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Are human eyes interferometers?

To do interferometry in post-processing after detection of radiation, the detector must be able to record the phase of the radiation. The eye cannot do this: the photochemical reactions that record ...
John Doty's user avatar
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22 votes

How does LIGO work?

This is an excellent question! The LIGO arm cavities are about 4 km, which takes a photon roughly $10^{-5} s$ to traverse. On top of that, as you mentioned a typical photon will bounce around a few ...
Andrew's user avatar
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22 votes
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Why are the Michelson-Morley experimental results interpreted more broadly than the scope of the tested medium?

why are the Michelson-Morley experimental results interpreted more broadly than the scope of the tested medium? This question has a scientific part and a social part. The scientific part is regarding ...
Dale's user avatar
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16 votes
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Photons with half integer angular momentum - what's happening?

Nothing is happening. At least, nothing except that a new generalized quantity suggestively called "angular momentum" was defined and subsequently measured. But nothing we know about the usual angular ...
ACuriousMind's user avatar
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16 votes
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Could the black hole photo be a gravastar?

The observations of M87* probe the spacetime geometry in the region around the photon sphere i.e. around a few Schwarzschild radii. A gravastar has the same spacetime geometry in this region, so the ...
John Rennie's user avatar
14 votes

Why is the Pauli's exclusion principle not violated in the two neutron beams interference experiments?

Neutron-interferometry experiments are intensity-starved. The most common number of neutrons in the interferometer at once is zero; the fraction of events where two neutrons were in the interferometer ...
rob's user avatar
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13 votes
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Michelson interferometer circular fringes

Here is a schematic diagram to show how the circular fringes are formed using the Michelson interferometer. These fringes are sometimes called fringes of equal inclination or Haidinger fringes. The ...
Farcher's user avatar
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11 votes
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Why is interference there when pulses do not overlap in space and time?

This is a very good question, because we like to think of spectrometers as black boxes, and indeed as seen from the outside there are only two clearly separate pulses going in, so how do they manage ...
Emilio Pisanty's user avatar
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Why don't (can't) astronomers take advantage of interferometry to the extreme?

Interferometry can and has been conducted with intercontinental baselines. This is how the Event Horizon Telescope works - but at microwave wavelengths. At optical wavelengths, the longest baselines ...
ProfRob's user avatar
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10 votes

Phase added on reflection at a beam splitter?

It actually depends on what kind of beam spitter you have. I'll give a general treatment and shows that the conclusions of both Emilio Pisanty and Steven Sagona are basically correct, corresponding ...
G.C.'s user avatar
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Why is the Pauli's exclusion principle not violated in the two neutron beams interference experiments?

Why the Pauli exclusion principle doesn't matter here Neutron interference experiments like this are done with no more than one neutron in the interferometer at any given time. Here's a quote from ...
Chiral Anomaly's user avatar
9 votes

Are human eyes interferometers?

You're looking at the wrong sense transducers. Having two ears does allow for forms of interferometry, as the frequencies of auditory signals are in a range that allows for the nervous system to ...
Michael MacAskill's user avatar
8 votes

Are human eyes interferometers?

Despite the other two answers denying this there is another possibility. The Hanbury Brown - Twiss intensity interferometer uses noncoherent detectors without a common phase reference. It is ...
hyportnex's user avatar
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In the context of atom interferometry, how are $\pi$ and $\frac{\pi}{2}$ pulse generated?

In general, you apply $r\pi$ pulses by turning on an interaction hamiltonian $H_I$, which couples both states, for long enough (or with a strong enough coupling) to achieve the desired effect. This ...
Emilio Pisanty's user avatar
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Michelson interferometer beam splitter phase shift

One minor detail, which is extremely important in this context, which you perhaps missed is that the beam-splitter is partially silvered at the lower surface, which implies that the appropriate ...
299792458's user avatar
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6 votes
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Fringes of equal inclination (Haidinger fringes) Why is the interference pattern circular?

This type of interference is called division of amplitude as opposed to division of wavefront which is applicable to Young's slits. If there was a point source $S$ then the ray diagram for the ...
Farcher's user avatar
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6 votes
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Difference between gravitational wave detectors

All three direct detectors, pulsar timing, space based interferometers, and terrestrial interferometers, all use the same principle to detect gravitational waves (GW). Measure the change in distance ...
Paul T.'s user avatar
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6 votes

Are human eyes interferometers?

I guess you’re imagining an interferometer like that used for long baseline radio interferometry. In this case it is necessary that the detectors can sensing the relative phase difference between ...
Jagerber48's user avatar
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5 votes

Why are they building eLISA and what implications would it have?

Space is, as you say, good for removing a lot of the background noise that spoils LIGO's data — like seismic noise, disturbances from traffic and logging activity, people shooting at the beam tubes, ...
Mike's user avatar
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5 votes
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Confusion in the Michelson-Morley experiment about beam-splitter vs compensator

A bit of background first: The reason glass (in air) reflects light is not that it has a refractive index; it is that its refractive index is different from the refractive index of air. Immerse the ...
S. McGrew's user avatar
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5 votes
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Why is it harder to use a white light source in a Michelson Interferometer?

Interference pattern has a visibility, meaning how better can the fringes distinguished. The visibility is related to the degree of first order coherence $g^{(1)}$, a measure of amplitude-amplitude ...
Mark_Bell's user avatar
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Could the Michelson-Morley experiment have detected gravitational waves?

Gravitational waves (GWs) cause space to stretch and shrink causing the distance between free falling objects to change as they pass. In the Michelson and Morley experiment the mirrors were stuck in ...
Paul T.'s user avatar
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I polarize the slits (one H, the other V) of a Young's double-slit. If my source is H or V, do I see fringes? What about if my source is D or AD?

I am going to assume a broad audience with some who have seen complex plane-wave analysis, and many who have not. Anyone who can do the ordinary Young's double-slit experiment should have no trouble ...
feuerstein's user avatar
5 votes
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Small crack in bottom corner of a beam splitter

If a piece has chipped off, you should be OK. You might smooth any sharp edges with fine sandpaper. If there is a crack, you might have trouble in the future. Cracks can grow. It should not affect ...
mmesser314's user avatar
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5 votes

Are human eyes interferometers?

As others have mentioned, for the brain to do optical interferometry the eyes would need to capture phase information from the light waves and send it to the brain, where simultaneous signals from ...
PM 2Ring's user avatar
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4 votes

Phase added on reflection at a beam splitter?

Your confusion stems basically from comparing results in different conventions. Basically, there is always a phase difference of $\pi$ between the two output ports of a beam splitter, but this can ...
Emilio Pisanty's user avatar
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How to measure an image's contrast?

Whatever software you use (e.g. ImageJ), you must convert the image from sRGB colorspace to a linear colorspace first. To convert to linear RGB using ImageJ, you should convert the image to 32 bit ...
Count Iblis's user avatar
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4 votes

Photons with half integer angular momentum - what's happening?

Just as a supplement to ACuriousMind's answer, it is worth noting that buried in the bottom of their paper they actually show what the "spin 1/2" eigenstates are in terms of the regular basis: $|j=1/...
Rococo's user avatar
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