Zarrin Arshia, Sivak David A, Brown Aidan I
Department of Physics, Simon Fraser University, Burnaby, British Columbia V5A1S6, Canada.
Department of Physics, University of California, San Diego, La Jolla, California 92093, USA.
Phys Rev E. 2019 Jun;99(6-1):062127. doi: 10.1103/PhysRevE.99.062127.
Biomolecular machines transduce free energy from one form to another to fulfill many important roles inside cells, with dissipation required to achieve directed progress. We investigate how to break time-reversal symmetry at a given dissipation cost by using deterministic protocols to drive systems over sawtooth potentials, which have frequently been used to model molecular machines as ratchets. Time asymmetry increases for sawtooth potentials with higher barriers and for driving potentials of intermediate width. For systems driven over a sawtooth potential according to a protocol, we find that symmetric sawtooths maximize time asymmetry, whereas earlier work examining ratchet models of molecular machines required asymmetric sawtooth potentials to achieve directed behavior. This distinction arises because deterministically driven machines are externally provided with direction, whereas autonomous machines must generate directed behavior.
生物分子机器将自由能从一种形式转换为另一种形式，以在细胞内发挥许多重要作用，而实现定向进展需要能量耗散。我们研究如何通过使用确定性协议驱动系统越过锯齿势来以给定的耗散成本打破时间反演对称性，锯齿势经常被用来将分子机器建模为棘轮。对于具有更高势垒的锯齿势以及中等宽度的驱动势，时间不对称性会增加。对于根据协议在锯齿势上驱动的系统，我们发现对称锯齿能使时间不对称性最大化，而早期研究分子机器棘轮模型的工作需要非对称锯齿势来实现定向行为。这种区别的出现是因为确定性驱动的机器从外部获得方向，而自主机器必须产生定向行为。
