12388929
Non-supersymmetric attractors in BI black holes
Abstract We study attractor mechanism in extremal black holes of Einstein–Born–Infeld theories in four dimensions. We look for solutions which are regular near the horizon and show that they exist and enjoy the attractor behavior. The attractor point is determined by extremization of the effective potential at the horizon. This analysis includes the backreaction and supports the validity of non-supersymmetric attractors in the presence of higher derivative interactions in the gauge field part.
118397938
BRANE SOLUTIONS WITH TENSION
In this note, we apply a special metric ansatz to simplify the equations of motion for gravitational systems. Then we construct charged brane solutions in D = n+p+2 dimensions which have spherical symmetry of Sn and translational symmetry along p directions. They are characterized by mass density, uniform tension and electric/magnetic charges, and nonsingular only for specific tension. In particular, we find the limits and the coordinate transformations which reduce the charged brane solutions to M2- and M5-branes. We also obtain the regularity condition for an electrically charged two-brane solution which has two tensions.
118481681
Thermal aspects of the ABJM theory: currents and condensations
To study thermal aspects of the ABJM theory in the strongly coupled regime, we carry out the invariant dimensional reduction of the type IIA supergravity down to four dimensions. We then investigate zero and finite temperature responses of the operators which are dual to the AdS scalar and vector fields. Two scalar operators are shown to have finite-temperature condensations by coupling of the constant source term. The currents dual to the massless and massive gauge fields are not induced by coupling of the constant boundary vector potential, which implies that the phase described by the black brane background is not superconducting. We also discuss a generalization to charged (dyonic) black holes.
113398368
Calabi-Yau Manifolds, Hermitian Yang-Mills Instantons, and Mirror Symmetry
We address the issue of why Calabi-Yau manifolds exist with a mirror pair. We observe that the irreducible spinor representation of the Lorentz group requires us to consider the vector spaces of two forms and four forms on an equal footing. The doubling of the two-form vector space due to the Hodge duality doubles the variety of six-dimensional spin manifolds. We explore how the doubling is related to the mirror symmetry of Calabi-Yau manifolds. Via the gauge theory formulation of six-dimensional Riemannian manifolds, we show that the curvature tensor of a Calabi-Yau manifold satisfies the Hermitian Yang-Mills equations on the Calabi-Yau manifold. Therefore, the mirror symmetry of Calabi-Yau manifolds can be recast as the mirror pair of Hermitian Yang-Mills instantons. We discuss the mirror symmetry from the gauge theory perspective.
15073869
Non-Supersymmetric Unattractors in Born-Infeld Black Holes
We investigate unattractor behavior in non-extremal black holes in Einstein-Born-Infeld-Dilaton theory of gravity in four-dimensional asymptotically flat spacetime. We obtain solutions which are non-singular near the horizon and dependent on the value of the dilaton field at the infinity, using perturbation method. It is shown that the value of the scalar field at the horizon is determined by its asymptotic value and the charges carried by the black hole. And we also find it is not true in general that the dilaton value at the horizon is a monotonically increasing function of the first coefficient of its series expansion in non-extremal Born-Infeld black holes.
11614231
Moduli flow and non-supersymmetric AdS attractors
We investigate the attractor mechanism in gauged supergravity in the presence of higher derivative terms. In particular, we discuss the attractor behavior of static black hole horizons in anti-de Sitter spacetime by using the effective potential approach as well as Sen's entropy function formalism. We use the holographic techniques to interpret the moduli flow as an RG flow towards the IR attractor horizon. We find that the holographic c-function obeys the expected properties and point out some subtleties in understanding attractors in AdS.
140083239
BEAM TESTS OF THE PEFP 20 MEV ACCELERATOR *
Proton Engineering Frontier Project (PEFP) 20MeV proton accelerator has been installed and tested at KAERI (Korea Atomic Energy Research Institute) site. After the radiation license was issued, some parts were modified to increase a peak beam current above 1mA. A proton injector composed of an ion source and a LEBT (Low Energy Beam Transport) was modified for better transmission rate through the LEBT. The field profile of the RFQ was measured to check the dipole field effect. In addition, beam loss was measured along the DTL to check and adjust the operating parameters. In this paper, the modifications of the 20MeV accelerator are summarized and the recent test results are presented.
124789806
INSTALLATION AND OPERATION OF THE BEAMLINES FOR THE 100-MeV PROTON LINAC
Beamlines and 100-MeV proton linac have been developed for 1st phase of KOMAC(Korea Multi-purpose Accelerator Complex) at the Gyeong-ju site. The linac supplies either 20-MeV or 100-MeV proton beams for beam applications. Each proton beam can be transported to 2 beamlines for industrial purpose and 3 beamlines for various researches. At the first phase, 2 beamlines were installed and under test.
113201344
Design of Machine Protection System for the PEFP 100MeV Linac
37852911
Design of 100 MeV Proton Beam Irradiation Facility for the PEFP 100 MeV Linac
The Proton Engineering Frontier Project (PEFP) will install a 100-MeV proton linear accelerator at Gyeong-ju site. For the beam commissioning of 100 MeV proton linac, the two target rooms (TR 103, TR 23) will be prepared as a starter among 10 target room. To design the irradiation equipment in TR 103, we have investigated general propagation shape and spatial distribution of proton beam, when 100 MeV proton beam extracted from vacuum in the beam lines through beam window by Monte carlo method. On the basis of this result, we have designed beam irradiation components and their configuration. The beam irradiation facility consist of beam window, beam dump, support frame, sample support and beam current monitor. To minimize residual radioactivity induced by incident proton beam, the pure aluminum was selected as the material of beam dump and the aluminum alloy was selected as material of other irradiation equipment. This residual radioactivity of equipment was estimated by Monte carlo method. In this paper, the details of this irradiation equipment design are presented.