High-Quality Axions in a Class of Chiral U(1) Gauge Theories.

We show that there are many candidates for the quintessence and/or the QCD axions in a class of chiral U(1) gauge theories. Their qualities are high enough to serve as the dark energy and/or to solve the strong CP problem. Interestingly, the high quality of axion is guaranteed by the gauged U(1) and Z_{2N} symmetries and hence free from the nonperturbative quantum gravity corrections.

Linking the supersymmetric standard model to the cosmological constant.

String theory has no parameter except the string scale , so the Planck scale , the supersymmetry-breaking scale , the electroweak scale as well as the vacuum energy density (cosmological constant) Λ are to be determined dynamically at any local minimum solution in the string theory landscape. Here we consider a model that links the supersymmetric electroweak phenomenology (bottom up) to the string theory motivated flux compactification approach (top down). In this model, supersymmetry is broken by a combination of the racetrack Kähler uplift mechanism, which naturally allows an exponentially small positive Λ in a local minimum, and the anti-D3-brane in the KKLT scenario.

Energy dynamics in a generalized compass chain.

We investigate the energy dynamics in a generalized compass chain under an external magnetic field. We show that the energy current operators act on three contiguous sites in the absence of the magnetic field, and they are incorporated with inhomogenous Dzyaloshinskii-Moriya interactions in the presence of the magnetic field. Under these complex interactions the Hamiltonian remains an exactly solvable spin model.