C. Reheating and thermalization In stringy models of inflation, reheating and thermalization of the SM or MSSM degrees of freedom are poorly understood. This is mainly due to the fact that inflation happens in a hidden sector as far the MSSM sector is concerned. One problem for all these models is that they are bound to excite possibly light non-SM like degrees of freedom, which can pose several challenges for a successful BBN $^{111}$. There are also some observational virtues of stringy reheating. For instance, inflation driven by D 3 − D 3 case has interesting consequences. Their annihilation leads to the pro- duction of D 1 branes and fundamental F 1 strings, which can be understood via tachyon condensation [924–927]. The tachyon couples to U (1) × U (1) gauge theory associated with each brane, as it develops a VEV it breaks the gauge group spontaneously, which results in formation of D 1 strings via Kibble mechanism and a confining flux tubes which become the fundamental closed strings [928]. In Type IIB setup domain walls and monopoles are not excited, which correspond to D 0 and D 2 branes. The cosmic string tension, µ , can be within 10 − 13 < Gµ < 10 − 6 [461, 915]. Brane-anti-brane annihilation also excited gravity waves, whose peak frequency is determined by the string scale [727]. A string scale greater than TeV makes it impossible for such gravity waves to be detected in future. Reheating in a warped geometry is a complicated process [883, 884, 929]. Especially, in a multiple throat picture, where inflation happens in one throat and the SM is in another, there are many possibilities to reheat not only the SM throat, but also the other throats. 111 One possibility would be to dilute all of them via late inflation, and create the MSSM degrees of freedom afresh within an observable sector [284]. 112 When the warping effects are small, as in the case of [930], reheating and preheating into the SM degrees of freedom have been studied systematically. The inflaton being the k¨ ahler modulus couples to the SM sector and the moduli sector. The moduli eventually decay into the SM sector. However the inflaton being a SM gauge singlet here, also couples to various hidden sectors and their couplings to the inflaton are largely unknown. It is therefore important to study the effects of reheating and preheating while taking 233 • Reheating various non-(MS)SM throats: First of all, by no means it is guaranteed that the (MS)SM throat will be the only re- cipient of the inflaton energy density, there are other throats with similar cosmological constant, which are also reheated simultaneously depending on the relative warping between the SM throat and the other throats $^{112}$.