Input states are written as \(\rho=\tfrac12(I+\vec r\cdot\vec\sigma)\), with Bloch vector \(\vec r=(r_x,r_y,r_z)\) and \(\|\vec r\|\le 1\).
In spherical coordinates, \(r_x=r\sin\theta\cos\phi,\; r_y=r\sin\theta\sin\phi,\; r_z=r\cos\theta\). \(r=1\) is pure and \(0\le r<1\) is mixed.
Drag the sphere to rotate the view.
Channel Parameters
Choose a channel family and set its parameters.
General Pauli channel with probabilities \((p_0,p_x,p_y,p_z)\), where \(p_0 = 1-p_x-p_y-p_z\).
Need \(p_x+p_y+p_z \le 1\).
Input State
Set \((r,\theta,\phi)\) to choose the input Bloch vector.