52 citations · 161 across the 17 of their papers we have counts for
17 papers
Magnetic Catalysis and Fermion Mass Generation in de Sitter Spacetime
Kohei Fujikura, Toshifumi Noumi, Shintetsu Yamazaki
We consider the dynamics of a charged fermion in de Sitter space in the presence of a uniform background magnetic field, and discuss magnetic catalysis of chiral symmetry breaking…
Dense with uniform matrix product states
Kohei Fujikura, Yoshimasa Hidaka
We study cold dense single-flavor gauge theory in dimensions in the thermodynamic limit using a gauge-invariant variational uniform matrix product state an…
Inflationary QCD phase diagram
Kohei Fujikura, Toshifumi Noumi
Motivated by the cosmological collider program, which aims to probe high-energy physics through inflation, we investigate the phase diagram of multi-flavor QCD in de Sitter spaceti…
Conformal Phase Transition in Supersymmetric QCD
Kohei Fujikura, Shota Nakagawa, Yuichiro Nakai +2
We construct a four-dimensional supersymmetric QCD in conformal window with a marginally relevant deformation which triggers the spontaneous breaking of (approximate) scale invaria…
Critical behavior of the Schwinger model via gauge-invariant VUMPS
Hirotsugu Fujii, Kohei Fujikura, Yoshio Kikukawa +2
We study the lattice Schwinger model by combining the variational uniform matrix product state (VUMPS) algorithm with a gauge-invariant matrix product ansatz that locally enforces…
Formation of defects associated with both spontaneous and explicit symmetry breaking
Kohei Fujikura, Mairi Sakellariadou, Michiru Uwabo-Niibo +1
We discuss formation of cosmic strings associated with a spontaneously broken approximate symmetry by performing classical field-theoretical simulations. An original …
Cold Darkogenesis: Dark Matter and Baryon Asymmetry in Light of the PTA Signal
Kohei Fujikura, Sudhakantha Girmohanta, Yuichiro Nakai +1
We build upon the intriguing possibility that the recently reported nano-Hz gravitational wave signal by Pulsar Timing Array (PTA) experiments is sourced by a strong first-order ph…
Interactions between several types of cosmic strings
Kohei Fujikura, Siyao Li, Masahide Yamaguchi
We study the interaction of several types of static straight cosmic strings, including local strings, global strings, and bosonic superconducting strings with and without magnetic…
NANOGrav Signal from a Dark Conformal Phase Transition
Kohei Fujikura, Sudhakantha Girmohanta, Yuichiro Nakai +1
We explore the possibility that a confining first-order phase transition of a nearly-conformal dark sector generates the reported NANOGrav signal of a stochastic gravitational wave…
Cosmological Phase Transitions in Composite Higgs Models
Kohei Fujikura, Yuichiro Nakai, Ryosuke Sato +1
We investigate cosmological phase transitions in various composite Higgs models consisting of four-dimensional asymptotically-free gauge field theories. Each model may lead to a co…
Generation of neutrino dark matter, baryon asymmetry, and radiation after quintessential inflation
Kohei Fujikura, Soichiro Hashiba, Jun'ichi Yokoyama
We construct a model explaining dark matter, baryon asymmetry and reheating in quintessential inflation model. Three generations of right-handed neutrinos having hierarchical masse…
Baryon Asymmetric Universe from Spontaneous CP Violation
Kohei Fujikura, Yuichiro Nakai, Ryosuke Sato +1
Spontaneous CP violation, such as the Nelson-Barr (NB) mechanism, is an attractive scenario for addressing the strong CP problem while realizing the observed phase of the Cabibbo-K…
Microlensing constraints on axion stars including finite lens and source size effects
Kohei Fujikura, Mark P. Hertzberg, Enrico D. Schiappacasse +1
A fraction of light scalar dark matter, especially axions, may organize into Bose-Einstein condensates, gravitationally bound clumps, "boson stars", and be present in large number…
Electroweak-like Baryogenesis with New Chiral Matter
Kohei Fujikura, Keisuke Harigaya, Yuichiro Nakai +1
We propose a framework where a phase transition associated with a gauge symmetry breaking that occurs (not far) above the electroweak scale sets a stage for baryogenesis similar to…
Observable Gravitational Waves in Minimal Scotogenic Model
Debasish Borah, Arnab Dasgupta, Kohei Fujikura +2
We scrutinise the widely studied minimal scotogenic model of dark matter (DM) and radiative neutrino mass from the requirement of a strong first order electroweak phase transition…
A more attractive scheme for radion stabilization and supercooled phase transition
Kohei Fujikura, Yuichiro Nakai, Masaki Yamada
We propose a new radion stabilization mechanism in the Randall-Sundrum spacetime, introducing a bulk gauge field which confines at a TeV scale. It turns out that the ra…
Phase Transitions in Twin Higgs Models
Kohei Fujikura, Kohei Kamada, Yuichiro Nakai +1
We study twin Higgs models at non-zero temperature and discuss cosmological phase transitions as well as their implications on electroweak baryogenesis and gravitational waves. It…