We calculate the highest possible information gain in a measurement of entangled states when employing a beamsplitter. The result is used to evaluate the fidelity, averaged over all unknown inputs, in a realistic teleportation protocol that takes account of the imperfect detection of Bell states. Finally, we introduce a probabilistic teleportation scheme, where measurements are made in a partia...

We discuss the criteria presently used for evaluating the efficiency of quantum teleportation schemes for continuous variables. It is argued that the fidelity criterion used so far has some severe drawbacks, and that a fidelity value larger than 2/3 is actually required for successful quantum teleportation. This value has never been reached experimentally so far.

Quantum teleportation [1-3] is a striking illustration of the difference between classical and quantum communication processes [4]. In teleportation, communication is facilitated by entanglement. But state transmission is predicated on belief that the entanglement between the resource particles is perfect and the protocol steps are error-free, both of which it is impossible to establish uncondi...

We propose a method to apply genetic algorithms to the quantum circuit design. We show by experiments that without any deep knowledge of the problem it is possible to evolve a circuit for the quantum teleportation simpler than ever known. keyword: genetic algorithms, quantum teleportation, quantum computer, quantum computing, quantum circuit.

A general matrix approach to study entangled states is presented, based on operator completeness relations. Bases of unitary operators are considered, with focus on irreducible representations of groups. Bell measurements for teleportation are considered, and robustness of teleportation to various kinds of non idealities is shown.

We make a brief comment on measurement of quantum operators with degenerate eigenstates and apply to quantum teleportation. We also try extending the quantum teleportation by Bennett et al [5] to more general situation by making use of generalized Bell states. E-mail address : [email protected] Home-page : http://fujii.sci.yokohama-cu.ac.jp

We show how to encode quantum dynamics in the state of a quantum system, in such a way that the system can be used to stochastically perform, at a later time, the stored transformation on some other quantum system. The probability of failure decreases exponentially with the number of qubits that store the transformation. We discuss optimality of this scheme, whose applications include viability...

By means of the Ising terms generated by Coulomb interaction between ions and the magnetic field gradient, we carry out teleportation with insurance with trapped ions. We show the feasibility and the favorable feature of our scheme by comparing with the recently achieved teleportation experiments with trapped ions.

     Multiple sclerosis (MS) is an inflammatory, demyelinating, neurodegenerative disorder of the central nervous system (CNS) of unknown etiology. Isolated oculomotor nerve palsy is found rarely in children with MS. We present a case of MS in 10-year-old boy, who had bilateral ptosis associated with medial gaze restriction. The extraocular muscle examination demonstrated bilateral adduction pa...

Recently, in Ref.[1] N. Ba An proposed a teleportation protocol, in which the new interesting idea of exploiting local resources to do teleportation [2] is generalized to the case of arbitrary quNits. After carefully rededucting the formulae in Ref.[1], however, we find some of them are wrong. As a consequence, the unitary operations which need to be performed to reconstruct the unknown biparti...