Perhaps the most important aspect of contemporary condensed matter physics involves understanding strong Coulomb interactions between the large number of electrons in a solid. Electronic correlations lead to the emergence of new system properties, such as metal-insulator transitions, superconductivity, magneto-resistance, Bose-Einstein condensation, the formation of excitonic gases, or the integer and fractional Quantum Hall effects. The discovery of high-Tc superconductivity in particular was a watershed event, leading to dramatic experimental and theoretical advances in the field of correlated-electron systems. Such materials often exhibit competition between the charge, lattice, spin, and orbital degrees of freedom, whose cause-effect relationships are difficult to ascertain. Experimental insight into the properties of solids is traditionally obtained by time-averaged probes, which measure e.g., linear optical spectra, electrical conduction properties, or the occupied band structure in thermal equilibrium. Many novel physical properties arise from excitations out of the ground state into energetically higher states by thermal, optical, or electrical means. This leads to fundamental interactions between the system's constituents, such as electron-phonon and electron-electron interactions, which occur on ultrafast timescales. While these interactions underlie the physical properties of solids, they are often only indirectly inferred from time-averaged measurements. Time-resolved spectroscopy, consequently, is playing an ever increasing role …

Carbon sequestration is the long term isolation of carbon dioxide from the atmosphere through physical, chemical, biological, or engineered processes. The largest potential reservoirs for storing carbon are the deep oceans and geological reservoirs in the earth's upper crust. This chapter focuses on geological sequestration because it appears to be the most promising large-scale approach for the 2050 timeframe. It does not discuss ocean or terrestrial sequestration. In order to achieve substantial GHG reductions, geological storage needs to be deployed at a large scale. For example, 1 Gt C/yr (3.6 Gt CO{sub 2}/yr) abatement, requires carbon capture and storage (CCS) from 600 large pulverized coal plants ({approx}1000 MW each) or 3600 injection projects at the scale of Statoil's Sleipner project. At present, global carbon emissions from coal approximate 2.5 Gt C. However, given reasonable economic and demand growth projections in a business-as-usual context, global coal emissions could account for 9 Gt C. These volumes highlight the need to develop rapidly an understanding of typical crustal response to such large projects, and the magnitude of the effort prompts certain concerns regarding implementation, efficiency, and risk of the enterprise. The key questions of subsurface engineering and surface safety associated with carbon sequestration …