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- Van De Bruck, C., et al.
(författare)
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Disformally coupled inflation
- 2016
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : Institute of Physics Publishing (IOPP). - 1475-7516. ; 2016:3
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Tidskriftsartikel (refereegranskat)abstract
- A disformal coupling between two scalar fields is considered in the context of cosmological inflation. The coupling introduces novel derivative interactions mixing the kinetic terms of the fields but without introducing superluminal or unstable propagation of the two scalar fluctuation modes. Though the typical effect of the disformal coupling is to inhibit one of the fields from inflating the universe, the energy density of the other field can drive viable near Sitter -inflation in the presence of nontrivial disformal dynamics, in particular when one assumes exponential instead of power-law form for the couplings. The linear perturbation equations are written for the two-field system, its canonical degrees of freedom are quantised, their spectra are derived and the inflationary predictions are reported for numerically solved exponential models. A generic prediction is low tensor-to-scalar ratio.
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2. |
- Miao, X. F., et al.
(författare)
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Short-range magnetic correlations and spin dynamics in the paramagnetic regime of (Mn,Fe)2(P,Si)
- 2016
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Ingår i: PHYSICAL REVIEW B. - 2469-9950. ; 94:1
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Tidskriftsartikel (refereegranskat)abstract
- The spatial and temporal correlations of magnetic moments in the paramagnetic regime of (Mn,Fe)(2)(P,Si) have been investigated by means of polarized neutron diffraction and muon-spin relaxation techniques. Short-range magnetic correlations are present at temperatures far above the ferromagnetic transition temperature (T-C). This leads to deviations of paramagnetic susceptibility from Curie-Weiss behavior. These short-range magnetic correlations extend in space, slow down with decreasing temperature, and finally develop into long-range magnetic order at T-C.
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