56 citations · 229 across the 24 of their papers we have counts for
27 papers
Phase transition dynamics of Abelian-Higgs vortices in the oscillating axion background
Naoya Kitajima, Shota Nakagawa
We investigate the effect of an oscillating axion background on thermally induced vortex-antivortex production in the Abelian-Higgs model. Through its coupling to the gauge field,…
Predictive Rerouting of Connected and Automated Vehicles Using Traffic and Charging Demand Forecasts
Tony Kinchen, Ting Bai, Andreas A. Malikopoulos
In this paper, we consider the problem of predictive rerouting of connected and automated vehicles (CAVs) in mixed traffic with electric vehicle charging demand. We provide a frame…
Particle Production via Rippled Bubble Walls
Ryusuke Jinno, Shota Nakagawa, Yuichiro Nakai +1
We investigate non-thermal particle production during first-order phase transitions in the presence of ultra-relativistic thick bubble walls with non-trivial internal structure. Ex…
Transient Bias for CP Domain Wall Decay and Dark Matter
Sally Yuxuan Hao, Fangchao Liu, Shota Nakagawa +1
Spontaneous CP violation (SCPV) provides an attractive solution to the strong CP problem. However, SCPV after inflation suffers from the formation of CP domain walls, requiring the…
Exploring the Landscape of Spontaneous CP Violation in Supersymmetric Theories
Fangchao Liu, Shota Nakagawa, Yuichiro Nakai +1
The strong CP problem remains one of the most important unresolved issues in the Standard Model. Spontaneous CP violation (SCPV) is a promising approach to the problem by assuming…
High Reheating Temperature without Axion Domain Walls
Shota Nakagawa, Yuichiro Nakai, Yu-Cheng Qiu +2
We investigate a cosmological scenario in which the Peccei-Quinn (PQ) symmetry remains broken in the entire history of the Universe, thereby avoiding the formation of axion strings…
Abelian-Higgs vortices in the oscillating axion background
Naoya Kitajima, Shota Nakagawa
We study the dynamics of Abelian-Higgs vortices in the background of a coherently oscillating axion field. We show that the electric field is induced in the magnetic core of the vo…
Bias with a Timer: Axion Domain Wall Decay and Dark Matter
Sally Yuxuan Hao, Shota Nakagawa, Yuichiro Nakai +1
We explore the interplay of the post-inflationary QCD axion and a light scalar field for the axion domain wall decay and dark matter (DM). The scalar field possesses a nonzero vacu…
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…
Interpreting Cosmic Birefringence and DESI Data with Evolving Axion in CDM
Shota Nakagawa, Yuichiro Nakai, Yu-Cheng Qiu +1
Recent cosmological observations have revealed growing tensions with the standard CDM model, including indications of isotropic cosmic birefringence and deviations from …
High Quality QCD Axion via Electric-Magnetic Duality
Shota Nakagawa, Yuichiro Nakai, Junxuan Xu +1
We propose a novel paradigm for the QCD axion with high-quality Peccei-Quinn (PQ) symmetry on the basis of electric-magnetic duality in the conformal window of a supersymmetric gau…
A Bound on Light Dark Photon Dark Matter
Naoya Kitajima, Shota Nakagawa, Fuminobu Takahashi +1
We derive a bound on dark photon dark matter scenarios where the dark photon mass is generated through the Higgs mechanism, based on the requirement that symmetry breaking must occ…
Cosmological Roles of Dark Photons in Axion-induced Electroweak Baryogenesis
Kwang Sik Jeong, Ju Hyeong Kang, Shota Nakagawa
By coupling to both the Higgs and electroweak gauge sectors, an axion can generate the matter-antimatter asymmetry in the universe via electroweak baryogenesis when the axion decay…
Spontaneous CP violation in Supersymmetric QCD
Shota Nakagawa, Yuichiro Nakai, Yaoduo Wang
We investigate a composite model of spontaneous CP violation based on a new supersymmetric QCD as a solution to the strong CP problem. The scalar components of the meson chiral sup…
Asymmetric Warm Dark Matter: from Cosmological Asymmetry to Chirality of Life
Wen Yin, Shota Nakagawa, Tamaki Murokoshi +1
We investigate a novel scenario involving asymmetric keV-range dark matter (DM) in the form of right-handed (sterile) neutrinos. Based on the Fermi-Dirac distribution, we demonstra…
How Viable Is a QCD Axion near 10 MeV?
Sudhakantha Girmohanta, Shota Nakagawa, Yuichiro Nakai +1
There has been an attempt to revive the visible QCD axion at the 10 MeV scale assuming that it exclusively couples to the first-generation quarks and the electron. This variant of…
Dissipation of axion energy via the Schwinger and Witten effects
Kwang Sik Jeong, Shota Nakagawa, Fuminobu Takahashi +1
In the presence of an anomalous CP phase in a U(1) gauge theory, a monopole becomes a dyon via the Witten effect. When the anomalous CP phase is promoted to a dynamical field, the…
Dynamics of Superconformal Axion: Quality and Scalegenesis
Shota Nakagawa, Yuichiro Nakai, Masaki Yamada +1
We explore a dynamical mechanism to realize the emergence of a global symmetry and its spontaneous breaking at an intermediate scale for an axion solution to the st…
Axion dark matter from first-order phase transition, and very high energy photons from GRB 221009A
Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada +1
We study an axion-like particle (ALP) that experiences the first-order phase transition with respect to its mass or potential minimum. This can be realized if the ALP obtains a pot…
Early dark energy by dark Higgs, and axion-induced non-thermal trapping
Shota Nakagawa, Fuminobu Takahashi, Wen Yin
We propose a new scenario of early dark energy (EDE) with a dark Higgs trapped at the origin. To keep this dark Higgs trapped until around the matter-radiation equality, we use dar…
Cosmological effects of Peccei-Quinn symmetry breaking on QCD axion dark matter
Kwang Sik Jeong, Kohei Matsukawa, Shota Nakagawa +1
We study cosmological effects of explicit Peccei-Quinn breaking on the QCD axion dark matter. We find that the axion abundance decreases or increases significantly depending on the…
Non-thermally trapped inflation by tachyonic dark photon production
Naoya Kitajima, Shota Nakagawa, Fuminobu Takahashi
We show that a dark Higgs field charged under U(1) gauge symmetry is trapped at the origin for a long time, if dark photons are produced by an axion condensate via tachyo…
Cosmic Birefringence Triggered by Dark Matter Domination
Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada
Cosmic birefringence is predicted if an axion-like particle (ALP) moves after the recombination. We show that this naturally happens if the ALP is coupled to the dark matter densit…
Trapping Effect for QCD Axion Dark Matter
Shota Nakagawa, Fuminobu Takahashi, Masaki Yamada
In the early universe, the potential of a scalar field can be significantly modified, and the scalar field may be trapped for a long time in a different location than the current v…