Photons are electromagnetic waves. They exhibit particle-like qualities in many situations and have zero rest mass.
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Is a photon “fixed in spacetime”?
From what I've read, according to relativity, a photon does not "experience" the passage of time. (Can we say there is no past/present/future for a photon?)
Would it be better to say a photon is ...
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Why do we use Planck's constant?
I have been trying to reason why energy packets (i.e. photons) are assumed to be quantized. I know this originated from Max Planck, but may someone explain why energy couldn't be emitted continuously ...
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Is there a point interaction model of the electron?
Is there a point interaction model of the electron? Is there a point interaction model of the electron? I imagine something like $\propto(\bar \psi\psi)^2$ (edited). Is such a thing in use?
Since I ...
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How do we know that internal conversion creates no intermediate photon?
I've read, from several sources, that in internal conversion -- an excited electron transferring its energy to another electron which is then emitted -- no intermediate gamma radiation is produced.
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If the EM Spectrum makes up all frequencies what is the connection between Photons and Electrons in electronics, mainly in RF Propagation?
I am trying to sort out my understanding regarding Photons. I understand the Electromagnetic Spectrum contains all radiation (energy) in all wavelengths (light) consisting of Photons. This can be ...
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Why don’t photons interact with the Higgs field?
Why don’t photons interact with the Higgs field and hence remain massless?
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Computing the path of photons near a black hole
For a simulation, I want to compute the path that light follows near a black hole.
Non-relativistically, a massive point particle in a central newtonian gravitational field follows either an ellipse, ...
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slit-screen and wave-particle duality
In a double-slit experiment, interference patterns are shown when lights pass through slits and illuminate the screen. So, the question is if one shoots a single photon, does the screen show ...
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Why can't a single photon produce an electron-positron pair?
In reading through old course material, I found the assignment (my translation):
Show that a single photon cannot produce an electron-positron pair, but needs additional matter or light quanta.
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How many photons does it take to measure a linear polarization?
A star emits perfectly (100%) linearly polarized light at an arbitrary angle.
How many photons must you detect to measure this angle to a precision of n binary digits? (with greater than 50% ...
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171 views
faster-than-c photons
As far as I know, according to quantum field theory, there are some photons that go faster than c, which is the speed of light in vacuum.
However, there seems to be a paper and a corresponding ...
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469 views
Deriving Planck's radiation law from microscopic considerations?
In the usual derivation of Planck's radiation law, the energies or frequencies $\omega$ of the oscillators depend on the measurements $L$ of the black body. The model is such that the only ...
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251 views
At what angle does a single atom “reflect” a single photon?
Does this question make sense in the quantum world?
Imagining a single photon (wave packet?) interacting with a single atom (its electrons etc) how do we currently describe/define the emitted photon ...
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1answer
333 views
Why can't we make measurements in a photon's rest frame when loop diagrams make measurements possible?
It is one of the axioms of special relativity that the photon has no rest frame; light travels at speed c when measured in any inertial frame of reference. As a corollary, it is often said that if one ...
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155 views
Quantum Cryptography
First question was a little bit ambiguous.
Photons are passed through a linear polarizer that is oriented $\theta$ degrees again the photon passes through another linear polarizer that also have a ...
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1answer
120 views
Can unbound electrons jump energy levels?
If an unbound electron (or indeed any charged particle) is moving through free space, is there a probability that it can spontaneously change energy by emitting a photon, or does this require the ...
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310 views
Have red shifted photons lost energy and where did it go?
I think the title says it. Did expansion of the universe steal the energy somehow?
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318 views
Is the electron wave function defined during photon emission
I have heard the term quantum leap to describe the (instantaneous?) transition from a higher energy orbital to a lower energy orbital. Yet, I understand that this transition time has now been ...
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408 views
What longest time ever was achieved at holding light in a closed volume?
For what longest possible time it was possible to hold light in a closed volume with mirrored walls?
I would be most interested for results with empty volume but results with solid-state volume may ...
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279 views
Entanglement and the double slit experiment
Is the double slit experiment an example of entanglement when it seems as if the photon is going through both slits? Or put another way, is it at this stage when we attempt measurement we see a photon ...
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151 views
Fields versus Photons
Does the field of a set of photons behave differently from a single photon.
e.g. Suppose I have a group of photons with their Electric fields $\mathbb{E}_n$ all aligned. So
$$\mathbb{E}_{\text{tot}} ...
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360 views
Is photon emission possible without electrons changing energy levels?
Does molecular vibrational transition and consequent emission of infrared radiation involve electrons changing energy level? In wikipedia, about vibronic transitions it says "Most processes leading to ...
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185 views
Why is $c$ considered as the speed of the photons?
Maxwell equations brought $\ c_{o}=\frac{1}{\sqrt{\mu_{o}\varepsilon_{o}}}\ $.
Since this is a constant, it made all physicists at that time wonder where was the frame of reference?
They ended up with ...
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1answer
142 views
For someone who only studied electromagnetism, what is the modern way to explain electromagnetic fields?
After reading most of the electromagnetism chapters of Feynman's lectures on physics, I would like to understand in more detail, at least an idea, of what causes the electromagnetic fields. Not sure ...
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386 views
What happens to a photon in a black hole?
Assume a photon enters the event horizon of a black hole. The gravity of the black hole will draw the photon into the singularity eventually. Doesn't the photon come to rest and therefore lose it's ...
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1answer
676 views
Signal-to-noise ratio of the difference between two signals
Something tells me this must be a fairly simple question, but I have somehow been unable to find an answer to it. In short: I need to calculate the difference between two signals, A and B, each one of ...
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111 views
Will a photon emitted from something moving quickly have a shorter wavelength?
If a photon is emitted from a light source moving at any speed, the photon will nonetheless always move at c (assuming it is emitted in a vacuum.)
If the speed of a photon's emitter cannot influence ...
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What frequency photons are involved in mediating physical force?
If the force felt when pushing an object is mediated by the electromagnetic interaction and hence photons, what is their frequency?
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209 views
What would be pressure of 1 kg of photon gas at room temperature put in a volume of 1 liter?
Suppose a number of photons with spectrum corresponding to black body spectrum at 293 K with total energy corresponding to 1 kg put in a box with ideal mirror walls with volume of 1/1000 of a cubic ...
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378 views
If photons are deflected by a strong gravitational field, then how come photons do not have mass? [duplicate]
Possible Duplicate:
Explain how (or if) a box full of photons would weigh more due to massless photons
It has been proved and showed through experiments that light can be bent by the Sun or ...
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541 views
What causes light to move through a vacuum
I was looking at rockets and stuff and thought about how they move through a vacuum using newtons 3rd law, and then I started thinking of any other ways you could move through a vacuum without using ...
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394 views
Can photons and gluons be holes in an aether?
Consider photons and gluons have 0 mass and 0 charge. In many respects they're already understood as the absence of a particle by mathematical models. Couldn't this be interpreted to mean they ...
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What exactly is a quantum of light?
I am currently trying to learn some basic quantum mechanics and I am a bit confused. Wikipedia defines a photon as a quantum of light, which it further explains as some kind of a wave-packet.
What ...
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Why are noble gases used for lights?
I know that neon is used in advert signs due to its inertness. However, I am not entirely sure how the inertness is exploited. I think it is because Ne being inert means that after electricity frees ...
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What about the other side of the Black Hole
I was wondering if on the recieving end of a black hole can you see the photons being sucked in
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What if we could give photons some mass?
I was reading an article and these paragraphs got me wondering...
Before I list the replies, here is some background. The Higgs mechanism describes an invisible field that, it is argued, split one
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Formation of black holes
If stars start with a finite density and light can escape from them, how can they be compacted to form a mass with infinite density which light cannot escape? The black hole will have the same mass as ...
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1answer
565 views
What are the specific requirements for a do-it-yourself quantum double-slit experiment?
I was shocked to recently learn that the double-slit experiment is not only possible to do with completely ordinary equipment (with photons of course), but it actually looks rather easy. This is from ...
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What are the polarization states of the photons in a polarized and unpolarized light?
The photons are completely polarized, i.e their polarization states can be expressed as $a|R\rangle+b|L\rangle$, where $|R\rangle$ and $|L\rangle$ are two helicity eigenstates of the photon. For ...
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Does a photon have a rest frame?
Quite a few of the questions given on this site mention a photon having a rest frame such as it having a zero mass in its rest frame. I find this contradictory since photons must travel at the seed of ...
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why isn't the variance of Fano noise proportional to the number of photon arrivals?
I've been reading "Photon Transfer" by James Janesick and in Chapter 3 (http://spie.org/samples/PM170.pdf) he describes the various sources of noise in a CCD. Basically, incoming photons interact with ...
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The energy carried from one winding of a transformer to another, in quantum terms
I have read in wikipedia this statement
"The energy carried from one winding of a transformer to another, in quantum terms is carried by virtual photons, not real photons" (wikipedia src: virtual ...
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High speed and low speed photons
Looking at the discovery of the neutron, and I came across this page: http://www-outreach.phy.cam.ac.uk/camphy/neutron/neutron3_1.htm
The animation on the left, talks about low energy photons and ...
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Question about Rayleigh scattering
To quote from Wikipedia on elastic scattering, "In this scattering process, the energy (and therefore the wavelength) of the incident photon is conserved and only its direction is changed."
How does ...
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Can you split a photon?
I was wondering if a photon is divisible.
If you look at a photon as a particle, then you may be able to split it (in theory).
Is it possible and how do you split it?
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Propagation of light in transparent media: absorption and reemission or scattering?
In the two Phys.SE questions What is the mechanism behind the slowdown of light/photons in a transparent medium? and Why glass is transparent? transparent media were discussed. But I'd like to clarify ...
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photons in expanding space: how is energy conserved?
If a photon (wave package) redshifts (streches) traveling in our expanding universe, is it's energy reduced? If so, where does it go?
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Spontaneous pair production?
So I've been looking into particle-antiparticle pair production from a gamma ray and don't understand one thing.
Let's say I have a 1,1 MeV photon and it hits a nucleus - electron-positron pair with ...
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1answer
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Photons in a “wrap-around” universe
This question was inspired by: How are photons "consumed"?
Imagine I have some number of photons, $N$, each of frequency $\nu$, moving randomly in a spherical "wrap-around" universe of ...
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How are photons “consumed”?
I have very little background in physics, so I apologize if this question is painfully naive.
Consider the following thought experiment: an observer is in a closed room whose walls, floor, and ...
