Publications
Dielectric breakdown and avalanches at nonequilibrium metal-insulator transitions
Motivated by recent experiments on the finite temperature Mott transition in VO 2 films, we propose a classical coarse-grained dielectric breakdown model where each degree of freedom represents a nanograin which transitions from insulator to metal with increasing temperature and voltage at random thresholds due to quenched disorder. We describe the properties of the resulting nonequilibrium metal-insulator transition and explain the universal characteristics of the resistance jump distribution.
Avalanche spatial structure and multivariable scaling functions: Sizes, heights, widths, and views through windows
We introduce a systematic method for extracting multivariable universal scaling functions and critical exponents from data. We exemplify our insights by analyzing simulations of avalanches in an interface using simulations from a driven quenched Kardar-Parisi-Zhang (qKPZ) equation. We fully characterize the spatial structure of these avalanches-we report universal scaling functions for size, height, and width distributions, and also local front heights.
Ensuring reliability, reproducibility and transferability in atomistic simulations: The knowledgebase of interatomic models (openKIM. org)
KIM application programmming interface as a standard for molecular simulations
Comment on "sloppy models, parameter uncertainty, and the role of experimental design"
We explain that part of the reduction in the parameter uncertainties in the computations of Apgar et al. (Mol. Biosyst. 2010, 6, 1890-900) is due to a greatly increased number of effective data points. © The Royal Society of Chemistry 2011.
The potential of atomistic simulations and the knowledgebase of interatomic models
Nucleation at the DNA supercoiling transition
Twisting DNA under a constant applied force reveals a thermally activated transition into a state with a supercoiled structure known as a plectoneme. Using transition-state theory, we predict the rate of this plectoneme nucleation to be of order 104 Hz. We reconcile this with experiments that have measured hopping rates of order 10 Hz by noting that the viscous drag on the bead used to manipulate the DNA limits the measured rate.
Minimal model of plasma membrane heterogeneity requires coupling cortical actin to criticality
We present a minimal model of plasma membrane heterogeneity that combines criticality with connectivity to cortical cytoskeleton. The development of this model was motivated by recent observations of micron-sized critical fluctuations in plasma membrane vesicles that are detached from their cortical cytoskeleton. We incorporate criticality using a conserved order parameter Ising model coupled to a simple actin cytoskeleton interacting through point-like pinning sites. Using this minimal model, we recapitulate several experimental observations of plasma membrane raft heterogeneity.
Universality beyond power laws and the average avalanche shape
The study of critical phenomena and universal power laws has been one of the central advances in statistical mechanicsduring the second half of the past century, explaining traditional thermodynamic critical points 1 , avalanche behaviour near depinning transitions 2,3 and a wide variety of other phenomena 4 . Scaling, universality and the renormalization group claim to predict all behaviour at long length and timescales asymptotically close to critical points.
Superheating field of superconductors within Ginzburg-Landau theory
We study the superheating field of a bulk superconductor within Ginzburg-Landau theory, which is valid near the critical temperature. We calculate, as functions of the Ginzburg-Landau parameter κ, the superheating field Hsh and the critical momentum kc characterizing the wavelength of the instability of the Meissner state to flux penetration. By mapping the two-dimensional linear stability theory into a one-dimensional eigenfunction problem for an ordinary differential equation, we solve the problem numerically.