but also the discovery of completely unexpected new states of matter, such as the fractional quantum Hall state. Efforts to understand magnets, ferroelectrics, superconductors, polymers, and liquid crystals, exploited in innumerable applications, spurred the development of the elegant, unified conceptual framework of broken symmetry that not only explains how the characteristic behaviors of these materials are related, but also underlies much of modern physics. The pure and applied aspects of condensed-matter and materials physics are opposite sides of the same coin that define and enrich the CMMP field.
One of the main findings of this report is the identification of six grand challenge areas in which CMMP research is poised to have a large and enduring impact in the next decade. These research areas reflect both fundamental intellectual challenges and societal challenges, in keeping with the dual pure and applied nature inherent to CMMP. While CMMP has been developing many of the needed key tools and is central to many of these challenge areas, all of them will require the combined efforts of researchers from many disciplines in order to succeed. The broad spectrum of research covered by CMMP includes many important problems outside those identified in this report, and areas currently unforeseen are certain to arise from discoveries in the next decade. Nonetheless, the challenges identified here capture much of the intellectual vitality and range of the field as it moves into the next decade. These scientific challenges, discussed in turn below, are as follows:
How do complex phenomena emerge from simple ingredients?
How will the energy demands of future generations be met?
What is the physics of life?
What happens far from equilibrium and why?
What new discoveries await us in the nanoworld?
How will the information technology revolution be extended?
The notably successful “reductionist” approach to physics focuses on the laws that govern the motion of ever-smaller fundamental constituents of matter. Indeed, in principle, all of CMMP, not to mention chemistry and biology, is believed to follow from the solution of one simple equation, the Schrödinger equation, governing the quantum dynamics of electrons and ions. Conversely, “emergence” refers to the fact that the behavior of large, complicated systems made of many diverse building blocks is often distinct from, and even relatively insensitive to, the detailed properties of the individual constituents. Reductionism stresses the understanding