where λ ∼ O (1). Therefore, exciting the SM gauge bosons and the SM fermions through parametric resonance of a gauge singlet inflaton is a daunting task. Inflaton would rather prefer perturbative decay $^{81}$. One very curious aspect of fermionic coupling to the inflaton is fragmentation of the inflaton to form an inflating non-topological solitons, known as Q-balls $^{82}$. Let us illustrate this idea by studying a chaotic inflation model where the inflaton field is not real but complex. Provided the fermions live in a larger representation than the bosons, the inflaton mass obtains a Logarithmic correction $^{83}$: 5. Fragmentation of the inflaton where the value of K is determined by the Yukawa coupling h with K = − C ( h $^{2}$/ 16 π $^{2}$), where C is some number. If K < 0, the inflaton condensate feels a negative pressure for field values φ ≪ M , we find: where we assume | K | ≪ 1. The equation of state for a field rotating in such a potential is where p and ρ is a pressure and energy density of the scalar field, respectively. Evidently, the negative value of K corresponds to the negative pressure, which signals the instability 81 The only way one can excite SM fermions and gauge fields copiously, if they are directly excited by the oscillations of the SM Higgs boson. This can happen in low scale electroweak baryogenesis [797–799], or in the context of SM Higgs inflation [124]. During the Higgs oscillations the SM degrees of freedom can be excited via parametric resonance, instant preheating and also via tachyonic preheating. All three phases of preheating are present. The other notable example is the MSSM inflation discussed in Sec. V D, where gluons and MSSM fermions were excited via instant preheating. 82 The Q-balls known to evaporate from their surface, see for a review [91], therefore suppressing the reheating and thermalization time scale. 83 Similar corrections to the potential arises for the MSSM flat directions in a gravity mediated scenarios, where m ∼ O (TeV) and K ∼ α 8 π m 2 1 / 2 m 2 ˜ l , where m$_{1}$$_{/}$$_{2}$ is the gaugino mass and m$_{˜}$$_{l}$ is the slepton mass. Fragmentation of such flat direction can excite Q-balls and also gravity waves, see [783, 784]. 184 V = m $^{2}$| Φ | 2 [ 1 − K log ( | Φ | 2 M 2 )] , (395) V ( φ ) ≃ 1 2 m 2 3 / $_{2}$φ 2 ( φ 2 2 M 2 ) K ∝ φ 2+2 $^{K}$. (396) p ≃ K 2 + K ρ ≃ − | K | 2 ρ , (397)