Higgs inflation and suppression of axion isocurvature perturbation

We point out that cosmological constraint from the axion isocurvature perturbation is relaxed if the Higgs field obtains a large field value during inflation in the DFSZ axion model. This scenario is consistent with the Higgs inflation model, in which two Higgs doublets have non-minimal couplings and play a role of inflaton.Comment: 5 pages; added reference

Nuclear coalescence from correlation functions

We derive a simple formula relating the cross section for light cluster production (defined via a coalescence factor) to the two-proton correlation function measured in heavy-ion collisions. The formula generalises earlier coalescence-correlation relations found by Scheibl & Heinz and by Mrowczynski for Gaussian source models. It motivates joint experimental analyses of Hanbury Brown-Twiss (HBT) and cluster yield measurements in existing and future data sets.Comment: 10 pages, 4 figures. v2: some clarifications. A missing (2\pi)^3 normalization factor, relating diff cross sec to density matrix traces, is corrected in Secs.II.A and II.B. It does not affect any of the result

Gravitational waves from bubble dynamics: Beyond the Envelope

We study gravitational-wave production from bubble dynamics (bubble collisions and sound waves) during a cosmic first-order phase transition with an analytic approach. We first propose modeling the system with the thin-wall approximation but without the envelope approximation often adopted in the literature, in order to take bubble propagation after collisions into account. The bubble walls in our setup are considered as modeling the scalar field configuration and/or the bulk motion of the fluid. We next write down analytic expressions for the gravitational-wave spectrum, and evaluate them with numerical methods. It is found that, in the long-lasting limit of the collided bubble walls, the spectrum grows from $\propto f^3$ to $\propto f^1$ in low frequencies, showing a significant enhancement compared to the one with the envelope approximation. It is also found that the spectrum saturates in the same limit, indicating a decrease in the correlation of the energy-momentum tensor at late times. We also discuss the implications of our results to gravitational-wave production both from bubble collisions (scalar dynamics) and sound waves (fluid dynamics).Comment: 94 pages, 39 figures, JCAP published versio

Signatures of hidden order symmetry in torque oscillations, elastic constant anomalies and field induced moments in URu2Si2

We discuss the conclusions on the symmetry of hidden order (HO) in URu2Si2 that may be drawn from recent torque experiments in rotating magnetic field by Okazaki et al. [1]. They are very sensitive to changes in the magnetic susceptibility induced by HO. We show that the observed twofold angular torque oscillations give evidence that hidden order has degenerate E- type (yz,zx) symmetry where both components are realised. The oscillations have the wrong characteristics or are absent for the 1D nontrivial representations like quadrupolar B1 (x^2-y^2) and B2 (xy) type HO or hexadecapolar A2(xy(x^2-y^2)) type HO. Therefore they may be excluded as candidates for hidden order. We also predict the field-angular variation of possible field-induced Bragg peaks based on underlying E-type order parameter and discuss the expected elastic constant anomalies.Comment: 11 pages, 1 figure ; to appear in Phys. Rev.

Derivation of the superconducting gap equation for the noncentrosymmetric superconductor Li2Pt3B

We present here the mathematical background of our approach, presented in Phys. Rev. B 86, 134526 (2012) regarding the gap function and symmetry for the noncentrosymmetric (NCS) superconductor $Li_2Pt_3B$. As revealed by the experiment, this NCS superconductor gives rise to line nodes in the superconducting order parameter, which is responsible for many of its experimental behaviors. Owing to the enhanced d-character of the relevant bands that cross the Fermi level,the system gets weakly correlated. The nature and symmetry of this nodal behavior is explained from a microscopic viewpoint. In this article starting with an Hubbard model relevant for this NCS system by considering the effect of the onsite Coulomb repulsion on the pairing potential perturbatively, we extract the superconducting gap equation. Further analysis of this equation predicts a $s_\pm$ wave gap function with line nodes as the most promising candidate in the superconducting state.Comment: 7 pages, Proceeding versio