Spin-Orbit Coupling Fluctuations as a Mechanism of Spin Decoherence

We discuss a general framework to address spin decoherence resulting from fluctuations in a spin Hamiltonian. We performed a systematic study on spin decoherence in the compound K$_6$[V$_{15}$As$_6$O$_{42}$(D$_2$O)] $\cdot$ 8D$_2$O, using high-field Electron Spin Resonance (ESR). By analyzing the anisotropy of resonance linewidths as a function of orientation, temperature and field, we find that the spin-orbit term is a major decoherence source. The demonstrated mechanism can alter the lifetime of any spin qubit and we discuss how to mitigate it by sample design and field orientation.Comment: submitte

A German employee network and union renewal: the Siemenskonflikt

The paper shows how redundancies were resisted by Hi-Tech workers in a large German company. It details an employee network’s emergence to provide support to individuals and to pursue legal cases against the company, and analyzes the network’s norms and operation. The network operated in complementary ways to the union and works council, to achieve a favourable outcome. The case is used to test theoretical propositions derived from literature on Hi-Tech workers, union renewal and mobilization theory and it is suggested that mobilization theory requires further extension in several directions

Meccanismi di Evoluzione del Cariotipo nei Monocelididi (Turbellaria Proseriata)

Mechanisms of karyotype evolution in the Monocelididae (Turbellaria Proseriata). Within the Proseriata (Turbellaria: Seriata), the family Monocelididae displays several interesting patterns of chromosomal evolution. A basic set of n = 3 -made up or one large metacentric, one medium-sized metacentric and one small clearly heterobrachial chromosome -has been detected. It is widely distributed in species pertaining to both the subfamilies in which the Monocelididae are subdivided. From this basic set, other complements -either with n = 3 or n > 3 -would be originated.Several karyological mechanisms or common occurrence within the family (translocations, small chromosome rearrangements involving the centromere, genome growth) have been detected. As to the chromosome complements with n > 3 -occurring within the subfamily Monocelidinae -they can be interpreted as the result of a fission of one or both the metacentric chromosomes of the basic set. Karyometrical data are in good agreement with this suggestion. Centric fusion or polyploidy, well known for fresh- water Triclads, have been never found in the family

Evolution and Conservation of Predicted Inclusion Membrane Proteins in Chlamydiae

Chlamydia spp. are obligate intracellular pathogens that replicate within a vacuole termed the inclusion. Chlamydiae extensively modify the inclusion membrane via the insertion of chlamydial inclusion membrane proteins (Incs) which decorate the cytosolic face of the inclusion. We have assessed the overall relatedness and phylogeny of Incs in order to identify potential evolutionary trends. Despite a high degree of conservation among Incs within C. trachomatis serovars, phylogenetic analysis showed that some Incs cluster according to clinical groupings suggesting that certain Incs may contribute to tissue tropism. Bioinformatic predictions identified Incs in five chlamydial species: 55 in C. trachomatis, 68 in C. felis, 92 in C. pneumoniae, 79 in C. caviae, and 54 in C. muridarum. Inc homologues were compared between chlamydial species and 23 core Incs were identified as shared among all species. Genomic expansion of Incs was identified in C. pneumoniae, C. caviae, and C. felis but not C. trachomatis or C. muridarum

The Order of Phase Transitions in Barrier Crossing

A spatially extended classical system with metastable states subject to weak spatiotemporal noise can exhibit a transition in its activation behavior when one or more external parameters are varied. Depending on the potential, the transition can be first or second-order, but there exists no systematic theory of the relation between the order of the transition and the shape of the potential barrier. In this paper, we address that question in detail for a general class of systems whose order parameter is describable by a classical field that can vary both in space and time, and whose zero-noise dynamics are governed by a smooth polynomial potential. We show that a quartic potential barrier can only have second-order transitions, confirming an earlier conjecture [1]. We then derive, through a combination of analytical and numerical arguments, both necessary conditions and sufficient conditions to have a first-order vs. a second-order transition in noise-induced activation behavior, for a large class of systems with smooth polynomial potentials of arbitrary order. We find in particular that the order of the transition is especially sensitive to the potential behavior near the top of the barrier.Comment: 8 pages, 6 figures with extended introduction and discussion; version accepted for publication by Phys. Rev.

Experimental research of a shared memory subsystem with limited queue length for specialized reconfigurable multiprocessor systems

Recently, reconfigurable systems based on field programmable logic devices (FPLDs) have been widely used in high-performance computing. The paper discusses issues related to the experimental research of a shared memory subsystem with a limited queue length of specialized reconfigurable multiprocessor systems using the developed mathematical modelling method. The paper presents the results of the method proposed by the authors for modelling multiprocessor systems based on open queuing networks with limited queue lengths. Based on these conditions, as well as the architectural features of the investigated processor-memory subsystem, expressions are calculated to estimate the exchange time and the resulting delays at each exchange stage. During the research, the main attention was paid to the dependence of the increase in the number of processor nodes in the processor-memory subsystem. As a result, the data obtained showed that the processor growth significantly affects the exchange time, creating a significant load on the common bus, as well as increasing delays at the stages when request transfer operation from the processor to the memory is performed. At the same time, the inadequate behaviour of experimental results and inaccuracy of their values when using the basic modelling method are explicitly tracked, which is reflected in the obtained graphs. Computational experiments were carried out to calculate the probabilistic-temporal characteristics of the "processor-memory" subsystem using the developed mathematical modelling methods. Based on the experimental results, it was determined that the delays occurring in subsystem's nodes and the time of exchange between the processor and memory modules depend on the query parameters and the processor-memory subsystem’s architectural characteristics

Biased Brownian motion in extreme corrugated tubes

Biased Brownian motion of point-size particles in a three-dimensional tube with smoothly varying cross-section is investigated. In the fashion of our recent work [Martens et al., PRE 83,051135] we employ an asymptotic analysis to the stationary probability density in a geometric parameter of the tube geometry. We demonstrate that the leading order term is equivalent to the Fick-Jacobs approximation. Expression for the higher order corrections to the probability density are derived. Using this expansion orders we obtain that in the diffusion dominated regime the average particle current equals the zeroth-order Fick-Jacobs result corrected by a factor including the corrugation of the tube geometry. In particular we demonstrate that this estimate is more accurate for extreme corrugated geometries compared to the common applied method using the spatially dependent diffusion coefficient D(x,f). The analytic findings are corroborated with the finite element calculation of a sinusoidal-shaped tube.Comment: 10 pages, 4 figure

Parameter estimation of S-distributions with alternating regression

We propose a novel 3-way alternating regression (3-AR) method as an effective strategy for the estimation of parameter values in S-distributions from frequency data. The 3-AR algorithm is very fast and performs well for error-free distributions and artificial noisy data obtained as random samples generated from S-distributions, as well as for traditional statistical distributions and for actual observation data. In rare cases where the algorithm does not immediately converge, its enormous speed renders it feasible to select several initial guesses and search settings as an effective countermeasure.Peer Reviewe