Integrated Calendar

Recent experimental results from the LHC have placed strong constraints on the masses of colored superpartners. The MSSM parameter space is also constrained by the measurement of the Higgs boson mass, and the requirement that the relic density of lightest neutralinos be consistent with observations. Although large regions of the MSSM parameter space can be excluded by these combined bounds, leptophilic versions of the MSSM can survive these constraints. We consider a scenario in which the requirements of minimal flavor violation, vanishing CP-violation, and mass universality are relaxed, specifically focusing on scenarios with light sleptons. We find a large region of parameter space, analogous to the original bulk region, for which the lightest neutralino is a thermal relic with an abundance consistent with that of dark matter. We find that these leptophilic models are constrained by measurements of the magnetic and electric dipole moments of the electron and muon, and that these models have interesting signatures at a variety of indirect detection experiments. We also consider a related scenario in which dark matter is bino-like and dark matter-nucleon spin-independent scattering occurs via the exchange of light squarks which exhibit left-right mixing. We show that direct detection experiments such as LUX and SuperCDMS will be sensitive to a wide class of such models through spin-independent scattering. Moreover, these models exhibit properties, such as isospin violation, that are not typically observed for the MSSM LSP if scattering occurs primarily through Higgs exchange. The dominant nuclear physics uncertainty is the quark content of the nucleon, particularly the strangeness content.

The discovery of topological band insulators is one of the most exciting developments in condensed matter physics in the last decade. In this talk I will describe how insights from the study of the relatively simple topological insulators are revolutionizing our theoretical understanding of more complex quantum many body systems. The latter include states of strongly interacting quantum matter which have been at the forefront of research in the last 3 decades. Specific examples include quantum spin liquid states of insulating magnets, and the theory of composite fermions in quantum Hall systems.
The theory of topological insulators unifies these seemingly diverse problems, and provides a new window through which to view them leading to many new and fundamental results.

Increasing concentrations of atmospheric carbon dioxide are expected to affect photosynthesis, evapotranspiration (ET) and ultimately plant growth. Numerical tools that simulate land-surface and vegetation dynamics are typically used to represent future scenarios of terrestrial carbon and water cycles. However, these tools are rarely tested to perform well in conditions different from the historical climate. A combination of numerical modeling and observations from flux-towers and free air CO2 enrichment (FACE) experiments is adopted to illustrate strengths and weaknesses of the mechanistic modeling approach in simulating hydrology and vegetation behavior of different ecosystems exposed to elevated CO2 concentrations. Additionally, an ecosystem model (T&C) is used to investigate the relative contributions of direct (through carbon assimilation) and indirect (via soil moisture savings due to stomatal closure, and changes in leaf area index) effects of elevated CO2. The simulations suggest that the indirect effects of elevated CO2 on net primary productivity are large and variable, ranging from less than 10% to more than 100% of the size of direct effects. For ET, indirect effects are on average 65% of the size of direct effects. Indirect effects tend to be considerably larger in water-limited sites, portraying a critical response of semi-arid ecosystems to elevated CO2. A further analysis demonstrates that introducing subtle changes in plant physiological traits in the simulations can also explain the unexpectedly large increase in water use efficiency (WUE) observed during the last two decades in forests across the north hemisphere.
These results have major implications for our understanding of the CO2-response of ecosystems and for global projections of CO2 fertilization because they emphasize the role of indirect effects and the importance of ecosystem adaptability in controlling water, carbon and energy fluxes with potential consequences for climate change and supply of ecosystem services.