arXiv subjects

Momtchil Peev

Publications and source records attributed to Momtchil Peev.

25 records · Page 2Linked to original sources

arXiv2011

Quantum Interference between a Single-Photon Fock State and a Coherent State

We derive analytical expressions for the single mode quantum field state at the individual output ports of a beam splitter when a single-photon Fock state and a coherent state are incident on the input ports. The output states turn out to be a statistical mixture between a displaced Fock state and a coherent state. Consequently we are able to find an analytical expression for the corresponding Wigner function. Because of the generality of our calculations the obtained results are valid for all passive and lossless optical four port devices. We show further how the results can be adapted to the case of the Mach-Zehnder interferometer. In addition we consider the case for which the single-photon Fock state is replaced with a general input state: a coherent input state displaces each general quantum state at the output port of a beam splitter with the displacement parameter being the amplitude of the coherent state.

quant-ph↗

arXiv2009

The Security of Practical Quantum Key Distribution

Quantum key distribution (QKD) is the first quantum information task to reach the level of mature technology, already fit for commercialization. It aims at the creation of a secret key between authorized partners connected by a quantum channel and a classical authenticated channel. The security of the key can in principle be guaranteed without putting any restriction on the eavesdropper's power. The first two sections provide a concise up-to-date review of QKD, biased toward the practical side. The rest of the paper presents the essential theoretical tools that have been developed to assess the security of the main experimental platforms (discrete variables, continuous variables and distributed-phase-reference protocols).

quant-ph↗

arXiv2009

Updating Quantum Cryptography Report ver. 1

Quantum cryptographic technology (QCT) is expected to be a fundamental technology for realizing long-term information security even against as-yet-unknown future technologies. More advanced security could be achieved using QCT together with contemporary cryptographic technologies. To develop and spread the use of QCT, it is necessary to standardize devices, protocols, and security requirements and thus enable interoperability in a multi-vendor, multi-network, and multi-service environment. This report is a technical summary of QCT and related topics from the viewpoints of 1) consensual establishment of specifications and requirements of QCT for standardization and commercialization and 2) the promotion of research and design to realize New-Generation Quantum Cryptography.

quant-ph↗

arXiv2009

Security of Trusted Repeater Quantum Key Distribution Networks

A Quantum Key Distribution (QKD) network is an infrastructure capable of performing long-distance and high-rate secret key agreement with information-theoretic security. In this paper we study security properties of QKD networks based on trusted repeater nodes. Such networks can already be deployed, based on current technology. We present an example of a trusted repeater QKD network, developed within the SECOQC project. The main focus is put on the study of secure key agreement over a trusted repeater QKD network, when some nodes are corrupted. We propose an original method, able to ensure the authenticity and privacy of the generated secret keys.

quant-ph↗

arXiv2008

Space-QUEST: Experiments with quantum entanglement in space

The European Space Agency (ESA) has supported a range of studies in the field of quantum physics and quantum information science in space for several years, and consequently we have submitted the mission proposal Space-QUEST (Quantum Entanglement for Space Experiments) to the European Life and Physical Sciences in Space Program. We propose to perform space-to-ground quantum communication tests from the International Space Station (ISS). We present the proposed experiments in space as well as the design of a space based quantum communication payload.

quant-ph↗

arXiv2008

Outline of the SECOQC Quantum-Key-Distribution Network in Vienna

A Quantum Key Distribution (QKD) network is currently implemented in Vienna by integrating seven QKD-Link devices that connect five subsidiaries of SIEMENS Austria. We give an architectural overview of the network and present the enabling QKD-technologies, as well as the novel QKD network protocols.

quant-ph↗

arXiv2007

Parameter Estimation in Biokinetic Degradation Models in Wastewater Treatment - A Novel Approach Relevant for Micro-pollutant Removal

In this paper we address a general parameter estimation methodology for an extended biokinetic degradation model [1] for poorly degradable micropollutants. In particular we concentrate on parameter estimation of the micropollutant degradation sub-model by specialised microorganisms. In this case we focus on the case when only substrate degradation data are available and prove the structural identifiability of the model. Further we consider the problem of practical identifiability and propose experimental and related numerical methods for unambiguous parameter estimation based on multiple substrate degradation curves with different initial concentrations. Finally by means of simulated pseudo-experiments we have found convincing indications that the proposed algorithm is stable and yields appropriate parameter estimates even in unfavourable regimes.

q-bio.QM↗