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| bio | website | sheerviscosity.net/blog |
|---|---|---|
| location | ||
| age | ||
| visits | member for | 9 months |
| seen | Sep 27 '12 at 16:03 | |
| stats | profile views | 129 |
String theory grad student.
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Sep 10 |
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Is the Higgs a quantum field or a particle? I agree that we cannot really claim at this point that the Higgs is elementary. |
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Aug 10 |
answered | Is there an analogue of configuration space in quantum mechanics? |
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Aug 10 |
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How can we be sure about the constancy of atomic clocks as in the Hafele and Keating time dilation test? @CaptainClaptrap Final comment: I think it is impossible to understand these things without learning a bit of general relativity. You can learn about the metric, coordinates systems and how to switch between them, and how to compute quantities by integrating over paths. I think that only then you can understand what is meant by 'sitting still', 'moving with the clock', frame-invariance and so on. These are not just everyday words -- they have precise definitions. The good news is that if you know these few things, you will be able to answer your own question with a simple calculation. |
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Aug 10 |
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How can we be sure about the constancy of atomic clocks as in the Hafele and Keating time dilation test? @CaptainClaptrap I am sorry if I was not clear, but dmckee and I are saying the same thing. If I am sitting in place, I will observe that a higher clock has different frequency compared to a lower clock, and this is due to time dilation. I will see this for example by comparing the higher clock with the lower one once they come to the same level. But if I am moving with the clock I will see no change in its frequency. The fact is that frequency is not a frame-invariant quantity. Different observers do not have to agree about the frequency. |
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Aug 10 |
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How can we be sure about the constancy of atomic clocks as in the Hafele and Keating time dilation test? Of course the frequency of the clock is changing, due the time dilation. I guess you are asking whether only the frequency of the clock can change, without time being dilated. This will be hard to explain, given the variety of clocks we have. But consider instead the Pound-Rebka experiment (see Wikipedia), where they measured time dilation by sending photons up and down a tower and measuring the shift in their energy (and therefore frequency). No clocks were involved. |
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Aug 10 |
answered | Is dimensional analysis used outside fluid mechanics and transport phenomena? |
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Aug 10 |
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How can we be sure about the constancy of atomic clocks as in the Hafele and Keating time dilation test? There is no need to discuss specific experiments, because atomic clocks are routinely tested in laboratories. Modern clocks are so accurate that they can detect a height difference of a few meters within a reasonable time frame, so you can measure gravitational time dilation in the lab. This guy took some atomic clocks up a mountain with his kids, and found the expected shift due to gravity: leapsecond.com/great2005 . This is not cutting-edge stuff -- these effects are very well established experimentally. |
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Aug 10 |
answered | How can we be sure about the constancy of atomic clocks as in the Hafele and Keating time dilation test? |
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Aug 10 |
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Why is Mendel Sachs's work not taken seriously? Or is it? Quantity of work is a poor measure of the work's value. |
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Aug 10 |
answered | Why are objects at rest in motion through spacetime at the speed of light? |
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Aug 10 |
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Constraining two-point functions of boundary operators on the disk I am certainly assuming unitarity. The fact that correlators of descendants are determined in terms of primaries is of course true, which is why we don't usually care about such correlators. Perhaps this is enough for your purposes, but note that this alone does not imply that the pairs of correlators you asked about are at all related to each other: each could be related to a different correlator of primaries. My suggestion is that they are in fact related. |
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Aug 9 |
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Constraining two-point functions of boundary operators on the disk Yes, I see what you mean now. I added an idea for the descendants. |
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Aug 9 |
revised |
Constraining two-point functions of boundary operators on the disk added 1182 characters in body |
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Aug 9 |
answered | Constraining two-point functions of boundary operators on the disk |
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Aug 9 |
revised |
Change in appearance of liquid drop due to gravity added 583 characters in body |
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Aug 9 |
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Change in appearance of liquid drop due to gravity @CrazyBuddy What confuses me at least is that you call them 'horizontal' lines -- I never saw a raindrop that looks like that. That is why I thought you meant this flattening. Do you mean vertical lines? |
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Aug 9 |
revised |
Change in appearance of liquid drop due to gravity added 186 characters in body |
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Aug 9 |
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Change in appearance of liquid drop due to gravity Their shape depends on their size. Small drops are spherical, larger ones look sort of like pancakes (this is what I mean by 'flat', perhaps this was not clear), yet larger ones look like parachutes. I don't know at which size (if any) they become elongated, but the shape is due to the flow of air and not gravity. I will try to clarify... |
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Aug 9 |
answered | Change in appearance of liquid drop due to gravity |
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Aug 8 |
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What is the fundamental differences between bound and entangled states Sorry, but I do not understand what you are asking. Specifically the phrases "the particle and the energy are bound to the process of entanglement" and "energy is determined to stay bound ..." make no sense to me. The photons do not exist before the decay. They are created when the particle decays. |
