64414878
IN-VACUUM UNDULATOR CONTROLLER DESIGN FOR SSRF
Two 25mm period in-vacuum undulators (IVU25) have been installed in SSRF 3.5 GeV storage ring. The controller for IVU25 based on Siemens S7-300 PLC is used to control two stepper motors for the gap and tapper of magnetic pole array. The controller monitors cooling water’s temperature and flux, monitor the array’s temperature, too. And configure Ethernet access for remote control as well as MPS and PPS interlock. A simple user interface supports routine operation and detail information is showed at cascading windows. With real time feedback of the linear absolute encoders (LAEs) the tracking precision of gap and taper are less than 1 micron. This paper describes the design of controller hardware and software.
121239786
Eddy current septum magnets for injection and extraction at SSRF
There are 6 in-vacuum eddy current septum magnets used for booster injection, extraction, and storage ring injection in SSRF. Special attention was paid to coils and their support designs because of the shock force they bear in the magnetic fields and the high heat which is hard to be dissipated in vacuum environment. For the storage ring magnets, good transverse homogeneity in the gap was achieved by careful design, precise machining and accurate assembly; and an extremely low leakage field on the stored beam is another key feature thanks to the high permeability Mu metal. Magnetic field measurement was conducted with both a point coil and a long integral coil, and the results agree well with the OPERA-2d/3d simulations. An inner tube is added to keep the continuity of impedance for the circulating beam with two RF finger flanges at each end. There is no vacuum separation between the inner tube and the magnet chamber. Sputter ion pumps integrated with NEG are used to acquire the UHV for the chamber.
10101389
Symplectic structure of Yang-Mills theory in BRST formalism.
We construct a symplectic form for classical Yang-Mills theory, which is manifestly covariant and Becchi-Rouet-Stora-Tyutin invariant. This suggests an approach to eliminate the degeneracy that exists in the initially given two-form for the theory.
28164273
General theory of quantum statistics with internal degrees of freedom in two dimensions.
The general theory of θ statistics with internal degrees of freedom is presented. The intrinsic parts of wave functions are expressed by means of the irreducible representations of the quantum group SU(2,q) with q=e −iθ . We show that the violation of P or T reflection symmetry is involved in two kinds of coproduct for constructing these representations
43134745
Free heterotic string field theory.
A gauge-fixed action is constructed for the free heterotic string based on the bosonic string and the Neveu-Schwarz-Ramond (NSR) superstring by the Becchi-Rouet-Stora-Tyutin approach. The field theory gives a balance condition; it replaces the Gliozzi-Scherk-Olive projector in the NS sector to eliminate the tachyons and to ensure that the states have the correct spin statistics. At the massless level we get a ten-dimensional linearized supergravity, a ten-dimensional linearized super-Yang-Mills field with the gauge group E/sub 8/ x E/sub 8/ or Spin(32)/Z/sub 2/, a dilaton, an interesting dilatonlike Majorana-Weyl spinor, and so on.
15105862
Two-loop analysis of non-Abelian Chern-Simons theory.
Perturbative renormalization of a non-Abelian Chern-Simons gauge theory is examined. It is demonstrated by explicit calculation that, in the pure Chern-Simons theory, the [beta] function for the coefficient of the Chern-Simons term vanishes to three-loop order. Both dimensional regularization and regularization by introducing a conventional Yang-Mills term in the action are used. It is shown that dimensional regularization is not gauge invariant at two loops. A variant of this procedure, similar to regularization by dimensional reduction used in supersymmetric field theories, is shown to obey the Slavnov-Taylor identity to two loops and gives no renormalization of the Chern-Simons term. Regularization with the Yang-Mills term yields a finite integer-valued renormalization of the coefficient of the Chern-Simons term at one loop, and we conjecture no renormalization at higher order. We also examine the renormalization of Chern-Simons theory coupled to matter. We show that in the non-Abelian case the Chern-Simons gauge field as well as the matter fields require infinite renormalization at two loops and therefore obtain nontrivial anomalous dimensions. We show that the [beta] function for the gauge coupling constant is zero to two-loop order, consistent with the topological quantization condition for this constant.
16855657
Critical statistical charge for anyonic superconductivity.
We examine a criterion for the anyonic superconductivity at zero temperature in Abelian matter-coupled Chern-Simons gauge-field theories in three dimensions. By solving the Dyson-Schwinger equations, we obtain a critical value of the statistical charge for the superconducting phase in a massless fermion-Chern-Simons model. {copyright} {ital 1996 The American Physical Society.}