11–20 of 28 posts
In gravitational wave detectors. Heard of the Casimir effect? Two plates can experience a force from vacuum fluctuations.
Also works in other geometries, e.g., sphere and plate, two spheres, etc. First experimental verification was a sphere and a plate, I think? https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.78...
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Hmm, at least with an audio waveform one can have a DC offset wherein the average is not zero.
The DC offset does not manifest when the waveform is translated into sound, which is an actual propagating wave, the appropriate analogy to light.
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Such conceptually dense language! Isn't the average amplitude of every wave just zero?
The amplitude is the difference between maximum and minimum, not the momentary value of a wave at some point.
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The amplitude is the difference between maximum and minimum, not the momentary value of a wave at some point.
Then how can the average amplitude be zero? If at any point the amplitude is nonzero, it must be positive (as it is the absolute value of the difference), thus the average can only be positive
Except there are ways to go below that, like a Casimir cavity.
I find these things confusing because when people explain Casimir cavities they never bother to say why the justification for zero point energy existing in the first place doesn’t apply within the cavity.
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The amplitude is the difference between maximum and minimum, not the momentary value of a wave at some point.
Then how can the average amplitude be zero? If at any point the amplitude is nonzero, it must be positive (as it is the absolute value of the difference), thus the average can only be positive
Of course in nature there is no such thing as a "classical wave", so this description has to break down at some point. This is the case for vacuum fluctuations which simply do not have a classical explanation.
"A special case of squeezed light, known as the squeezed vacuum, forms when the average amplitude of the light is zero." I love this. Don't ask me what it means.
"A special case of squeezed light, known as the squeezed vacuum, forms when the average amplitude of the light is zero." I love this. Don't ask me what it means.
It looks like physicists are building the wrong abstractions. Abstractions are here to help us, not fool us.
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Then how can the average amplitude be zero? If at any point the amplitude is nonzero, it must be positive (as it is the absolute value of the difference), thus the average can only be positive
Indeed this is not possible for a classical wave. However, in a quantum description there exists a so-called "vacuum state" for which the expectation value of the electric field operator vanishes at all times, but the expectation value of the square of this operator does not. In the classical approximation of quantum optics, the expectation value of the electric field operator corresponds to the amplitude of the clas…