CMB spectral distortions in generic two-field models

Abstract

Abstract. We investigate the CMB µ distortion in models where two uncorrelated sources contribute to primordial perturbations. We parameterise each source by an amplitude, tilt, running and running of the running. We perform a detailed analysis of the distribution signal as function of the model parameters, highlighting the differences compared to single-source models. As a specific example, we also investigate the mixed inflaton-curvaton scenario. We find that the µ distortion could efficiently break degeneracies of curvaton parameters especially when combined with future sensitivity of probing the tensor-to-scalar ratio r. For example, assuming bounds µ < 0.5 × 10 −8 and r < 0.01, the curvaton contribution should either vanish or the curvaton should dominate primordial perturbations and its slow-roll parameter η χ is constrained to the interval −0.007 < η χ < 0.045.

Imprint of entanglement entropy in the power spectrum of inflationary fluctuations

“…However, future surveys may tighten this bound [48]. Values of α s , β s larger (and of different sign) than those predicted in the simple single field slow roll inflation can be obtained by allowing entropy perturbations [49] or from contributions of other sources [50].…”

Hidden symmetries of two-field cosmological models

“…In this case, relation (C. 15) gives (C.7), whereB 1 andB 2 are defined through (C.6) and hence satisfy (C.4), which implies:…”

“…Scalar multifield models were considered in cosmology from various points of view (see, for example, [5][6][7][8][9][10][11]), including numerically [12][13][14] and to some extent phenomenologically [15]. However, current insight into their dynamics (which, as outlined in [16][17][18], is quite interesting from the perspective of the geometric theory of dynamical systems [19]) is far more limited than for one-field models.…”

“…cos(a − b) sinh(t) − sin(a − b) sinh(t) cos(a+b)sinh(t) cos(2a) cosh 2 t 2 + cos(2b) sinh 2 t sin(2a) cosh 2 t 2 sin(a+b)sinh(t) sin(2a) cosh 2 t 2 + sin(2b) sinh 2 t cos(2b) sinh 2 t . (B 15). …”

Generalizedα-Attractor Models from Elementary Hyperbolic Surfaces

“…The recognition of this possibility has lead to renewed interest in the study of multi-field models [23][24][25][26] and in particular to the development of numerical methods for determining the effect of their cosmological perturbations [27][28][29] beyond the limitations of the SRST approximation [30,31]. As a single example, see [32] for a recent investigation of constraints imposed on such models by Planck 2015 data [33].…”