Quantum Teleportation Using Quantum Non-Demolition Technique

Quantum teleportation is a transport of quantum state of a system to another similar system via a classical channel [1]. The principles of quantum mechanics demand that for realization of such a transport, the sender and the receiver must have two ancillary quantum systems, being strongly quantum-mechanically correlated (entangled). Quantum teleportation is a fundamental phenomenon of quantum world and also one of the key procedures in the rapidly growing area of quantum information [2]. Recently several teleportation schemes have been proposed [3] and the successful realization of some of them has been reported: teleportation of the polarization state of a single photon [4] [5], of the state of a single-mode optical field [6], [7] and of nuclear spin state [8]. In this Letter we propose a new scheme for quantum teleportation of the state of single-mode optical field. In contrast to the existing schemes [6], [7], where a superposition of two squeezed fields has been used as a source of entanglement, we propose to use the entanglement produced by quantum non-demolition (QND) interaction [9], [10], realized in the last years for optical fields in various media [11], the best results being obtained for coupling two optical beams by parametric interaction in a χ crystal [12] or using cold atoms in a trap [13]. Our scheme is depicted in Fig. 1. The nonlinear QND interaction produces the following coupling between two bright coherent fields Ea and Eb [10]