Photon Definition and 1000 Threads

I have been studying the "fallen" photon experiment, in which the frequency of a photon changes as it falls through a height H. f'=f_0(1+\frac{gH}{c^2}) It is often stated that this is a huge factor in the application of GPS. However, I do not understand why. I understand that the photon will...

Hello, I need to learn as much as I can about single photon counting pixel detectors (producing a signal for each photons hitting the detector) e.g. PILATUS. I do not understand how this type of detectors counts single photons as opposed to integrating the energy of multiple photons (CCD, MOS...

Hi. I'd like to learn how to calculate the probability of a photon being emitted from a radio antenna where the energy per wavelength is below the threshold to emit photons. Let's assume the electrical thermal noise is insignificant. The antenna temperature could be sufficient low or the...

In order to get my head around virtual particles I've created the following question. Maybe some bright person can answer this. If I can answer this question I feel I would have the required understanding to explain virtual particles to other people. In the diagram below, A is a radioactive...

Consider photoluminescence in GaAs. I have been told that if excitation of electrons from the valence band happens with the light energy of wavelength of which is higher than the band gap energy, then electron gets excited to the conduction band, but not to the edge of the conduction band. And...

If instead of sending electromagnetic wave in transmitting antenna by shuttling electrons.. what would happen if we emit photons from photon emitters like in double slit.. would receiving antenna that receive wave receive the photons?

I learned that photons can exite and ionize electrons in an atom, bring them to higher energy level etc. However I've seen a few questions on electrons bombarding electrons in an atom and exiting the orbital electrons to higher energy level. Is this the same as the photoelectric effect when...

Homework Statement Two equal-energy photons collide head-on and annihilate each other, producing a u+ and u- pair. The muon mass is about 207 times the electron mass. Calculate the maximum wavelength of the photons for this to occur. If the photons have this wavelength, describe the motion of...

I have a question about photon speed and time releation. When photon is speeding at the speed of light, the time for him stops as i understand. So that means that from photon perspective to travel 1 light year takes no time and that means, that from it's perspective at the same time it is in all...

Entanglement with negative Wigner function of almost 3,000 atoms heralded by one photon...

Consider a single accelerating electron, this electron emits a single photon wave which radiates out spherically in a superposition, What direction does the electron recoil if there is no defined direction for the photon?

Homework Statement A blackbody photon gas is contained within an evacuated cavity (V = 0.01 m^3). Calculate C_p for the photon gas at T = 1000K Homework Equations C_p - C_v = T(\frac{\partial S} {\partial V}) (\frac{\partial V}{\partial T}) C_v = T(\frac{\partial S} {\partial T}) S =...

Homework Statement In the spectrum of the blue part in a candle flame, there’s a violet emission at 432 nm due to excited CH* molecules (chemiluminescence). Why 432? Why not 400 or 500? There are emissions at 436, 475 and 520 nm too. Why these numbers? 2. The attempt at a solution Is it...

Consider another situation where electron A accelerates past stationary electron B. However. from the perspective of electron A, Electron B appears to be accelerating, does this mean that A could absorb a photon from electron B?

Light is form of energy. Accordingto einstine theory if we concentrate the energy of light we have to get mass of light. But their is no mass of light. Acc.to E⇒mc2.

Is it possible to create a space void of photons? Or rather free from photon interference? I know single photon emitters have been made to test the behaviour of photons. However it would appear that space...well everything is jam packed with photons in various forms, and therefore "observing" a...

At the risk of making my inexperience in quantum mechanics plainly obvious, I have a question to ask. Say you emit a photon from one side of a room. As I've come to learn, light is not only a particle, but a wave. Say there are two photomultipliers, both encompassed within the wave of light...

Homework Statement A certain material is kept at very low temperature. It is observed that when photons with energies between 0.23 eV and 0.85 eV strike the material, only photons of 0.37 eV and 0.64 eV are absorbed. Next the material is warmed up so that it starts to emit photons. When it has...

so i had this idea for a while now, if you would take a black hole, and put a laser next to the event horizon, facing away from the black hole, the gravity from the black hole would pull the photons in right? I was thinking that the force that it takes must be bigger than the power from the...

Do photons have quantum mechanical wave functions like other particles do? If so, would I use some alternate version of Schrodinger's equation when deriving said wave function? I ask this because as we know, the Schrodinger equation is as follows: (-ħ2/2m)∇2 + v(x,y,z)Ψ = EΨ Photons however...

i'm still wondering, i know a bit of quantum mechanics and general relativity. well... very very little, if photon is a particle, it must be "something" right? i mean, something that exist in this space and time. why is "something" that "exist" don't have a mass? what is it consist of? or...

(Moderator's Note: this thread was split from https://www.physicsforums.com/threads/no-such-thing-as-instantaneous-speed.800941/) Does a particle reach its terminal speed instantaneously or not? Specifically a massless photon (restmass). Without mass there is no inertia. Without inertia, how...

When you hit a hydrogen atom with a photon, would it always register a hit 100% of the time? so do you have to compute for probability if it would hit it? I'd like to know if it is the photon wave function that interacts with the electron wave function so there should always be a hit all the...

Homework Statement Photons and electrons interact via Compton scattering. If the photon scattering angle is θ=30, compute the relative change in wavelength for photons of wavelength λ=10-2 m. Is the photon scattering elastically? (The electron Compton wavelength is: λc=2.4x10-12m)I've solved...

Hello, I was trying to solve a problem in my course book, and I noticed I don't really understand energy levels completely. My ignorance covers more than one specific problem, so I figured I'd ask a general question, rather than post the problem. The Rydberg formula: ##...

As many of you know better than me, photons are the carriers of the electromagnetic force, so they exchange is necessary for example in order to keep an electron around a proton in a hydrogen atom. So how does this work exactly? What is this “exchange”? In the mentioned system, which one of the...

Hello every one, I would like to find out the output signal voltage due to a single photon detected by H9500 PMT. I was able to calculate the charge collected on the anode due to a single photon but How do I get the voltage? I would appreciate any help with that Thank you

What type of photon or electron detector is typically used to observe the slits in double slit experiments?

Hello. I want to play around with the process of one photon splitting into more lower energy photons and vice versa. As I understand it one can quite easily make a Feynman diagram of a photon splitting into two lower energy photons by interacting with virtual electron/positrons. And also the...

Hi Scholars!The two slit experiment is like studying the fundamentals of Quantum Physics. Anyway, on the two slit experiment, where individual photons are fire one at a time on the 1st screen that has two slits. The photons would either go through both slits, or through the left slit or through...

... and its classical wave equation? Suppose in our double sit experimental setup with the usual notion of d,D we have a light of known frequency (v) and wavelength (L)- so its y=Asin(kx-wt). It passes through the two hole and move ahead doing the usual interference stuff, so final wave equation...

My question is a little more broad than I could make clear in the title but here goes. First of all, to be clear, am I correct in understanding that light behaves in precisely the same way as an electron in the sense that there exists a wave function which evolves according the Schrodinger...

Hello! I have questions in regards to the Two Slit Experiment. If the photon splits in two and passes through both slits at the same time and interferes with itself on the other side of the screen and then it hits on the second screen thereby creating the interference pattern. At what point...

if so, what is that and how is resting mass different than just mass?

Homework Statement a) Particle A decays at rest into two photons. Calculate, in terms of the rest mass of A, the energy and momentum of each photon. b) In a different reference frame, particle A is initially in motion such that its kinetic energy is equal to its rest energy. Find the momentum...

I read in few places that the virtual photons have longitudinal polarization while in some papers they say virtual photons have both transverse and longitudinal polarizations. Can anyone please help me to understand this

I have a number of questions about the wave function - 1. Do photons have wave functions like the one in Schrodinger equation? 2. If they do, when you send out a wave function with a certain wavelength, then because you know the momentum with no uncertainty the uncertainty of the position...

In de Broglie's matter wave equation, a book(namely Concepts of Modern Physics) derived the matter wavelength by putting ##E=hf## and ##E=\gamma mc^2## as equals. However I thought that ##hf## was energy of a photon, not a particle. Aren't these two very different concepts?

Hello guys, I am having a bit of trouble with some homework So I am told that a photon in a light beam has an energy og 2,12 eV. First i have to calculate the energy of it in joules, and since 1 eV is 1,60*10^-19 Joules 2,12 eV in joules is just 2,12*1,60*10^-19 = 3.392*10−19 J i got that. Then...

A thought experiment that is a consequense of a question someone asked in my particle physics class: We place an isolated electron. We wait 10 years, and place a half ring of electrons (spaced far apart from each other, but uniform) 10 LY away from our central e. Will our charges move? If so...

what is the correct understanding of a virtual particle? the popular science books would have us believe that a virtual particle magically pops up out of the woodwork, steals some energy and then puts it back before it ( the particl) disappears. Like a thieving employee who steal $100 out of the...

Hi, I'm a vet with an amateur interest in physics. In discussion with a friend about the usefulness of physics he stated that physicists had not even decided whether light was a wave or a particle. I said the following: 'The question of whether light is a wave or particle is not one which...

Q. If a photon travels in an electric field(usually by a nucleus,such as ^12C),it can spontaneously disintegrate into an electron and a positron--known as pair production. A)Calculate the smallest possible photon frequency that produces pair production by assuming that both electron and positron...

Wasnt it ? So I stumbled upon this fragment from wikipedia's photon page "Current commonly accepted physical theories imply or assume the photon to be strictly massless, but this should be also checked experimentally. If the photon is not a strictly massless particle, it would not move at the...

When we dissect the photon we find an electric field and a magnetic field according to Maxwell. In order to determine the propagation mechanism of a single photon through the fabric of space-time, is there an experimental apparatus designed to determine which field may plow the path, in order...

hello, is the wave function of a photon is as same as the classical wave exhibited by a group of photons ? If no, what is the relationship between the wave function associated with a single photon and the classical wave which describes the behavior (such as diffraction) of light (a group of...

I read an article about creating molecules from photon, and this part- As the photons enter the cloud of cold atoms, Lukin said, its energy excites atoms along its path, causing the photon to slow dramatically. As the photon moves through the cloud, that energy is handed off from atom to atom...

I know what the letters mean, E = Energy of the photon, h = Planck's constant, f = frequency of the photon. But what does it mean for a particle to have a frequency, something that I'd associate with a wave. And what can you think Planck's constant is representing? Any replies would be much...

If photons have no mass, why would black holes attract light? I was told that photons have no mass. However I thought that black holes are called "black" because no light can go escape the gravity force in their vicinity. I somehow think that, if light is just photons, then it should not be...

When a photon is at a large distance fom it's starting position then the wave is spread-out laterally. How can a wavefront for one photon collapse instantly over a massive surface area?