Thank you Prof. Neumaier.
So it is an approximation for ease of calculations. Because I feel like if linearity is violated the theory shouldn't be reversible which might have serious consequences, also it might be possible to clone quantum states and faster than light signalling must be...
Hello all,
you may already know that Q.M. is a linear theory however there is something called nonlinear Sch. eq. for example Gross-Pitaevskii equation. How can such a thing exist considering that Q.M. is a strictly linear theory.
Cheers.
As I noted in my first post I am talking about bosonic mode operators, not matrices, the squares doesn't equal to I. Consider the annihilation and creation operators:
$$a,a^{\dagger}$$
Now they constitutes the Heisenberg algebra and as I pointed in my post:
$$a^2,a^{\dagger^2},a^{\dagger}...
Thank you for the reply. My point was if it is possible to construct a finite algebra easily from the squares of operators that constitutes a finite Lie algebra already. For example consider the following algebra:
$$[L_1,L_2]=I$$
Where I represents identity. Now basically these operators form a...
I am trying to decompose some exponential operators in quantum optics. The interesting thing is that the operators includes operators from Su(1,1) algebra $$ [K_+,K_-]=-2K_z \quad,\quad [K_z,K_\pm]=\pm K_\pm.$$
For example this one: $$ (K_++K_-)^2.$$ But as you can see they are squares of it.
I...