Quaternions, octonions and Bell-type inequalities

Multipartite Bell-type inequalities are derived for general systems. They involve up to eight observables with arbitrary spectra on each site. These inequalities are closely related to the algebras of quaternions and octonions.Comment: 4 pages, no figure

Universal measurement of quantum correlations of radiation

A measurement technique is proposed which, in principle, allows one to observe the general space-time correlation properties of a quantized radiation field. Our method, called balanced homodyne correlation measurement, unifies the advantages of balanced homodyne detection with those of homodyne correlation measurements.Comment: 4 pages, 4 figures, small misprints were corrected, accepted to Phys. Rev. Let

Cavity-assisted spontaneous emission as a single-photon source: Pulse shape and efficiency of one-photon Fock state preparation

Within the framework of exact quantum electrodynamics in dispersing and absorbing media, we have studied the quantum state of the radiation emitted from an initially in the upper state prepared two-level atom in a high-$Q$ cavity, including the regime where the emitted photon belongs to a wave packet that simultaneously covers the areas inside and outside the cavity. For both continuing atom--field interaction and short-term atom--field interaction, we have determined the spatio-temporal shape of the excited outgoing wave packet and calculated the efficiency of the wave packet to carry a one-photon Fock state. Furthermore, we have made contact with quantum noise theories where the intracavity field and the field outside the cavity are regarded as approximately representing independent degrees of freedom such that two separate Hilbert spaces can be introduced.Comment: 16 pages, 7 eps figures; improved version as submitted to Phys. Rev.

How Sensitive are Di-Leptons from Rho Mesons to the High Baryon Density Region?

We show that the measurement of di-leptons might provide only a restricted view into the most dense stages of heavy ion reactions. Thus, possible studies of meson and baryon properties at high baryon densities, as e.g. done at GSI-HADES and envisioned for FAIR-CBM, might observe weaker effects than currently expected in certain approaches. We argue that the strong absorption of resonances in the high baryon density region of the heavy ion collision masks information from the early hot and dense phase due to a strong increase of the total decay width because of collisional broadening. To obtain additional information, we also compare the currently used approaches to extract di-leptons from transport simulations - i.e. shining, only vector mesons from final baryon resonance decays and instant emission of di-leptons and find a strong sensitivity on the method employed in particular at FAIR and SPS energies. It is shown explicitly that a restriction to rho meson (and therefore di-lepton) production only in final state baryon resonance decays provide a strong bias towards rather low baryon densities. The results presented are obtained from UrQMD v2.3 calculations using the standard set-up.Comment: 8 pages, 6 figures, expanded versio

Cabbage Diseases

Cabbage diseases are the chief limiting factor In profitable commerclal cabbage growing In Iowa. The most destructive of these are black·leg, black-rot, and cabbage yellows. Any one may destroy the greater portion of a crop. The first two are known to be distributed with the seed and cause Infection of the young plants In the seed bed. Some of these naturally find their way Into the field and under favorable conditions become destructive. Cabbage yellows may also be distributed with the seed but Is probably more commonly spread with the plants by the soil adhering to the roots

Orbital order-disorder transition in La(1-x)Nd(x)MnO(3) (x = 0.0-1.0) and La(1-x-y)Nd(yx)Sr(y)MnO(3) (x = 0.1; y = 0.05,0.1)

The nature of orbital order-disorder transition has been studied in the La(1-x)Nd(x)MnO(3) (x = 0.0-1.0) series which covers the entire range between two end points - LaMnO(3) and NdMnO(3) - as well as in La(0.85)Nd(0.1)Sr(0.05)MnO(3) and La(0.8)Nd(0.1)Sr(0.1)MnO(3). It has been observed that the first-order nature of the transition gives way to higher order with the increase in "x" in the case of pure manganites. The latent heat (L) associated with the transition, first, drops with a steeper slope within x = 0.0-0.3 and, then, gradually over a range 0.3<x<0.9. This drop could, possibly, be due to evolution of finer orbital domain structure with "x". In the case of Sr-doped samples, the transition appears to be of higher-order nature even for a doping level 5 at%. In both cases, of course, the transition temperature T(JT) rises systematically with the drop in average A-site radius or rise in average Mn-O-Mn bond bending angle while no apparent correlation could be observed with doping induced disorder sigma^2. The cooperative nature of the orbital order, therefore, appears to be robust.Comment: 15 pages including 4 figures; pdf onl

Neutrino fluence after r-process freeze-out and abundances of Te isotopes in presolar diamonds

Using the data of Richter et al. (1998) on Te isotopes in diamond grains from a meteorite, we derive bounds on the neutrino fluence and the decay timescale of the neutrino flux relevant for the supernova r-process. Our new bound on the neutrino fluence F after freeze-out of the r-process peak at mass number A = 130 is more stringent than the previous bound F < 0.045 (in units of 10**37 erg/cm**2) of Qian et al. (1997) and Haxton et al. (1997) if the neutrino flux decays on a timescale tau > 0.65 s. In particular, it requires that a fluence of F = 0.031 be provided by a neutrino flux with tau < 0.84 s. Such a fluence may be responsible for the production of the solar r-process abundances at A = 124-126 (Qian et al. 1997; Haxton et al. 1997). Our results are based on the assumption that only the stable nuclei implanted into the diamonds are retained while the radioactive ones are lost from the diamonds upon decay after implantation (Ott 1996). We consider that the nanodiamonds are condensed in an environment with C/O > 1 in the expanding supernova debris or from the exterior H envelope. The implantation of nuclei would have occurred 10**4-10**6 s after r-process freeze-out. This time interval may be marginally sufficient to permit adequate cooling upon expansion for the formation of diamond grains. The mechanisms of preferential retention/loss of the implanted nuclei are not well understood.Comment: AASTeX, 11 pages, 3 Postscript figure

The Stokes-Einstein Relation in Supercooled Aqueous Solutions of Glycerol

The diffusion of glycerol molecules decreases with decreasing temperature as its viscosity increases in a manner simply described by the Stokes-Einstein(SE) relation. Approaching the glass transition, this relation breaks down as it does with a number of other pure liquid glass formers. We have measured the diffusion coefficient for binary mixtures of glycerol and water and find that the Stokes-Einstein relation is restored with increasing water concentration. Our comparison with theory suggests that addition of water postpones the formation of frustration domainsComment: 4 Pages and 3 Figure

Changes in domestic heating fuel use in Greece : Effects on atmospheric chemistry and radiation

For the past 8 years, Greece has been experiencing a major financial crisis which, among other side effects, has led to a shift in the fuel used for residential heating from fossil fuel towards biofuels, primarily wood. This study simulates the fate of the residential wood burning aerosol plume (RWB smog) and the implications on atmospheric chemistry and radiation, with the support of detailed aerosol characterization from measurements during the winter of 2013–2014 in Athens. The applied model system (TNO-MACC_II emissions and COSMO-ART model) and configuration used reproduces the measured frequent nighttime aerosol spikes (hourly PM₁₀  >  75 µg m⁻³) and their chemical profile (carbonaceous components and ratios). Updated temporal and chemical RWB emission profiles, derived from measurements, were used, while the level of the model performance was tested for different heating demand (HD) conditions, resulting in better agreement with measurements for T$_{min}$ < 9 °C. Half of the aerosol mass over the Athens basin is organic in the submicron range, of which 80 % corresponds to RWB (average values during the smog period). Although organic particles are important light scatterers, the direct radiative cooling of the aerosol plume during wintertime is found low (monthly average forcing of –0.4 W m⁻² at the surface), followed by a minor feedback to the concentration levels of aerosol species. The low radiative cooling of a period with such intense air pollution conditions is attributed to the timing of the smog plume appearance, both directly (longwave radiation increases during nighttime) and indirectly (the mild effect of the residual plume on solar radiation during the next day, due to removal and dispersion processes