The phase-space method is applied for considering continuous variable quantum teleportation. It is found that the continuous variable quantum teleportation transforms the $s$-parametrized phase-space function of an input state into the $\left(s+\delta \right)$-parametrized phase-space function, where the parameter $\delta$ is determined by the shared quantum entanglement. It is shown from this result that the Wigner function of the teleported state is always non-negative for ${\mathcal{F}}_c⩽2∕3$ and the Glauber-Sudarshan $P$ function non-negative for ${\mathcal{F}}_c⩽1∕2$, where ${\mathcal{F}}_c$ is the fidelity of the coherent-state teleportation. Furthermore the fidelity between input and output states is calculated when Gaussian states are teleported.

• Received 15 January 2004

DOI:https://doi.org/10.1103/PhysRevA.69.054304