Active Casimir image


Active Matter

Active matter is a growing field spanning soft matter, biological physics, and statistical mechanics. Active matter systems are intrinsically nonequilibrium and can exhibit transitions between motility-induced cluster and uniform liquid phases as a function of density and activity. Most studies of active matter have focused on systems with a smooth substrate, but soft matter systems interacting with disordered pinning substrates are known to exhibit a variety of order-disorder transitions. An open question is what happens when active matter systems are coupled to structured substrates. We use numerical simulations to examine the dynamics of active run-and-tumble disks moving and/or driven through a variety of structured environments.

Preprints:

  1. Phase separation, edge currents, and Hall effect for active matter with Magnus dynamics
    B. Adorjani, A. Libal, C. Reichhardt, and C.J.O. Reichhardt
    We examine run and tumble disks in two-dimensional systems where the particles also have a Magnus component to their dynamics. For increased activity, we find that the system forms a motility-induced phase-separated (MIPS) state with chiral edge flow around the clusters, where the direction of the current is correlated with the sign of the Magnus term. The stability of the MIPS state is non-monotonic as a function of increasing Magnus term amplitude, with the MIPS region first extending down to lower activities followed by a break up of MIPS at large Magnus amplitudes into a gel-like state. We examine the dynamics in the presence of quenched disorder and a uniform drive, and find that the bulk flow exhibits a drive-dependent Hall angle. This is a result of the side jump effect produced by scattering from the pinning sites, and is similar to the behavior found for skyrmions in chiral magnets with quenched disorder.
    arXiv


Papers:

  1. Motility induced phase separation and frustration in active matter swarmalators
    B. Adorjani, A. Libal, C. Reichhardt, and C.J.O. Reichhardt
    Phys. Rev. E 109, 024607 (2024). arXiv


  2. Vortex lattices in active nematics with periodic obstacle arrays
    C.D. Schimming, C.J.O. Reichhardt, and C. Reichhardt
    Phys. Rev. Lett. 132, 018301 (2024). arXiv


  3. Characterizing different motility induced regimes in active matter with machine learning and noise
    D. McDermott, C. Reichhardt, and C.J.O. Reichhardt
    Phys. Rev. E 108, 064613 (2023). arXiv


  4. Dynamic phases and combing effects for elongated particles moving over quenched disorder
    A. Libal, S. Stepanov, C. Reichhardt, and C.J.O. Reichhardt
    Soft Matter 19, 7937 (2023). arXiv


  5. Transient pattern formation in an active matter contact poisoning model
    P. Forgacs, A. Libal, C. Reichhardt, N. Hengartner, and C.J.O. Reichhardt
    Commun. Phys. 6, 294 (2022). arXiv


  6. Friction mediated phase transition in confined active nematics
    C.D. Schimming, C.J.O. Reichhardt, and C. Reichhardt
    Phys. Rev. E 108, L012602 (2023). arXiv


  7. Pattern formation and transport for externally driven active matter on periodic substrates
    C. Reichhardt and C.J.O. Reichhardt
    EPL 142, 37001 (2023). arXiv


  8. Transition from susceptible-infected to susceptible-infected-recovered dynamics in a susceptible-cleric-zombie-recovered active matter model
    A. Libal, P. Forgacs, A. Neda, C. Reichhardt, N. Hengartner, and C.J.O. Reichhardt
    Phys. Rev. E 107, 024604 (2023). arXiv


  9. Pattern formation and flocking for particles near the jamming transition on resource gradient substrates
    L. Varga, A. Libal, C. Reichhardt, and C.J.O. Reichhardt
    Phys. Rev. E 106, 064602 (2022). arXiv


  10. Future directions for active matter on ordered substrates
    C. Reichhardt, A. Libal, and C.J.O. Reichhardt
    EPL 139, 27001 (2022). arXiv


  11. Using active matter to introduce spatial heterogeneity to the susceptible infected recovered model of epidemic spreading
    P. Forgacs, A. Libal, C. Reichhardt, N. Hengartner, and C.J.O. Reichhardt
    Sci. Rep. 12, 11229 (2022). arXiv


  12. Active rheology in odd viscosity systems
    C.J.O. Reichhardt and C. Reichhardt
    EPL 137, 66004 (2022). arXiv


  13. Active regimes for particles on resource landscapes
    L. Varga, A. Libal, C.J.O. Reichhardt, and C. Reichhardt
    Phys. Rev. Res. 4, 013061 (2022). arXiv


  14. Crystals break up with a twist
    C.J.O. Reichhardt and C. Reichhardt
    Nature Phys.18, 134 (2022).


  15. Active matter shepherding and clustering in inhomogeneous environments
    P. Forgacs, A. Libal, C. Reichhardt, and C.J.O. Reichhardt
    Phys. Rev. E 104, 044613 (2021). arXiv


  16. An exceptional view of phase transitions in non-equilibrium systems
    C.J.O. Reichhardt and C. Reichhardt
    Nature 592, 363 (2021).


  17. Clogging, dynamics and reentrant fluid for active matter on periodic substrates
    C. Reichhardt and C.J.O. Reichhardt
    Phys. Rev. E 103, 062603 (2021). arXiv


  18. Active matter commensuration and frustration effects on periodic substrates
    C. Reichhardt and C.J.O. Reichhardt
    Phys. Rev. E 103, 022602 (2021). arXiv


  19. Directional locking effects for active matter particles coupled to a periodic substrate
    C. Reichhardt and C.J.O. Reichhardt
    Phys. Rev. E 102, 042616 (2020). arXiv

  20. Active microrheology, Hall effect, and jamming in chiral fluids
    C. Reichhardt and C.J.O. Reichhardt
    Phys. Rev. E 100, 012604 (2019). arXiv

  21. Reversibility, pattern formation and edge transport in active chiral and passive disk mixtures
    C. Reichhardt and C.J.O. Reichhardt
    J. Chem. Phys. 150, 064905 (2019). arXiv

  22. Laning and clustering transitions in driven binary active matter systems
    C. Reichhardt, J. Thibault, S. Papanikolau, and C.J.O. Reichhardt
    Phys. Rev. E 98, 022603 (2018). arXiv

  23. Clogging and depinning of ballistic active matter systems in disordered media
     C. Reichhardt and C.J.O. Reichhardt
    Phys. Rev. E 97, 052613 (2018). arXiv

  24. Avalanche dynamics for active matter in heterogeneous media
     C.J.O. Reichhardt and C. Reichhardt
    New J. Phys. 20, 025002 (2018). arXiv


  25. Negative differential mobility and trapping in active matter systems
     C. Reichhardt and C.J.O. Reichhardt
    J. Phys.: Condens. Matter 30, 015404 (2018). arXiv


  26. Dewetting and spreading transitions for active matter on random pinning substrates
     Cs. Sandor, A. Libal, C. Reichhardt, and C.J. Olson Reichhardt,
    J. Chem. Phys. 146, 204903 (2017). arXiv


  27. Dynamic phases of active matter systems with quenched disorder
     Cs. Sandor, A. Libal, C. Reichhardt, and C.J. Olson Reichhardt,
    Phys. Rev. E 95, 032606 (2017). arXiv


  28. Ratchet effects in active matter systems (invited review)
    C.J. Olson Reichhardt and C. Reichhardt,
    Ann. Rev. Condens. Matt. Phys. 8, 51 (2017). arXiv


  29. Collective transport for active matter run-and-tumble disk systems on a traveling-wave substrate
     Cs. Sandor, A. Libal, C. Reichhardt, and C.J. Olson Reichhardt,
    Phys. Rev. E 95, 012607 (2017). arXiv


  30. Collective motion: Disorder in the wild
    C.J. Olson Reichhardt and C. Reichhardt,
    Nature Phys. 13, 10 (2017).


  31. Collective ratchet effects and reversals for active matter particles on quasi-one-dimensional asymmetric substrates
     D. McDermott, C.J. Olson Reichhardt, and C. Reichhardt,
    Soft Matter 12, 8606 (2016). arXiv


  32. Active microrheology in active matter systems: Mobility, intermittency, and avalanches
    C. Reichhardt and C.J. Olson Reichhardt,
    Phys. Rev. E 91, 032313 (2015). arXiv


  33. Absorbing phase transitions and dynamic freezing in running active matter systems
    C. Reichhardt and C.J. Olson Reichhardt,
    Soft Matter 10, 7502 (2014). arXiv


  34. Active matter transport on complex substrates
    C.J. Olson Reichhardt, D. Ray, and C. Reichhardt,
    Proc. SPIE 9164, Optical Trapping and Optical Micromanipulation XI, 91641N (2014).


  35. Casimir effect in active matter systems
    D. Ray, C. Reichhardt and C.J. Olson Reichhardt,
    Phys. Rev. E 90, 013019 (2014). arXiv


  36. Active matter transport and jamming on disordered landscapes
    C. Reichhardt and C.J. Olson Reichhardt,
    Phys. Rev. E 90, 012701 (2014). arXiv


  37. Active matter ratchets with an external drift
    C. Reichhardt and C.J. Olson Reichhardt,
    Phys. Rev. E 88, 062310 (2013). arXiv


  38. Dynamics and separation of circularly moving particles in asymmetrically patterned arrays
    C. Reichhardt and C.J. Olson Reichhardt
    Phys. Rev. E 88, 042306 (2013). arXiv


  39. Self-driven particles on asymmetric trap arrays
    L.M. Lopatina, C. Reichhardt, and C.J. Olson Reichhardt,
    Proc. SPIE 8810, Optical Trapping and Optical Micromanipulation X, 881016 (2013).


  40. Dynamics of self-driven and flocking particles on periodic arrays
    J.A. Drocco, L.M. Lopatina, C. Reichhardt, and C.J. Olson Reichhardt,
    Proc. SPIE 8458, Optical Trapping and Optical Micromanipulation IX, 84581I (2012).


  41. Bidirectional sorting of flocking particles in the presence of asymmetric barriers
    J.A. Drocco, C.J. Olson Reichhardt, and C. Reichhardt,
    Phys. Rev. E 85, 056102 (2012). arXiv


  42. Dynamical freezing of active matter
    C. Reichhardt and C.J. Olson Reichhardt,
    Proc. Natl. Acad. Sci. (USA) 108, 19099 (2011).


  43. Active matter on asymmetric substrates
    C.J. Olson Reichhardt, J. Drocco, T. Mai, M.B. Wan, and C. Reichhardt,
    Proc. SPIE 8097, Optical Trapping and Optical Micromanipulation VIII, 80970A (2011). arXiv


  44. Rectification of swimming bacteria and self-driven particle systems by arrays of asymmetric barriers
    M.B. Wan, C.J. Olson Reichhardt, Z. Nussinov, and C. Reichhardt,
    Phys. Rev. Lett. 101, 018102 (2008). arXiv


  45. Cooperative behavior and pattern formation in mixtures of driven and nondriven colloidal assemblies
     C. Reichhardt and C.J. Olson Reichhardt
    Phys. Rev. E 74, 011403 (2006). arXiv

Last modified Jan 7, 2019