| 1. |
- Bugge, Audun Nystad, et al.
(författare)
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Laser Damage Helps the Eavesdropper in Quantum Cryptography
- 2014
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 112:7, s. 070503-
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Tidskriftsartikel (refereegranskat)abstract
- We propose a class of attacks on quantum key distribution (QKD) systems where an eavesdropper actively engineers new loopholes by using damaging laser illumination to permanently change properties of system components. This can turn a perfect QKD system into a completely insecure system. A proof-of-principle experiment performed on an avalanche photodiode-based detector shows that laser damage can be used to create loopholes. After similar to 1 W illumination, the detectors' dark count rate reduces 2-5 times, permanently improving single-photon counting performance. After similar to 1.5 W, the detectors switch permanently into the linear photodetection mode and become completely insecure for QKD applications.
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| 2. |
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| 3. |
- Joshi, Siddarth Koduru, et al.
(författare)
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Space QUEST mission proposal : experimentally testing decoherence due to gravity
- 2018
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 20
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Tidskriftsartikel (refereegranskat)abstract
- Models of quantum systems on curved space-times lack sufficient experimental verification. Some speculative theories suggest that quantum correlations, such as entanglement, may exhibit different behavior to purely classical correlations in curved space. By measuring this effect or lack thereof, we can test the hypotheses behind several such models. For instance, as predicted by Ralph et al [5] and Ralph and Pienaar [1], a bipartite entangled system could decohere if each particle traversed through a different gravitational field gradient. We propose to study this effect in a ground to space uplink scenario. We extend the above theoretical predictions of Ralph and coworkers and discuss the scientific consequences of detecting/failing to detect the predicted gravitational decoherence. We present a detailed mission design of the European Space Agency's Space QUEST (Space-Quantum Entanglement Space Test) mission, and study the feasibility of the mission scheme.
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| 4. |
- Kim, Yong-Su, et al.
(författare)
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Ultra-low noise single-photon detector based on Si avalanche photodiode
- 2011
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 82:9, s. 093110-
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Tidskriftsartikel (refereegranskat)abstract
- We report operation and characterization of a lab-assembled single-photon detector based on commercial silicon avalanche photodiodes (PerkinElmer C30902SH, C30921SH). Dark count rate as low as 5Hz was achieved by cooling the photodiodes down to -80 degrees C. While afterpulsing increased as the photodiode temperature was decreased, total afterpulse probability did not become significant due to detector's relatively long deadtime in a passively-quenched scheme. We measured photon detection efficiency >50% at 806 nm.
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| 5. |
- Knop, Katrin, et al.
(författare)
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Amphiphilic star-shaped block copolymers as unimolecular drug delivery systems : investigations using a novel fungicide
- 2013
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 9:3, s. 715-726
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Tidskriftsartikel (refereegranskat)abstract
- Amphiphilic star-shaped poly(epsilon-caprolactone)-block-poly(oligo(ethylene glycol) methacrylate) [PCLa-b-POEGMA(b)](4) block copolymers with four arms and varying degrees of polymerization for the core (PCL) and the shell (POEGMA) were used to investigate the solution behavior in dilute aqueous solution using a variety of techniques, including fluorescence and UV/Vis spectroscopy, dynamic light scattering, analytical ultracentrifugation, and isothermal titration calorimetry. Particular emphasis has been applied to prove that the systems form unimolecular micelles for different hydrophilic/lipophilic balances of the employed materials. In vitro cytotoxicity and hemocompatibility have further been investigated to probe the suitability of these structures for in vivo applications. A novel fungicide was included into the hydrophobic core in aqueous media to test their potential as drug delivery systems. After loading, the materials have been shown to release the drug and to provoke therewith an inhibition of the growth of different fungal strains.
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| 6. |
- Sauge, Sebastien, et al.
(författare)
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Controlling an actively-quenched single photon detector with bright light
- 2011
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Ingår i: Optics Express. - 1094-4087. ; 19:23, s. 23590-23600
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Tidskriftsartikel (refereegranskat)abstract
- We control using bright light an actively-quenched avalanche single-photon detector. Actively-quenched detectors are commonly used for quantum key distribution (QKD) in the visible and near-infrared range. This study shows that these detectors are controllable by the same attack used to hack passively-quenched and gated detectors. This demonstrates the generality of our attack and its possible applicability to eavsdropping the full secret key of all QKD systems using avalanche photodiodes (APDs). Moreover, the commercial detector model we tested (Perkin-Elmer SPCM-AQR) exhibits two new blinding mechanisms in addition to the previously observed thermal blinding of the APD, namely: malfunctioning of the bias voltage control circuit, and overload of the DC/DC converter biasing the APD. These two new technical loopholes found just in one detector model suggest that this problem must be solved in general, by incorporating generally imperfect detectors into the security proof for QKD.
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