119600456
Quantum mechanical Hamiltonians with large ground-state degeneracy
Abstract Nonrelativistic Hamiltonians with large, even infinite, ground-state degeneracy are studied by connecting the degeneracy to the property of a Dirac operator. We then identify a special class of Hamiltonians, for which the full space of degenerate ground states in any spatial dimension can be exhibited explicitly. The two-dimensional version of the latter coincides with the Pauli Hamiltonian, and recently-discussed models leading to higher-dimensional Landau levels are obtained as special cases of the higher-dimensional version of this Hamiltonian. But, in our framework, it is only the asymptotic behavior of the background ‘potential’ that matters for the ground-state degeneracy. We work out in detail the ground states of the three-dimensional model in the presence of a uniform magnetic field and such potential. In the latter case one can see degenerate stacking of all 2d Landau levels along the magnetic field axis.
119250832
New BPS configurations of BMN matrix theory
We explore the 1/2 BPS configurations in BMN matrix theory with SO(3) angular momentum of SO(3) × SO(6) symmetry. The fluctuation analysis of the BPS configurations near the abelian solutions and also the fuzzy two sphere vacua reveals how nonabelian BPS configurations emerge. Especially the irreducible nonabelian configurations seem to have the maximal angular momentum of order N3, beyond which they collapse to abelian ones. We also find some new BPS configurations explicitly.
119199828
The general M5-brane superconformal index
We calculate and study the general superconformal index for the 6d U(N) (2,0) theory with four chemical potentials, from the indices of gauge theories on CP^2 x R. Our index agrees with the large N supergravity index on AdS_7 x S^4 at low energies, and also yields the negative 'Casimir energy' with an N^3 scaling which was recently calculated from a QFT on S^5. Our approach also suggests a systematic study of the (1,0) superconformal indices.
29030259
Magnetic monopole with Wilson-loop symmetry breaking.
A nonsingular classical magnetic-monopole solution is obtained in a theory with Wilson-loop symmetry breaking. The solution is used to elucidate the quantization rules governing the magnetic charge, which are more restrictive than those for Higgs monopoles.
7063414
Mass-Deformed Bagger-Lambert Theory and its BPS Objects
We find a 16-supersymmetric mass-deformed Bagger-Lambert theory with SO(4)xSO(4) global R symmetry. The R charge plays the role of the noncentral term in the superalgebra. This theory has one symmetric vacuum and two inequivalent broken sectors of vacua. Each sector of the broken symmetry has SO(4) geometry. We find the 1/2 BPS domain walls connecting the symmetric phase and any broken phase, and 1/4 BPS supertubelike objects, which may appear as anyonic q-balls in the symmetric phase or vortices in the broken phase. We also discuss mass deformations, which reduce the number of supersymmetries.
11205361
The CP(n) model on noncommutative plane
We construct the consistent CP(n) model on noncommutative plane. The Bogomolny bound on the energy is saturated by (anti-)self-dual solitons with integer topological charge, which is independent of their scaling and orientation. This integer quantization is satisfied for our general solutions, which turns out regular everywhere. We discuss the possible implication of our result to the instanton physics in Yang–Mills theories on noncommutative R4.
119422313
Spin configuration of top quark pair production with large extra dimensions at photon-photon colliders
Top quark pair production at photon-photon colliders is studied in low scale quantum gravity scenario. From the dependence of the cross sections on the spin configuration of the top quark and anti-quark, we introduce a new observable, top spin asymmetry. It is shown that there exists a special top spin basis where with the polarized parent electron beams the top spin asymmetry vanishes in the standard model but retains substantial values with the large extra dimension effects. We also present lower bounds of the quantum gravity scale $M_S$ from total cross sections with various combinations of the laser, electron beam, and top quark pair polarizations. The measurements of the top spin state $(t_\uparrow\bar{t}_\downarrow)$ with unpolarized initial beams are shown to be most effective, enhancing by about 5% the $M_S$ bounds with respect to totally unpolarized case.
118645218
Incorporation of fermions into double field theory
A bstractBased on the stringy differential geometry we proposed earlier, we incorporate fermions such as gravitino and dilatino into double field theory in a manifestly covariant manner with regard to O(D, D) T-duality, diffeomorphism, one-form gauge symmetry for B-field and a pair of local Lorentz symmetries. We note that there are two kinds of fermions in double field theory: O(D, D) singlet and non-singlet which may be identified, respectively as the common and the non-common fermionic sectors in type IIA and IIB suergravities. For each kind, we construct corresponding covariant Dirac operators. Further, we derive a simple criterion for an O(D, D) rotation to flip the chirality of the O(D, D) non-singlet chiral fermions, which implies the exchange of type IIA and IIB supergravities.
8269651
Neutralino dark matter in mirage mediation
We study the phenomenology of neutralino dark matter (DM) in a mirage mediation scenario of supersymmetry breaking which results from the moduli stabilization in some string/brane models. Depending upon the model parameters, especially the anomaly to modulus mediation ratio determined by the moduli stabilization mechanism, the nature of the lightest supersymmetric particle (LSP) changes from bino-like neutralino to Higgsino-like neutralino via a bino–Higgsino mixing region. For the bino-like LSP, the standard thermal production mechanism can give the right amount of relic DM density through the stop/stau–neutralino coannihilation or the pseudoscalar Higgs resonance process. We also examine the prospect of direct and indirect DM detection in various parameter regions of mirage mediation. Neutralino DM in the galactic halo might be detected by near future direct detection experiments in the case of the bino–Higgsino mixed LSP. The gamma ray flux from the galactic centre might be detectable also if the DM density profile takes a cuspy shape.
118585424
Double field formulation of Yang–Mills theory
Abstract Based on our previous work on the differential geometry for the closed string double field theory, we construct a Yang–Mills action which is covariant under O ( D , D ) T-duality rotation and invariant under three-types of gauge transformations: non-Abelian Yang–Mills, diffeomorphism and one-form gauge symmetries. In double field formulation, in a manifestly covariant manner our action couples a single O ( D , D ) vector potential to the closed string double field theory. In terms of undoubled component fields, it couples a usual Yang–Mills gauge field to an additional one-form field and also to the closed string background fields which consist of a dilaton, graviton and a two-form gauge field. Our resulting action resembles a twisted Yang–Mills action.
119961422
Search for collective flow in relativistic heavy-ion collisions using transverse momentum spectra of emitted hadrons☆