Biomedical subjects

Ch Silberhorn

Publications and source records attributed to Ch Silberhorn.

3 recordsLinked to original sources

PubMed2004

Sub-shot-noise phase quadrature measurement of intense light beams.

We present a setup for performing sub-shot-noise measurements of the phase quadrature of intense pulsed light without the use of a separate local oscillator. A Mach-Zehnder interferometer with an unbalanced arm length is used to detect the fluctuations of the phase quadrature at a single sideband frequency. With this setup, the nonseparability of a pair of quadrature-entangled beams is demonstrated experimentally.

Journal Article↗

PubMed2002

Continuous variable quantum cryptography: beating the 3 dB loss limit.

We demonstrate that secure quantum key distribution systems based on continuous variable implementations can operate beyond the apparent 3 dB loss limit that is implied by the beam splitting attack. The loss limit was established for standard minimum uncertainty states such as coherent states. We show that, by an appropriate postselection mechanism, we can enter a region where Eve's knowledge on Alice's key falls behind the information shared between Alice and Bob, even in the presence of substantial losses.

Journal Article↗

PubMed2002

Quantum key distribution with bright entangled beams.

We suggest a quantum cryptographic scheme using continuous EPR-like correlations of bright optical beams. For binary key encoding, the continuous information is discretized in a novel way by associating a respective measurement, amplitude, or phase, with a bit value "1" or "0." The secure key distribution is guaranteed by the quantum correlations. No predetermined information is sent through the quantum channel contributing to the security of the system.

Journal Article↗