37 research outputs found
Holographic Confining Gauge theory and Response to Electric Field
We study the response of confining gauge theory to the external electric
field by using holographic Yang-Mills theories in the large limit.
Although the theories are in the confinement phase, we find a transition from
the insulator to the conductor phase when the electric field exceeds its
critical value. Then, the baryon number current is generated in the conductor
phase. At the same time, in this phase, the meson melting is observed through
the quasi-normal modes of meson spectrum. Possible ideas are given for the
string state corresponding to the melted mesons, and they lead to the idea that
the source of this current may be identified with the quarks and anti-quarks
supplied by the melted mesons. We also discuss about other possible carriers.
Furthermore, from the analysis of the massless quark, chiral symmetry
restoration is observed at the insulator-conductor transition point by studying
a confining theory in which the chiral symmetry is broken.Comment: 27 pages, 14 figure
Holographic Approach to Regge Trajectory and Rotating D5 brane
We study the Regge trajectories of holographic mesons and baryons by
considering rotating strings and D5 brane, which is introduced as the baryon
vertex. Our model is based on the type IIB superstring theory with the
background of asymptotic . This background is dual to a
confining supersymmetric Yang-Mills theory (SYM) with gauge condensate,
, which determines the tension of the linear potential between the quark
and anti-quark. Then the slope of the meson trajectory () is given
by this condensate as at large spin . This
relation is compatible with the other theoretical results and experiments. For
the baryon, we show the importance of spinning baryon vertex to obtain a Regge
slope compatible with the one of and series. In both cases, mesons
and baryons, the trajectories are shifted to large mass side with the same
slope for increasing current quark mass.Comment: 28 pages, 7 figure
Holographic Penta and Hepta Quark State in Confining Gauge Theories
We study a new embedding solutions of D5 brane in an asymptotic
AdS space-time, which is dual to a confining gauge
theory. The D5 brane is wrapped on as in the case of the vertex of
holographic baryon. However, the solution given here is different from the
usual baryon vertex in the point that it couples to -anti-quarks and
quarks on the opposite two points of , the north and south poles,
respectively. The total quark number of this state is preserved as when
minus one is assigned to anti-quark, then it forms a color singlet like the
baryon. However, this includes anti-quarks and quarks, whose number is larger
than that of the baryon. When we set as , we find the so called penta
and hepta-quark states. We study the dynamical properties of these states by
solving the vertex and string configurations for such states. The mass spectra
of these states and the tension of the stretched vertex are estimated, and they
are compared with that of the baryon.Comment: 24 pages, 6 figure
Holographic Glueballs and Infrared Wall Driven by Dilaton
We study glueballs in the holographic gauge theories, supersymmetric and
non-super symmetric cases, which are given by the type IIB superstring
solutions with non-trivial dilaton. In both cases, the dilaton reflects the
condensate of the gauge field strength, , which is responsible to the
linear confining potential between the quark and anti-quark. Then we could see
the meson spectra. On the other hand, the glueball spectra are not found in the
supersymmetric case. We need a sharp wall, which corresponds to an infrared
cutoff, in order to obtain the glueballs. In the non-supersymmetric case, the
quantized glueballs are actually observed due to the existence of such a wall
driven by the dilaton. The strings and D-branes introduced as building blocks
of hadrons are pushed out by this wall, and we could see the Regge behavior of
the higher spin meson and glueball states. We find that the slope of the
glueball trajectory is half of the flavor meson's one. As for the low spin
glueballs, they are studied by solving the fluctuations of the bulk fields, and
their discrete spectra are shown.Comment: 35 pages, 6 figure
Roles of the DYRK Kinase Pom2 in Cytokinesis, Mitochondrial Morphology, and Sporulation in Fission Yeast
Pom2 is predicted to be a dual-specificity tyrosine-phosphorylation regulated kinase (DYRK) related to Pom1 in Schizosaccharomyces pombe. DYRKs share a kinase domain capable of catalyzing autophosphorylation on tyrosine and exogenous phosphorylation on serine/threonine residues. Here we show that Pom2 is functionally different from the well-characterized Pom1, although they share 55% identity in the kinase domain and the Pom2 kinase domain functionally complements that of Pom1. Pom2 localizes to mitochondria throughout the cell cycle and to the contractile ring during late stages of cytokinesis. Overexpression but not deletion of pom2 results in severe defects in cytokinesis, indicating that Pom2 might share an overlapping function with other proteins in regulating cytokinesis. Gain and loss of function analyses reveal that Pom2 is required for maintaining mitochondrial morphology independently of microtubules. Intriguingly, most meiotic pom2Δ cells form aberrant asci with meiotic and/or forespore membrane formation defects. Taken together, Pom2 is a novel DYRK kinase involved in regulating cytokinesis, mitochondrial morphology, meiosis, and sporulation in fission yeast