118661785
Holographic nuclei: supersymmetric examples
We provide a dual gravity description of a supersymmetric heavy nucleus, following the idea of our previous paper arXiv/0809.3141. The supersymmetric nucleus consists of a merginal bound state of A baryons distributed over a ball in 3 dimensions. In the gauge/string duality, the baryon in = 4 super Yang-Mills (SYM) theory corresponds to a D5-brane wrapping S5 of the AdS5×S5 spacetime, so the nucleus corresponds to a collection of A D5-branes. We take a large A and a near horizon limits of a back-reacted geometry generated by the wrapped A D5-branes, where we find a gap in the supergravity fluctuation spectrum. This spectrum is a gravity dual of giant resonances of heavy nuclei, in the supersymmetric toy example of QCD.
14363850
BIRTH OF CLOSED STRINGS AND DEATH OF OPEN STRINGS DURING TACHYON CONDENSATION
The tremendous progress achieved through the study of black holes and branes suggests that their time-dependent generalizations called Spacelike branes (S-branes) may prove similarly useful. An example of an established approach to S-branes is to include a string boundary interaction and we first summarize evidence for the death of open string degrees of freedom for the homogeneous rolling tachyon on a decaying brane. Then, we review how to extract the flat S-brane worldvolumes describing the homogeneous rolling tachyon and how large deformations correspond to creation of lower dimensional strings and branes. These S-brane worldvolumes are governed by S-brane actions which are on equal footing to D-brane actions, since they are derived by imposing conformality on the string worldsheet, as well as by analyzing fluctuations of time-dependent tachyon configurations. As further examples we generalize previous solutions of the S-brane actions so as to describe multiple decaying and nucleating closed fundamenta...
53953635
Rapid Thermalization by Baryon Injection in Gauge/Gravity Duality
Using the AdS/CFT correspondence for strongly coupled gauge theories, we calculate thermalization of mesons caused by a time-dependent change of a baryon number chemical potential. On the gravity side, the thermalization corresponds to a horizon formation on the probe flavor brane in the AdS throat. Since heavy ion collisions are locally approximated by a sudden change of the baryon number chemical potential, we discuss implication of our results to RHIC and LHC experiments, to find a rough estimate of rather rapid thermalization time-scale t_{th} < 1 [fm/c]. We also discuss universality of our analysis against varying gauge theories.
8625540
Solitons in supersymmety breaking meta-stable vacua
In recently found supersymmetry-breaking meta-stable vacua of the supersymmetric QCD, we examine possible exsitence of solitons. Homotopy groups of the moduli space of the meta-stable vacua show that there is no nontrivial soliton for SU(Nc) gauge group. When U(1)B symmetry present in the theory is gauged, we find non-BPS solitonic (vortex) strings whose existence and properties are predicted from brane configurations. We obtain explicit classical solutions which reproduce the predicitions. For SO(Nc) gauge group, we find there are solitonic strings for N≡Nf−Nc+4 = 2, and Z2 strings for the other N. The strings are meta-stable as they live in the meta-stable vacua.
16844941
ADHM is tachyon condensation
We completely realize the ADHM construction of instantons in D-brane language of tachyon condensations. Every step of the construction is given a physi- cal interpretation in string theory, in a boundary state formalism valid all order in � ' . Accordingly, equivalence between Yang-Mills configurations on D4-branes and D0-branes inside the D4-branes is proven, which shows that small instanton config- urations of the Yang-Mills fields are protected against stringy � ' corrections. We provide also D-brane realizations of the inverse ADHM construction, the complete- ness, and the noncommutative ADHM construction.
14655561
Metamorphosis of tachyon profile in unstable D9-branes
We explored a variety of brane configurations in our previous paper within the two derivative truncation of the unstable D9-brane effective theory. In this paper we extend our previous results with emphasis on the inclusion of the higher derivative corrections for the tachyon and the gauge fields computed in the boundary string field theories. We give the exact solutions to BPS brane configurations studied in our previous paper and find remarkable exact agreements of their energies and RR-charges with the expected results. We further find a few more solutions that we could not construct in the two derivative truncations, such as a (F,D6) bound state ending on a D8-brane whose existence turns out to be due to a higher derivative effect and also the dielectric brane of Emparan and Myers as a nonsupersymmetric example. These are also in exact agreements with the results obtained in the effective theory of supersymmetric D-branes.
119245910
Development of lattice QCD tool kit on cell broadband engine processor
Research Institute for Information Science and Education, Hiroshima University,Higashi-Hiroshima, Hiroshima, 739-8521, JapanE-mail: nakamura@riise.hiroshima-u.ac.jpWe report an implementation of a code for SU(3) matrix multiplication on Cell/B.E., which is apart of our project, Lattice Tool Kit on Cell/B.E.. On QS20, the speed of the matrix multiplicationon SPE in single precision is 227GFLOPS and it becomes 20GFLOPS together with data transferfrom main memory by DNA transfer, which is 4.6% of the hardware peak speed (460GFLOPS),and is 7.4% of the theoretical peak speed of this calculation (268.77GFLOPS). We brieﬂy describeour tuning procedure.The XXVII International Symposium on Lattice Field Theory - LAT2009July 26-31 2009Peking University, Beijing, China
17561372
The static quark potential in 2+1 flavour Domain Wall QCD from QCDOC
We report our present status of on-going project on the measurement of the static quark potential in 2+1 flavour domain wall QCD with various improved gauge actions and couplings. Lattice spacing determined from Sommer scale on these ensembles are from 1.6 GeV to 2.0 GeV for $16^3 \times 32$ lattice with fifth dimension size 8. We also examine size of discretization error from scaling of a pair of dimensionless quantities, $(r_0 m_\pi)^2$ and $r_0 m_\rho$, and found small scaling violation.