Quadrature distribution for an optical mode in the coherent state

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The discussion centers on finding the quadrature distribution ρ(q) for an optical mode in a coherent state |α>. The user expresses difficulty in understanding the task and references a hint involving a series expansion. The provided formula for ρ(q) includes terms related to the thermal photon number, n_th, and indicates a Gaussian distribution. Participants seek clarification on the variable q, with one suggesting it represents a generalized coordinate. The conversation highlights the need for further explanation and understanding of the underlying concepts in quantum optics.
proton4ik
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Hey there, the task I'm working on is written below.

Find the quadrature distribution ρ(q), for an optical mode being in the coherent state |α>.
Hint: use ∑Hn
(x)*(t^n)/(n!)

I really am struggling with this type of tasks :D
I tried to follow a solved example that I found in my workbook, but there are no explanations and I'm really not sure if I do anything correctly.

\rho(q)=<q|\hat{\rho}|q>=\sum_{n=0}^{\infty} <q| \hat{\rho} {{\psi}_n}^* |n> = \frac {1} {1+n_{th}} \sum_{n=0}^{\infty} (\frac{n_{th}}{1+n_{th}})^n {{\psi}_n}^* |{\psi}_n (q)|^2=\frac{e^{\frac{-q^2}{1+2n_{th}}}}{{\pi (1+2n_{th})}^{1/2}}

I have five more exercises like that, but I can't understand the concept. Any help is much appreciated!
 
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You'll have to give more details. What is q here?
 
DrClaude said:
You'll have to give more details. What is q here?
I think that q is a generalized coordinate
 

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