Pushing the glass transition towards random close packing using self-propelled hard spheres

Although the concept of random close packing with an almost universal packing fraction of approximately 0.64 for hard spheres was introduced more than half a century ago, there are still ongoing debates. The main difficulty in searching the densest packing is that states with packing fractions beyond the glass transition at approximately 0.58 are inherently non-equilibrium systems, where the dynamics slows down with a structural relaxation time diverging with density; hence, the random close packing is inaccessible. Here we perform simulations of self-propelled hard spheres, and we find that with increasing activity the relaxation dynamics can be sped up by orders of magnitude. The glass transition shifts to higher packing fractions upon increasing the activity, allowing the study of sphere packings with fluid-like dynamics at packing fractions close to RCP. Our study opens new possibilities of investigating dense packings and the glass transition in systems of hard particles.

[1]  A. Scala.  Brownian dynamics simulation of polydisperse hard spheres , 2012, 1207.0531.

[2]  Ramin Golestanian,et al.  Self-motile colloidal particles: from directed propulsion to random walk. , 2007, Physical review letters.

[3]  L. Berthier,et al.  Probing the equilibrium dynamics of colloidal hard spheres above the mode-coupling glass transition. , 2010, Physical review letters.

[4]  Srikanth Sastry,et al.  Jamming transitions in amorphous packings of frictionless spheres occur over a continuous range of volume fractions. , 2009, Physical review letters.

[5]  J. Fredberg,et al.  Glass-like dynamics of collective cell migration , 2011, Proceedings of the National Academy of Sciences.

[6]  P. Leiderer,et al.  Various driving mechanisms for generating motion of colloidal particles , 2008 .

[7]  David A. Weitz,et al.  Structural Rearrangements That Govern Flow in Colloidal Glasses , 2007, Science.

[8]  David J. Pine,et al.  Living Crystals of Light-Activated Colloidal Surfers , 2013, Science.

[9]  Andrea J Liu,et al.  Why is random close packing reproducible? , 2007, Physical review letters.

[10]  Thomas M Truskett,et al.  Is random close packing of spheres well defined? , 2000, Physical review letters.

[11]  Stephen J. Ebbens,et al.  In pursuit of propulsion at the nanoscale , 2010 .

[12]  B. Lubachevsky,et al.  Geometric properties of random disk packings , 1990 .

[13]  A Scala,et al.  Event-driven Brownian dynamics for hard spheres. , 2007, The Journal of chemical physics.

[14]  Re-entrant glass transition in a colloid-polymer mixture with depletion attractions. , 2002, Physical review letters.

[15]  M Fuchs,et al.  Multiple Glassy States in a Simple Model System , 2002, Science.

[16]  M E Cates,et al.  Phase separation and rotor self-assembly in active particle suspensions , 2012, Proceedings of the National Academy of Sciences.

[17]  Florent Krzakala,et al.  Jamming versus glass transitions. , 2008, Physical review letters.

[18]  G. Biroli,et al.  Spatial correlations in the dynamics of glassforming liquids: experimental determination of their temperature dependence. , 2007, Physical review. E, Statistical, nonlinear, and soft matter physics.

[19]  David R. Reichman,et al.  Soft colloids make strong glasses , 2009, Nature.

[20]  Clemens Bechinger,et al.  Microswimmers in patterned environments , 2011, 1104.3203.

[21]  G. Parisi,et al.  Theory of amorphous packings of binary mixtures of hard spheres. , 2009, Physical review letters.

[22]  Jamming of polydisperse hard spheres: The effect of kinetic arrest , 2010 .

[23]  Giorgio Parisi,et al.  Mean-field theory of hard sphere glasses and jamming , 2008, 0802.2180.

[24]  Christophe Ybert,et al.  Sedimentation and effective temperature of active colloidal suspensions. , 2010, Physical review letters.

[25]  Acknowledgements , 1992, Experimental Gerontology.

[26]  Samuel Sanchez,et al.  Transport of cargo by catalytic Janus micro-motors , 2012 .

[27]  J. D. BERNAL,et al.  Packing of Spheres: Co-ordination of Randomly Packed Spheres , 1960, Nature.

[28]  Andrea J Liu,et al.  Random packings of frictionless particles. , 2001, Physical review letters.

[29]  Marcus L. Roper,et al.  Microscopic artificial swimmers , 2005, Nature.

[30]  Ludovic Berthier,et al.  Glass transition of dense fluids of hard and compressible spheres. , 2009, Physical review. E, Statistical, nonlinear, and soft matter physics.

[31]  L. Berthier,et al.  Probing the equilibrium dynamics of colloidal hard spheres above the mode-coupling glass transition. , 2008, Physical review letters.

[32]  Kenneth S. Schweizer,et al.  Entropic barriers, activated hopping, and the glass transition in colloidal suspensions , 2003 .

[33]  A. Puertas,et al.  Tagged-particle dynamics in a hard-sphere system: mode-coupling theory analysis. , 2004, Physical review. E, Statistical, nonlinear, and soft matter physics.

[34]  Jack F Douglas,et al.  Nature of the breakdown in the Stokes-Einstein relationship in a hard sphere fluid. , 2006, The Journal of chemical physics.

[35]  Thomas Speck,et al.  Crystallization in a dense suspension of self-propelled particles. , 2011, Physical review letters.

[36]  Ludovic Berthier,et al.  Non-equilibrium glass transitions in driven and active matter , 2013, Nature Physics.

[37]  Daniela A Wilson,et al.  Autonomous movement of platinum-loaded stomatocytes. , 2012, Nature chemistry.

[38]  Ludovic Berthier,et al.  Nonequilibrium glassy dynamics of self-propelled hard disks. , 2013, Physical review letters.