558 research outputs found
Boundary effects on radiative processes of two entangled atoms
We analyze radiative processes of a quantum system composed by two identical
two-level atoms interacting with a massless scalar field prepared in the vacuum
state in the presence of perfect reflecting flat mirrors. We consider that the
atoms are prepared in a stationary maximally entangled state. We investigate
the spontaneous transitions rates from the entangled states to the collective
ground state induced by vacuum fluctuations. In the empty-space case, the
spontaneous decay rates can be enhanced or inhibited depending on the specific
entangled state and changes with the distance between the atoms. Next, we
consider the presence of perfect mirrors and impose Dirichlet boundary
conditions on such surfaces. In the presence of a single mirror the transition
rate for the symmetric state undergoes a slight reduction, whereas for the
antisymmetric state our results indicate a slightly enhancement. Finally, we
investigate the effect of multiple reflections by two perfect mirrors on the
transition rates.Comment: submitted version to the journa
Enhanced degradation of softwood versus hardwood by the white-rot fungus Pycnoporus coccineus
16 p.-8 fig.-1 tab. Courier, Marie et al.This study was also funded by the French National Research Agency (A*MIDEX project ANR11-IDEX-0001-02;ANR FUNLOCK ANR-13-BIME-0002-01). The work by the US Department of Energy Joint Genome Institute, a DOE Office of Science User
Facility, is supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231.Peer reviewe
Conformational mobility in a polymer with mesogenic side groups- dielectric and DSC studies
The relaxation times of the conformational rearrangements of the main-chain segments of a liquid crystalline side-chain polymer was
determined from differential scanning calorimetry experiments in the temperature interval around and below its glass transition. Phenomenological
models with fitting parameters were used to evaluate the temperature dependence of the relaxation times and the form parameter
of the relaxation times distribution. These parameters were compared with its counterparts in the dielectric a relaxation process which appear
in the temperature interval immediately above the calorimetric glass transition. For the temperature interval below the calorimetric glass
transition the differential scanning calorimetry (DSC) results were compared with the dielectric results obtained by the thermally stimulated
depolarisation technique
Costismo y anarquismo en las letras aragonesas : el grupo de Talión (Samblancat, Alaiz, Acín, Bel Maurín)
Validation of age determination using otoliths of the European anchovy (Engraulis encrasicolus L.) in the Bay of Biscay
Validation of the age determination procedure using otoliths of European anchovy in the Bay of Biscay was achieved by monitoring very strong year-classes in successive spring catches and surveys, as well as the seasonal occurrence of edge types. Historical corroboration of the ageing method was obtained by cross-correlation between successive age groups by year-classes in catches and surveys (1987–2013). Summary annual growth in length is also presented. Yearly annuli consist of a hyaline zone (either single or composite) and a wide opaque zone, disrupted occasionally by some typical checks (mainly at age-0 and age-1 at peak spawning time). Age determination, given a date of capture, requires knowledge of the typical annual growth pattern of otoliths, their seasonal edge formation by ages and the most typical checks. Most opaque growth occurs in summer and is minimal (translucent) in winter. Opaque zone formation begins earlier in younger fish (in spring), and this helps distinguish age-1 from age-2þ.Versión del edito
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