8 papers
Highly asymmetric quantum cloning in arbitrary dimension
Jaromir Fiurasek, Radim Filip, Nicolas J. Cerf
We investigate the universal asymmetric cloning of states in a Hilbert space of arbitrary dimension. We derive the class of optimal and fully asymmetric 1->3 cloners, which produce…
Partial deterministic non-demolition Bell measurement
Ladislav Mišta, Radim Filip
We propose the scheme implementing partial deterministic non-demolition Bell measurement. When it is used in quantum teleportation the information about an unknown input state is o…
Knowledge excess duality and violation of Bell inequalities
R. Filip, M. Gavenda
A constraint on two complementary knowledge excesses by maximal violation of Bell inequalities for a single copy of any mixed state of two qubits is analyzed. The complementa…
Squeezing concentration for Gaussian states with unknown parameter
Radim Filip, Ladislav Mišta
A continuous-variable analog of the Deutsch's distillation protocol locally operating with two copies of the same Gaussian state is suggested. Irrespectively of the impossibility o…
Optimization of security costs in nested purification protocol
Radim Filip
We analyse security costs in one segment of nested purification protocol in a large quantum cryptography network, employing the quantum switchers and repeaters. We demonstrate that…
Nonlocality degradation of two-mode squeezed vacuum in absorbing optical fibers
Radim Filip, L. Mista
Transfer of nonlocal two-mode squeezed vacuum state through symmetrical and asymmetrical lossy channel is analysed and we demonstrate that the nonlocality is more robust against lo…