Photon Wavefunction Evolution

[Flamel]

From what I understand, the rate of a wavefunction's spread after its collapse can be manipulated if one starts with particular states. How would one calculate this, specifically in the case of photons if the calculations are different from other particles?

[Mordred]

Your going to need to clarify this question. Are you talking about entangled states or superposition states ?

Though entangled included superposition. A particle state can be in superposition without being entangled.

[Flamel]

40 minutes ago, Mordred said:

Your going to need to clarify this question. Are you talking about entangled states or superposition states ?

Though entangled included superposition. A particle state can be in superposition without being entangled.

I'm talking about entangled states.

[Mordred]

Ok this  simplifies the question.  When a state is entangled the two particles are in a superposition state. once entangled the particle regardless of type that superposition state  has a correlation function(probabilistic ) Once you examine  one of the  states. You have removed the probabilistic state to a determined state.

 As a consequence of being entangled you will instantly know the state of the other particle.

This does not violate FTL as it's really a case of preparation. In order to entangle two particles you must first prepare them. Ie monochromatic beams passing through a beam splitter (Bells experiment). Factors in the correlation function include spin conservation and other conservation laws. Number of polarity states possible. Etc.

 

Edited August 3, 2019 by Mordred

[Flamel]

8 minutes ago, Mordred said:

Ok this  simplifies the question.  When a state is entangled the two particles are in a superposition state. once entangled the particle regardless of type that superposition state  has a correlation function(probabilistic ) Once you examine  one of the  states. You have removed the probabilistic state to a determined state.

 As a consequence of being entangled you will instantly know the state of the other particle.

This does not violate FTL as it's really a case of preparation. In order to entangle two particles you must first prepare them. Ie monochromatic beams passing through a beam splitter (Bells experiment). Factors in the correlation function include spin conservation and other conservation laws. Number of polarity states possible. Etc.

 

How would one calculate how the wavefunction spreads out again after the observation collapses it?

[Mordred]

A complicated procedure called path integrals of QFT. They vary on the particles properties. Each particle has its own wavefunctions based upon its principle quantum numbers.

 Those path integrals are represented by the Feymann diagrams. Unfortunately there is no easy way to describe them as it's a lengthy process to understand a vertex formula.

[Wulphstein]

6 minutes ago, Mordred said:

A complicated procedure called path integrals of QFT. They vary on the particles properties. Each particle has its own wavefunctions based upon its principle quantum numbers.

 Those path integrals are represented by the Feymann diagrams. Unfortunately there is no easy way to describe them as it's a lengthy process to understand a vertex formula.

Can you post a description of vertex formulas?

[Mordred]

The best way to demonstrate the complexity is to post the following beginner's guide to path integrals.

It would take far too long to latex and explain the relevant formulas

Arxiv article on phone atm.

https://www.google.com/url?sa=t&source=web&rct=j&url=https://arxiv.org/pdf/1602.04182&ved=2ahUKEwjTvbWChubjAhXTqp4KHXwVDYsQFjAAegQIAhAB&usg=AOvVaw1RmEFniQcXGeRgZn8jX5Cz