763 citations · 3k across the 68 of their papers we have counts for
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Isospin QCD as a laboratory for dense QCD
Toru Kojo, Daiki Suenaga, Ryuji Chiba
QCD with the isospin chemical potential, , is a useful laboratory to delineate the microphysics in dense QCD. To study the quark-hadron-continuity we use a quark-meson model t…
Thermal effects on sound velocity peak and conformality in isospin QCD
Ryuji Chiba, Toru Kojo, Daiki Suenaga
We study thermal effects on equations of state (EOS) in isospin QCD, utilizing a quark-meson model coupled to a Polyakov loop. The quark-meson model is analyzed at one-loop that is…
Parity doublet model for baryon octets: diquark classifications and mass hierarchy based on the quark-line diagram
Takuya Minamikawa, Bikai Gao, Toru kojo +1
We construct invariant parity doublet models within the linear realization of the chiral symmetry. Describing baryons as the supe…
Sound velocity peak and conformality in isospin QCD
Ryuji Chiba, Toru Kojo
We study zero temperature equations of state (EOS) in isospin QCD within a quark-meson model which is renormalizable and hence eliminates high density artifacts in models with the…
Meson resonance gas in a relativistic quark model: scalar vs vector confinement and semishort range correlations
Toru Kojo, Daiki Suenaga
Smooth transitions from hadronic matter to hot and dense matter of quantum chromodynamics accompany continuous transformations in effective degrees of freedom. The microscopic desc…
Peaks of sound velocity in two color dense QCD: quark saturation effects and semishort range correlations
Toru Kojo, Daiki Suenaga
We discuss stiffening of dense matter in two color QCD (QCD) where hadrons are mesons and diquark baryons. We study two models which describe a transition of matter from the Bo…
Delineating chiral separation effect in two-color dense QCD
Daiki Suenaga, Toru Kojo
We study the chiral separation effect (CSE) in two-color and two-flavor QCD (QCD) to delineate quasiparticle pictures in dense matter from low to high temperatures. Both massle…
Neutral and charged mesons in magnetic fields: A resonance gas in a non-relativistic quark model
Toru Kojo
We analyze mesons in constant magnetic fields () within a non-relativistic constituent quark model. Our quark model contains a harmonic oscillator type confining potential, and…
Thermal quarks and gluon propagators in two-color dense QCD
Toru Kojo, Daiki Suenaga
We study Landau gauge gluon propagators in two-color QCD at finite quark chemical potential () and temperature (). We include medium polarization effects at one-loop by qua…
Hard-core deconfinement and soft-surface delocalization from nuclear to quark matter
Kenji Fukushima, Toru Kojo, Wolfram Weise
We propose a conceptual distinction between hard and soft realizations of deconfinement from nuclear to quark matter. In the high density region of Hard Deconfinement the repulsive…
Quark fluctuations and anisotropic confinement in magnetic fields
Gaoqing Cao, Toru Kojo
We study the string tension of quantum chromodynamics (QCD) in external magnetic fields by combining the quasi-particle treatments for quarks with the collective treatments…
Gluon propagator in two-color dense QCD: Massive Yang-Mills approach at one-loop
Daiki Suenaga, Toru Kojo
We study the Landau gauge gluon propagators in dense two-color QCD at quark chemical potential, , in the range from 0.5 to 1.0 GeV not reachable by the perturbative method at…
Zero point energy of composite particles: The medium effects
Toru Kojo
We analyze the zero point energy of composite particles (or resonances) which are dynamically created from relativistic fermions. We compare the zero point energies in medium to th…
Renormalizing the zero point energy in dense QCD
Toru Kojo
We analyze the zero point energy in a dense matter of quarks or hadrons with particular attention on the renormalization of the UV divergences. Besides divergences removable by the…
Functional renormalization group study of the Quark-Meson model with meson
Hui Zhang, Defu Hou, Toru Kojo +1
We study the phase diagram of two-flavor massless QCD at finite baryon density by applying the functional renormalization group (FRG) for a quark-meson model with , and m…
Pseudo Nambu-Goldstone modes in neutron stars
Toru Kojo
If quarks and gluons are either gapped or confined in neutron stars (NSs), the most relevant light modes are Nambu-Goldstone (NG) modes. We study NG modes within a schematic quark…
Phenomenological QCD equations of state for neutron stars
Toru Kojo, Philip D. Powell, Yifan Song +1
We delineate the properties of QCD matter at baryon density n_B=1-10n_0 (n_0: nuclear saturation density), through the construction of neutron star equations of state that satisfy…
Mesons in strong magnetic fields: (I) General analyses
Koichi Hattori, Toru Kojo, Nan Su
We study properties of neutral and charged mesons in strong magnetic fields |eB|>> Lambda_QCD^2 with Lambda_QCD being the QCD renormalization scale. Assuming long-range interaction…
Phenomenological neutron star equations of state: 3-window modeling of QCD matter
Toru Kojo
We discuss the 3-window modeling of cold, dense QCD matter equations of state at density relevant to neutron star properties. At low baryon density, n_B < ~ 2n_s (n_s: nuclear satu…
Phenomenological QCD equation of state for massive neutron stars
Toru Kojo, Philip D. Powell, Yifan Song +1
We construct an equation of state for massive neutron stars based on quantum chromodynamics phenomenology. Our primary purpose is to delineate the relevant ingredients of equations…
The quark mass gap in strong magnetic fields
Toru Kojo, Nan Su
Quarks in strong magnetic fields (|eB|>>Lambda_QCD^2 ~ 0.04 GeV^2) acquire enhanced infrared phase space proportional to |eB|. Accordingly they provide larger chiral condensates an…
Chiral Spirals from Noncontinuous Chiral Symmetry: The Gross-Neveu model results
Toru Kojo
It is shown that the inhomogeneous chiral condensate in the Gross-Neveu (GN) model takes the chiral spiral form, even though the thermodynamic functional depends only on the chiral…
Color screening in cold quark matter
Toru Kojo, Gordon Baym
We compute---at finite quark chemical potentials---the color screening of cold quark matter at the one-loop level, comparing the normal, BCS-paired U(1)em (or Higgs) phase and a si…
A renormalization group approach for QCD in a strong magnetic field
Toru Kojo, Nan Su
A Wilsonian renormalization group approach is applied, in order to include effects of the higher Landau levels for quarks into a set of renormalized parameters for the lowest Landa…