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Colloidal ratchets

In ratcheting systems, a dc current or flux arises upon application of a periodic drive, such as when the underlying potential substrate is flashed, or, for a fixed substrate, when alternating forces are applied. Ratchet effects, which can be deterministic or stochastic in nature, have been studied in a wide variety of systems, including biological motors, flux motion in superconductors, granular transport, and colloidal transport. In many of these systems, an underlying asymmetric potential acts to break the left-right spatial symmetry. Alternative ratchet systems that have recently been investigated have symmetric substrates, and rely on ac drives to provide symmetry breaking. In each of these cases, the particles move through some form of fixed substrate. We consider colloidal ratchets that arise due to fixed substrates, flashing substrates, and with no substrate at all, where colloid-colloid interactions are responsible for breaking the symmetry.

Papers:

1. Transverse ac-driven and geometric ratchet effects for vortices in conformal crystal pinning arrays
   C. Reichhardt and C.J. Olson Reichhardt
   Phys. Rev. B 93, 064508 (2016). arXiv

   
   

2. Reversible ratchet effects for vortices in conformal pinning arrays
   C. Reichhardt, D. Ray, and C.J. Olson Reichhardt
   Phys. Rev. B 91, 184502 (2015). arXiv

   
   

3. Dynamics, rectification, and fractionation for colloids on flashing substrates
   A. Libal, C. Reichhardt, B. Janko, and C.J. Olson Reichhardt
   Phys. Rev. Lett. 96, 188301 (2006). arXiv

   
   

4. Ratchet cellular automata for colloids in dynamic traps
   C.J. Olson Reichhardt and C. Reichhardt
   Europhys. Lett. 74, 792 (2006). arXiv

   
   

5. Ratchet effect and nonlinear transport for particles on random substrates with crossed ac drives
   C. Reichhardt and C.J. Olson Reichhardt
   Phys. Rev. E 73, 011102 (2006). arXiv

   
   

6. Glassy ratchets for collectively interacting particles
   C. Reichhardt, C.J. Olson Reichhardt, and M.B. Hastings
   Phys. Lett. A 342, 162 (2005). arXiv

   
   

7. Nonlinear dynamics, rectification, and phase locking for particles on symmetrical two-dimensional periodic substrates with dc and circular ac drives
   C. Reichhardt, C.J. Olson Reichhardt, and M.B. Hastings
   Phys. Rev. E 69, 056115 (2004). arXiv

   
   

8. Absolute transverse mobility and ratchet effect on periodic 2D symmetric substrates
   C. Reichhardt and C.J. Olson Reichhardt
   Phys. Rev. E 68, 046102 (2003). arXiv
   

   
   

9. Rectification and phase locking for particles on two dimensional periodic substrates
   C. Reichhardt, C.J. Olson, and M.B. Hastings
   Phys. Rev. Lett. 89, 024101 (2002). arXiv