What is the Mass of Photons According to QFT?

In summary, according to the theory of quantum field theory, fundamental particles are excitations in their underlying fields. This means that the photon, which corresponds to an oscillation of the electromagnetic field, should have some mass since it takes energy to excite the field. This is supported by the equation E=mc^2, which shows that energy and mass are equivalent. However, this equation is incomplete and there is ongoing debate about whether photons actually have mass.
  • #1
FallenApple
566
61
So according to QFT, fundamental particles are just excitations in their underlying fields.

So the photon would correspond to an oscillation of the EM field.

But it takes energy to excite this field. And E=mc^2. So therefore the photon should have some mass. Energy was put into create it. That energy has to be concentrated somewhere.
 
Physics news on Phys.org

Related to What is the Mass of Photons According to QFT?

1. Why are photons considered massless?

Photons are considered massless because they do not have any rest mass. This means that they do not have any mass when they are at rest, unlike other particles such as electrons or protons. Photons only have energy and momentum, which are related to their frequency and wavelength.

2. How can something have energy and momentum but no mass?

According to Einstein's theory of relativity, energy and mass are interchangeable. Photons have energy in the form of electromagnetic radiation, but they do not have any mass. This is because the energy of a photon is directly proportional to its frequency, but not its mass.

3. What is the evidence for photons being massless?

There have been numerous experiments and observations that support the idea of photons being massless. One of the most famous is the Michelson-Morley experiment, which showed that the speed of light is constant, regardless of the observer's frame of reference. This supports the idea that photons do not have any rest mass.

4. Can photons ever have mass?

No, photons cannot have mass. They are considered fundamental particles, meaning that they cannot be broken down into smaller components. Additionally, the theory of relativity has been extensively tested and confirmed, and it states that photons cannot have mass.

5. What implications does the masslessness of photons have in physics?

The masslessness of photons has significant implications in many areas of physics, including particle physics, astrophysics, and cosmology. For example, the masslessness of photons allows them to travel at the speed of light, making them essential for understanding the behavior of particles at high energies. Additionally, the energy and momentum of photons are crucial in processes such as photosynthesis and the formation of stars and galaxies.

Similar threads

I QED Picture of static EM Fields
    • Quantum Physics
Replies
3
Views
794
A QED Formulation with Massive Photon Fields
    • Quantum Physics
Replies
3
Views
1K
I How indistinguishable are photons?
    • Quantum Physics
Replies
32
Views
2K
I Feedback on Educational Script: What's a particle in QFT?
    • Quantum Physics
Replies
5
Views
387
I The general structure of relativistic QFTs
    • Quantum Physics
3
Replies
87
Views
5K
A Photon Statistics in QFT & String Theory
    • Quantum Physics
Replies
13
Views
1K
A Is the quantum mechanics explanation for the propagation of light adequate enough to be understood?
    • Quantum Physics
Replies
6
Views
541
I Qualitative description of particles in QFT
    • Quantum Physics
Replies
15
Views
2K
I Why is Photon Energy Quantized in Terms of Sine Wave Frequency?
    • Quantum Physics
3
Replies
78
Views
3K
I Excited electrons' behaviour, how do they work?
    • Quantum Physics
Replies
1
Views
722

Hot Threads

Recent Insights

Back
Top