Recent content by Chiara

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    A Is it correct to state that all measurements count photons?

    You need your ear to compare the tuning fork and the piano - or some other sense. That uses electromagnetism. Reading signs in Braille requires electromagnetic interactions with your skin. Tasting whisky requires electromagnetic interactions with the receptors on your tongue. All feelings, also...
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    A Is it correct to state that all measurements count photons?

    Measuring weight uses a scale. Even reading a hand on a watch uses photons to determine if the hand went over a line.on the scale. I would say that all devices with hands thus count the difference between 0 and 1 or more photons. Measuring sound uses a microphone; it also uses electromagnetic...
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    A Is it correct to state that all measurements count photons?

    Indeed. But is there a really precise measurement device that does not count photons?
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    A Is it correct to state that all measurements count photons?

    A text I read some weeks ago claimed that all measurements count photons. Indeed, even a thermometer requires light to be read off, and also a balance. Is there a type of measurement or a measurement device that does not count photons?
    • Chiara
    • Thread
    • Quantum electrodynamics Quantum theory
    • Replies: 19
    • Forum: Quantum Physics
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    I On the Quantum Mechanics of Entropic Forces

    "Black" means: "It does not shine". This is the prediction of general relativity. A non-zero BH temperature means: it does shine, it is not black. That was the discovery. By the way: "Jacobson gave a purely mathematical proof: the entropy of black holes, their temperature, and their...
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    I On the Quantum Mechanics of Entropic Forces

    Jacobson gave a purely mathematical proof: the entropy of black holes, their temperature, and their mass/energy, taken together, imply the field equations. Various experiments, e.g. about Unruh temperature, imply that black holes have a temperature. General relativity predicts that black hole...
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    I On the Quantum Mechanics of Entropic Forces

    He showed in his paper that the entropy of black holes, their temperature, and their mass/energy, taken together, imply the field equations. Here is his 1995 paper: https://arxiv.org/abs/gr-qc/9504004
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    I On the Quantum Mechanics of Entropic Forces

    The abstract starts with "It was conjectured 30 years ago that gravity could arise from the entropic rearrangement of information." It seems to me that Jacobson proved that gravity is entropic. He did not conjecture anything. Am I wrong?
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    Curious

    I am new here. Above all, I am passionately curious about fundamental physics.