Growing interfaces uncover universal fluctuations behind scale invariance

Stochastic motion of a point -- known as Brownian motion -- has many successful applications in science, thanks to its scale invariance and consequent universal features such as Gaussian fluctuations. In contrast, the stochastic motion of a line, though it is also scale-invariant and arises in nature as various types of interface growth, is far less understood. The two major missing ingredients are: an experiment that allows a quantitative comparison with theory and an analytic solution of the Kardar-Parisi-Zhang (KPZ) equation, a prototypical equation for describing growing interfaces. Here we solve both problems, showing unprecedented universality beyond the scaling laws. We investigate growing interfaces of liquid-crystal turbulence and find not only universal scaling, but universal distributions of interface positions. They obey the largest-eigenvalue distributions of random matrices and depend on whether the interface is curved or flat, albeit universal in each case. Our exact solution of the KPZ equation provides theoretical explanations.Comment: 5 pages, 3 figures, supplementary information available on Journal pag

Cover and Uncover

Eric Cameron is a major contemporary Canadian artist. Born in 1935 in Leicester, England, he arrived in Canada in the 1970s and has taught at the University of Guelph, the Nova Scotia College of Art and Design, and at the University of Calgary. Over the years Cameron has also continued to work in his primary medium, painting, but moved from traditional figuration to a highly conceptual practice with both his process paintings and his "thick" paintings. He has also expanded into video and has written a great deal about his work. His inspired teaching and unusual art have been recognized with major awards, including the Victor Lynch-Staunton Award (1993), the Gershorn Iskowitz Prize (1994), and the Governor General's Award (2004). Despite Cameron's prominence, much of the writing about him to date, primarily essays in exhibition catalogues, is by the artist himself. Cover and Uncover thus makes a major contribution to the field as it explores in depth Eric Cameron's art and philosophy. The book is composed of four essays, each covering a different aspect of Cameron's art, starting with Peggy Gale's analysis of his writing, then turning to Ann Davis's consideration of his process paintings and his philosophy, moving to Diana Nemiroff's review of his videos, and concluding with Thierry de Duve's observations on his Thick Paintings and his blind rejection of chance. The essays, though written independently, resonate with each other so that the reader comes away with a full picture of a complex artist, his life, his thought, his art production, and how these elements inform each other and have evolved through time. The expert commentary here, richly illustrated with Cameron's works in multiple media, provides a vital and long overdue critical lens through which to view this important artist

Photon number statistics uncover the fluctuations in non-equilibrium lattice dynamics

Fluctuations of the atomic positions are at the core of a large class of unusual material properties ranging from quantum para-electricity to high temperature superconductivity. Their measurement in solids is the subject of an intense scientific debate focused on seeking a methodology capable of establishing a direct link between the variance of the atomic displacements and experimentally measurable observables. Here we address this issue by means of non-equilibrium optical experiments performed in shot-noise limited regime. The variance of the time dependent atomic positions and momenta is directly mapped into the quantum fluctuations of the photon number of the scattered probing light. A fully quantum description of the non-linear interaction between photonic and phononic fields is benchmarked by unveiling the squeezing of thermal phonons in $\alpha$-quartz.Comment: 7 pages (main text), 5 figures, 11 pages (supplementary information