remain unresolved that the onset of glassy behavior is generally considered one of the most intriguing unsolved problems in CMMP.

The concept of jamming has fueled an explosion of new interactions and cross-cutting research between previously separate communities working on the glass transition, gelation, granular materials, foams, and dense colloidal suspensions. It also has driven much fruitful interaction between condensed-matter physicists and engineers in this field.


Far-from-equilibrium behavior is emerging as one of the major challenges within CMMP and beyond. The importance of making progress in this field is underlined by several key facts. First, far-from-equilibrium behavior is not rare but ubiquitous, occurring from the nanometer scale on up, in daily life as well as in high-technology applications. Second, it connects directly to critical, national needs for the next decade, affecting a large fraction of the manufacturing base as well as the U.S. economy, climate, and environment. The committee emphasizes that far-from-equilibrium behavior cannot be understood simply through small modifications of equilibrium physics. Because it differs so strikingly and at the same time represents largely uncharted intellectual territory, it provides exciting opportunities for major scientific breakthroughs.

CMMP researchers are tackling ever-bigger and -broader problems in far-from-equilibrium phenomena. This expansion drives critical needs. Currently, research on far-from-equilibrium phenomena is fragmented into small subfields. These are typically divided along the types of materials or specific phenomena studied—for example, fracture in solids or turbulence in fluids. The field of far-from-equilibrium physics is vast, and it is unlikely that any one organizing principle will work for all far-from-equilibrium systems. Nonetheless, there is great value in identifying classes of systems that might have common underlying physics or that might be tackled by common methods. There have been few incentives to adopt such broader approaches, but this will be increasingly required in order to make progress.

Recent work within the CMMP community has set the stage for fresh approaches to long-standing problems concerning far-from-equilibrium behavior by introducing new model systems such as granular matter, new unifying paradigms such as jamming, new organizing principles such as robustness, and new formal approaches such as steady-state thermodynamics. The community is also finding important connections to a wide range of other fields, both within and outside physics, connections that are likely to amplify the impact of CMMP even further. Over the next decade it will be critical to find ways to stimulate new links and nurture crosscutting approaches.

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