Article
Astronomy & Astrophysics
J. McDonald
Summary: In comparison to the conventional metric formulation, reconsideration of unitarity violation in the electroweak vacuum under the Palatini formulation reveals that Higgs Inflation model does not violate unitarity at low energies. This suggests that Palatini Higgs Inflation may have a significant advantage over metric Higgs Inflation in terms of conservation of unitarity.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Zhu Yi, Yungui Gong, Bin Wang, Zong-hong Zhu
Summary: Researchers have proposed a novel mechanism to demonstrate the ability of the Higgs model in particle physics to drive inflation in the universe. The study also suggests that secondary gravitational waves induced by Higgs fluctuations could provide clues for detecting primordial black holes.
Article
Astronomy & Astrophysics
J. Mcdonald
Summary: In this paper, we explore the possibility of Higgs inflation in the positive stable region of the potential by introducing a nonminimally coupled induced gravity sector to the Standard Model. We show that under certain conditions, conventional Higgs inflation can be achieved by increasing the effective Planck mass during inflation through a phase transition of another scalar field chi.
Article
Astronomy & Astrophysics
Mikhail Shaposhnikov, Andrey Shkerin, Inar Timiryasov, Sebastian Zell
Summary: The study focuses on inflation driven by the Higgs field in the Einstein-Cartan formulation of gravity, finding that inflation is possible and consistent with observations for a broad range of parameters. The results show that the spectral index is typically given by n(s) = 1-2/N-* and the tensor-to-scalar ratio r can vary between about 10(-10) and 1. This suggests the potential detection of gravitational waves from inflation in certain scenarios of Higgs inflation in the Einstein-Cartan framework.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
Yang Liu
Summary: In this article, we investigate three inflation models - Higgs inflation model, Higgs-dilaton model, and Palatini Higgs inflation model - to simultaneously satisfy the further refining dS swampland conjecture and scalar weak gravity conjecture (SWGC). We determine the conditions for these three models to satisfy scalar weak gravity conjecture (SWGC) and strong scalar weak gravity conjecture (SSWGC).
EUROPEAN PHYSICAL JOURNAL C
(2022)
Article
Astronomy & Astrophysics
Aliki Litsa, Katherine Freese, Evangelos I. Sfakianakis, Patrick Stengela, Luca Visinellij
Summary: We propose a new way of studying the Higgs potential at extremely high energies by considering the space dependence and non-Gaussianity of the resulting temperature anisotropy spectrum. The observed temperature anisotropies in the Cosmic Microwave Background (CMB) are largely excluded to be primarily caused by Higgs effects. Observational searches for non-Gaussianity in the CMB can be used to constrain the dynamics of the Higgs boson at very high energies.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2023)
Article
Physics, Multidisciplinary
Neil D. Barrie, Chengcheng Han, Hitoshi Murayama
Summary: This study finds that the triplet Higgs can explain the neutrino masses, observed baryon asymmetry, and inflation simultaneously, and can be tested in upcoming experiments. This simple framework provides a unified solution to the three major unknowns in modern physics.
PHYSICAL REVIEW LETTERS
(2022)
Article
Astronomy & Astrophysics
N. Mohammedi
Summary: Models of inflation with non-minimal coupling between the Higgs field and gravity result in a complex expression for the potential of the inflaton field after metric rescaling. However, this potential satisfies the desired theoretical and experimental features with certain approximations. This note also explores the modification of the Higgs kinetic term to obtain the simplest form of the inflaton field potential without any approximation after metric rescaling.
Article
Astronomy & Astrophysics
Ryodai Kawaguchi, Shinji Tsujikawa
Summary: Primordial black holes (PBHs) can potentially account for all or part of the dark matter in the universe. Inflation provides a mechanism for generating the seeds of PBHs when the velocity of an inflaton field rapidly decreases. By studying the curvature perturbations during Gauss-Bonnet corrected Higgs inflation, we find that certain parameter spaces allow for the formation of PBHs that can contribute to all dark matter. In addition, we show that models with certain types of potential exhibit power spectra consistent with observational data.
Article
Astronomy & Astrophysics
Alberto Salvio
Summary: The study calculates the relic gravitational wave background generated by tensor linear perturbations during Higgs inflation, considering both the Standard Model and a well-motivated phenomenological completion. It focuses on critical Higgs inflation, which amplifies the tensor fluctuations and suggests that future space-borne interferometers may detect the corresponding primordial gravitational waves.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Particles & Fields
Yang Liu
Summary: The study examines if the Higgs inflation model and its variations can satisfy the further refining de Sitter swampland conjecture by adjusting relevant parameters, based on observational data. The results indicate that these inflationary models might all be in landscape if the further refining de Sitter swampland conjecture holds.
EUROPEAN PHYSICAL JOURNAL C
(2021)
Review
Physics, Nuclear
Oleg Lebedev
Summary: The Higgs portal has opened up new opportunities for exploring physics beyond the Standard Model, with implications for inflation, vacuum stability, and dark matter. The couplings to the hidden sector can have a significant cosmological impact, even for tiny values.
PROGRESS IN PARTICLE AND NUCLEAR PHYSICS
(2021)
Article
Astronomy & Astrophysics
Alonso Izquierdo, W. Garcia Fuertes, J. Mateos Guilarte
Summary: We investigate topological vortex solutions in a generalized Abelian Higgs model with nonpolynomial dielectric and potential functions. These quantities are chosen by requiring integrability of the self-dual limit of the theory for all values of the magnetic flux. The model only has a symmetry-breaking superconducting phase and can sustain regular phenomenology.
Article
Astronomy & Astrophysics
J. G. Rodrigues, S. Santos da Costa, J. S. Alcaniz
Summary: Researchers investigated the observational viability of a class of alpha-attractors inflationary models using a double-well potential and slow-roll analysis. They found a continuous interpolation model between chaotic inflation and the universal attractor, and explored the parameter space of the model through MCMC analysis, determining the range of alpha values.
Article
Physics, Nuclear
C. J. Ouseph, Kingman Cheung
Summary: In this model, the four-form field induces modifications to the Higgs self-coupling constant, the cosmological constant, and the non-minimal coupling constant, resulting in a modification to the inflaton potential. It is also demonstrated that in the presence of four-form gravity interaction, the Higgs-gravity coupling is not necessary, yet it can still produce the right amount of density perturbation for inflation.
JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS
(2021)
Article
Astronomy & Astrophysics
Kohei Kamada, Jun'ya Kume, Yusuke Yamada, Jun'ichi Yokoyama
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
Article
Physics, Particles & Fields
Kohei Kamada, Chang Sub Shin
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Astronomy & Astrophysics
Kohei Kamada, Jun'ya Kume, Yusuke Yamada
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2020)
Article
Physics, Particles & Fields
Takumi Hayashi, Kohei Kamada, Naritaka Oshita, Jun'ichi Yokoyama
JOURNAL OF HIGH ENERGY PHYSICS
(2020)
Article
Astronomy & Astrophysics
Kohei Kamada, Fumio Uchida, Jun'ichi Yokoyama
Summary: The decay of hypermagnetic helicity at electroweak symmetry breaking may have produced baryon asymmetry, however, fully helical magnetic field may not be strong enough to explain the origin of intergalactic magnetic field; the combination of helical and nonhelical primordial magnetic fields may explain both, but is ruled out by the constraint on amplitude of baryon isocurvature perturbations.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2021)
Article
Physics, Multidisciplinary
Valerie Domcke, Kohei Kamada, Kyohei Mukaida, Kai Schmitz, Masaki Yamada
Summary: This mechanism, wash-in leptogenesis, operates at low masses of right-handed neutrinos without requiring CP violation, even in the regime of strong wash-out. By generalizing standard freeze-out leptogenesis to a nonminimal cosmological background, it allows for the generation of a nonvanishing B - L asymmetry using chemical potentials generated at high temperatures.
PHYSICAL REVIEW LETTERS
(2021)
Article
Astronomy & Astrophysics
Takumi Hayashi, Kohei Kamada, Naritaka Oshita, Jun'ichi Yokoyama
Summary: We apply the Lorentzian path integral to analyze the decay of a false vacuum and predict the decay rate. By utilizing the Picard-Lefschetz theory, we deform the integration contour to ensure the convergence of the Lorentzian path integral. Our findings indicate that the nucleation rate of a critical bubble, where the corresponding bounce action is extremized, follows the same exponent as the Euclidean approach. Furthermore, we extend our computation to the nucleation of bubbles larger or smaller than the critical one, where the Euclidean formalism is not applicable.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Astronomy & Astrophysics
Soichiro Hashiba, Kohei Kamada, Hiromasa Nakatsuka
Summary: By studying the Chern-Simons coupling between the pseudoscalar inflaton and the gauge field, and examining the subsequent pair-particle production induced by the amplified gauge field known as the Schwinger effect during the kination era, we find that successful reheating of the Universe can be achieved through the domination of the pair-produced particles over the kinetic energy of the inflaton.
JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS
(2022)
Article
Physics, Particles & Fields
Valerie Domcke, Kohei Kamada, Kyohei Mukaida, Kai Schmitz, Masaki Yamada
Summary: CP violations and B-L violations are not required to occur simultaneously for successful leptogenesis. New CP-violating interactions at high energies can result in primordial charge asymmetries, which can then be transformed into a nonvanishing B-L asymmetry by right-handed neutrinos at lower energies. In this paper, we study a novel mechanism known as wash-in leptogenesis, using axion inflation as the source of high-scale CP violation. We find a large range of viable scenarios and provide insights into intergalactic magnetic fields, primordial black holes, and gravitational waves.
JOURNAL OF HIGH ENERGY PHYSICS
(2023)
Review
Physics, Nuclear
Kohei Kamada, Naoki Yamamoto, Di-Lun Yang
Summary: The microscopic quantum nature of elementary particles, chirality, leads to macroscopic phenomena like the chiral anomaly, chiral magnetic effect, and chiral plasma instability. Recent progress in studying these chiral effects in high-energy astrophysics and early Universe cosmology are reviewed, including pulsar kicks, magnetars, core-collapse supernovae, primordial magnetic fields, baryogenesis, and chiral gravitational waves. Additionally, a pedagogical introduction to chiral effects and low-energy effective theories, such as chiral (magneto)hydrodynamics, chiral kinetic theory, and chiral radiation transport theory for neutrinos, is provided.
PROGRESS IN PARTICLE AND NUCLEAR PHYSICS
(2023)
Article
Physics, Multidisciplinary
Valerie Domcke, Kohei Kamada, Kyohei Mukaida, Kai Schmitz, Masaki Yamada
Summary: This letter investigates the relationship between helical hypermagnetic fields and fermion asymmetry in the early Universe caused by chiral chemical potential. The study demonstrates that even with zero total lepton number, a mechanism can be triggered through lepton flavor asymmetry. This sets a constraint on lepton flavor asymmetry at temperatures above 106 GeV, which is about two orders of magnitude stronger than current limits from cosmic microwave background and primordial nucleosynthesis.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Axel Brandenburg, Kohei Kamada, Jennifer Schober
Summary: In plasmas composed of massless electrically charged fermions, chirality can be interchanged with magnetic helicity while preserving the total chirality through the quantum chiral anomaly. The decay of turbulent energy in plasmas such as those in the early Universe and compact stars is usually controlled by certain conservation laws. We propose that in such a case, an adaptation to the Hosking integral, which is conserved in nonhelical magnetically dominated turbulence, controls the decay in turbulence with helicity balanced by chiral fermions.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Astronomy & Astrophysics
Tetsutaro Higaki, Kohei Kamada, Kentaro Nishimura
Summary: The chiral soliton lattice (CSL) is a lattice structure composed of domain walls aligned in parallel at equal intervals, which is energetically stable in the presence of a background magnetic field and a finite (baryon) chemical potential. In this study, the formation of CSL from the vacuum state is investigated by describing it as a layer of domain-wall disks surrounded by the vortex or string loop, based on the Nambu-Goto-type effective theory.
Article
Physics, Particles & Fields
Kohei Kamada, Jun'ya Kume, Yusuke Yamada
Summary: The study investigates the gravitational counterpart of the chiral magnetic effect, known as the chiral gravitational effect, in a cosmological setup. It reveals that the non-trivial time dependence of the chiral chemical potential is a key ingredient of the effect, with its memory imprinted on high frequency gravitational waves. Cosmological implications and potential effects on gravitational wave observation are briefly discussed.
JOURNAL OF HIGH ENERGY PHYSICS
(2021)
Article
Astronomy & Astrophysics
Tomohiro Fujita, Kohei Kamada, Yuichiro Nakai
