Kenji Fukushima

Topological charge changing transitions can induce chirality in the quark-gluon plasma by the axial anomaly. We study the equilibrium response of the quark-gluon plasma in such a situation to an external magnetic field. To mimic the effect of the topological charge changing transitions we will introduce a chiral chemical potential. We will show that an electromagnetic current is generated along the magnetic field. This is the chiral magnetic effect. We compute the magnitude of this current as a

Current status of theoretical researches on the QCD phase diagram at finite temperature and baryon chemical potential is reviewed with special emphasis on the origin of various phases and their symmetry breaking patterns. Topics include; quark deconfinement, chiral symmetry restoration, order of the phase transitions, QCD critical point(s), colour superconductivity, various inhomogeneous states and implications from QCD-like theories.

We discuss how the simultaneous crossovers of deconfinement and chiral restoration can be realized. We propose a dynamical mechanism assuming that the effective potential gives a finite value of the chiral condensate if the Polyakov loop vanishes. Using a simple model, we demonstrate that our idea works well for small quark mass, though there should be further constraints to reach the perfect locking of two phenomena.

We present extensive studies on hot and dense quark matter with two light and one heavy flavors in the Nambu--Jona-Lasinio model with the Polyakov loop (so-called PNJL model). First we discuss prescription dependence in choosing the Polyakov loop effective potential and propose a simple and rather sensible ansatz. We look over quantitative comparison to the lattice measurement to confirm that the model captures thermodynamic properties correctly. We then analyze the phase structure by changing t

We discuss the fate of chiral symmetry in an extremely strong magnetic field B. We investigate not only quark fluctuations but also neutral meson effects. The former enhances the chiral-symmetry breaking at finite B according to the magnetic catalysis, while the latter suppresses the chiral condensate once B exceeds the scale of the hadron structure. Using a chiral model, we demonstrate how neutral mesons are subject to the dimensional reduction and the low dimensionality favors the chiral-symme

We study the two-flavor Nambu--Jona-Lasinio model with the Polyakov loop in the presence of a strong magnetic field and a chiral chemical potential ${\ensuremath{\mu}}_{5}$, which mimics the effect of imbalanced chirality due to QCD instanton and/or sphaleron transitions. First, we focus on the properties of chiral symmetry breaking and deconfinement crossover under the strong magnetic field. Then we discuss the role of ${\ensuremath{\mu}}_{5}$ on the phase structure. Finally, the chirality char

We found an error in the numerical implementation to estimate the effect of the vector-channel interaction with g V 0. We replace Fig. 18 in Ref. [1] by Fig. 1 in this erratum.The corrected results shown in Fig. 1 become closer to the value reported in the two-flavor case [2,3] where the critical value of g V =g S is between 0.15 and 0.2.It should be noted that the normalization of g S in our work is different from Refs.[2,3] by a factor 2. To make sure of the validity and the normalization conv

In quantum chromodynamics, a gauge field configuration with nonzero topological charge generates a difference between the number of left- and right-handed quarks. When a (electromagnetic) magnetic field is added to this configuration, an electromagnetic current is induced along the magnetic field; this is called the chiral magnetic effect. We compute this current in the presence of a color-flux tube possessing topological charge, with a magnetic field applied perpendicular to it. We argue that t

We discuss a puzzle in relativistic spin hydrodynamics; in the previous formulation the spin source from the antisymmetric part of the canonical energy-momentum tensor (EMT) is crucial. The Belinfante improved EMT is pseudo-gauge transformed from the canonical EMT and is usually a physically sensible choice especially when gauge fields are coupled as in magnetohydrodynamics, but the Belinfante EMT has no antisymmetric part. We find that pseudo-transformed entropy currents are physically inequiva

We investigate the effect of a magnetic field on cold dense quark matter using an effective model with four-Fermi interactions. We find that the gap parameters representing the predominant pairing between the different quark flavors show oscillatory behavior as a function of the magnetic field. We point out that due to electric and color neutrality constraints the magnetic fields as strong as presumably existing inside magnetars might induce significant deviations from the gap structure at a zer

We compute the momentum diffusion coefficients of heavy quarks, ${\ensuremath{\kappa}}_{\ensuremath{\parallel}}$ and ${\ensuremath{\kappa}}_{\ensuremath{\perp}}$, in a strong magnetic field $B$ along the directions parallel and perpendicular to $B$, respectively, at the leading order in QCD coupling constant ${\ensuremath{\alpha}}_{s}$. We consider a regime relevant for the relativistic heavy ion collisions, ${\ensuremath{\alpha}}_{s}eB\ensuremath{\ll}{T}^{2}\ensuremath{\ll}eB$, so that thermal

We analyze chiral symmetry breaking in quark matter in an external magnetic field at zero and finite temperature and quark chemical potential. We first give a brief overview of analytic results within the mean-field approximation. There the critical temperature for chiral restoration is increased by the magnetic field effect. Then we investigate the effects of matter and quantum fluctuations on the magnetic catalysis. More specifically, we compute the critical value of the four-Fermi coupling co