Research interests and activities:

SOFT-MATTER AND NONEQUILIBRIUM STATISTICAL PHYSICS: the statistical mechanics of sedimentation; dynamics and rheological chaos in surfactant solutions; theory and experiments on ordered nonequilibrium steady states in agitated monolayers of granular rods
THE MECHANICS OF LIVING MATTER: statistical hydrodynamics of self-driven organisms --- fish, bacteria, cell-membranes with pumps, motors, filaments, and ATP; the rheology of the living cell.

Recent publications and preprints

2012

• Oscillatory settling in wormlike-micelle solutions: bursts and a long time scale, Nitin Kumar, Sayantan Majumdar, Aditya Sood, Rama Govindarajan, Sriram Ramaswamy and A.K. Sood, Soft Matter 8 (2012) 4310
• A drop of active matter, J.-F. Joanny and S. Ramaswamy, J. Fluid Mech. (in press) (arxiv.org/1201.2794)

  2011

• Mechanotaxis reveals that neurons are steered by actin and propelled by microtubules, A.J. Ehrlicher, C. Brunner, T. Ruempel, Madan Rao, S. Ramaswamy, D. Koch, J.A. Kaes, submitted to J. Cell Biol. 2011.
• Mode-coupling glass transition in a fluid confined by a periodic potential, S.K. Nandi, S.M. Bhattacharyya, S. Ramaswamy, Phys. Rev. E 84 (2011) 061501.
• Symmetry Properties of the Large-Deviation Function of the Velocity of a Self-Propelled Polar Particle, Nitin Kumar, Sriram Ramaswamy, and A. K. Sood, Phys. Rev. Lett. 106 (2011) 118001 (Editor's Suggestion)

  2010

• The Mechanics and Statistics of Active Matter, S Ramaswamy, Annu. Rev. Condens. Matt. Phys. 1 (2010) 323-345 (Inaugural Issue) (arxiv.org/1004.1933)
• A Dynamic Renormalization Group Study of Active Nematics, S Mishra, R A Simha, S Ramaswamy (J. Stat. Mech.(2010) P02003) (arxiv.org/0912.2283)
• Nonequilibrium noise in electrophoresis: the microion wind, S Saha, S Ramaswamy (arxiv.org/0907.0469)

2009

• Dynamics of a stiff biopolymer in an actively contractile background: buckling, stiffening and negative dissipation, N Kikuchi, A Ehrlicher, D Koch, J A Kaes, S Ramaswamy, M Rao [PNAS 106 (2009) 19776-19779] (arxiv.org/0901.4126)
• Universality Class of the Reversible-Irreversible Transition in Sheared Suspensions, G I Menon, S Ramaswamy, Phys Rev E 79 (2009) 061108 (arxiv.org/0801.3881)
• Instabilities and waves in thin films of living fluids, Sumithra Sankararaman and Sriram Ramaswamy, Phys Rev Lett 102 (2009) 118107 (arxiv.org/0809.4918)

2008

• Exact solution of a Brownian inchworm model for self-propulsion, A. Baule, K. Vijay Kumar and S. Ramaswamy, J. Stat. Mech. (2008) P11008 (arxiv.org/0903.1572)
• Active elastic dimers: self-propulsion and current reversal on a featureless track, K. Vijay Kumar, S. Ramaswamy and M. Rao, Phys Rev E (Rapid Comm.) 77 (2008) 020102 R (arxiv.org/0708.1802)

2007

• Active-filament hydrodynamics: instabilities, boundary conditions and rheology, S. Ramaswamy and M. Rao, New Journal of Physics 9 (2007) 423 (Focus Issue on Physics of the Cytoskeleton).
• Perspectives on the mode-coupling approximation for the dynamics of interacting Brownian particles, A. Basu and S. Ramaswamy, J. Stat. Mech. (2007) P11003.
• Long-lived giant number fluctuations in a swarming granular nematic, V. Narayan, S. Ramaswamy, N. Menon, Science 317 (2007) 105 [see Perspective: M van Hecke, Science 317 (2007) 49]; (cond-mat/0612020)
• Shear-flow-induced isotropic to nematic transition in a suspension of active filaments, S. Muhuri, M. Rao and S. Ramaswamy, Europhys Lett 78 (2007) 48002; (cond-mat/0610025)
• Superdiffusion of concentration in wormlike-micelle solutions, Rajesh Ganapathy, A.K. Sood, and Sriram Ramaswamy, Europhys Lett 77 (2007) 18007.

2006

• Active nematics are intrinsically phase-separated, Shradha Mishra and Sriram Ramaswamy, Phys Rev Lett 97 (2006) 090602 (cond-mat/0603051)
• Brownian-drag induced particle current in a model colloidal system, Moumita Das, Sriram Ramaswamy, A.K. Sood, and G. Ananthakrishna, Phys. Rev. E 73 (2006) 061409
• Do current-density nonlinearities cut off the glass transition? M. E. Cates and S. Ramaswamy, Phys. Rev. Lett. 96 (2006) 135701 (cond-mat/0511260)
• Vijay Narayan, Narayanan Menon and Sriram Ramaswamy, Nonequilibrium steady states in a vibrated-rod monolayer: tetratic, nematic and smectic correlations, J. Stat. Mech. (2006) P01005. (cond-mat/0510082)
• The mechanics of active matter: Broken-symmetry hydrodynamics of motile particles and granular layers, S. Ramaswamy and R.A. Simha, Solid State Communications 139 (2006) 617-622
• Rheological chaos in wormlike micelles and nematic hydrodynamics Moumita Das, Ranjini Bandyopadhyay, Buddhapriya Chakrabarti, Chandan Dasgupta, Sriram Ramaswamy and Ajay Sood, in Molecular Gels: Materials with Self-Assembled Fibrillar Networks, Richard G. Weiss and Pierre Terech (editors), Kluwer, Amsterdam (2006).

2005

• Hydrodynamics and phases of flocks, J. Toner, Y. Tu and S. Ramaswamy, Ann. Phys. 318 (2005) 170
• Routes to spatiotemporal chaos in the rheology of nematogenic fluids B. Chakrabarti, M. Das, C. Dasgupta, S. Ramaswamy, A.K. Sood Phys. Rev. E 71 (2005) 021707 (cond-mat/0408282)

  2004

• Spatiotemporal rheochaos in nematic hydrodynamics B. Chakrabarti, M. Das, C. Dasgupta, S. Ramaswamy, A.K. Sood Phys Rev Lett 92 (2004) 055501 (cond-mat/0311101)
• Rheology of active-particle suspensions, Y. Hatwalne, S. Ramaswamy, M. Rao and R. A. Simha, Phys Rev Lett 92 (2004) 118101 (cond-mat/0308529)
• Flow-induced current and voltage generation in carbon nanotubes, S. Ghosh, A.K. Sood, S. Ramaswamy, N. Kumar, Phys. Rev. B 70 (2004) 205423 (cond-mat/0407803)

  2003

• The segregation instability of a sheared suspension film, R. Govindarajan, P.R. Nott and S. Ramaswamy, submitted to Phys. Fluids (2003) (cond-mat/0312189)
• Rheology of disordered lamellar phases, S. Sukumaran, S. Ramaswamy, P.R. Nott and V. Kumaran, submitted to Phys Rev Lett (2003).
• Collective stochastic resonance in shear-induced melting of sliding bilayers M. Das, G. Ananthakrishna and S. Ramaswamy, Phys. Rev. E 68, 061402 (2003) (cond-mat/0307519)
• Active nematics on a substrate: giant number fluctuations and long-time tails, S. Ramaswamy, R.A. Simha and J. Toner, Europhys.Lett. 62 (2003) 196-202 (cond-mat/0208573)

  2002

• Melting-freezing cycles in a relatively sheared pair of crystalline monolayers, M. Das, S. Ramaswamy and G. Ananthakrishna, Europhys Lett 60 (2002) 636-642 (cond-mat/0205030)
• Ratchet for energy transport between identical reservoirs, S. Das, O. Narayan and S. Ramaswamy, Phys Rev E (Rapid Comm) 66, 050103 (2002) (cond-mat/0206372)
• Anomalous heat conduction in one dimensional momentum-conserving systems, O. Narayan and S. Ramaswamy, Phys Rev Lett 89 (2002) 200601 (cond-mat/0205295) [highlighted in R Livi and S Lepri, Nature (News and Views) 421 (2003) 327]
• Driven Heisenberg Magnets: Nonequilibrium Criticality, Spatiotemporal Chaos and Control, J. Das, M. Rao and S. Ramaswamy, Europhys. Lett., 60 (2002) 418-424 (cond-mat/0104566)
• Stripes in sheared non-brownian suspensions with a free surface, R. Govindarajan, P.R. Nott and S. Ramaswamy, Proc. Statphys Kolkata 2002 (Physica A, in press).
• Phase Diagram of a Two-Species Lattice Model with a Linear Instability, S. Ramaswamy, M. Barma, D. Das, and A. Basu (Proc. Discussion Meeting on Slow Dynamics and Freezing, Jawaharlal Nehru University), Phase Transitions B 75 (2002) 363-375
• Hydrodynamic fluctuations and instabilities in ordered suspensions of self-propelled particles, R. A. Simha and S. Ramaswamy Phys Rev Lett 89 (2002) 058101 (pdf file of paper)
• Statistical hydrodynamics of ordered suspensions of self-propelled particles: waves, giant number fluctuations and instabilities, R.A. Simha and S. Ramaswamy (Proc. STATPHYS21) Physica A 306 (2002) 262-269 (pdf file of paper)

  2001

• Theory of Suspension Segregation in Partially Filled Horizontal Rotating Cylinders, R. Govindarajan, P.R. Nott and Sriram Ramaswamy, Phys. Fluids (Lett.) 13 (2001) 3517-3520 (pdf file of paper) (cond-mat/0109428)
• The physics of active membranes, S. Ramaswamy and Madan Rao, C.R. Acad. Sci. Paris (special issue on Physics at the Scale of the Cell) t. 2, Ser. IV, 817-839 (2001).
• Issues in the statistical mechanics of steady sedimentation, S. Ramaswamy, Adv. Phys. 50 (2001) 297-341. (pdf file of paper)
• Weak and strong dynamic scaling in a one-dimensional driven coupled-field model: Effects of kinematic waves, D. Das, A. Basu, M. Barma and S. Ramaswamy, Phys. Rev. E 64 (2001) 021402 (pdf file of paper)
• Active Membrane Fluctuations Studied by Micropipet Aspiration, J-B. Manneville, P. Bassereau, S. Ramaswamy, J. Prost, Phys. Rev. E 64 (2001) 021908 (pdf file of paper)

  2000

• Nonequilibrium noise, steady states, and instabilities in membranes with active proteins
  S. Ramaswamy, J. Toner, and J. Prost, Phys. Rev. Lett. 84 (2000) 3494-3497 (pdf file of paper)
• Strong phase separation in a model for sedimenting lattices
  R. Lahiri, M. Barma, and S. Ramaswamy
  Phys. Rev. E 61 (2000) 1648 (pdf file of paper)
• Inequivalence of ensembles in a driven diffusive system
  M. Acharyya, A. Basu, R. Pandit, and S. Ramaswamy
  Phys. Rev. E 61 (2000) 1139 (pdf file of paper)

  1999

• Travelling waves in a drifting flux lattice
  R. Aditi Simha and S. Ramaswamy
  Phys. Rev. Lett 83 (1999) 3285 (pdf file of paper)
• Structure and rheology of the defect-gel states of pure and particle-dispersed lyotropic lamellar phases,
  G. Basappa, Suneel, V. Kumaran, P.R. Nott, S. Ramaswamy, V.M. Naik and D. Rout
  Eur. Phys. Jour. B 12 (1999) 269-276. (pdf file of paper)
• Mean magnetic field and noise cross-correlation in magnetohydrodynamic turbulence: results from a one-dimensional model,
  A. Basu, J.K. Bhattacharjee and S. Ramaswamy,
  Eur. Phys. Jour. B 9 (1999) 725-730 (pdf file of paper)

  1998

• Screened and unscreened phases in sedimenting suspensions,
  A. Levine, S. Ramaswamy, E. Frey and R. Bruinsma,
  Phys. Rev. Lett. 81, 5944-5947 (1998) (pdf file of paper)

  1997

• (i) Self-diffusion of colloids at freezing;
  (ii) Shear-enhanced diffusion in colloids;
  (iii) Excess dissipation in dense emulsions;
  three chapters in Theoretical Challenges in the Dynamics of Complex Fluids
  (lectures in a NATO Advanced Study Institute), Ed. T C B McLeish, Kluwer 1997 (three .ps files tarred into a single file)
• Are steadily moving crystals unstable? R. Lahiri and S. Ramaswamy, Phys. Rev. Lett. 79, 1150-1153 (1997) (pdf file of paper)