Quantum entanglement and secrecy
Acta Physica Polonica B 33:8 (2002) 2069-2080
Abstract:
We describe how quantum entanglement can be used in secure communication.Direct estimations of linear and nonlinear functionals of a quantum state.
Phys Rev Lett 88:21 (2002) 217901
Abstract:
We present a simple quantum network, based on the controlled-SWAP gate, that can extract certain properties of quantum states without recourse to quantum tomography. It can be used as a basic building block for direct quantum estimations of both linear and nonlinear functionals of any density operator. The network has many potential applications ranging from purity tests and eigenvalue estimations to direct characterization of some properties of quantum channels. Experimental realizations of the proposed network are within the reach of quantum technology that is currently being developed.Detection of entanglement with few local measurements
ArXiv quant-ph/0205089 (2002)
Abstract:
We introduce a general method for the experimental detection of entanglement by performing only few local measurements, assuming some prior knowledge of the density matrix. The idea is based on the minimal decomposition of witness operators into a pseudo-mixture of local operators. We discuss an experimentally relevant case of two qubits, and show an example how bound entanglement can be detected with few local measurements.Detection of entanglement with few local measurements
(2002)
Direct estimations of linear and non-linear functionals of a quantum state
(2002)