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exmarine
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I can't find this in any textbook, so I must not understand something about it. What is the Lagrangian of a photon? Would it be just h*nu?
Which part ofexmarine said:OK, then how does one calculate the action (S) for the amplitude of a photon?
was unclear? You need to specify exactly what it is you are trying to do.Orodruin said:There is no such thing as the lagrangian of a photon. Photons are quantum excitations of the electromagnetic field,
You don't. You compute the action of the electromagnetic field and correlation functions (essentially amplitudes) between different excitations of the field.exmarine said:So if a photon has no Lagrangian, how does one calculate the action, amplitude, probability, etc. for a photon?
exmarine said:Feynman & Hibbs, p. 29, eqn 2.15:
The Lagrangian of a photon is a mathematical function that describes the energy and motion of a photon, which is the fundamental particle of light. It takes into account the photon's properties, such as its frequency and direction of travel, to determine its behavior.
The Lagrangian of a photon is directly related to the photon's properties. It takes into account the photon's energy, which is determined by its frequency, and its momentum, which is determined by its direction of travel. This allows us to understand how a photon behaves in different situations.
Understanding the Lagrangian of a photon is important because it allows us to make predictions about the behavior of light in various situations. This is crucial in fields such as optics, where precise control over light is necessary for technologies like lasers and fiber optics.
The Lagrangian of a photon is derived using the principles of quantum mechanics and special relativity. It is based on the idea that the energy and momentum of a photon are related to its frequency and direction of travel, and that these properties are quantized, meaning they can only take on certain discrete values.
While the Lagrangian of a photon is specifically derived for the behavior of light, the same principles can be applied to other particles. In fact, the concept of a Lagrangian is used in many areas of physics to describe the behavior of particles, including electrons, protons, and even larger objects like planets and stars.