Continuous variable quantum cryptography

We propose a quantum cryptographic scheme in which small phase and amplitude modulations of CW light beams carry the key information. The presence of EPR type correlations provides the quantum protection.Comment: 8 pages, 3 figure

Proposal of an experimental scheme for realising a translucent eavesdropping on a quantum cryptographic channel

Purpose of this paper is to suggest a scheme, which can be realised with today's technology and could be used for entangling a probe to a photon qubit based on polarisation. Using this probe a translucent or a coherent eavesdropping can be performed.Comment: in pres

Information theoretic security by the laws of classical physics

It has been shown recently that the use of two pairs of resistors with enhanced Johnson-noise and a Kirchhoff-loop-i.e., a Kirchhoff-Law-Johnson-Noise (KLJN) protocol-for secure key distribution leads to information theoretic security levels superior to those of a quantum key distribution, including a natural immunity against a man-in-the-middle attack. This issue is becoming particularly timely because of the recent full cracks of practical quantum communicators, as shown in numerous peer-reviewed publications. This presentation first briefly surveys the KLJN system and then discusses related, essential questions such as: what are perfect and imperfect security characteristics of key distribution, and how can these two types of securities be unconditional (or information theoretical)? Finally the presentation contains a live demonstration.Comment: Featured in MIT Technology Review http://www.technologyreview.com/view/428202/quantum-cryptography-outperformed-by-classical/ ; Plenary talk at the 5th IEEE Workshop on Soft Computing Applications, August 22-24, 2012, (SOFA 2012). Typos correcte

Morphology diagram of a diblock copolymer - aluminosilicate nanoparticle system

We explore the morphology space of nanocomposites prepared from poly(isoprene-block-ethylene oxide) (PI-b-PEO) diblock copolymers as structure directing agents for aluminosilicate nanoparticles prepared from (3-glycidyloxypropyl)trimethoxysilane (GLYMO) and aluminum(III) sec-butoxide. The results of structural investigations of over 60 polymer-inorganic nanocomposites are reported. They are obtained from 12 different block copolymers of varying molecular weight (10-100 kg/mol) and PEO weight fraction (fw 0.1-0.8) through addition of different amounts of inorganic components. Eight different morphologies as well as composites with biphasic character are observed. Individual block copolymers show up to five different well-defined morphologies upon addition of the inorganic sols. Differential scanning calorimetry (DSC) studies on the composites show that the addition of the inorganic components suppresses PEO crystallization when the inorganic to PEO weight fraction ratio of the composites is greater than 1.3-1.5. The eight phases are mapped out using two- and three-component morphology diagrams

Metal nanoparticle - block copolymer composite assembly and disassembly

Ligand-stabilized platinum nanoparticles (Pt NPs) were self-assembled with poly(isoprene-block-dimethylaminoethyl methacrylate) (PI-b-PDMAEMA) block copolymers to generate organic-inorganic hybrid materials. High loadings of NPs in hybrids were achieved through usage of N,N-di-(2-(allyloxy)ethyl)-N-3-mercaptopropyl-N-methylammonium chloride as the ligand, which provided high solubility of NPs in various solvents as well as high affinity to PDMAEMA. From NP synthesis, existence of subnanometer Pt NPs was confirmed by high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) images. Estimations of the Pt NP ligand headgroup density based on HAADF-STEM images and thermogravimetric analysis (TGA) data yielded results comparable to what has been found for alkanethiol self-assembled monolayers (SAMs) on flat Pt {111} surfaces. Changing the volume fraction of Pt NPs in block copolymer-NP composites yielded hybrids with spherical micellar, wormlike micellar, lamellar, and inverse hexagonal morphologies. Disassembly of hybrids with spherical, wormlike micellar, and lamellar morphologies generated isolated metal NP-based nanospheres, cylinders, and sheets, respectively. Results suggest the existence of powerful design criteria for the formation of metal-based nanostructures from designer blocked macromolecules

Human epithelial model systems for the study of Candida infections in vitro. Pt.I: Adhesion to epithelial models

Adhesion to host tissue represents one of the first steps during the early phase of fungal infections. In order to mediate pathogenesis in the infected host, this process is crucial for colonization and subsequent penetration of the respective tissue. In vivo analyses of the adhesion process in whole organisms are limited because of difficulties in providing reproducible and comparable conditions in the host environment. Therefore, in vitro assays provide the opportunity to study such processes under more defined conditions thus allowing for the analysis of events that are involved in more detail. Here we describe an in vitro adhesion assay making use of human epithelial cell lines to study fungal associations with host epithelia. This assay not only is suited to determine the rate of adhesion in a time-dependent manner but also facilitates global transcriptional profiling in order to determine the fungal response during adhesion at the molecular level