- #1

- 284

- 14

- Thread starter fxdung
- Start date

- #1

- 284

- 14

- #2

DrDu

Science Advisor

- 6,092

- 803

- #3

- 284

- 14

What is super selection rule for electrons?

- #4

DrDu

Science Advisor

- 6,092

- 803

- #5

- 284

- 14

Why is coherence state when the number of photons tend to infinite?

- #6

atyy

Science Advisor

- 14,200

- 2,466

There are many types of single photons. Some types are "monochromatic" and other types are not.

- #7

blue_leaf77

Science Advisor

Homework Helper

- 2,629

- 784

The uncertainty relation in the case of electron wavepacket is between position and momentum. Localized electron wavefunction in free space is supposed to be realized by introducing uncertainty in momentum, I guess it is this momentum spread which you referred to as "multi-frequency".I know that because quantum mechanics particle ''lies'' in wave packet,so it has multi-frequence due to Heizenberg relation.

I think your English skill obscures your intention about what you actually wanted to say. The state of a quantum system is something one can control, for the states of photon, it can beWhy is coherence state when the number of photons tend to infinite?

However, for the special case of coherent state, the observed electric field does exhibit certain dependency between the coherency, which may be defined as the uncertainty in phase at a given time, and the expected number of photons ##\langle \hat{n} \rangle##. For sufficiently large value of ##\langle \hat{n} \rangle##, the uncertainty in the phase of the electric field turns out to have the form ##\Delta \phi = 1/(2\sqrt{\langle \hat{n} \rangle})##. Therefore, if the number of photons is very large, the electric field becomes more and more coherent (i.e. it gets closer to being a classical field oscillation), in the sense that its phase becomes more definite.

- #8

- 284

- 14

- #9

DrDu

Science Advisor

- 6,092

- 803

- #10

blue_leaf77

Science Advisor

Homework Helper

- 2,629

- 784

Yes, that's the right expression. Now express the field operator in terms of the lowering and raising operators (similar to those in harmonic oscillator) and also remember that ##|\textrm{number of photons}\rangle## behaves exactly like the eigenstates of harmonic oscillator.Is it correct that the average value of electric field is<number photons/operator of the field/number of photons>?

- #11

- 284

- 14

So there are two types of oscilation phase: one is classical phase of field that has raise and lower operator as amplitude of Fourier component of field; the other is oscilation phase of quantum of field(phase of wave function of the particle?).

Another question is if we interpret quantum of field as a packet of field why we know quantum of field is a point size particle or we have an axiom about the dual: particle- wave or particle-field.

Is there a uncertainty relation between position and momentum for zero mass particle?

Another question is if we interpret quantum of field as a packet of field why we know quantum of field is a point size particle or we have an axiom about the dual: particle- wave or particle-field.

Is there a uncertainty relation between position and momentum for zero mass particle?

Last edited:

- Last Post

- Replies
- 6

- Views
- 11K

- Last Post

- Replies
- 4

- Views
- 2K

- Last Post

- Replies
- 10

- Views
- 1K

- Replies
- 1

- Views
- 2K

- Last Post

- Replies
- 1

- Views
- 226

- Last Post

- Replies
- 17

- Views
- 178

- Last Post

- Replies
- 10

- Views
- 1K

- Last Post

- Replies
- 3

- Views
- 2K

- Last Post

- Replies
- 3

- Views
- 2K

- Last Post

- Replies
- 2

- Views
- 6K