Orthogonality of Biphoton Polarization States

Orthogonality of two-photon polarization states belonging to a single frequency and spatial mode is demonstrated experimentally, in a generalization of the well-known anti-correlation 'dip' experiment.Comment: Submitted to Phys.Rev.Let

Structure-Based Rational Design of Small α-Helical Peptides with Broad-Spectrum Activity against Multidrug-Resistant Pathogens

A series of small (7–12 mer) amphipathic cationic peptides were designed and synthesized to create short helical peptides with broad-range bactericidal activity and selectivity toward the bacterial cells. The analysis identified a lead 12-mer peptide 8b with broad-spectrum activity against Gram-positive (MIC = 3.1–6.2 μg/mL) and Gram-negative (MIC = 6.2–12.5 μg/mL) bacteria and selectivity toward prokaryotic versus eukaryotic cells (HC50 = 280 μg/mL, \u3e75% cell viability at 150 μg/mL). The rapid membranolytic action of 8b was demonstrated by a calcein dye leakage assay and confirmed using scanning electron microscopy. According to circular dichroism and NMR spectroscopy, the peptides have an irregular spatial structure in water. A lipid bilayer induced an amphipathic helix only in 12-mer peptides, including 8b. Molecular dynamics simulations provided detailed information about the interaction of 8b and its closest analogues with bacterial and mammalian membranes and revealed the roles of particular amino acids in the activity and selectivity of peptides

Qutrit state engineering with biphotons

The novel experimental realization of three-level optical quantum systems is presented. We use the polarization state of biphotons to generate a specific sequence of states that are used in the extended version of BB84 protocol. We experimentally verify the orthogonality of the basis states and demonstrate the ability to easily switch between them. The tomography procedure is employed to reconstruct the density matrices of generated states.Comment: 5 pages, 4 figures. typos correcte

Polarization ququarts

We discuss the concept of polarization states of four-dimensional quantum systems based on frequency non-degenerate biphoton field. Several quantum tomography protocols were developed and implemented for measurement of an arbitrary state of ququart. A simple method that does not rely on interferometric technique is used to generate and measure the sequence of states that can be used for quantum communication purposes.Comment: 13 pages, 10 figure

Football history: a German perspective on current research fields

In the last 25 years, German football has experienced several turning points. First, the collapse of communism in 1989 rendered necessary a complete reorganisation of the sport and football landscape in eastern Germany. Second, in parallel with the award in the year 2000 of the right to host the 2006 FIFA World Cup in the Federal Republic of Germany, a significant upturn took place in academic research on football. The reappraisal of the National Socialist era, in particular, has experienced a noticeable upswing since the year 2000. The present article focuses on several key thematic areas that shape current research and will shape research in the future. They include, first, the question of the character of the Vereine (here: football clubs) under the conditions of a communist dictatorship, and second, an increased interest in the biographical component of the history of the development of football. At the same time, it is clear that by now the question of a memory culture in football is no longer limited to national perspectives such as the reappraisal of the "Miracle of Bern". Rather, the dynamic development of European football renders possible the emergence of European realms of shared memory. At the same time, a boom in public engagement with football history can be observed in Germany and elsewhere. This holds true for both the social commemoration of footballers who were victims of war and tyranny and for popular cultural publications. In recent years, therefore, there has not only been an increase in the “museumisation” but also in the media marketing of football history. Thus, football history itself has become a market that is served by various stakeholders, such as clubs, companies, and the media

Experimental investigation of high-energy photon splitting in atomic fields

The new data analysis of the experiment, where the photon splitting in the atomic fields has been observed for the first time, is presented. This experiment was performed at the tagged photon beam of the ROKK-1M facility at the VEPP-4M collider. In the energy region of 120-450 MeV, the statistics of $1.6\cdot 10^9$ photons incident on the BGO target was collected. About 400 candidates to the photon splitting events were reconstructed. Within the attained experimental accuracy, the experimental results are consistent with the cross section calculated exactly in an atomic field. The predictions obtained in the Born approximation significantly differ from the experimental results.Comment: 11 pages, 6 figures, LaTe