Photon Definition and 1000 Threads

Assumptions: 1] I'm an observer at inertial rest 2] Light is going c 3] Gravitational interaction can't exceed c I'm going to use "photon" and "graviton" as shorthand to pose the questions initially. Maybe correcting the form or assumptions of the questions will provide the answer...

If we perform the two slit experiment vertically - so the slots are above one another - we should observe a small amount of red / blue shift in the energy of the photons when they hit the screen (due to gravity). The path length from each slit is not symetric so the arriving photons energy would...

Hi, Energy is expressed in J or eV, but E= hf As Planck constant h is J.s is it possible to express the energy of a photon in h/s? If not, why? Can we say that the energy of a photon is 2.41 x 10^14 h/s?

Hi, I've read that the frequency of EMR is found by means of a spectroscope , which uses diffraction grating and that it is derived indirectly from its wavelength. Is that true? Is there a way, an instrument that count directly the frequency of a photon or a y-ray? and up to what frquency? Is...

With a double slit measurement a single photon is a wave which goes throught both slits. To extinguish each other at certain places the wave must have the same amplitude at both slits, also at large distance between the slit. The positions also extinguish with 0.5, 1,5, ... periode difference...

Please help me to understand why the path of the photon changes when travels close to a material (for example the edge of a hole)? I'm aware that the path of the photon can be calculated by the QM principles as a probability wave and by this the change of the wavefront follows the...

With great interest I read an article about a paper where scientists were able to create two photon bound states ("molecules of light"). http://physicsworld.com/cws/article/news/2013/sep/26/physicists-create-molecules-of-light I was quite astonished since light normally does not...

Hi there, Having done a Google, I wasn't able to find much information relating specifically to Poisson statistics and photon detections. I was wondering why photon detection experiments are calculated using Poisson statistics? (So for example, would Poisson distribution calculations be...

i was learning about laser cooling in thermodynamics, and my professor said that as the photon gets absorbed by the electron, the electron gets excited and re-emits the energy in the form of a photon, and that this process was continuous since it's getting hit by a continuous laser beam and that...

Exercise 22 on p108 of Schutz's 'A first course in General Relativity' is to prove that, for an isotropic, monochromatic, photon gas, p=ρ/3, where p is pressure and ρ is mass-energy density. When I try to do it I get p=ρ/6. I was hoping somebody could tell me where I'm going wrong. Here is...

[b]1. An elementary particle of mass M completely absorbs a photon, after which its mass is 1.01M. (a) What was the energy of the incoming photon? (b) Why is that energy greater than 0.01Mc2? Homework Equations p (photon) = E/c p (particle) = γmv p(i) = p(f) Ek = γmc^2 -mc^2...

Could anyone guide me through this problem? https://www.physicsforums.com/showthread.php?t=348863 Just need to get started. Note that this would need to be solved in the proton rest frame.

A high energy proton can collide with a photon to produce a charged pion and a neutron. If the photon comes from the cosmic microwave background and has an energy equivalent to a temperature of 3 K, what is the minimum energy of the proton in eV necessary to allow this reaction? I'm thinking...

What if an electron at a certain energy level receive a little bit more energy from a photon than the difference between its current energy level and the next one, will it jump to it ? I see written in textbooks that the photon energy must exactly match the difference between two energy level...

Can we have a coherent state between a fermion and a photon! I mean can there ever be a fermionic polariton?

1. (How) Is the frequency of a photon effected after encountering a double-slit or a half silvered mirror (say in a Mach-zehnder)? 2. Are particles such as photon, electron, assumed to be entangled, at all points in time-space, with something or the other?

Hey! Maybe this is a "piece of cake" question, but here is the thing, i have the Maxwell equations in the Lorenz gauge are \begin{array}{c} \partial_{\mu}\partial^{\mu}A^{\nu}=\mu_{0}j^{\nu} \end{array} In vacuum this gets reduced into \begin{array}{c} \partial_{\mu}\partial^{\mu}A^{\nu}=0...

1.photon has no mass . so m=0.hence, p=mv=0.by doing some calculations , we can get that p=h/lambda.we can prove p=mv experimentally.but how can we prove the second one experimentally?

Energy Of A "Single" Photon In Em Radiation? Is the energy of all photons in em radiation same? That is, say light differs from radio waves only in the number of photons per second

Hi all, It was recently pointed out to me that the finite electron mass puts a lower bound on the Mandelstam variable t describing the square of the transferred momentum in the centre-of-mass frame, t_{min}=m_{e}^{2}. This solved a problem I was worrying about (the finiteness of the...

Hello, I was just reading optics and I thought that if photon doesn't has mass it can't be accelerated.. If it is so then how it gets reflected off a smooth surface, why don't it just passes from the plane. As any reaction force by the plane couldn't accelerate it , it mustn't rebond as...

what is the source of the first photon in the laser ? i understand there is a burst of light or electricity that excites up the medium , but what is the source of the first photon ? is it the light source or is it one atom of the medium itself releasing photon as it gets de-excited * if...

In trying to understand relativity, I once read a statement that even traveling at the speed of light, an emitted photon traveling in your direction would still move away from you at the speed of light. This confuses me as I have a hard time correlating it to a real scenario. Say "The Flash"...

What are the properties of a photon with Planck energy? Is it even possible to interact with it, or does it just travel trough all matter?

basically any time i have an arc, i have electrons flowing in the opposite direction to the field gradient. so when the electrons reach the other side, they will be stopped, which will then produce an EM wave. In, class, my professor drew the direction of radiation in a particular direction, but...

I have come across a problem which is a homework indeed, but i tried to pack this question up so that it is more theoretical. What i want to know is if i am alowed to write energy conservation for an atom which emitts a photon (when his electron changes energy for a value ##\Delta E##) like...

hi all, i learned that only certain orbits were allowed in the atom and that if the electrons occupied any of the orbits in between, that they would no longer be in a resonance orbit (i was taught that the allowed orbits were the electron probability wave in resonance and therefore no EM...

When a single plane-wave photon/electron passes a slit/orifice, its direction of travel becomes random. Although there is the well-known Uncertainty Principle, it is not a replacement of the law of conservation of momentum for the phonon/electron before and after passing the slit. Question...

Does anyone have any information regarding if a photon will at some point obtain mass at huge energy amounts? Let's say perhaps the photon gains so much energy that it's wavelength reaches Planck's length, is it possible that it would gain mass? Is there any information regarding this inquiry...

Am I correct in thinking it is currently believed that a single photon at rest has no mass a single photon in motion does have mass ?

According to the Einstein light-quantum hypothsis, the photon energy is given by E = hbar*ω. If taking the photon as a very short light pulse, then the frequency spectrum is extremely wide in terms of Fourier-transform theory. How to understand the frequency ω in E = hbar*ω if taking the...

I've heard that photons have a mass. If a photon were to be stationary, would it have mass? If not, then where does the mass of a photon come from? I know that if an object has stationary mass (forgive me if this isn't the correct term), then it takes an infinite amount of energy in order to...

I know this thread is similar to another one that was posted recently (I really enjoyed reading it), but I think I have some other questions which aren't entirely redundant. BTW, I'm not looking for really mathematically rigorous explanations, because I probably wouldn't understand them...

How does the energy of a photon change by Doppler shift? Let's say we have an IR photon, but due to Doppler shift it shifts towards UV wavelengts. Shorter wavelength/higher frequency means more energy, but where does this energy come from? How do you connect this with Photoelectric effect...

When a photon is produced when an atom raised to excited state return to ground state it's frequency can be calculated. but can we predict the direction and polarization of that photon.

My understanding is that the presence of energy and matter curve spacetime. Is a photon considered energy? If so, how can it curve spacetime while having zero rest mass?

How does a photon "know" to pass through without interacting? The usual explanation given for transparency is that when the energy of a photon is smaller than the band gap energy of an atom, the photons don't interact with the electrons and pass through, so the material is transparent. But...

Wiki in birefringence says, "light with linear polarizations parallel and perpendicular ... the component with polarization perpendicular to this axis will be refracted as per the standard law of refraction, while the complementary polarization component will refract at a nonstandard angle...

Dear all respected expert/collegues, I'm setting out a photoelectrochemical cell. I'm facing problem to regulate temperature in my photoreactor durng reaction. Can i just dip the photoreactor inside a big water jacket? But i wondering incoming photon or light supplied by my Xenon arc lamp...

In Peskin at page 248 he finds that if he calculates the vacuum polarization that $$\Pi(q)^{\mu \nu} \propto g^{\mu \nu}\Lambda^2$$ a result which violates the Ward identity and would cause a non-zero photon mass $$M \propto \Lambda$$. But as Peskin states, the proof of the Ward identity...

Homework Statement What is the photon flux (photons/ m2 s) at a distance of 1 km from a light source emitting 50W of radiation in the visible domain, with wavelength 6000 Angstroms. Homework Equations The Attempt at a Solution Energy of one photon = hc/λ = 3.32 x 10-19J. So, number...

Homework Statement The maximum proper distance a photon can travel in the interval (0,t) is given by the horizon size h(t) = R(t) ∫0t dt' / R(t') Show that, for a matter dominated universe h(z) = H0-1(1+z)-1(Ω-1)-1/2cos-1(1-2(Ω-1)/(Ω(1+z))) for Ω>1 = 2H0-1(1+z)-3/2...

Dear all, I am using stress-energy tensor to derive equation of state of photon gas (assuming it as a perfect fluid). I completed all the steps except one: average value of [cos(θ)]^2 over unit sphere = 1/3. I have no idea how this is so. (θ is polar angle). I tried integrating over...

Let's say we pass a photon through a 0 degree polarizer. the photon is now oriented at 0 degrees, meaning it will pass through subsequent polarizeres oriented at 0 degrees. (note - Not all photons will pass through the 0 degree polarizer, roughly 50% will pass through. we are talking about...

Do we measure different frequencies of light in frames moving relatively at constant velocities? Because when we look at an annihilation reaction from the view of different frames, we see different energies of the reactants which seem to affect the frequency of the produced photons. your kind...

A stationary hydrogen atom with a mass of 1.67 x10^-27 kg absorbs a photon of light with an energy of 10.2eV.What is the velocity of the hydrogen atom after absorbing the photon? This is my question: Is it true that the atom has no speed since all the energy is completely absorbed at the...

Is it possible for two photons to join their energy to structure a one photon of higher frequency? Let's assume that the two incoming (IR) photons are prepared specially: coming in the same time, same wavelength, phase, appropriate (complementer) spins and angle, etc. They arrive the...

Typically (in popular literature) the process of photon emission by an excited atom is considered as an instant event. But actually it is quite likely that it is a continuous process. Such processes are usually described by evolutionary differential equations (ODEs or PDEs). Assume that we...

Hello folks. 2-dimensional spectroscopic techniques have been used to investigate biological systems and found that they transfer energy via coherent pathways. However, some have argued that this has no bearing on how these systems behave in nature, as the sun is not a coherent source and the...

1. I have never understood Purcell's explanation of the Hanbury Brown Twiss effect saying that the correlation they measured is only due to the clumping of the bosons; that the pure shot effect would not yield any correlation. Why not? 2. I was reminded of this by Purdy's recently announced...