Photon Definition and 1000 Threads

Lately, I have been giving a lot of thought to whether or not photons would have mass or not. I know most on here an on other sites say that they do not have mass, but I think differently. If light has no mass, then theoretically, it shouldn't have any speed limit (186,282 mi/sec) because...

Consider this: Two antennas are set up in a vacuum. They both radiate electromagnetic waves of the exact same frequency, and an interference pattern can be observed on a screen placed some distance away. Now suppose the emission density was reduced (in both antennas) to one photon at a...

Homework Statement A gammaphoton with a frequency of 5,49*10^20 Hz passes by near a nucleus, and turns into a electron/positron pair. The electron has an kinetic energy of 1,20*10^-13 J. How much kinetic energi is in the posistron?(we can neglect the energyexchange with the nucleus) The...

Hello all, I have a question on cosmic redshift and I am really hoping that one of you can solve this for me, as you have many times in the past. Consider a quasar that is emitting a steady stream of X-ray photons many billions of years into the Universe's past. When the X-rays finally...

I'm not sure if there's a satisfying answer to this question, but I'd at least like to incite some discussion. I haven't had a formal education about photons or quantum mechanics, so all I know is what I've read about outside the classroom, but a buddy and I have been talking about them, as...

Homework Statement A beam of 13.0 eV electrons is used to bombard gaseous hydrogen in ground state. What photon energies will be emitted?Homework Equations ΔE = -13.6 (\frac{1}{n^{2}_{f}} - \frac{1}{n^{2}_{i}}) However hydrogen is in the ground state therefore n_i= 1: ΔE = -13.6...

http://http://education-portal.com/cimages/multimages/16/photonpar.jpg is this image correct does the photon move in a pattern like a wave?

Hey, this question did not come with a mark scheme and I want to make sure that I am going about it in a correct manner, please could someone check what I've done (and answer a couple of questions I have raised)? Thank you in advance! :D Homework Statement Give expressions for the total...

This is not exactly a homework question. In a physics textbook, they derive an expression for gravitational redshift of a photon emitted by a star at a large distance from the source by taking photon as a mass traveling up, against a gravitational potential and hence expending its...

Homework Statement Consider a photon colliding with an electron and scattered directly backward. If the electron is initially at rest and the incident photon has frequency f, determine the frequency of the back-scattered photon Homework Equations The Attempt at a Solution Since the...

(disregard my improvised science lingo) so like... a radio wave has a rather macroscopic wavelength. the photon is depicted as traveling back and forth in unison with the wavelength. I am having trouble understanding why the photon can't hit you from the "side". if the photon is traveling a...

Hello, What does less than one photon mean? 0.5 or 1/2 photon what does it mean?

I understand mathematically etc how light can doppler shift when looked at as a wave but can it be understood how light doppler shifts as a photon i.e. could just one photon be doppler shifted? For example; Say there is an atom with energy levels 1 and 2. One observer, stationary relative to...

I have few questions to ask: 1. Can a photon state be written as |ψ> = [cos(θ) sin(θ) exp(i*ø)] in column vector form 2. When a general photon state|ψ> = [cos(θ) sin(θ) exp(i*ø)] passes through a linear polarizer [1 0; 0 0] we get [cos(θ) 0] at the output but not [1 0] as is usually...

Hi, I was wondering what the frequency of a photon is according to maxwell's equations. Does the energy of a photon really oscillate over time? I'm having a hard time picturing what is actually happening. Thanks!

A homework question is asking for a diagram illustrating a photon becoming a electron-positron pair (please don't post an image as it's homework). Looking through the internet there seems to be some disagreement as to whether a single photon can create an electron-positron pair: "Show that...

Does Casimir plates prevent photon existence only perpendicular to them? I mean, Casimir attraction arises from the fact that the plates prevent some wavelenghts of photons to exist in between them, so an imbalance arises and pushes the plates together, right? But what about photons in other...

When we say the frequency of electromagnetic radiation, how can we conceptualize this property's manifestation in photons? Are the photons oscillating in space with the corresponding frequency? If yes, would this oscillation be parallel, perpendicular, or something else with respect to the...

I'm pretty sure this is a fairly obvious question, but I can't ever be sure.. So, if a photon is "scattered" 180 degrees. Its not being scattered at all, correct? So, then the energy of the "recoiling electrons" would be 0. It makes sense mathematically if I'm doing it right...

Time in the "eye" of a photon Dumb question...but thought I'd throw it out there. So, ever since I was a little kid of 6 or so, I loved to look up at the sky. I knew all those stars were just suns. I also knew I was looking back in time, many thousands to millions of years, since all the...

Let's imagine a rocket orbiting the earth. The rocket could be any real rocket with moderate speed, so that relativistic effects are not significant, and also rocket does not experice notable centrifugal or other acceleration (so the rockets reference frame would appear almost inertial). A...

Homework Statement See attachment. Homework Equations The Attempt at a Solution So I have shown that the plane wave sol'n satisfies the Klein-Gordon equation by subbing in and reducing the equation to: E^2 = p^2c^2 + m^2c^4 which reduces to: E = pc for an m = 0...

Hi! I would like to ask if there is possible to find out the photon flux emitted by a uv source having only the intensity/wavelength spectrum of the source? pp

How do photons carry information? For instance, when a photon is emitted by the sun, it seems to carry information about the sun- color, intensity, etc... If that photon bounces off a blade of grass then it carries new information- color, shape, etc... What is it it about the blade of grass that...

I'm trying to get the hang of labview and it's going pretty well so far. My plan is to control a SR400 photon counter and I seem to get it to do stuff on my commands even though there's no manual for the drivers. (does anyone have one? :) ) My problem/question: I can get the counts for each...

1. A photon that emerges when an electron jumps one orbital down -- will have a fixed energy ...i.e. the different between the (potential) energy of the orbitals. However a "free/unbound" photon can have any energy level. Is that correct? 2. What is the lowest level of energy a...

Quantum View of the Electron and Photon Sorry if the questions sound too amateurish. 1. Is electron a packet of matter, while a photon a packet of energy? or is photon just a force carrier? 2. Can the mass of an electron be converted into energy, and then into electromagnetic radiation...

Since the four forces are a "closed list", one of them should be present in each interaction and, according to Standard model, a boson or mediating particle should be doing the job of the relevant force. For instance, the photon is the mediating particle of electromagnetic force. In turn...

Hi, i have a question about the center of mass change during photon emission in terms of the polarization of the emitted photon. first, a few facts are as follows: i) selection rule: if delta m=0, that means p (atomic recoil) = p (photon) in magnitude. This is of pi transition and...

Hi, I'm trying to write down the stress-energy tensor for a single photon in GR, but I'm running into trouble with its transformation properties. I'll demonstrate what I do quickly and then illustrate the problem. Given a photon with wavevector p, we write {\bf T} = \int \frac{\mathrm{d}^3...

Homework Statement Consider a photon gas (particle-like nature) with N photons of monochromatic light in a box that has a volume V. You can assume everything is perfectly reflecting. What is the pressure of the photon gas based on the ideal gas law derivation? Homework Equations N/A. The...

Hey, in my notes I have calculated the Eigenenergie of the Hamiltonian: H= \hbar \omega (n+\frac{1}{2}) \cdot \begin{pmatrix} 1 & 0 \\ 0 & 1 \end{pmatrix} +\hbar \begin{pmatrix} \frac{\Omega_0 -\omega_0}{2} & g \sqrt{n+1} \\ g \sqrt{n+1}& -\frac{\Omega_0...

Photon and "anti-photon" annihilation? In quantum field theory pairs of virtual particles can appear from vacuum and quickly annihilate each other, for example an electron/positron or a proton/antiproton. But how does this work with photons?From what I know, the photon is its own anti-particle...

Back in October, while contributing to a thread in this forum, I ran into an interesting description of a entanglement/double slit interference experiment. One of the contributors cited a 1999 "Reviews of Modern Physics" article. This remark is made on page S290: Let me see if I can explain...

What is the link between the polarisation of light and photon spin?

The definition of the Gaunt factor. Hello. I'm wondering about the Gaunt factor. I'm currently interesting in the spectroscopy in which the Gaunt factor is the correction factor to the classical cross section associated to the photon with electron thus the corrected formula is the identical...

I have a question. I was wondering if it was possible to put a vibrational sound frequency to a photon? Another way of putting it, is it possible to pump sound into a laser beam and give the photon a vibrational frequency consistent with the sound added? Thanks.

Does a photon, or any particle that travels at c, believe the universe to be 2 dimensional?

Homework Statement See attachment. Homework Equations The Attempt at a Solution So, \gamma + D \rightarrow p + n (E_1,\underline{k}_1) + (E_2,\underline{0}) = 2(E_3,\underline{k}_3) where I have assumed E3 ≈ E4 and k3 ≈ k4 as mn≈ mp and vp = vn then splitting E and K components up and...

Hello, I'm currently in my last year of high school and I'm doing a project about the higgs particle decaying to two photons. I am using HYPATIA to analyse ATLAS events. When a higgs boson decays into two photons, you can see activity in the electromagnetic calorimeter without seeing a track...

What is the Lagrangian of interaction of photon and spin zero charge scalar?The vertex of photon and spin 1/2 charge fermion is proportional with e multiplied vertor gamma matrix,but I do not know what is the vertex of photon and charge scalar.I hear that a vertex is proportional with polynomial...

1. What (property) makes a photon less likely to decohere/(entangle with the environment) relative to other "fundamental" particles (non leptons?) such as an electron?...say during single particle interference experiment Photon single particle interference can done without the need for a...

Do photons bounce off after they hit each other or they just pass through one and another?

My question comes from seeing this: http://pdg.lbl.gov/2009/tables/rpp2009-sum-gauge-higgs-bosons.pdf From where we know that the photon has mass less than something. First of all it means that experimentalists have looked at it. So, what would be the impact on the physics we already know, if...

Homework Statement I'll copy down the exact phrasing, so there's no question that this is what we're being asked: "An atom in an excited state of energy Qo (as measured in its rest frame) above the ground state moves towards a scintillation counter with speed v. The atom decays to its...

I want to apologize first of i post at the wrong section, not very sure if this is the right place for this post. First question, does the photon get absorbed when it hit highly reflecting material like mirror ? What make them look so different from the other transparent object? And I just...

I would like to hear comments about interpretation of photon interference in context with Pfleegor-Mandel experiment "Interference of Independent Photon Beams". There is a blog post about this experiment: http://scienceblogs.com/principles/2010/11/19/interference-of-independent-ph/. Original...

How do we know a "photon" is massless? Do we have any experimental proof? Photon has momentum, it even bends in gravity, doesn't that mean photon has mass? A radioactive material will go on emitting radiations until it balances, a way in which it reduces it's mass. So, isn't photon the...

Does the wavelength of a photon actually mean wavelength? Because as I understand it, a force field, be it gravity, EM, ect..., has influence at any distance. Theoretically, the field never has an end, reaching out across the whole diameter of the universe, even though the effects would be...

[Mentor's note: This thread does not use the template because it started in one of the non-homework forums. I moved it here instead of deleting it and asking the poster to repost here, because it had accumulated several useful replies.] Hi. I have the exact same problem that ZachWeiner had in...