13858547
Dynamical aspects of the plane-wave matrix model at finite temperature
We study dynamical aspects of the plane-wave matrix model at finite temperature. One-loop calculation around general classical vacua is performed using the background field method, and the integration over the gauge field moduli is carried out both analytically and numerically. In addition to the trivial vacuum, which corresponds to a single M5-brane at zero temperature, we consider general static fuzzy-sphere type configurations. They are all 1/2 BPS, and hence degenerate at zero temperature due to supersymmetry. This degeneracy is resolved, however, at finite temperature, and we identify the configuration that gives the smallest free energy at each temperature. The Hagedorn transition in each vacuum is studied by using the eigenvalue density method for the gauge field moduli, and the free energy as well as the Polyakov line is obtained analytically near the critical point. This reveals the existence of fuzzy sphere phases, which may correspond to the plasma-ball phases in = 4 SU(?) SYM on S1 ? S3. We also perform Monte Carlo simulation to integrate over the gauge field moduli. While this confirms the validity of the analytic results near the critical point, it also shows that the trivial vacuum gives the smallest free energy throughout the high temperature regime.
15711173
Non-relativistic string and D-branes on AdS5 × S5 from semiclassical approximation
We show that non-relativistic actions of string and D-branes on AdS5???S5 can be reproduced as a semiclassical approximation of the string and D-brane actions around static 1/2 BPS configurations. This is contrastive to the Penrose limit. For example, the pp-wave string can be recaptured as a semiclassical approximation around a 1/2 BPS particle rotating at the velocity of light. We argue that small deformation of a straight Wilson line would give a composite operator in the gauge-theory side that corresponds to a semiclassical state of the non-relativistic string, according to the semiclassical interpretation.
2088281
A tunneling picture of dual giant Wilson loop
We further discuss a rotating dual giant Wilson loop (D3-brane) solution constructed in Lorentzian AdS by Drukker et al. The solution is shown to be composed of a dual giant Wilson loop and a dual giant graviton by minutely examining its shape. Hence it may be supposed that the dual gauge-theory operator should be a k-th symmetric Wilson loop with insertions of dual giant graviton operators. To give a convincing argument for this observation, the classical action of the solution should be evaluated in Euclidean signature. For this purpose we perform a Wick rotation to the Lorentzian solution by following the tunneling prescription and obtain Euclidean solutions attaching to a circle or a straight line on the AdS boundary. The classical action contains a logarithmic divergence which is proportional to the R-charge. It is consistent with the correlation function of the dual giant graviton operators. Because of ambiguities concerning regularization, finite terms of the action do not lead to conclusive evidence. However we may expect that the ambiguities would cancel by subtracting the action of the D3-brane with a straight-line boundary from that with a circular boundary. It is really shown that the difference is consistent with the expectation value of the k-th symmetric Wilson loop. Although our analysis does not specify the unique dual gauge-theory operator, we discuss possible candidates implied by the D3-brane computation.
119327427
Hidden Yangian symmetry in sigma model on squashed sphere
We discuss a hidden symmetry of a two-dimensional sigma model on a squashed S3. The SU(2) current can be improved so that it can be regarded as a flat connection. Then we can obtain an infinite number of conserved non-local charges and show the Yangian algebra by directly checking the Serre relations. This symmetry is also deduced from the coset structure of the squashed sphere. The same argument is applicable to the warped AdS3 spaces by the double Wick rotations.
119324390
Hybrid classical integrable structure of squashed sigma models - a short summary
We give a short summary of our recent works on the classical integrable structure of two-dimensional non-linear sigma models defined on squashed three-dimensional spheres. There are two descriptions to describe the classical dynamics, 1) the rational description and 2) the trigonometric description. It is possible to construct two different types of Lax pairs depending on the descriptions, and the classical integrability is shown by computing classical r/s-matrices satisfying the extended Yang-Baxter equation in both descriptions. In the former the system is described as an integrable system of rational type. On the other hand, in the latter it is described as trigonometric type. There exists a non-local map between the two descriptions and those are equivalent. This is a non-local generalization of the left-right duality in principal chiral models.
18362159
Partition function and open/closed string duality in type IIA string theory on a pp-wave
Abstract We discuss partition functions of N =(4,4) type IIA string theory on the pp-wave background. This theory is shown to be modular invariant. The boundary states are constructed and possible D-brane instantons are classified. Then we calculate cylinder amplitudes in both closed and open string descriptions and check the open/closed string duality. Furthermore we consider general properties of modular invariant partition functions in the case of pp-waves.
106401285
Shape evolution of giant resonances in Nd and Sm isotopes
Giant multipole resonances in Nd and Sm isotopes are studied by employing the quasiparticle-random-phase approximation on the basis of the Skyrme energy-density-functional method. Deformation effects on giant resonances are investigated in these isotopes, which manifest a typical nuclear shape change from spherical to prolate shapes. The peak energy, the broadening, and the deformation splitting of the isoscalar giant monopole (ISGMR) and quadrupole (ISGQR) resonances agree well with measurements. The magnitude of the peak splitting and the fraction of the energy-weighted strength in the lower peak of the ISGMR reflect the nuclear deformation. The experimental data on ISGMR, isoscalar giant dipole (ISGDR), and ISGQR are consistent with the nuclear-matter incompressibility K � 210‐230 MeV and the effective mass m ∗/m � 0.8‐0.9. However, the high-energy octupole resonance (HEOR) in 144 Sm seems to indicate a smaller effective mass, m ∗ /m � 0.7‐0.8. A further precise measurement of HEOR is desired to determine the effective mass.
118539918
A new vector-tensor theory and higher-dimensional cosmology
A new vector-tensor model of classical gravity, which contains coupling between the field strength of the vector field and the curvature tensors in six dimensions, is proposed. Cosmological solutions of the scale factors in this model with the compactified space are obtained. The generalization of the model is also considered.
120866230
Z-trigger system with the BELLE Central Drift Chamber
Abstract We describe the design and performance of a fast Z -trigger system with the BELLE Central Drift Chamber. It utilizes z -position information from the axial/stereo wire hits as well as the cathode strip. This system is essential to reduce the false trigger rate from caused by the spent electrons or positrons interacting with the material around the beam pipe. We tested the performance of the system using cosmic rays in a magnetic field of 1.5 T, provided by a superconducting solenoid. The trigger efficiency was 98% for a single track passing through the interaction region. This trigger was effective in rejecting tracks originating from points more than 10 cm away from the interaction point.
121845872
Test of charge-to-time conversion and multi-hit TDC technique for the BELLE CDC readout
We tested a new CDC readout scheme utilizing a Charge-to-Time conversion (QTC) technique and multi-hit TDC to record both time and charge information. The new scheme is planned to be used in the BELLE experiment at the KEK B-Factory. We built a prototype Shaper/QTC board and examined the performance with a beam test. This new scheme worked successfully. We obtained the same spatial and dEdx resolutions as those using an ordinary TDC and ADC readout scheme.
15470225
Analysis of the phase structure of thermal QED/QCD through the HTL improved ladder Dyson-Schwinger equation: On the gauge dependence of the solution
We solved with a numerical procedure the HTL improved ladder DS equation for the retarded fermion self-energy function $\Sigma_R$ to study the spontaneous generation of fermion mass in thermal QCD/QED, and studied the gauge-dependence of the solution within a general covariant gauge where the gauge parameter $\xi$ is any constant number. 
With the numerical solutions thus obtained, we found the followings; i) The fermion wave function renormalization function $A(P)$ always deviates largely from unity even at the momentum where the mass is defined, thus the corresponding solutions explicitly contradict with the Ward-Takahashi identity. ii) As a result, the obtained solutions strongly depend on the choice of gauge parameters: the critical temperatures and the critical coupling constants significantly change gauge by gauge. In all gauges we studied in the present analysis, we could not find any solution, having a possibility to be consistent with the Ward-Takahashi identity. Thus we are forced to investigate the procedure to find a gauge which enables us to get a solution being consistent with the Ward-Takahashi identity, otherwise we can not obtain any physically sensible conclusions through the analysis of the point-vertex ladder DS equation no matter how the gauge propagator gets improved.