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2 votes

One-way photon detector

This statement holds for all devices that are reciprocal, or time reversal invariant, One Way Mirrors do not exist. Thus your detector doesn't exist. However, let's look at 2 situations where you ...
JQK's user avatar
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2 votes

Density of photons in an expanding image?

How much must the sphere expand so that there are gaps in the image when sampled at different locations on the 'instant-sphere' image? The photons (at least prior to detection), don't have a specific ...
BowlOfRed's user avatar
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1 vote

Equation-of-state for a photon gas

Under some conditions, radiation can be modelled as a fluid with a proper equation of state. The idea is that the photon gas should be close to equilibrium with a second fluid (matter), making the ...
Quillo's user avatar
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1 vote

Number of incident photons

You've provided enough information. Assuming every photon emitted is of the same wavelength, we can use the following equations. First, to related power and intensity: $$I = \frac{P}{4πr²}$$ I for ...
Hokon's user avatar
  • 263
1 vote

How to understand the Orbital angular momentum of a photon that is not an integer?

As a starting point, topological charges associated with light have integer values as they represent the "holes" in the topology describing the phase space of the light. In this regard they ...
Doctor Lighthouse's user avatar
1 vote

Which is the lightest thing in this universe? Is that a photon or neutrino?

Photons are massless particles, while neutrinos have a tiny but non-zero mass.
Priyanka Garai's user avatar

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