116270550
N=8 SCFT and M theory on AdS(4) x RP**7
We study M theory on ${\mathrm{AdS}}_{4}\ifmmode\times\else\texttimes\fi{}{\mathrm{RP}}^{7}$ corresponding to 3 dimensional $\mathcal{N}=8$ superconformal field theory which is the strong coupling limit of 3 dimensional super Yang-Mills theory. For $\mathrm{SU}(N)$ theory, a wrapped M5 brane on ${\mathrm{RP}}^{5}$ can be interpreted as the baryon vertex. For $\mathrm{SO}(N)/Sp(2N)$ theory, by using the property of (co)homology of ${\mathrm{RP}}^{7},$ we classify various wrapping branes and consider domain walls and the baryon vertex.
12060341
ALE spaces from noncommutative U(1) instantons via exact Seiberg-Witten map
The exact Seiberg–Witten (SW) map of a noncommutative (NC) gauge theory gives the commutative equivalent as an ordinary gauge theory coupled to a field dependent effective metric. We study instanton solutions of this commutative equivalent whose self-duality equation turns out to be the exact SW map of NC instantons. We derive general differential equations governing U(1) instantons and we explicitly get an exact solution corresponding to the single NC instanton. Remarkably the effective metric induced by the single U(1) instanton is related to the Eguchi–Hanson metric—the simplest gravitational instanton. Surprisingly the instanton number is not quantized but depends on an integration constant. Our result confirms the expected non-perturbative breakdown of the SW map. However, the breakdown of the map arises in a consistent way: the instanton number plays the role of a parameter giving rise to a one-parameter family of Eguchi–Hanson metrics.
15769713
A Complete Classification of D-branes in Type IIB Plane Wave Background
We give a complete classification of D-branes in the type IIB plane wave background using Green-Schwarz superstring theory. We find all possible supersymmetric oblique and curved D-branes and consider their intersections. The supersymmetries preserved by various configurations of these D-branes are also identified. In particular, we show that D+-branes of type (+,−, n, n) for n = 1, 2, 3, 4 preserve 4 dynamical supersymmetries by introducing gauge field excitations and newly discovered oblique D5and D7-branes also preserve four or two dynamical supersymmetries with gauge field condensates. Furthermore we find new curved D-branes preserving four dynamical supersymmetries.
119204681
Emergent Spacetime and The Cosmological Constant
We address issues on the origin of gravity and the dark energy (or the cosmological constant) from the perspectives of emergent gravity. We discuss how the emergent gravity reveals a noble, radically different picture about the origin of spacetime, which is crucial for a tenable solution of the cosmological constant problem. In particular, the emergent gravity naturally explains the dynamical origin of flat spacetime, which is absent in Einstein gravity.
118454134
BRST Cohomology and Its Application to QED
We construct the BRST cohomology under a positive definite inner product and obtain the Hodge decomposition theorem at a non-degenerate state vector space $V$. The harmonic states isomorphic with a BRST cohomology class correspond to the physical Hilbert space with positive norm as long as the completeness of $Q_{BRST}$ is satisfied. We explicitly define ``co-BRST'' operator and analyze the quartet mechanism in QED.
12059305
Superstrings and D-branes in A Plane Wave
We carefully analyze the supersymmetry algebra of closed strings and open strings in a type IIB plane wave background. We use eight component chiral spinors, SO(8) MajoranaWeyl spinors, in light-cone gauge to provide a useful basis of string field theory calculation in the plane wave. We consider the two classes of D-branes, D±-branes, and give a worldsheet derivation of conserved supercurrents for all half BPS D-branes preserving 16 supersymmetries in the type IIB plane wave background. We exhaustively provide the supersymmetry algebra of the half BPS branes as well. We also point out that the supersymmetry algebra distinguishes the two SO(4) directions with relative sign which is consistent with the Z2 symmetry of the string action.
15273018
Testing closed string field theory with marginal fields
We study the feasibility of level expansion and test the quartic vertex of closed string field theory by checking the flatness of the potential in marginal directions. The tests, which work out correctly, require the cancellation of two contributions: one from an infinite-level computation with the cubic vertex and the other from a finite-level computation with the quartic vertex. The numerical results suggest that the quartic vertex contributions are comparable or smaller than those of level four fields.
55601550
Fermion's Tunnelling with Effects of Quantum Gravity
In this paper, using Hamilton-Jacobi method, we address the tunnelling of fermions in a 4-dimensional Schwarzschild spacetime. Based on the generalized uncertainty principle, we introduce 
the influence of quantum gravity. After solving the equation of motion of the spin-1/2 field, we 
derive the corrected Hawking temperature. It turns out that the correction depends not only on 
the black hole’s mass but also on the mass (energy) of emitted fermions. It is of interest that, in 
our calculation, the quantum gravity correction decelerates the temperature increase during the radiation 
explicitly. This observation then naturally leads to the remnants in black hole evaporation. 
Our calculation shows that the residue mass is , where is the Planck mass and is a dimensionless parameter accounting for quantum gravity effects. The evaporation singularity is 
then avoided.
17682877
Impact of Tracker Design on Higgs and Slepton Measurements
We have studied the impact of charged track resolution on Higgs mass and production cross section measurement in the process e+e− → Z0H,Z0 → + −,H → X for Higgs masses between 120 and 160 GeV, and on smuon mass measurement using smuon pair production for three different mass pairs, assuming the International Linear Collider(ILC) is operated at 500 GeV center of mass energies (CME) with integrated luminosities of 500 fb−1. The effect of initial state radiation (ISR), beamstrahlung and beam energy spread on Higgs and smuon mass measurement are also estimated. Using fast Monte Carlo simulations of the 2001 North American baseline detector designs (LD and SD), we find that the ISR and beamstrahlung have significant impact on Higgs and smuon mass measurement; Charged track momentum resolution affect Higgs mass significantly with better track performance yielding better Higgs mass resolution and precision for the track momentum resolution improvement up to a factor of about 5; Track momentum resolution has little effect on the measurement precision of the Higgsstrahlung cross section, the branching ratio of H → CC, the smuon and neutralino masses; Beam energy spread better than about 0.2% has little effect on Higgs, smuon and neutralino masses; The SD detector provides a more accurate measurement than the LD of the Higgs mass.
117792048
Superluminal neutrinos and domain walls
In this letter, we propose that the recent measurement of superluminal neutrinos in OPERA could be explained by the existence of a domain wall which is left behind after the phase transition of some scalar field in the universe. The scalar field couples to the neutrino and photon field with different effective couplings. It causes different effective metrics and the emergence of superluminal neutrinos. Moreover, if the supernova and the earth are in the same plane parallel to the wall, or the thickness of the wall is much smaller than the distance from the supernova to the earth, the contradiction between OPERA and SN1987a can be reconciled.
800216
A closed string tachyon vacuum
In bosonic closed string field theory the ``tachyon potential" is a potential for the tachyon, the dilaton, and an infinite set of massive fields. Earlier computations of the potential did not include the dilaton and the critical point formed by the quadratic and cubic interactions was destroyed by the quartic tachyon term. We include the dilaton contributions to the potential and find that a critical point survives and appears to become more shallow. We are led to consider the existence of a closed string tachyon vacuum, a critical point with zero action that represents a state where space-time ceases to be dynamical. Some evidence for this interpretation is found from the study of the coupled metric-dilaton-tachyon effective field equations, which exhibit rolling solutions in which the dilaton runs to strong coupling and the Einstein metric undergoes collapse.