Constraint dependence of average potential energy of a passive particle in an active bath

Ye Simin^{1, 2, †}, Liu Peng^{1, 2}, Wei Zixuan², Ye Fangfu^{1, 2, 3, 4, ‡}, Yang Mingcheng^{1, 2, §}, Chen Ke^{1, 2, 3, ¶}

(a) Position distribution of the passive particle in an optical trap in x and y directions without bacteria, where the extracted stiffness k is 2.65 pN/μm. Blue and red lines are fits with Eq. (1) for x and y directions, respectively. (b) Exponential fit (red line) of the radial position distribution measured in experiment (black circles) in a semi-log plot, where N is the total number of frames.