Projection of two biphoton qutrits onto a maximally entangled state

Bell state measurements, in which two quantum bits are projected onto a maximally entangled state, are an essential component of quantum information science. We propose and experimentally demonstrate the projection of two quantum systems with three states (qutrits) onto a generalized maximally entangled state. Each qutrit is represented by the polarization of a pair of indistinguishable photons - a biphoton. The projection is a joint measurement on both biphotons using standard linear optics elements. This demonstration enables the realization of quantum information protocols with qutrits, such as teleportation and entanglement swapping.Comment: 4 pages, 3 figures, published versio

Simulations of Photon Detection in SiPM Number-Resolving Detectors

Number-resolving single photon detectors are essential for the implementation of numerous innovative quantum information schemes. While several number-discriminating techniques have been previously presented, the Silicon Photo-Multiplier (SiPM) detector is a promising candidate due its rather simple integration in optical setups. On the other hand, the photon statistics obtained with the SiPM detector suffer from inaccuracies due to inherent distortions which depend on the geometrical properties of the SiPM. We have simulated the detection process in a SiPM detector and studied these distortions. We use results from the simulation in order to interpret experimental data and study the limits in which available models prevail

High oxygen load causes damage to lens epithelium which is reduced by antioxidants

Цель: Изучить механизмы воздействия кислорода на хрусталик и возможный защитный эффект цинк-дезферриоксамина (Zn-DFO). Методы: Хрусталики, полученные из глаза быка, хранили на культуре, полученной из тканей данного органа. Хрусталик подвергали воздействию значительной кислородной нагрузки либо в присутствии, либо без комплекса Zn-DFO (20 ЦІМ). Оптические свойства хрусталика оценивали через семь дней от начала выращивания культуры. По завершении периода, хрусталик извлекали и проводили его морфологический и ферментный анализ. Результаты: В хрусталиках, подвергнутых воздействию больших концентраций кислорода, наблюдали уменьшение оптических свойств и изменение активности энзимов эпителия изучаемого органа. При анализе активности энзимов изучали цикл Кребса, течение гликолиза и состояние АТФ пограничных мембран. Добавление Zn-DFO к культуре клеток до начала воздействия кислородом, элиминировало большую часть кислородозависимых повреждений. Выводы: Полученные результаты могут указывать на возможную роль Zn-DFO как защитного агента при возникновении кислород-индуцированных катаракт.Purpose: To investigate the mechanisms involved in the effects of oxygen on the eye lens and the possible protective effects of Zinc-desferrioxamine (Zn-DFO) using lens organ culture system. Methods: Bovine lenses, kept in an organ culture system, were exposed to high oxygen load in the presence or absence of Zn-DFO complex (20 MM). Lens optical quality was assessed throughout the 7 days of the culture period. At the end of the culture, lenses were taken for morphological and enzyme analysis. Results: Decreased lenticular optical quality and changes in lens epithelium enzymatic activities were observed in lenses exposed to high oxygen concentration. The enzymes analyzed were from Krebs cycle, glycolysis pathway and membrane bound ATPase. Addition of Zn-DFO to the culture before the exposure to oxygen eliminated most of the oxygen-induced damage. 126) Conclusions: The present results may indicate a possible role of Zn-DFO as a protective agent against oxygen-induced cataract formation

The biaxial nonlinear crystal BiB3O6 as a polarization entangled photon source using non-collinear type-II parametric down-conversion

We describe the full characterization of the biaxial nonlinear crystal BiB3O6 (BiBO) as a polarization entangled photon source using non-collinear type-II parametric down-conversion. We consider the relevant parameters for crystal design, such as cutting angles, polarization of the photons, effective nonlinearity, spatial and temporal walk-offs, crystal thickness and the effect of the pump laser bandwidth. Experimental results showing entanglement generation with high rates and a comparison to the well investigated beta-BaB2O4 (BBO) crystal are presented as well. Changing the down-conversion crystal of a polarization entangled photon source from BBO to BiBO enhances the generation rate as if the pump power was increased by more than three times. Such an improvement is currently required for the generation of multiphoton entangled states.Comment: 15 pages, 13 figures, published versio

Mutations at the Subunit Interface of Yeast Proliferating Cell Nuclear Antigen Reveal a Versatile Regulatory Domain

Acknowledgments We thank Szilvia Minorits for technical assistance. I.U. conceived and designed the project and wrote the manuscript. All authors participated in designing and performing the experiments, and analyzing the results. The authors declare no competing financial interests. This work was also supported by a grant from the National Research, Development and Innovation Office GINOP-2.3.2-15-2016-00001. Funding: This work was supported by Hungarian Science Foundation Grant OTKA 109521 and National Research Development and Innovation Office GINOP-2.3.2-15-2016-00001. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Subtle Alterations in PCNA-Partner Interactions Severely Impair DNA Replication and Repair

Dynamic switching of PCNA-partner interactions is essential for normal DNA replication and repair in yeast