The Effective Kahler Potential, Metastable Vacua and R-Symmetry Breaking in O'Raifeartaigh Models

Much has been learned about metastable vacua and R-symmetry breaking in O'Raifeartaigh models. Such work has largely been done from the perspective of the superpotential and by including Coleman-Weinberg corrections to the scalar potential. Instead, we consider these ideas from the perspective of the one loop effective Kahler potential. We translate known ideas to this framework and construct convenient formulas for computing individual terms in the expanded effective Kahler potential. We do so for arbitrary R-charge assignments and allow for small R-symmetry violating terms so that both spontaneous and explicit R-symmetry breaking is allowed in our analysis.Comment: 15 pages; minor correction

Spin density wave and superconducting properties of nanoparticle organic conductor assemblies

The magnetic susceptibilities of nanoparticle assemblies of two Bechgaard salts (TMTSF)2PF6 and (TMTSF)2ClO4, have been studied vs temperature and magnetic field. In the bulk these materials exhibit a spin density wave formation (TSDW=12K) and superconductivity (Tc=1.2K), respectively. We show from inductive (susceptibility) measurements that the nanoparticle assemblies exhibit ground-state phase transitions similar to those of randomly oriented polycrystalline samples of the parent materials. Resistivity and diamagnetic shielding measurements yield additional information on the functional nanoparticle structure in terms of stoichiometric and nonstoichiometric composition

Superconducting properties of a nanoparticle assembly of the organic conductor (TMTSF)2ClO4

Resumen del trabajo presentado al APS March Meeting, celebrado en Baltimore, Maryland (USA) del 14 al 18 de marzo de 2016.While the study of thin-film and nanoparticle geometries on semiconductor devices, type-I elemental superconductors, and even single-molecular magnet materials have been explored, progress on thin-film and nanoparticle organic superconductors - in particular charge-transfer organic salts - has remained elusive. Recent refinements of synthesis conditions have produced nanoparticles of the Bechgaard salt (TMTSF)2ClO4. High resolution TEM studies have determined these nanoparticles are approximately 3-5 nm in size, which form nanoparticle clusters that are on average 34 nm in size. In order to investigate the properties of these nanoparticles, randomly oriented assemblies were studied in magnetic fields up to 16 T, using a high sensitivity inductive method in a dilution refrigerator, the results of which show that the ground-state properties of the nanoparticle assembly compares favorably with the bulk-single-crystal material.Peer reviewe