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Is light particle Elastic? Do they collide?

Do they exchange energy?

The question came from this imagination. If light particles interact, exchange energy, Then we could transmute data with light from the Sun by bombarding it with light carrying data. And that means network will be everywhere. Better than LiFi. So I just wanted to know light nature.

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    $\begingroup$ Have you done any internet searches on photon-photon interactions? $\endgroup$
    – Kyle Kanos
    Commented Jan 7, 2018 at 3:17
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    $\begingroup$ Perhaps this link on two photon physics will help. $\endgroup$
    – StephenG - Help Ukraine
    Commented Jan 7, 2018 at 4:04

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Is light particle Elastic?

Light is an emergent phenomenon from the quantum mechanical superposition of a large number of elementary particles called photons. Superposition is not interaction. It is an addition of probabilities for finding a photon at an (x,y,z,t) spot. This double slit , single photon answer of mine might help to understand this .

A building is made of bricks, but a brick is not a building. In the same way light is built up by photons, but photons are not light and cover a large spectrum of electromagnetic energy, a small part of which is visible light..

If by elastic you mean "can they scatter" off each other, the answer is yes, with very small probability.

Do they collide?

At high energies photons are called gammas, and the probability of scattering off each other rises with energy. They are even considering gamma gamma colliders. Due to the relativistic nature of the collisions pairs of particles may be generated.

Do they exchange energy

They may collide elastically , no change in energy and momentum, or exchange energy and momentum, depending on the probability of two photon interactions/scattering.

Light has very low energy photons , a small part of the electromagnetic spectrum, and as the other answer says,the light beams, even though composed out of zillions of photons, interact very very rarely. It is only at the invisible energies of gamma radiation that interactions are measurable.

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  • $\begingroup$ "can they scatter" --@Anna V. You got me right. I was wondering if light collide why don't it diffuse like gas. Thanks. I should really go back to school. $\endgroup$
    – Timothy Nwanwene
    Commented Jan 7, 2018 at 21:24
  • $\begingroup$ Anna, you describe photons very real and physical just as I would but there are many people on this site including high-ranking ones who don’t consider photons physical at all. Sometimes they treat photons like they’re not real, and when they do you usually don’t disagree with them. I’m not saying photons are little solid balls. They are oscillating systems of their own and your oscillating frequency determines their energy. $\endgroup$
    – Bill Alsept
    Commented Jan 8, 2018 at 1:23
  • $\begingroup$ @BillAlsept I am an experimentalist, a doubting Thomas. I look at the data, and model it. If I see cat paws in the cement, I say a cat passed here while the cement was wet. If I see dots in single photon experiment screens ( link above) I say a particle passed through here, call it a photon, because the experiment shows it builds up the final light interference pattern. People theoretically/mathematically inclined, tend to assign reality to the mathematics. The Platonic, Pythagorean point of view. Mathematics is the mold, nature fills it. It is a philosophical distinction. I see field theory $\endgroup$
    – anna v
    Commented Jan 8, 2018 at 5:19
  • $\begingroup$ as a successful model in fitting laboratory data. They see it as the end all mathematical mold.It might be true, but having first met field theory in a mathematical model for nuclear physics ( creation and annihilation operators and all) I tend to see it as a very good tool for modeling nature, not nature itself, which for me still is "turtles all the way down". $\endgroup$
    – anna v
    Commented Jan 8, 2018 at 5:22
  • $\begingroup$ "Sometimes they treat photons like they’re not real, and when they do you usually don’t disagree with them." real or not-real" are philosophical assignments and I do not want to get into a philosophical discussion, as this is a physics site. On the philosophy side, it might be true that the music of the spheres generates everything we see. I was amused when string theory came up as a candidate for a theory of everything , but at the moment physics experiments cannot solve philosophical discussions on the same data. $\endgroup$
    – anna v
    Commented Jan 8, 2018 at 5:36
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Is light particle Elastic?

Yes, light undergoes elastic scattering.

Do they collide?

Yes. Refer to explanation below.

Do they exchange energy?

Yes, but very little energy is exchange(anna v corrected me). Every photon(light particle) carries information about its existence and frequency. Low-energy photons have insignificant results when colliding, and thus can be said to pass through each other. It is only at very high energy levels do we see a significant observation. For instance, 2 photons from a gamma ray can collide to form an electron and a positron. However, such an instance is rather rare, as most of the times, light waves simply pass through each other. Hence they do not exchange energy, but forms new particles(electron and positron for instance).

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    $\begingroup$ I am sorry , in two photon interactions they do exchange energy, just with very small probability en.wikipedia.org/wiki/Two-photon_physics $\endgroup$
    – anna v
    Commented Jan 7, 2018 at 5:22
  • $\begingroup$ Ok i changed that $\endgroup$
    – QuIcKmAtHs
    Commented Jan 7, 2018 at 5:22

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