# Tag Info

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Your main assumption is that "we have a photon source that allows us to emit a set amount of photons," and you ask if that's possible. Certainly. However, except for when you are calibrating an emission source, you are usually just measuring a source that is not under your control. Then, for sheer probabilistic reasons, event counts should follow a Poisson ...

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Quantum mechanics is not about particles but about quanta. The quanta are the quantized changes of a single object called a quantum field. One can not, in all generality, assume that single particles have "independent" wave functions. That's ca useful approximation some systems, but it is certainly not the case for systems that emit photons. Instead we have ...

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You have to keep in mind that all physical experiments are merely approximations of idealized experiments. No real setup will actually measure a theoretical quantity. They will only measure a reasonable estimate of the quantity, and the measurement will always be marred by statistical and systematic errors. In addition you have to consider sampling errors, ...

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Yes, there is a limitation, and it comes from mathematics itself. Gödel's first incompleteness theorem states that no consistent system of axioms whose theorems can be listed by an "effective procedure" (e.g., a computer program, but it could be any sort of algorithm) is capable of proving all truths about the relations of the natural numbers (arithmetic). ...

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No such algorithm is known. The natural language description of experimental setups is far too informal to be turned into precise quantum mechanical statements. Therefore, we will in the following suppose that a quantum mechanical description of the measurement apparatus in spe has been provided. In the von Neumann measurement scheme, it is not subjective ...

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Now let's find out its volume: 16777.216. Now if I wanna report my result with the least significant figures (3), I would get an answer 168 which is plain wrong. Your problem is that you seem to be truncating the value! When employing the significant figure rule, you turn all other values to zero. Trailing zeros are placeholders, so they can be ...

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Assume you have quantum mechanical oscillator, e.g. a particle in a potential V(qx)∝q2x. Now the position of the particle shall be measured by having photons scattered from the particle and then detect k vector and phase of the photons (in fact an indirect quantum measurement). Note that in a quantum mechanical potential the particle is in a stable ...

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The tentative answer to your question is "No" - not all quantum interactions produce a back action. There is an entire field of study under the heading of "Quantum Non Demolition Measurement". A simple example of this is illustrated by the Bomb Detector thought experiment.

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Several things spring to mind here. The "brain dead" way to estimate things would be to take the mean of all the samples and divide by the standard deviation. But as you point out, that gives you a rather large standard deviation and it does not take advantage of everything you know. In general, such an approach would suffer very badly from aliasing: if you ...

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Consider the following image, we have some fluid volume, $V$, having density $\rho$ and traveling at a velocity $v$ along a pipe with some cross-sectional area $A$. The rate at which the water flows through the pipe is called the volumetric flow rate. This is given by, $$\frac{dV}{dt}\equiv Q=\mathbf v\cdot\mathbf A$$ where $V$ is the volume of the ...

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This is really the same as a couple of the other answers, but I note that in the comments to those answers you are insistent that your experiment is a test of general relativity. However this is not the case. As long as spacetime is flat the experiment can be analysed using special relativity, and in this answer I shall explain why. It's commonly believed ...

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Short answer: I'm afraid this is not a test of general relativity. I'll tell you why. I'll try to keep simple. You may use special relativity when your frame of reference is inertial. Let's say you see a Ultra-centrifuge spinning. You are experiencing no gravity at all (Earth's gravity is negligible for time dilation effects). You are experiencing no ...

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A good start here would be to compute the time dilation effect expected from a centrifuge operating with a million Gs. With $\frac{v^2}{r} = 10^6 g$ I would assume something like a radius of 10 cm, in which case $v\approx 1000$ m/s. We know gamma is $\gamma=\frac{1}{\sqrt{1-\frac{v^2}{c^2}}}$, which means that $gamma-1$ is about $6\cdot 10^{-12}$. Using ...

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You recently commented I think the special relativity influence is absolutely negligible. It's exactly the opposite. It's the influence from general relativity that's absolutely negligible. Time dilation is a prediction of both general and special relativity. In general relativity, it's caused by an object being near a massive body. In special ...

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It is a nice very idea for an experiment, but I don't think that radioactive decay would be an accurate enough 'clock' to use because generally with these types of measurements very small differences in time are detected - generally atomic clocks are used to measure the time in these experiments. With the radioactive decay process it is random decay and ...

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Is there a way of [theoretically] defining the "length" of some object? We agree that the length of an object is the distance between two points A and B. The naive approach would be using a meter stick in the usual way: this method does not take into account a possible problem, that of the simultaneity of the measurement; that is, information from ...

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The naive approach would be using a meter stick in the usual way: this method does not take into account a possible problem, that of the simultaneity of the measurement; Well, the usual way seems to keep the two "meter stick" ends (or markings) in touch with the two ends (or elements) of the object under consideration sufficiently long (i.e. typically ...

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Everything you said seems correct. The only thing that looks like it needs to be resolved is this: How do we know that this is the best method? Einstein synchronization gives us a way of measuring times and lengths, but it's equivalent to various other methods. For example, Einstein-synchronizing two clocks at a distance is equivalent to synchronizing ...

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