cause of anything physical:
    https://arxiv.org/abs/hep-th/0503158
     
  20. paddoboy Valued Senior Member

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    Patently false and a lie, since it's your own mythical claims that many on this forum see as ignorant.

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    Ahh the usual pedant from the fanatic shown many times to be indulging in fanciful myth. Now he pollutes the sciences.

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    And you'll probably see 201 results.

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    Is this all you have after being totally dismantled in your religious and political threads?
    Take a deep breath my vociferous friend!
     
  21. Vociferous Valued Senior Member

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    Well, some people will never learn.
     
  22. paddoboy Valued Senior Member

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    https://www.nature.com/articles/s41586-020-2420-8


    Quantum correlations between light and the kilogram-mass mirrors of LIGO

    Abstract
    The measurement of minuscule forces and displacements with ever greater precision is inhibited by the Heisenberg uncertainty principle, which imposes a limit to the precision with which the position of an object can be measured continuously, known as the standard quantum limit1,2,3,4. When light is used as the probe, the standard quantum limit arises from the balance between the uncertainties of the photon radiation pressure applied to the object and of the photon number in the photoelectric detection. The only way to surpass the standard quantum limit is by introducing correlations between the position/momentum uncertainty of the object and the photon number/phase uncertainty of the light that it reflects5. Here we confirm experimentally the theoretical prediction5 that this type of quantum correlation is naturally produced in the Laser Interferometer Gravitational-wave Observatory (LIGO). We characterize and compare noise spectra taken without squeezing and with squeezed vacuum states injected at varying quadrature angles. After subtracting classical noise, our measurements show that the quantum mechanical uncertainties in the phases of the 200-kilowatt laser beams and in the positions of the 40-kilogram mirrors of the Advanced LIGO detectors yield a joint quantum uncertainty that is a factor of 1.4 (3 decibels) below the standard quantum limit. We anticipate that the use of quantum correlations will improve not only the observation of gravitational waves, but also more broadly future quantum noise-limited measurements.
     
  23. paddoboy Valued Senior Member

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    Your Avatar photo is a good example.
     

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