Leverhulme-Peierls fellow at @OxfordPhysics. Fascinated by active matter 🦠, dynamical systems 🪐 & fluid dynamics 💦.
Oxford, England
Joined June 2019
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In a recent work, we show that a suspension of (non-interacting) deformable, elongated particles in oscillatory shear flow can develop nematic order via a phase synchronization mechanism. The work is published in @PhysRevLett :
journals.aps.org/prl/abstrac…
@OxfordPhysics
Can classical active particles give wave-like statistics? Our new work shows how Lorenz-like internal dynamics can organize classical active particles into wave-like spatial statistics.
#activematter #chaos #HQA
journals.aps.org/pre/abstrac…
Rahil Valani retweeted
Active Soft-Impact Oscillator: Dynamics of a Walking Droplet in a Non-Smooth Potential
Titir Mukherjee, Rahil N Valani, Soumitro Banerjee
arxiv.org/abs/2602.05913 [𝚗𝚕𝚒𝚗.𝙲𝙳 𝚙𝚑𝚢𝚜𝚒𝚌𝚜.𝚏𝚕𝚞-𝚍𝚢𝚗]
Wave-mediated interactions can drive rich collective dynamics in active particle clusters. We study walking droplet clusters that form stable bound states with collective excitation modes and show similarities with nuclear physics.
Paper: doi.org/10.1103/4cgg-hnyh
In a joint work led by Brendan Harding, and with Yvonne Stokes, we develop a unified Hamiltonian framework for how active particles move in channel flows. Particles undergo complex trajectories but remain confined within predictable regions. @PhysRevE
doi.org/10.1103/m9ks-mq3d
Quincke rotation, a particle spinning in an electric field, exhibits complex dynamics and follows the Lorenz equations. In a recent work, we show that fluid memory reshapes this chaos and delays its onset.
@AdityaSKhair1 @PhysRevFluids
journals.aps.org/prfluids/ab…
Rahil Valani retweeted
More on collective behavior: Our new Annual Review of Biophysics piece - with the stellar Danielle Chase - explores how animals sense, share information, and make group decisions. In honeybees and beyond 🐝
annualreviews.org/content/jo…
New preprint - We show a Hamiltonian formulation for the motion of a simple active particle interacting with unidirectional steady flow. This provides insights into organization of the active particle trajectories as defined by a potential well.
arxiv.org/abs/2506.11388
Rahil Valani retweeted
Postdoctoral position open in Bacterial-Algal Symbiosis! This interdisciplinary role will involve experimental and theoretical research using microfluidics, microscopy and modelling. Applications close May 13 (Aust. time). Please RT!
@SciMelb @UniMelb
jobs.unimelb.edu.au/caw/en/j…
An active particle inspired from walking droplets can unpredictably cross a potential barrier. Using a minimal model, we show that the unpredictability lies in non-equilibrium features of a perturbed Lorenz system @PhysRevE
journals.aps.org/pre/abstrac…
Attending the @APSphysics Global Physics Summit in Anaheim #APSSummit25. If you would like to learn about our recent work on active particles/mechanobiology, or just want to say hi, then I am presenting at the below sessions:
summit.aps.org/events/MAR-T5…
summit.aps.org/events/MAR-M0…
Using a simple model of a walking droplet in a harmonic potential, we show countably infinite quantized orbits, as opposed to a continous spectrum that one gets for a classical simple harmonic oscillator. See our open access paper below @PhysRevE :
journals.aps.org/pre/abstrac…
Thanks @PhysRevE for highlighting our work :)
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Our below work in now published in @PhysRevE! We show that asymmetric limit cycles within Lorenz chaos can induce motion for an active particle in a direction opposite to an applied force.
#chaos #activematter #walkingdroplet
doi.org/10.1103/PhysRevE.110…
Non-equilibrium systems can appear to contradict Newton's 2nd law by responding with persistant motion in the direction opposite to an applied force. We find a dynamical mechanism for this behaviour rooted in asymmetric limit cycles within Lorenz chaos.
doi.org/10.48550/arXiv.2408.…
Rahil Valani retweeted
Congratulations to Xinyi for the fist paper from her PhD. This work, together with @PrakashLab, is published in @RSocPublishing today, and examines individual and collective behaviour of magnetotactic bacteria in an oxygen gradient. @SciMelb @MelbMathBio
royalsocietypublishing.org/d…
Rahil Valani retweeted
#ICYMI: In wave-particle duality, electrons can become trapped in disordered environments. Now, researchers show that a similar effect can be seen in droplets on a vibrating fluid surface – results that could inform research on #ActiveMatter systems.
🔗 go.aps.org/3zwaFNB
ALT A small liquid droplet hovers above a rippled, light pink and blue fluid surface that takes up the entire image. The droplet is reflected on the surface, and it appears to be at a standstill as the surface ripples interact with it.
We are advertising a postdoc position at @UniofAdelaide to work on mathematical modelling of inertial microfluidic technologies. If this sounds interesting please see below link or if you know anyone who might be interested please help spread the word
Great postdoc opportunity working with my awesome colleague Yvonne Stokes! careers.adelaide.edu.au/cw/e…
Within the chaotic sea of the parameter space, a pair of coexisting asymmetric limit cycles separate and migrate, resulting in anomalous transport behaviors that are sensitive to the particle’s memory.
Non-equilibrium systems can appear to contradict Newton's 2nd law by responding with persistant motion in the direction opposite to an applied force. We find a dynamical mechanism for this behaviour rooted in asymmetric limit cycles within Lorenz chaos.
doi.org/10.48550/arXiv.2408.…
We consider a simple model of a memory-driven active particle, inspired from experiments with walking/superwalking droplets, with a small external force that takes the form of a perturbed Lorenz system. #activeparticle #Lorenzsystem #chaos #walkingdroplet