Dispersion relation and Photonic Energy and Momentum Equations in QM

In summary, a dispersion relation is a mathematical relationship between the energy and momentum of a wave. In quantum mechanics, it is used to describe the behavior of particles and explain the particle-wave duality of light. Photonic energy, which describes the energy of photons, is a fundamental concept in QM and is quantized. The equations for calculating photonic energy and momentum in QM are different from those in classical physics, where energy and momentum are continuous quantities. In QM, the energy and momentum of a particle are related through the dispersion relation, which is important in understanding particle behavior at the quantum level.
  • #1
DaTario
1,039
35
Hi All,

In quantum mechanics, related to photon, we have these two equations as valid ones:

E = h x f

p = h / lambda

But we have in vacuum the dispersion relation c = lambda x f.

1) How these relations change when the dispersion relation change ?

2) Is it universally correct to write p = h x f / c ?


Thanks ALL

Best Regards

DaTario
 
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  • #2
Or still, is it correct to write:

E = h c / lambda ?

Best wishes

DaTario
 
  • #3
Yes, but at least c should be understood to mean not the vacuum velocity but the velocity of the wave in the medium.
 

Related to Dispersion relation and Photonic Energy and Momentum Equations in QM

1. What is a dispersion relation?

A dispersion relation is a mathematical relationship between the energy and momentum of a wave. It describes how the energy and momentum of a wave are related to each other, and how they change as the wave propagates through a medium.

2. How does the dispersion relation relate to quantum mechanics?

In quantum mechanics, the dispersion relation is used to describe the behavior of particles at the microscopic level. It helps to explain how particles can have both wave-like and particle-like properties, and how their energy and momentum are related.

3. What is the significance of photonic energy in QM?

Photonic energy is a fundamental concept in quantum mechanics, as it describes the energy of photons – the basic units of light. In QM, the energy of a photon is quantized, meaning it can only have certain discrete values, rather than being continuous. This is a key aspect of the particle-wave duality of light.

4. How do the photonic energy and momentum equations in QM differ from classical physics?

In classical physics, energy and momentum are continuous quantities that can take on any value. In QM, however, they are quantized, meaning they can only have certain discrete values. Additionally, the equations used to calculate photonic energy and momentum in QM are different from those used in classical physics.

5. What is the relationship between energy and momentum in QM?

In QM, the energy and momentum of a particle are related through the dispersion relation. This means that as the energy of a particle changes, its momentum will also change, and vice versa. This relationship is important in understanding the behavior of particles at the quantum level.

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