Absolute negative mobility of the chain of Brownian particles in steady laminar flows

Abstract

Transport of the chain of Brownian particles driven by a constant force is investigated in steady laminar flow. Within tailored parameter regimes, this system exhibits absolute negative mobility (ANM), which means that the chain travels in a direction opposite to the external force. When the constant force is applied to all particles, the phenomenon of ANM is observed for large spring constant. When the force is applied to the first particle of the chain, the emergence of ANM can occur for both small and large spring constant. In addition, we can obtain multiple current reversals by suitably changing the spring constant.

Absolute negative mobility of active polymer chains in steady laminar flows

“…Under appropriate conditions, the phenomenon of ANM can be observed. Compared with the system of Brownian particles 54 or Brownian particle chains, 59 we can find a new movement pattern (preferential movement direction) in the present system and observe giant negative mobility in a broad range of parameter regimes.…”

“…Thus stable preferential channels cannot be generated, which is different from the case of Brownian particle chains. 59 The average velocity hv x i increases monotonically with increasing constant force f 0 (i.e., normal mobility). When the bending rigidity is large enough (e.g., k b = 100), the polymer chain is rodshaped.…”

“…The negative average velocity is obviously much larger than in previous studies. [54][55][56][57][58][59] For appropriate f a (e.g., f a = 1.5), the range of f 0 for the appearance of ANM is very large (|f 0 | o 0.45). Here, we only consider the case of f 0 4 0 because the results are symmetric for f 0 -Àf 0 .…”

“…[49][50][51][52][53] It is known that an inertial Brownian particle may show some surprising effects (e.g., negative differential mobility and absolute negative mobility) when it is immersed in an incompressible laminar flow. [54][55][56][57][58][59] Relatively speaking, the phenomenon of negative differential mobility (NDM) can occur in the presence of obstacles or in a crowded environment, where the velocity-force relation shows a nonmonotonic behavior. [60][61][62] Absolute negative mobility (ANM) is a more counterintuitive phenomenon and can only be observed in specific models, where the tracer moves in a direction opposite to that of the driving force.…”