Brownian Ratchet in a Thermal Bath Driven by Coulomb Friction

被引：65

作者：

Gnoli, Andrea ^{[1
,2
,3
]}

Petri, Alberto ^{[1
]}

Dalton, Fergal ^{[1
]}

Pontuale, Giorgio ^{[1
]}

Gradenigo, Giacomo ^{[2
,3
]}

Sarracino, Alessandro ^{[2
,3
]}

Puglisi, Andrea ^{[2
,3
]}

机构：

[1] CNR, Ist Sistemi Complessi, I-00133 Rome, Italy

[2] CNR, Ist Sistemi Complessi, I-00185 Rome, Italy

[3] Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy

来源：

PHYSICAL REVIEW LETTERS | 2013年 / 110卷 / 12期

关键词：

TRANSPORT; MOTORS;

D O I：

10.1103/PhysRevLett.110.120601

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

The rectification of unbiased fluctuations, also known as the ratchet effect, is normally obtained under statistical nonequilibrium conditions. Here we propose a new ratchet mechanism where a thermal bath solicits the random rotation of an asymmetric wheel, which is also subject to Coulomb friction due to solid-on-solid contacts. Numerical simulations and analytical calculations demonstrate a net drift induced by friction. If the thermal bath is replaced by a granular gas, the well-known granular ratchet effect also intervenes, becoming dominant at high collision rates. For our chosen wheel shape the granular effect acts in the opposite direction with respect to the friction-induced torque, resulting in the inversion of the ratchet direction as the collision rate increases. We have realized a new granular ratchet experiment where both these ratchet effects are observed, as well as the predicted inversion at their crossover. Our discovery paves the way to the realization of micro and submicrometer Brownian motors in an equilibrium fluid, based purely upon nanofriction. DOI: 10.1103/PhysRevLett.110.120601

引用

页数：5