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Of all publications in the section: 6
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Article
Elezov M., Ozhegov R., Kurochkin Y. et al. EPJ Web of Conferences. 2015. Vol. 103. P. 10002-p.1-10002-p.2.

Nowadays, the superconducting single-photon detectors (SSPDs) are used in Quantum Key Distribution (QKD) instead of single-photon avalanche photodiodes. Recently bright-light control of the SSPD has been demonstrated. This attack employed a "backdoor" in the detector biasing technique. We developed the autoreset system which returns the SSPD to superconducting state when it is latched. We investigate latched state of the SSPD and define limit conditions for effective blinding attack. Peculiarity of the blinding attack is a long nonsingle photon response of the SSPD. It is much longer than usual single photon response. Besides, we need follow up response duration of the SSPD. These countermeasures allow us to prevent blind attack on SSPDs for Quantum Key Distribution.

Added: Oct 13, 2017
Article
Elezov M., Ozhegov R., Goltsman G. et al. EPJ Web of Conferences. 2017. Vol. 132. P. 1-2.

Recently bright-light control of the SSPD has been demonstrated. This attack employed a "backdoor" in the detector biasing scheme. Under bright-light illumination, SSPD becomes resistive and remains "latched" in the resistive state even when the light is switched off. While the SSPD is latched, Eve can simulate SSPD single-photon response by sending strong light pulses, thus deceiving Bob. We developed the experimental setup for investigation of a dependence on latching threshold of SSPD on optical pulse length and peak power. By knowing latching threshold it is possible to understand essential requirements for development countermeasures against blinding attack on quantum key distribution system with SSPDs.

Added: Oct 13, 2017
Article
Florya I., Korneeva Y., Sidorova M. et al. EPJ Web of Conferences. 2015. Vol. 103. P. 10004.

We have studied the mechanism of energy relaxation and resistive state formation after absorption of a single photon for different wavelengths and materials of single photon detectors. Our results are in good agrreement with the hot spot model.

Added: Oct 15, 2015
Article
Borovský M., Weigel M., Barash L.Yu. et al. EPJ Web of Conferences. 2016. Vol. 108. P. 02016-p.1-02016-p.6.

The population annealing algorithm is a novel approach to study systems with rough free-energy landscapes, such as spin glasses. It combines the power of simulated annealing, Boltzmann weighted differential reproduction and sequential Monte Carlo process to bring the population of replicas to the equilibrium even in the low-temperature region. Moreover, it provides a very good estimate of the free energy. The fact that population annealing algorithm is performed over a large number of replicas with many spin updates, makes it a good candidate for massive parallelism. We chose the GPU programming using a CUDA implementation to create a highly optimized simulation. It has been previously shown for the frustrated Ising antiferromagnet on the stacked triangular lattice with a ferromagnetic interlayer coupling, that standard Markov Chain Monte Carlo simulations fail to equilibrate at low temperatures due to the effect of kinetic freezing of the ferromagnetically ordered chains. We applied the population annealing to study the case with the isotropic intra- and interlayer antiferromagnetic coupling (J2/|J1| = −1). The reached ground states correspond to non-magnetic degenerate states, where chains are antiferromagnetically ordered, but there is no long-range ordering between them, which is analogical with Wannier phase of the 2D triangular Ising antiferromagnet.

Added: Jan 31, 2018
Article
Kamashev A., Validov A., Garif’yanov N. et al. EPJ Web of Conferences. 2018. Vol. 185. P. 08001.
Added: Oct 31, 2018
Article
Fedorov G., Gaiduchenko I., Golikov A. et al. EPJ Web of Conferences. 2015. Vol. 103. P. 10003.

In this work we report on the response of asymetric graphene based devices to subterahertz and terahertz radiation. Our devices are made in a configuration of a field-effect tranistor with conduction channel between the source and drain electrodes formed with a VD-grown graphene. The radiation is coupled through a spiral antenna to source and top gate electrodes. Room temperature responsivity of our devices is close to the values that are attractive for commercial applications. Further optimization of the device configuration may result in appearance of novel terahertz radiation detectors.

Added: Oct 15, 2015