22 research outputs found
Secure quantum conversation through non-destructive discrimination of highly entangled multipartite states
"Quantum conversation" is a way in which two parties can communicate
classical information with each other using entanglement as a shared resource.
We present this scheme using a multipartite entangled state after describing
its generation through appropriate circuit diagrams. We make use of a
discrimination scheme which allows one to perform a measurement on the system
without destroying its entanglement. We later prove that this scheme is secure
in a noiseless and a lossless quantum channel.Comment: 6 page
Perfect Teleportation, Quantum state sharing and Superdense Coding through a Genuinely Entangled Five-qubit State
We investigate the usefulness of a recently introduced five qubit state by
Brown \it et al. \normalfont \cite{Brown} for quantum teleportation, quantum
state sharing and superdense coding. It is shown that this five-qubit state can
be utilized for perfect teleportation of arbitrary single and two qubit
systems. We devise various schemes for quantum state sharing of an arbitrary
single and two particle state via cooperative teleportation. We later show that
this state can be used for superdense coding as well. It is found that five
classical bits can be sent by sending only three quantum bits.Comment: 8 Pages, added sections on state sharin
Efficient long distance quantum communication
Despite the tremendous progress of quantum cryptography, efficient quantum
communication over long distances (>1000km) remains an outstanding challenge
due to fiber attenuation and operation errors accumulated over the entire
communication distance. Quantum repeaters, as a promising approach, can
overcome both photon loss and operation errors, and hence significantly speedup
the communication rate. Depending on the methods used to correct loss and
operation errors, all the proposed QR schemes can be classified into three
categories (generations). Here we present the first systematic comparison of
three generations of quantum repeaters by evaluating the cost of both temporal
and physical resources, and identify the optimized quantum repeater
architecture for a given set of experimental parameters. Our work provides a
roadmap for the experimental realizations of highly efficient quantum networks
over transcontinental distances.Comment: Sreraman Muralidharan and Linshu Li contributed equally to this wor