COSMOS- $$e'$$ e ′ -soft Higgsotic attractors

Abstract

In this work, we have developed an elegant algorithm to study the cosmological consequences from a huge class of quantum field theories (i.e. superstring theory, supergravity, extra dimensional theory, modified gravity, etc.), which are equivalently described by soft attractors in the effective field theory framework. In this description we have restricted our analysis for two scalar fields -dilaton and Higgsotic fields minimally coupled with Einstein gravity, which can be generalized for any arbitrary number of scalar field contents with generalized non-canonical and non-minimal interactions. We have explicitly used R 2 gravity, from which we have studied the attractor and non-attractor phases by exactly computing two point, three point and four point correlation functions from scalar fluctuations using the InIn (Schwinger-Keldysh) and the δN formalisms. We have also presented theoretical bounds on the amplitude, tilt and running of the primordial power spectrum, various shapes (equilateral, squeezed, folded kite or counter-collinear) of the amplitude as obtained from three and four point scalar functions, which are consistent with observed data. Also the results from two point tensor fluctuations and the field excursion formula are explicitly presented for the attractor and non-attractor phase. Further, reheating constraints, scale dependent behavior of the couplings and the dynamical solution for the dilaton and Higgsotic fields are also presented. New sets of consistency relations between two, three and four point observables are also presented, which shows significant deviation from canonical slow-roll models. Additionally, three possible theoretical proposals have presented to overcome the tachyonic instability at the time of late time acceleration. Finally, we have also provided the bulk interpretation from the three and four point scalar correlation functions for completeness.S. Choudhury: Presently working as a Visiting (Post-Doctoral) fellow at DTP, TIFR, Mumbai. a

Electrons and Polarons at Oxide Interfaces Explored by Soft-X-Ray ARPES

“…Optical studies on bulk STO (van Mechelen et al 2010) have not only confirmed the involvement of the LO3 phonon in EPI but also found the corresponding effective mass renormalization m*/m 0 ~3.0 close to our value. The same phonon was observed by Raman (Cardona 1965) and neutron spectroscopy (Choudhury et al 2008) as well as by VUV-ARPES at the bare STO(001) surface (Chang et al 2010;Wang et al 2016) with the strength of the polaronic structure depending on n s (see Chapter 4). The LO3 energy ~100 meV found in all these experiments perfectly matches the DFT calculations, Fig, 13 (a).…”

Superconductivity in the two-dimensional electron gas induced by high-energy optical phonon mode and large polarization of theSrTiO3substrate

“…The band is flat with only a small momentum transfer to electrons. This identification is supported by the earlier ARPES on STO surface states, which shows a phonon-induced hump at approximately 100meV away from the main band and through inelastic neutron scattering 8 . The role of substrate in assisting superconductivity is not limited to generation of phonons.…”

“…The single phonon band 8,13 near Ω = 100meV is most probably associated with pairing attractive electron-electron force is the ferroelectric LO that involves the relative displacement of the T i and O atoms. The high energy STO oxygen LO phonon band mode is separated from all the other phonon bands by a substantial energy gap 8 . The single branch of the optical phonons described by the bosonic field 22…”

Aspects of electron–phonon interactions with strong forward scattering in FeSe Thin Films on SrTiO3substrates

“…We approximate the relevant phonon branch with a dispersionless Ω q = Ω = 100 meV optical oxygen phonon mode. This is supported by several ab initio calculations that indicate that the highest lying phonon branch in bulk STO [41] and FeSe/STO interfaces [42,43] is relatively flat in the vicinity of q = 0. The e-ph matrix element is taken to depend on the momentum transfer only, as derived microscopically in previous works [11,14].…”