arXiv subjects

T. K. Haxton

Publications and source records attributed to T. K. Haxton.

2 recordsLinked to original sources

arXiv2011

Temperature-pressure scaling for air-fluidized grains on approaches to Point J

We present experiments on a monolayer of air-fluidized beads in which a jamming transition is approached by increasing pressure, increasing packing fraction, and decreasing kinetic energy. This is accomplished, along with a noninvasive measurement of pressure, by tilting the system and examining behavior vs depth. We construct an equation of state and analyze relaxation time vs effective temperature. By making time and effective temperature dimensionless using factors of pressure, bead size, and bead mass, we obtain a good collapse of the data but to a functional form that differs from that of thermal hard-sphere systems. The relaxation time appears to diverge only as the effective temperature to pressure ratio goes to zero.

cond-mat.soft↗

arXiv2010

Kinetic Heterogeneities at Dynamical Crossovers

We perform molecular dynamics simulations of a model glass-forming liquid to measure the size of kinetic heterogeneities, using a dynamic susceptibility $χ_{\rm ss}(a, t)$ that quantifies the number of particles whose dynamics are correlated on the length scale $a$ and time scale $t$. By measuring $χ_{\rm ss}(a, t)$ as a function of both $a$ and $t$, we locate local maxima $χ^\star$ at distances $a^\star$ and times $t^\star$. Near the dynamical glass transition, we find two types of maxima, both correlated with crossovers in the dynamical behavior: a smaller maximum corresponding to the crossover from ballistic to sub-diffusive motion, and a larger maximum corresponding to the crossover from sub-diffusive to diffusive motion. Our results indicate that kinetic heterogeneities are not necessarily signatures of an impending glass or jamming transition.

cond-mat.soft↗