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Dive into the research topics where Naoki Yamamoto is active.

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Featured researches published by Naoki Yamamoto.


Physical Review Letters | 2012

Berry Curvature, Triangle Anomalies, and the Chiral Magnetic Effect in Fermi Liquids

Dam Thanh Son; Naoki Yamamoto

In a three-dimensional Fermi liquid, quasiparticles near the Fermi surface may possess a Berry curvature. We show that if the Berry curvature has a nonvanishing flux through the Fermi surface, the particle number associated with this Fermi surface has a triangle anomaly in external electromagnetic fields. We show how Landaus Fermi liquid theory should be modified to take into account the Berry curvature. We show that the chiral magnetic effect also emerges from the Berry curvature flux.


Physical Review Letters | 2006

New critical point induced by the axial anomaly in dense QCD

Tetsuo Hatsuda; Motoi Tachibana; Naoki Yamamoto; Gordon Baym

We study the interplay between chiral and diquark condensates within the framework of the Ginzburg-Landau free energy, and classify possible phase structures of two and three-flavor massless QCD. The QCD axial anomaly acts as an external field applied to the chiral condensate in a color superconductor and leads to a crossover between the broken chiral symmetry and the color superconducting phase, and, in particular, to a new critical point in the QCD phase diagram.


FEBS Letters | 1987

Nucleotide sequence of the PR-1 gene of Nicotiana tabacum

Masahiro Ohshima; Makoto Matsuoka; Naoki Yamamoto; Yoshiyuki Tanaka; Yuriko Kano-Murakami; Yoshihiro Ozeki; Akira Kato; Naoki Harada; Yuko Ohashi

A gene encoding one of the pathogenesis‐related proteins, PR1a, and two related pseudogenes were isolated from Nicotiana tabacum. The cloned PR1a gene (pPR‐γ) and one of the pseudogenes (pPR‐α) were sequenced and found to have similar structures. The sequence of pPR‐γ was quite similar to that of the cDNA clone of PR1a. The plasmid pPR‐γ did not contain an intron and had a typical promoter sequence in the 5′‐flanking region.


Infection and Immunity | 2011

Essential Role of Transcription Factor Nuclear Factor-κB in Regulation of Interleukin-8 Gene Expression by Nitrite Reductase from Pseudomonas aeruginosa in Respiratory Epithelial Cells

Naoki Mori; Kazunori Oishi; Borann Sar; Naofumi Mukaida; Tsuyoshi Nagatake; Kouji Matsushima; Naoki Yamamoto

Persistent infection with Pseudomonas aeruginosa increases interleukin-8 (IL-8) levels and causes dense neutrophil infiltrations in the airways of patients with chronic airway diseases. Recently, we have reported that nitrite reductase from P. aeruginosa induces the production of IL-8 in respiratory cells, including bronchial epithelial cells. To determine the molecular mechanism(s) of nitrite reductase-induced IL-8 expression in respiratory cells, A549 epithelial cells were transfected with plasmids containing serial deletions of the 5′-flanking region of the IL-8 gene and then exposed to nitrite reductase. Nitrite reductase significantly enhanced IL-8 gene promoter-driven reporter activity. This increased IL-8 gene expression was inhibited by mutating the nuclear factor-κB (NF-κB) binding element. Nitrite reductase enhanced nuclear localization of the NF-κB binding complex. Furthermore, nitrite reductase induced the degradation of IκBα, the major cytoplasmic inhibitor of NF-κB, and the expression of IκBα mRNA. These data support the critical role of the activation of NF-κB in nitrite reductase-induced IL-8 gene expression in airway epithelium.Persistent infection with Pseudomonas aeruginosa increases interleukin-8 (IL-8) levels and causes dense neutrophil infiltrations in the airways of patients with chronic airway diseases. Recently, we have reported that nitrite reductase from P. aeruginosa induces the production of IL-8 in respiratory cells, including bronchial epithelial cells. To determine the molecular mechanism(s) of nitrite reductase-induced IL-8 expression in respiratory cells, A549 epithelial cells were transfected with plasmids containing serial deletions of the 5-flanking region of the IL-8 gene and then exposed to nitrite reductase. Nitrite reductase significantly enhanced IL-8 gene promoter-driven reporter activity. This increased IL-8 gene expression was inhibited by mutating the nuclear factor-kappaB (NF-kappaB) binding element. Nitrite reductase enhanced nuclear localization of the NF-kappaB binding complex. Furthermore, nitrite reductase induced the degradation of IkappaBalpha, the major cytoplasmic inhibitor of NF-kappaB, and the expression of IkappaBalpha mRNA. These data support the critical role of the activation of NF-kappaB in nitrite reductase-induced IL-8 gene expression in airway epithelium.


Physical Review D | 2007

Phase structure, collective modes, and the axial anomaly in dense QCD

Naoki Yamamoto; Motoi Tachibana; Tetsuo Hatsuda; Gordon Baym

Using a general Ginzburg-Landau effective Lagrangian, we study the topological structure and low-lying collective modes of dense QCD having both chiral and diquark condensates, for two and three massless flavors. As we found earlier, the QCD axial anomaly acts as an external field applied to the chiral condensate in a color superconductor and, as a new critical point emerges, leads to a crossover between the broken chiral symmetry and color superconducting phases. At intermediate densities where both chiral and diquark condensates are present, we derive a generalized Gell-Mann-Oakes-Renner relation between the masses of pseudoscalar bosons and the magnitude of the chiral and diquark condensates. We show explicitly the continuity of the ordinary pion at low densities to a generalized pion at high densities.


Journal of High Energy Physics | 2012

Universality of Phases in QCD and QCD-like Theories

Masanori Hanada; Naoki Yamamoto

A bstractWe argue that the whole or the part of the phase diagrams of QCD and QCD-like theories should be universal in the large-Nc limit through the orbifold equivalence. The whole phase diagrams, including the chiral phase transitions and the BEC-BCS crossover regions, are identical between SU(Nc) QCD at finite isospin chemical potential and SO(2Nc) and Sp(2Nc) gauge theories at finite baryon chemical potential. Outside the BEC-BCS crossover regions in these theories, the phase diagrams are also identical to that of SU(Nc) QCD at finite baryon chemical potential. We give examples of the universality in some solvable cases: (i) QCD and QCD-like theories at asymptotically high density where the controlled weak-coupling calculations are possible, (ii) chiral random matrix theories of different universality classes, which are solvable large-N (large volume) matrix models of QCD. Our results strongly suggest that the chiral phase transition and the QCD critical point at finite baryon chemical potential can be studied using sign-free theories, such as QCD at finite isospin chemical potential, in lattice simulations.


Journal of High Energy Physics | 2011

Singular values of the Dirac operator in dense QCD-like theories

Takuya Kanazawa; Tilo Wettig; Naoki Yamamoto

A bstractWe study the singular values of the Dirac operator in dense QCD-like theories at zero temperature. The Dirac singular values are real and nonnegative at any nonzero quark density. The scale of their spectrum is set by the diquark condensate, in contrast to the complex Dirac eigenvalues whose scale is set by the chiral condensate at low density and by the BCS gap at high density. We identify three different low-energy effective theories with diquark sources applicable at low, intermediate, and high density, together with their overlapping domains of validity. We derive a number of exact formulas for the Dirac singular values, including Banks-Casher-type relations for the diquark condensate, Smilga-Stern-type relations for the slope of the singular value density, and Leutwyler-Smilga-type sum rules for the inverse singular values. We construct random matrix theories and determine the form of the microscopic spectral correlation functions of the singular values for all nonzero quark densities. We also derive a rigorous index theorem for non-Hermitian Diracoperators. Our results can in principle be tested in lattice simulations.


Physical Review Letters | 2010

Instabilities of Non-Abelian Vortices in Dense QCD

Minoru Eto; Muneto Nitta; Naoki Yamamoto

We construct a low-energy effective theory describing non-abelian vortices in the color superconducting quark matter under stress. We demonstrate that all the vortices are radically unstable against decay into the only one type of vortices due to the potential term induced by the explicit flavor symmetry breaking by the strange quark mass. A simple analytical estimate for the lifetime of unstable vortices is provided under the controlled weak-coupling calculations. We briefly discuss the (non)existence of magnetic monopoles at high density.


Physical Review D | 2010

Nambu-Jona-Lasinio model of dense three-flavor matter with axial anomaly: The low temperature critical point and BEC-BCS diquark crossover

Hiroaki Abuki; Gordon Baym; Tetsuo Hatsuda; Naoki Yamamoto

We study the QCD phase structure in the three-flavor Nambu-Jona-Lasinio model, incorporating the interplay between the chiral and diquark condensates induced by the axial anomaly. We demonstrate that for an appropriate range of parameters of the model, the interplay leads to the low temperature critical point in the phase structure predicted by a previous Ginzburg-Landau analysis. We also show that a Bose-Einstein condensate (BEC) of diquark molecules emerges in the intermediate density region, and as a result, a BEC-BCS crossover is realized with increasing quark chemical potential.


Journal of High Energy Physics | 2009

Chiral Lagrangian and spectral sum rules for dense two-color QCD

Takuya Kanazawa; Tilo Wettig; Naoki Yamamoto

We analytically study two-color QCD with an even number of flavors at high baryon density. This theory is free from the fermion sign problem. Chiral symmetry is broken spontaneously by the diquark condensate. Based on the symmetry breaking pattern we construct the low-energy effective Lagrangian for the Nambu-Goldstone bosons. We identify a new epsilon-regime at high baryon density in which the quark mass dependence of the partition function can be determined exactly. We also derive Leutwyler-Smilga-type spectral sum rules for the complex eigenvalues of the Dirac operator in terms of the fermion gap. Our results can in principle be tested in lattice QCD simulations.

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Tilo Wettig

University of Regensburg

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Yoshimasa Hidaka

Brookhaven National Laboratory

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