Isothermal transport of a Brownian particle at a finite time

John Andrew Albay^1*, Sarah Rizky Wulaningrum¹, Pik Yin Lai¹, Yonggun Jun¹

¹Physics, National Central University, Taoyuan, Taiwan

* Presenter:John Andrew Albay, email:albayjohnandrew@gmail.com

An isothermal transport is a very slow process that can be achieved in infinite time. Here, we show the experimental realization of an isothermal transport at a finite time. We move a Brownian particle one equilibrium position to another using the optical tweezers faster than the natural relaxation time of the harmonic potential by the shortcuts-to-isothermal protocol [1]. We observe that after shifting of the particle, the relaxation of the particle to equilibrium is faster than the natural relaxation time and that the instantaneous distributions of particle position during transport are constant. We also calculate, from the particle trajectories, the non-equilibrium thermodynamic quantities such as work done and free energy to confirm the isothermal process at the short transition time.

References
[1] Geng Li, H.T. Quan, and Z.C. Tu, Shortcuts to isothermality and nonequilibrium work
relations Phys. Rev. E, 2017

Keywords: Brownian particle, isothermal process, optical tweezers, auxiliary potential, relaxation time