Direct Interactions in Relativistic Statistical Mechanics

Directly interacting particles are considered in the multitime formalism of predictive relativistic mechanics. When the equations of motion leave a phase-space volume invariant, it turns out that the phase average of any first integral, covariantly defined as a flux across a $7n$-dimensional surface, is conserved. The Hamiltonian case is discussed, a class of simple models is exhibited, and a tentative definition of equilibrium is proposed.Comment: Plain Tex file, 26 page

Memory and superposition in a spin glass

Non-equilibrium dynamics in a Ag(Mn) spin glass are investigated by measurements of the temperature dependence of the remanent magnetisation. Using specific cooling protocols before recording the thermo- or isothermal remanent magnetisations on re-heating, it is found that the measured curves effectively disclose non-equilibrium spin glass characteristics such as ageing and memory phenomena as well as an extended validity of the superposition principle for the relaxation. The usefulness of this "simple" dc-method is discussed, as well as its applicability to other disordered magnetic systems.Comment: REVTeX style; 8 pages, 4 figure

A comparison of optical and radar measurements of mesospheric winds and tides

Optical measurements of mesospheric winds by Fabry‐Perot spectrometers, FPSs, at Mawson, 67.6°S 62.9°E, and Davis, 68.6°S 78.0°E, Antarctica are compared with similar measurements obtained using a spaced‐antenna MF radar at Davis. The FPSs observed the OH emission. Different analysis procedures, used to determine the mean wind, and amplitude and phase of the semidiurnal tide, have been compared. At these latitudes the diurnal tide is weak and the semi‐diurnal tide, although highly variable in amplitude, is usually the dominant periodicity. When comparing the amplitude and phase of the semidiurnal tide good agreement is obtained between measurements by the two instruments

Structural precursor to the metal-insulator transition in V_2O_3

The temperature dependence of the local structure of V_2O_3 in the vicinity of the metal to insulator transition (MIT) has been investigated using hard X-ray absorption spectroscopy. It is shown that the vanadium pair distance along the hexagonal c-axis changes abruptly at the MIT as expected. However, a continuous increase of the tilt of these pairs sets in already at higher temperatures and reaches its maximum value at the onset of the electronic and magnetic transition. These findings confirm recent theoretical results which claim that electron-lattice coupling is important for the MIT in V_2O_3. Our results suggest that interactions in the basal plane play a decisive role for the MIT and orbital degrees of freedom drive the MIT via changes in hybridization.Comment: 6 pages, 5 figures, 2 table

Antigenic and genetic evolution of contemporary swine H1 influenza viruses in the United States

Several lineages of influenza A viruses (IAV) currently circulate in North American pigs. Genetic diversity is further increased by transmission of IAV between swine and humans and subsequent evolution. Here, we characterized the genetic and antigenic evolution of contemporary swine H1N1 and H1N2 viruses representing clusters H1-α (1A.1), H1-β (1A.2), H1pdm (1A.3.3.2), H1-γ (1A.3.3.3), H1-δ1 (1B.2.2), and H1-δ2 (1B.2.1) currently circulating in pigs in the United States. The δ1-viruses diversified into two new genetic clades, H1-δ1a (1B.2.2.1) and H1-δ1b (1B.2.2.2), which were also antigenically distinct from the earlier H1-δ1-viruses. Further characterization revealed that a few key amino acid changes were associated with antigenic divergence in these groups. The continued genetic and antigenic evolution of contemporary H1 viruses might lead to loss of vaccine cross-protection that could lead to significant economic impact to the swine industry, and represents a challenge to public health initiatives that attempt to minimize swine-to-human IAV transmission

Many-body quantum dynamics of polarisation squeezing in optical fibre

We report new experiments that test quantum dynamical predictions of polarization squeezing for ultrashort photonic pulses in a birefringent fibre, including all relevant dissipative effects. This exponentially complex many-body problem is solved by means of a stochastic phase-space method. The squeezing is calculated and compared to experimental data, resulting in excellent quantitative agreement. From the simulations, we identify the physical limits to quantum noise reduction in optical fibres. The research represents a significant experimental test of first-principles time-domain quantum dynamics in a one-dimensional interacting Bose gas coupled to dissipative reservoirs.Comment: 4 pages, 4 figure

Symmetrical Temperature-Chaos Effect with Positive and Negative Temperature Shifts in a Spin Glass

The aging in a Heisenberg-like spin glass Ag(11 at% Mn) is investigated by measurements of the zero field cooled magnetic relaxation at a constant temperature after small temperature shifts $|\Delta T/T_g| < 0.012$. A crossover from fully accumulative to non-accumulative aging is observed, and by converting time scales to length scales using the logarithmic growth law of the droplet model, we find a quantitative evidence that positive and negative temperature shifts cause an equivalent restart of aging (rejuvenation) in terms of dynamical length scales. This result supports the existence of a unique overlap length between a pair of equilibrium states in the spin glass system.Comment: 4 page

Discrete transverse superconducting modes in nano-cylinders

Spatial variation in the superconducting order parameter becomes significant when the system is confined at dimensions well below the typical superconducting coherence length. Motivated by recent experimental success in growing single-crystal metallic nanorods, we study quantum confinement effects on superconductivity in a cylindrical nanowire in the clean limit. For large diameters, where the transverse level spacing is smaller than superconducting order parameter, the usual approximations of Ginzburg-Landau theory are recovered. However, under external magnetic field the order parameter develops a spatial variation much stronger than that predicted by Ginzburg-Landau theory, and gapless superconductivity is obtained above a certain field strength. At small diameters, the discrete nature of the transverse modes produces significant spatial variations in the order parameter with increased average magnitude and multiple shoulders in the magnetic response.Comment: 10 pages, 8 figure

Relative Astrometry of Compact Flaring Structures in Sgr A* with Polarimetric VLBI

We demonstrate that polarimetric interferometry can be used to extract precise spatial information about compact polarized flares of Sgr A*. We show that, for a faint dynamical component, a single interferometric baseline suffices to determine both its polarization and projected displacement from the quiescent intensity centroid. A second baseline enables two-dimensional reconstruction of the displacement, and additional baselines can self-calibrate using the flare, enhancing synthesis imaging of the quiescent emission. We apply this technique to simulated 1.3-mm wavelength observations of a "hot spot" embedded in a radiatively inefficient accretion disk around Sgr A*. Our results indicate that, even with current sensitivities, polarimetric interferometry with the Event Horizon Telescope can achieve ~5 microarcsecond relative astrometry of compact flaring structures near Sgr A* on timescales of minutes.Comment: 9 Pages, 4 Figures, accepted for publication in Ap

The type of adjuvant in whole inactivated influenza a virus vaccines impacts vaccine-associated enhanced respiratory disease

Influenza A virus (IAV) causes a disease burden in the swine industry in the US and is a challenge to prevent due to substantial genetic and antigenic diversity of IAV that circulate in pig populations. Whole inactivated virus (WIV) vaccines formulated with oil-in-water (OW) adjuvant are commonly used in swine. However, WIV-OW are associated with vaccine-associated enhanced respiratory disease (VAERD) when the hemagglutinin and neuraminidase of the vaccine strain are mismatched with the challenge virus. Here, we assessed if different types of adjuvant in WIV vaccine formulations impacted VAERD outcome. WIV vaccines with a swine δ1-H1N2 were formulated with different commercial adjuvants: OW1, OW2, nano-emulsion squalene-based (NE) and gel polymer (GP). Pigs were vaccinated twice by the intramuscular route, 3 weeks apart, then challenged with an H1N1pdm09 three weeks post-boost and necropsied at 5 days post infection. All WIV vaccines elicited antibodies detected using the hemagglutination inhibition (HI) assay against the homologous vaccine virus, but not against the heterologous challenge virus; in contrast, all vaccinated groups had cross-reactive IgG antibody and IFN-γ responses against H1N1pdm09, with a higher magnitude observed in OW groups. Both OW groups demonstrated robust homologous HI titers and cross-reactivity against heterologous H1 viruses in the same genetic lineage. However, both OW groups had severe immunopathology consistent with VAERD after challenge when compared to NE, GP, and non-vaccinated challenge controls. None of the WIV formulations protected pigs from heterologous virus replication in the lungs or nasal cavity. Thus, although the type of adjuvant in the WIV formulation played a significant role in the magnitude of immune response to homologous and antigenically similar H1, none tested here increased the breadth of protection against the antigenically-distinct challenge virus, and some impacted immunopathology after challenge