18614999
Suppression of superheavy magnetic monopoles in grand unified theories
The superheavy magnetic monopoles predicted by grand unified theories would not be produced in significant numbers if electromagnetic gauge invariance is spontaneously broken when the temperature T is greater than Tc≳1 TeV.
122337528
Cosmological consequences of a hierarchical supersymmetric model
Abstract Unusual finite-temperature behavior of Witten's supersymmetric model is discussed. A high-temperature phase persists to the weak-interaction scale. Initial monopole density can be strongly suppressed and production of heavy particles is inhibited. Difficulties with baryon generation are suggested.
122674516
Point splitting regularization in a supersymmetric gauge field theory
Abstract Point splitting regularization is discussed in a supersymmetric Yang-Mills field theory. A supersymmetry and gauge invariant point-split supercurrent operator, along with the point-split lagrangian density, is constructed. A superconformal anomaly is computed.
122607008
Goldstone and pseudo-Goldstone bosons in unified gauge-field models
124346945
Fluctuations in the New Inflationary Universe
This invention relates to novel rolling type athletic apparatus taking advantage of the characteristic of stilts which comprises a pair of vertical rods each consisting of two pipces telescopically connected to each other. The upper end of each vertical rod is bent to form a handle. Each rod is provided at its lower end with a wheel having a brake and a one-way clutch. A step is mounted on the upper portion of the wheel.
118191225
Cosmological Consequences of Grand Unified Theories
118701741
Curvature perturbation spectrum in two-field inflation with a turning trajectory
We revisit a two-component inflaton model with a turning trajectory in the field space, where the field slowly rolls down along the trajectory. We consider the case when the effective mass in the direction perpendicular to the trajectory, namely the isocurvature direction, is either of the same order as or much larger than the Hubble parameter. Assuming that the turning angular velocity is small, we compute analytically the corrections to the power spectrum of curvature perturbation caused by the mediation of the heavy isocurvature perturbation, and compare our analytic results with the numerical ones. Especially, when Meff2 H2, we find that it is proportional to Meff−2. This result is consistent with the one obtained previously by an effective field theory approach.
119157556
Inflation beyond T-models and primordial B-modes
Abstract We describe extended theories which shares the gauge transformation symmetry of the T-models, and takes the T-models as well as Starobinsky model as special cases. We derive a general relation between the two slow-roll parameters, and find that a large class of models can be embedded. Such models include more general Starobinsky-like inflation as well as the chaotic inflation with a large tensor-to-scalar ratio consistent with the BICEP2 result.
117214043
Cosmological perturbations in inflation with multiple sound speeds
Abstract We study a multi-field inflationary theory with separable Lagrangian, which has different speed of sound for each field. We find that the fields always coupled at perturbative level through gravitational interaction. We show that if the coupling terms among the perturbation fields are weak enough, these fields can be treated as a combination of decoupled fields, which are similar to normal modes in coupled oscillation. By virtue of such fields, the curvature perturbation at horizon crossing can be calculated up to the leading order of slow-variation parameters via δ N formalism. Explicitly, we consider a model of multi-speed DBI inflation, and calculate the power spectrum in detail. The result depends on the ratio of different speeds of sound, and shows an apparent amplification when the ratio deviates from unity.
118471930
Equilateral non-Gaussianity from heavy fields
The effect of self-interactions of heavy scalar fields during inflation on the primordial non-Gaussianity is studied. We take a specific constant-turn quasi-single field inflation as an example. We derive an effective theory with emphasis on non-linear self-interactions of heavy fields and calculate the corresponding non-Gaussianity, which is of equilateral type and can be as relevant as those computed previously in the literature. We also derive the non-Gaussianity by directly using the in-in formalism, and verify the equivalence of these two approaches.
118390460
1/R correction to gravity in the early universe
To explain the accelerated expansion of the late universe, the 1/R correction to Einstein gravity is usually considered, where R is the Ricci scalar. This correction term, if stable, is generally believed to be negligible during inflation. However, if the 1/R term is inflaton dependent, it will dramatically change the story of inflation. The entropy perturbation will naturally appear and drive the evolution of curvature perturbation outside the Hubble horizon. In a large class of models, the entropy perturbation can be made nearly scale invariant. In Einstein gravity the single-field inflation with a quartic potential has been ruled out by recent observations, but it revives when the 1/R term is turned on. The evolution of non-Gaussianities on a large scale are also studied and applied to inflation with 1/R correction. In some specific models, a large non-Gaussianity can be naturally generated outside the horizon. A recent study ruled out almost all f(R) models during the matter-dominated phase. Taking this into consideration, we are left with a limited class of model which recovers the Einstein gravity soon after reheating.