Search

We have developed the radio wave repeater employing analog-radio over grated-index plastic optical fiber toward mm-radio wave of 5th generation new radio (5G-NR). In this work, we have demonstrated mm-radio wave transmission over graded-index plastic optical fiber for dead zones inside small office by using 5G experimental base station and cellular phone. [ABSTRACT FROM AUTHOR]

Possible nature of strongly magnetized white dwarfs (SMWDs) is studied. It is shown that for relatively low values of the equatorial surface magnetic field B ~ 109 - 1011G they can be good candidates for soft gamma-ray repeaters and anomalous X-ray pulsars (SGRs/AXPs). For the case of iron SMWDs the influence of a neutrinoless electron to positron conversion on the SGRs/AXPs luminosity is estimated. [ABSTRACT FROM AUTHOR]

Quantum key distribution over probabilistic quantum repeaters is addressed. We compare, under practical assumptions, two such schemes in terms of their secure key generation rate per memory, RQKD. The two schemes under investigation are the one proposed by Duan et al. in [Nat. 414, 413 (2001)] and that of Sangouard et al. proposed in [Phys. Rev. A 76, 050301 (2007)]. We consider various sources of imperfections in the latter protocol, such as a nonzero double-photon probability for the source, dark count per pulse, channel loss and inefficiencies in photodetectors and memories, to find the rate for different nesting levels. We determine the maximum value of the double-photon probability beyond which it is not possible to share a secret key anymore. We find the crossover distance for up to three nesting levels. We finally compare the two protocols. [ABSTRACT FROM AUTHOR]

The article offers information on quantum communication networks. Topics discussed include elements of future quantum networks which include quantum repeaters and network nodes, solid state systems such as superconducting quantum circuits, nanomechinical devices and spin doped solids and use of quantum media converter device for establishing a fiber optical link between solid state devices.