9703916
Thermodynamic behavior of fuzzy membranes in pp-wave matrix model
Abstract We discuss a two-body interaction of membrane fuzzy spheres in a pp-wave matrix model at finite temperature by considering the system that a fuzzy sphere rotates with a constant radius r around the other one sitting at the origin in the SO ( 6 ) symmetric space. This system of two fuzzy spheres is supersymmetric at zero temperature and there is no interaction between them. Once the system is coupled to the heat bath, supersymmetries are completely broken and non-trivial interaction appears. We numerically show that the potential between fuzzy spheres is attractive and so the rotating fuzzy sphere tends to fall into the origin. The analytic formula of the free energy is also evaluated in the large N limit. It is well approximated by a polylog function.
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.
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.
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.
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.
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.
123690671
Non-local representation of (2+1)-dimensional quantum gravity with spinor field
Non-local representation of(2+1)-dimensional quantum gravity coupled with the spinor field is considered. We first introduce non-local variables and obtain non-local quantities that are equivalent to the local constraints in some limit. The quantization of these non-local variables is executed in a non-local representation that is similar to the loop representation of pure gravity. The contribution of spinor fields in the state functionals depends not only on the space of loops but also on the space of lines. A state functional which is the solution of all constraint equations is also obtained.
121806959
Measurements of interaction cross sections for light neutron-rich nuclei at relativistic energies and determination of effective matter radii
Abstract We measured the interaction cross sections ( σ I ) of 10,11B, 12–20C, 14–23N, 16–24O and 18–26F on carbon targets at energies of around 950 A MeV. We then deduced the effective matter radii of the nuclei by a Glauber-model analysis. Based on the assumption of a core plus a valence neutron structure, we applied a Glauber-model analysis for a few-body system adapted for nuclei with an odd neutron number. We also deduced the effective nucleus-matter densities as well as some spectroscopic information for selected nuclei. Evidence for a one-neutron halo structure was found for 22N, 23O and 24F, as well as 19C.
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.
121300048
DECAY PATTERN OF PYGMY STATES OBSERVED IN NEUTRON-RICH 26Ne
Coulomb excitation of the exotic neutron-rich nucleus 26Ne on a 208Pb target was measured at 58 A.MeV in order to search for low-lying E1 strength above the neutron emission threshold. The radioactive beam was produced by fragmentation of a 95 A.MeVAr beam delivered by the RIKEN Accelerator Research Facility. The set-up included a NaI(Tl) gamma-ray array, a charged fragment hodoscope and a neutron wall. Using the invariant mass method in the 25Ne+n channel, we observe by multipole decomposition a sizable amount of E1 strength between 6 and 10 MeV excitation energy. For the first time, the decay pattern of low-lying strength in a neutron-rich nucleus is measured.
118850311
Phase Structure of Thermal QCD/QED:A Gauge Invariant Solution of the HTL Resummed Improved Ladder Dyson-Schwinger Equation
Based on the hard-thermal-loop resummed improved ladder Dyson-Schwinger quation for the fermion mass function, we propose a procedure how we can get the gauge invariant solution in the sense it satisfies the Ward-Takahashi identity. Results of the numerical analysis are shown and properties of the ``gauge-invariant'' solutions are discussed.