Teleportation using continuous variable quantum cloning machine

We show that an unknown quantum state in phase space can be teleported via three-mode entanglement generated by continuous variable quantum cloning machine (transformation). Further, proceeding with our teleportation protocol we are able to improve the fidelity of teleportation obtained by Loock et.al. [Phys.Rev.Lett. 84, 3482(2000)]. Also we study here the entanglement between the two output copies from cloning machine. PACS Numbers: 03.67.-a, 03.65.Bz,42.50.Dv Quantum information theory was initiated with the discrete quantum variables but now a days it has been extended to the domain of continuous quantum variables. The possible reason for this may be the continuous spectrum systems are experimentally simpler to manipulate than their discrete counterparts in order to process quantum information. The second reason to switch over from the discrete quantum variables to the continuous variables is the Unconditionalness, which is one of the valuable feature of quantum optical implementations based upon continuous variables. But this valuable feature give a price in terms of the quality of the entanglement. The entanglement and the entanglement-based quantum protocol is always imperfect and the degree of imperfection depends on the amount of squeezing of the laser light involved. Good performance of the entanglement-based quantum protocol can be achieved for large squeezing (about 10 dB [24]) which is technologically demanding also. In this letter, our aim is two fold: First, we consider the continuous variable cloning transformation and study the entanglement between the two output copies by covariance matrix approach. Second, We will show that the three-mode entanglement (two copy mode and one ancilla mode) generated by cloning procedure can be used to teleport a single arbitrary mode with optimum fidelity F opt = [ +2e+2e 1+2e ] −1 2 . We will observe that ∗Corresponding Author:Satyabrata Adhikari,E-Mail:[email protected]