Table 2 Criteria applied to distinguish phases in Figs. 5a and 4a

From: Self-sustained frictional cooling in active matter

Phase

Local packing fraction, ϕ

Orientational order parameter, ψ6

Mode speed, vm

Cooled homogeneous

Unimodal Prob(ϕ) μ3(ϕ) ≥ 0

No peak at ψ6 ≥ 0.95

\({v}_{{{{\rm{m}}}}}\, < \,7{\tau }_{0}^{-1}\)

Heated homogeneous

Unimodal Prob(ϕ) μ3(ϕ) ≥ 0

No peak at ψ6 ≥ 0.95

\({v}_{{{{\rm{m}}}}}\ge 7{\tau }_{0}^{-1}\)

Cooled clustering

Unimodal Prob(ϕ) μ3(ϕ) < 0

No peak at ψ6 ≥ 0.95

\({v}_{{{{\rm{m}}}}}\, < \,7{\tau }_{0}^{-1}\)

Cooled solid

Unimodal Prob(ϕ) μ3(ϕ) < 0

A peak at ψ6 ≥ 0.95

\({v}_{{{{\rm{m}}}}}\, < \,7{\tau }_{0}^{-1}\)

Heated clustering

Unimodal Prob(ϕ) μ3(ϕ) < 0

No peak at ψ6 ≥ 0.95

\({v}_{{{{\rm{m}}}}}\ge 7{\tau }_{0}^{-1}\)

Mixed

Bimodal Prob(ϕ), with peaks at ϕ ≤ Φ and ϕ > Φ

Bimodal Prob(ψ6), with peaks at ψ6 ≤ 0.95 and ψ6 > 0.95

Inside the cluster, \({v}_{{{{\rm{m}}}}} < \, 7{\tau }_{0}^{-1}\) Outside the cluster, \({v}_{{{{\rm{m}}}}}\ge 7{\tau }_{0}^{-1}\)

  1. The skewness (third standardized moment) μ3(ϕ) is defined as \({\mu }_{3}(\phi )=\frac{\int_{0}^{1}{({\phi }^{{\prime} }-\Phi )}^{3}\,{{{\rm{Prob}}}}({\phi }^{{\prime} })\,{{{\rm{d}}}}{\phi }^{{\prime} }}{{\left(\int_{0}^{1}{({\phi }^{{\prime} }-\Phi )}^{2}{{{\rm{Prob}}}}({\phi }^{{\prime} }){{{\rm{d}}}}{\phi }^{{\prime} }\right)}^{3/2}}\) and indicates, whether the mass of the distribution is concentrated on the right (negative skewness) or on the left (positive skewness).