| ICTS In-House 2026 Schedule, Venue- Ramanujan Lecture Hall | |||
| Day 1, 6th April-Monday | |||
| 6TH April | |||
| 10:00-10:30 | Inaugural Remarks and Director's Address | ||
| 6TH April | Speaker | Title | Abstract |
| Session 1 (10:30-11:30), Session Chair: Abhinav Dhawan | |||
| 10:30 | Anikat Kankaria | Dynamical slowdown, bottlenecks, and multiscaling in Voigt-regularised turbulence | We study bottleneck formation in turbulence using the SABRA shell model of the α–Voigt regu- larised Navier–Stokes equations. The Voigt regularisation introduces a scale–dependent retardation of the nonlinear dynamics, progressively suppressing energy transfer at small scales without directly enhancing dissipation. Numerical simulations of the second–order equal–time structure function re- veal three distinct scaling regimes: a Kolmogorov–like inertial range at low wavenumbers, an inter- mediate regime with a flat spectrum associated with partial thermalisation, and a high–wavenumber equilibrium regime with k−2 scaling arising from equipartition of the Voigt-modified energy. We pro- vide a theoretical explanation for these regimes based on a scale–dependent nonlinear time scale and the structure of the conserved invariant, showing that the breakdown of the forward cascade occurs at a wavenumber independent of the Voigt parameter α, while the onset of the Voigt-dominated equilibrium scales as k∼ 1/α. Probability distribution functions in the thermalised regimes are Gaussian, and direct numerical simulations of the Voigt–regularised Navier–Stokes equations show consistent spectral and statistical signatures. We also examine time-dependent structure functions and discuss the implications of partial thermalisation for dynamic multiscaling. |
| 10:45 | Rahul Metya | Classical String solutions in Blackhole background and their holographic dual | String solutions in black hole backgrounds are not yet well understood. In this talk, we will consider a simple three-dimensional black hole, known as the BTZ black hole, and attempt to construct classical string solutions in this geometry. We will exploit the connection between the BTZ black hole and AdS_3 spacetime—where string solutions are comparatively better understood—to guide our construction. We will also discuss the boundary field theory interpretation of these solutions. |
| 11:00 | Atharva Naik | Dynamics of Eigenvalues of the Correlation Matrix in Free Fermionic Systems with point defect. | I will discuss the evolution of the eigenvalues of the correlation matrix in a free fermionic system with a point defect. Specifically, I will talk about a system with a special type of defect called a conformal defect and show some interesting relation of the eigenvalues and the transport properties of the system. |
| 11:15 | Savita Rani | Quasi-*Einstein Hopf real hypersurfaces in complex space forms | Einstein metrics and their generalizations, such as Ricci solitons, $\eta$-Einstein metrics, pseudo-Einstein metrics, and Miao-Tam critical metrics, play a significant role in both mathematics and physics. While it is well known that non-flat complex space forms do not admit Einstein real hypersurfaces, they do admit *Einstein real hypersurfaces. Motivated by this, we investigate quasi-*Einstein structures. Specifically, we examine the existence and non-existence of quasi-*Einstein Hopf real hypersurfaces in complex space forms. |
| TEA BREAK | |||
| Session 2 (11:45-12:45), Session Chair: Saiba Ayoub | |||
| 11:45 | Priyanka Sinha | Modeling Spin-Precessing Binaries using the Twisting Approximation: A Systematic Accuracy Assessment | Gravitational waves emitted from eccentric and precessing binary systems provide vital clues regarding their formation pathways and stellar environments. When the spins of objects in a binary system are misaligned with their orbital angular momentum, the orbital plane undergoes precession. Modeling these systems is challenging due to the expanded parameter space. To simplify this, the community often employs an approximation where a precessing binary in an inertial frame is mapped to a non-precessing binary in a non-inertial (co-precessing) frame. This mapping involves transforming precessing waveform modes into co-precessing modes using rotation quaternions. Since co-precessing modes can be identified with aligned-spin waveform modes, 'twisting' the aligned-spin modes back with the rotation produces approximate precessing waveforms. This study evaluates the accuracy of this 'twisting-up' approximation across the mass ratio and spin parameter space for both quasi-circular and eccentric binary systems. |
| 12:00 | Suruj Jyoti Kalita | Turbulence in a stable background studied at particle level | When an infinitesimal perturbation triggers transition to turbulence, it is called a supercritical transition to turbulence. But when a finite-amplitude perturbation triggers transition to turbulence in a stable base flow, it is called subcritical transition to turbulence. A plane Couette flow (PCF) is known to be stable at all the values of Reynolds number, but it is non-linearly unstable. I shall present a study on subcritical transition to turbulence in PCF performed in a Complex plasma medium at particle levels using first-priciples calssical MD simulations. |
| 12:15 | Abhishek Dhar | Chiral proximity effects and a topological invariant in a Chern insulator connected to leads | The observed robustly quantized Hall conductance in quantum Hall systems and Chern insulators (CI) have so far been understood in terms of the topology of isolated systems, which are not coupled to leads. It is assumed that the leads act as inert reservoirs that simply supply/absorb electrons to/from the sample. Within a model of a CI coupled to leads with a cylindrical geometry, we show that this is not true. In the proximity of the CI, the edge current leaks into the leads, with the Hall conductance quantized only if this novel proximity effect is taken into account. We identify the conductance with a topological invariant of the system, in terms of the winding number of the phase of the reflection coefficients of the scattering states. |
| LUNCH | |||
| Session 3 (14:15-15:15), Session Chair: Kanak Sorari | |||
| 14:15 | Alorika Kar | Reconstructing and distinguishing the formation and evolution of supermassive black holes using multi-wavelength gravitational wave observations (Online preferred) | The formation and evolution of supermassive black holes (SMBHs) remain a central problem in modern astrophysics. Astrophysical models typically invoke the formation of some ‘seed’ black holes at high redshifts, which grow into SMBHs over cosmic time through a combination of gas accretion and mergers. Although the observation of high-redshift quasars has provided useful constraints on these models, the details remain unclear. We explore how future multi-wavelength gravitational-wave (GW) observations using ground- and space-based detectors can collectively constrain these formation scenarios. By observing a larger range of black-hole masses and redshifts, multi-wavelength GW observations will significantly improve constraints on the SMBH growth models compared to observations using any single detector. We also identify remaining gaps in parameter space where detection remains challenging, highlighting areas where future GW detector development or complementary electromagnetic observations could provide breakthroughs. |
| 14:30 | Kunal Kumar | Active Filaments in Turbulence :Propulsion Direction Controls Transport | We investigate the transport of elastic active filaments in two-dimensional turbulence, focusing on the role of propulsion geometry and elasticity. We show that activity along the filament backbone remains coupled to vortex trapping and does not lead to escape from coherent structures. Instead, activity enhances motion within vortices, leading to increased but constrained transport. We further demonstrate that propulsion direction controls transport efficiency, with misalignment enabling stronger spreading. |
| 14:45 | Rukmini Dey | Berezin Quantization on smooth manifolds | We embed the smooth manifold into CP^n and induce the quantization from CP^n to the smooth manifold. The Poisson structure is also induced from the ambient space. If time permits we mention a few other quantization methods,like Odzijewicz and Fedosov quantizations, which can be evhibited in a similar way. |
| 15:00 | Nitesh Kumar Patro | Emergent self-inhibition governs the landscape of stable states in complex ecosystems | Species-rich ecosystems often exhibit multiple stable states with distinct species compositions. Yet, the factors determining the likelihood of each state’s occurrence remain poorly understood. Here, we characterize and explain the landscape of stable states in the random Generalized Lotka–Volterra (GLV) model, in which multistability is widespread. We find that the same pool of species with random initial abundances can result in different stable states, whose likelihoods typically differ by orders of magnitude. A state’s likelihood increases sharply with its total biomass, or inverse selfinhibition. We develop a simplified model to predict and explain this behavior, by coarse-graining ecological interactions so that each stable state behaves as a unit. In this setting, we can accurately predict the entire landscape of stable states using only two macroscopic properties: the biomass of each state and species diversity. Our theory also provides insight into the biomass–likelihood relationship: High-biomass states have low self-inhibition and thus grow faster, outcompete others, and become much more likely. These results reveal emergent self-inhibition as a fundamental organizing principle for the attractor landscape of complex ecosystems—and provide a path to predict ecosystem outcomes without knowing microscopic interactions. |
| TEA BREAK+POSTER | |||
| Day 2 ,7th April-Tuesday | |||
| 7TH April | Speaker | Title | Abstract |
| Session 1 (10:20-11:20), Session Chair: Swadesh Bhandari | |||
| 10:20 | Jyotirmoy Barman | ZZ instantons in minimal type 0A superstring theory | We have computed the disk one-point, disk two-point, and annulus one-point function of the cosmological constant operator in the minimal superstring theory using worldsheet formalism. The results precisely match the expectations from KPZ scaling. Our computation of disk two-point and annulus one-point function uses picture-changing operators and a prescription for vertical integration. Both of these contributions contain open string divergences that we resolved using open-closed string field theory insights, leading to unambiguous results. |
| 10:35 | Bibek Saha | Anderson localisation in spatially structured random graphs | We study Anderson localisation on high-dimensional graphs with spatial structure induced by long-ranged but distance-dependent hopping. To this end, we introduce a class of models that interpolate between the short-range Anderson model on a random regular graph and fully connected models with statistically uniform hopping, by embedding a random regular graph into a complete graph and allowing hopping amplitudes to decay exponentially with graph distance. The competition between the exponentially growing number of neighbours with graph distance and the exponentially decaying hopping amplitude positions our models effectively as power-law hopping generalisation of the Anderson model on random regular graphs. Using a combination of numerical exact diagonalisation and analytical renormalised perturbation theory, we establish the resulting localisation phase diagram emerging from the interplay of the lengthscale associated to the hopping range and the onsite disorder strength. We find that increasing the hopping range shifts the localisation transition to stronger disorder, and that beyond a critical range the localised phase ceases to exist even at arbitrarily strong disorder. Our results indicate a direct Anderson transition between delocalised and localised phases, with no evidence for an intervening multifractal phase, for both deterministic and random hopping models. A scaling analysis based on inverse participation ratios reveals behaviour consistent with a Kosterlitz-Thouless-like transition with two-parameter scaling, in line with Anderson transitions on high-dimensional graphs. We also observe distinct critical behaviour in average and typical correlation functions, reflecting the different scaling properties of generalised inverse participation ratios. |
| 10:50 | Shashank Singh | Internal gravity wave continuum | Internal waves in the ocean are one of the major factors responsible for ocean mixing. In this study, we aim to understand the energy cascade and exchange associated with these internal waves. In the ocean, internal gravity waves are generated when barotropic tides interact with topography and generates baroclinic internal gravity waves, wind is also one major effect for generating wave at surface at coriolis frequency which with shear effect travel to the deeper part of the ocean and generates waves with coriolis frequency. The formation of internal gravity waves requires a stratified medium, as stratification acts as a restoring force. Previous studies have primarily focused on constant background stratification; however, in the ocean, stratification varies with depth, which significantly alters the behaviour of internal waves and their energy exchange processes. In our study, we introduce internal waves into the system at a specific frequency and analyze their temporal evolution, investigating how these waves exchange energy with both smaller-scale and larger-scale flows over time. |
| TEA BREAK+POSTER | |||
| Session 2 (11:45-12:45), Session Chair: Vibhu Pandya | |||
| 11:45 | Muhammed Irshad P | Study of small scale dynamo using EDQNM closure | The magnetic field amplification via Small scale dynamo is explored using Eddy Damped Quasi normal Markovian approximation. On the analytical side we show an equivalence of this with the already existing formalism and on the numerical side we show an asymptotic regime in the growth rate and saturation field strength with high and low magnetic prandtl numbers. |
| 12:00 | Shubhadeep Chakraborty | Jamming in a System of Persistent Active Particles in One Dimension | We investigate jamming in a one-dimensional active system with infinite persistence time, with an emphasis on the structure of force-balanced clusters and on the time it takes to reach a jammed state. In the steady state, mechanical force balance expresses the contact forces as partial sums of the underlying ± active-force sequence, which maps the problem to lattice paths constrained to stay on one side of a boundary. This correspondence yields exact counting results for cluster configurations, the probability of forming a single jammed cluster, and the distribution of contact forces inside a cluster, including the scaling of typical forces with system size. To address dynamics, we use a minimal sticky-collision description and define the jamming time as the time of the final merger. Spatiotemporal trajectories and finite-size scaling show that the dominant contribution comes from the last collision event, reducing the problem to the statistics of the inverse relative speed of the final two aggregates. We compute ⟨1/v⟩ by mapping to a first- passage problem for a drift–diffusion process with an absorbing boundary, obtaining an explicit asymptotic form for the mean jamming time. |
| 12:15 | Sam K Mathew | Height Function Transformations of Minimal Surfaces | In this talk, I present a complete classification of minimal graph surfaces that admit transformations of their height functions into new minimal graph surfaces. While trivial transformations such as translations and reflections are well-understood, the existence of non-trivial cases has remained largely unexplored. I define this as the Non-Trivial Minimal Graph Transformation Problem, which I reduce from a coupled system of nonlinear PDEs to a single problem involving a harmonic function. By employing a complex variable approach and a weakening technique, the analysis is further simplified to an ODE dependent on a real parameter k. I explicitly solve this ODE for all k using elliptic integrals and identities, providing a full classification of admissible transformations and yielding several families of minimal surfaces which, to the best of my knowledge, are new. |
| 12:30 | Anjali Kundalpady | Synchronization in Flappers | Flapping is a common mode of locomotion in nature, used by fish to swim and by birds to fly. The surrounding fluid mediates interactions between nearby flapping bodies. When two or more such flappers move in close proximity, these fluid-mediated interactions can lead to emergent synchronization. In this talk, we explore whether such collective behavior arises naturally and how it can be understood. From a biological perspective, we also discuss how adaptive responses from individual flyers can be modeled. Through this framework, we aim to gain insight into the mechanisms underlying coordinated motion in flapping systems. |
| LUNCH | |||
| Session 3 (14:15-15:15), Session Chair: Tannu | |||
| 14:15 | Ashif Seikh | First Detection in a Coined Quantum Walk: A Matrix-Valued Renewal Approach and the Effect of Restart | We investigate first-detection statistics in a one-dimensional discrete-time coined quantum walk subject to repeated projective measurements at a target site. Because the detector is insensitive to the internal coin state, the detection process is naturally described in a two-dimensional detection subspace. We formulate the problem through a matrix-valued renewal equation and obtain closed-form generating functions for the spin-resolved first-arrival amplitudes for different initial coin states. From these expressions we extract the first-detection probabilities and their large-time asymptotics, finding a parity-restricted decay with oscillatory envelopes. We further study a sharp-restart protocol in which the walk is reset after a fixed number of unsuccessful detection attempts, and show that restart converts incomplete detection in the monitored coherent walk into eventual detection whenever each cycle has nonzero success probability. The analysis also clarifies how the initial coin state controls detection efficiency through the directional bias of the walk. Our work gives an exact treatment of monitored detection and restart in discrete-time quantum walks and highlights restart as a simple mechanism for avoiding dark-state trapping. |
| 14:30 | Souryajit Roy | Neural network models for acoustic wave scattering | In this work we develop a data-driven model for the scattering of acoustic waves by a turbulent vortex. The dynamics are governed by the linearized compressible Euler equations. The wave–vortex interaction term present in the equation drives the scattering process. Using data generated from numerical simulations with different plane-wave initializations and vortex configurations, we train several neural network architectures— ANN, U-Net, and Fourier Neural Operators—to learn the wave–vortex interaction dynamics. The resulting models take the initial acoustic field and background vorticity as input and accurately time-step, reproducing the scattering dynamics. |
| 14:45 | Ken Kikuchi | Refined half-integer condition on RG flows | Renormalization group flows are constrained by symmetries. Traditionally, we have made the most of 't Hooft anomalies associated to the symmetries. The anomaly is mathematically part of the data for the monoidal structure on symmetry categories. The symmetry categories sometimes admit additional structures such as braiding. It was found that the additional structures give further constraints on renormalization group flows. One of these constraints is the half-integer condition. The condition claims the following. Braidings are characterized by conformal dimensions. A symmetry object $c$ in a braided symmetry category surviving all along the flow thus has two conformal dimensions, one in ultraviolet $h_c^{\text{UV}}$ and the other in infrared $h_c^{\text{IR}}$. In a renormalization group flow with a renormalization group defect, they add up to a half-integer $h_c^{\text{UV}}+h_c^{\text{IR}}\in\frac12\mathbb Z$. We find a necessary condition for the sum to be half-integer. We solve some flows with the refined half-integer condition. |
| 15:00 | Rukmani R | Energy flow controls the stability of multitrophic ecosystems with stratified nonreciprocity | Complex systems with nonreciprocal interactions are often stratified into layers. Ecosystems are a prime example, where species at one trophic level grow by consuming those at another. Yet the dynamical consequences of such stratified non-reciprocity—where the correlation between growth and consumption differs across trophic levels—remain unexplored. Here, using an ecological model with three trophic levels, we reveal an emergent asymmetry: nonreciprocal interactions between consumers and predators (top and middle level) destabilize ecosystems far more readily than non-reciprocity between consumers and resources (middle and bottom level). We analytically derive the phase diagram for the model and show that its stability boundary is controlled by energy flow across trophic levels. Because energy flows upward—from resources to predators—diversity is progressively lower at higher trophic levels, which we show explains the asymmetry. Lowering energy flow efficiency flips the asymmetry toward resources and remarkably expands the stable region of the phase diagram, suggesting that the famous “10% energy transfer” seen in natural ecosystems might promote stability. More broadly, our findings show that the location of non-reciprocity within a complex network, not merely its magnitude, determines stability. |
| TEA BREAK+POSTER | |||
| Session 4( 15:45-16:45), Session Chair: Rajeev Ranjan Mishra | |||
| 15:45 | Sandip Sahoo | Fluctuating Interfaces in Barotropic Beta-Plane Turbulence | Zonal jets manifest themselves as bands with sharp interfaces in the vorticity configuration. I'll talk about how to track these fluctuating vorticity interfaces and systematically investigate their characteristic spatio-temporal behavior. While the interfacial height fluctuations are typically sub-Gaussian, the corresponding fluctuation speeds exhibit wider, heavy-tailed distributions reflecting the influence of lateral dispersion induced by the zonal velocity profile along the interfacial contours. The temporal evolution of these fluctuations is further characterized through their power spectrum displaying scale invariance in the frequency domain. Finally, the fractal nature of these boundaries is investigated systematically through a multifractal approach, revealing the non-trivial, complex statistics of interfaces in such geophysical, turbulent flows. |
| 16:00 | Satyen Patel | Star products on Poisson manifolds from the Poisson Sigma Model | The Poisson sigma model (PSM) provides a physical origin for Kontsevich's deformation star product on Poisson manifolds as the perturbative expansion of a path integral on the PSM. Geometrically, this produces a formal symplectic groupoid that "integrates" the Poisson structure. In this talk, I describe how one can perform Fedosov-type quantization on this formal symplectic groupoid and descend the resulting star product to the base Poisson manifold, giving a more geometrically insightful construction for the same. Additionally, when a Lie group acts by Poisson symmetries, this procedure naturally produces quantized moment maps. |
| 16:15 | Ritesh Harshe | Could the high-mass black holes from gravitational-wave observations be explained by lensing? | The high-mass ($M \gtrsim 30 M_\odot$) black holes (BHs) from the gravitational-wave (GW) observations of LIGO and Virgo came as a surprise to many astronomers. While such BHs could be produced by the collapse of the metal-poor massive stars, gravitational lensing has been invoked as an explanation for the high masses. Broadhurst, Diego, and Smoot (henceforth BDS) argued that the mass distribution of BHs in coalescing binaries is very similar to that of the galactic BHs, and the inferred high masses are the result of neglecting the lensing magnification. They also proposed a redshift distribution of binary BH (BBH) mergers that would explain the observed LIGO-Virgo mass distribution. We ask whether such a model is consistent with different aspects of the GW observations: 1) the observed number of BBH mergers, 2) their redshifted total mass - apparent luminosity distance distribution, 3) the fraction of detectable strongly lensed events, and 4) the non-observation of the stochastic GW background. By simulating lensed BBH mergers with the BDS model and comparing them with observations, we conclude that no BDS model parameter choice is consistent with all aspects of the observations. Lensing magnification is not a viable explanation for the high-mass BHs discovered by LIGO and Virgo --- those BHs must be intrinsically massive. |
| 16:30 | Mayank Kumar Bijay | Unsupervised diffusion model for parameterization is sumesoscale ocean dynamics | We develop a diffusion madel based parameterization of baroclinic instability in ocean dynamics. This gives us a single surrogate pde, replacing multiple pdes, while realising similar dynamics. The model is trained in an unsupervised way without any data for targets fields of the output, instead using data of flow trajectories. |
| ICTS In-House Culturals (5:30-7:00 PM) | |||
| Day 3, 8th April-Wednesday | |||
| 8TH April | Speaker | Title | Abstract |
| Session 1 (10:30-11:15), Session Chair: Pareekshit Sinwar | |||
| 10:20 | Aiswarya NS | Active Nematic Patterns in Bacterial Colonies | TBA |
| 10:30 | Bikram Pain | Krylov-space anatomy and spread complexity of a disordered quantum spin chain | We investigate the anatomy and complexity of quantum states in Krylov space, in the ergodic and many-body localised (MBL) phases of a disordered, interacting spin chain. The Krylov basis generated by the Hamiltonian from an initial state provides a representation in which the spread of the time-evolving state defines a basis-optimised measure of complexity. We show that the long-time Krylov spread complexity sharply distinguishes the two phases. In the ergodic phase, the infinite-time complexity scales linearly with the Fock-space dimension, indicating that the state spreads over a finite fraction of the Krylov chain. By contrast, it grows sublinearly in the MBL phase, implying that the long-time state occupies only a vanishing fraction of the chain. Further, the profile of the infinite-time state along the Krylov chain exhibits a stretched-exponential decay in the MBL phase. This behaviour reflects a broad distribution of decay lengthscales, associated with different eigenstates contributing to the long-time state. Consistently, a large-deviation analysis of the statistics of eigenstate spread complexities shows that while the ergodic phase receives contributions from almost all eigenstates, the complexity in the MBL phase is dominated by a vanishing fraction of eigenstates, which have anomalously large complexity relative to the typical ones. |
| 10:45 | Santana Majee | Curvature estimates for minimal surfaces associated with harmonic mappings having nonzero pole | In this talk, we will present an estimate for the Gaussian curvature of minimal surfaces obtained (using the Weierstrass–Enneper lift) from sense-preserving univalent harmonic mappings of the unit disc having a nonzero pole whenever these harmonic mappings take the unit disc onto the complement of a real line segment. We also obtain an explicit upper bound for the Gauss curvature when the underlying harmonic mapping (with nonzero pole) of the minimal surface sends the unit disc onto a domain whose complement is convex in the horizontal direction, and present concrete example showing that this bound can be attained. |
| 11:00 | Rajarshi | Lucky droplets in cloud turbulence | In a sea of tiny droplets, a larger drop, owing to its larger inertia, has more potential to collide with smaller drops, coalesce with them, and grow. We derive an equation of motion of these big lucky droplets. In 2D turbulence we show that their growth scales with the smaller drops’ inertia, and point to the advantage enjoyed by luckier drops starting out in vortical regions. |
| TEA BREAK+POSTER | |||
| Session 2 (11:45-12:45), Session Chair: Shreyash Bhattacharjee | |||
| 11:45 | Priyadharshini V | TBA | TBA |
| 12:00 | Shridhar Vinayak | Sudden Thermalising Quench of a Complex Scalar Field | We start with a complex scalar field in a thermal state. Suddenly, something mysterious happens to it, which instantly takes it to a different thermal state. We call this a ‘sudden thermalising quench’. Can we investigate the quench systematically? In particular, can we model it in a simple way and then gauge its parameters from some observables purely of the system on which it acted? We show how all these questions can indeed be answered within a simple model. |
| 12:15 | Naveen Kumar D | Collective Dynamics and Fluid Transport in Bacterial Carpets | Microorganisms, active cytoskeletal structures, and their synthetic analogs perform mechanical work on their surroundings by consuming chemical energy. This activity, coupled with long-range hydrodynamic interactions in bulk suspensions, is known to drive large-scale collective flows – a hallmark of active matter. In this work, we reveal an analogous class of novel hydrodynamic instabilities in thin films of surface-bound driven chiral particles. Such active chiral films have been experimentally realized in the context of bacterial carpets that are known to drive large-scale flows, pump fluid, and enhance mixing. However, the mechanistic underpinning of such emergent dynamics remained poorly understood. In this work, we bridge this gap by developing a bottom-up continuum theory. Our theoretical model builds upon a kinetic theory of surface-bound chiral rods and accounts for their orientation dynamics and associated hydrodynamic signatures in a surrounding Stokesian fluid. Our model provides us with coarse-grained PDEs that describe the emergent flows in thin films and their feedback on the orientation dynamics of the chiral particles. This micro-macro framework predicts a shear-driven alignment instability within the chiral thin film that leads to states of spontaneous pumping and chiral flows. Numerical simulations confirm our theoretical predictions and highlight how motifs of such chiral carpets can be harnessed to design efficient Stokesian mixers and micro-pumps. Our results have implications for active matter, the design of synthetic systems, and the fluid dynamics of active carpets |
| 12:30 | Sunit Banerjee | Aspects of Enumerative Geometry and QFT | Quantum fields can be used as probes to study the geometry and topology of spaces, and the partition function of certain quantum field theories (or QFTs) lead to new mathematical invariants. Examples of such invariants include solutions to counting problems of geometric objects, and the mathematics developed to study these problems is called enumerative geometry. In this talk, we will look at the key ideas that connect QFTs to enumerative geometry, and how such ideas hint towards a generalization of the notion of space itself. |
| LUNCH | |||
| Session 3 (14:15-15:15), Session Chair: Sangeetha S | |||
| 14:15 | Seema | Quasiparticle dynamics in Toda system | I will begin with a short introduction to integrable systems, emphasizing their special properties such as the presence of extensively many conserved quantities. This will be followed by a brief mention of their hydrodynamic description, where the large-scale dynamics can be understood by viewing the system as a gas of quasiparticles. I will then move on to my current work on quasiparticle dynamics in the Toda system. |
| 14:30 | Ratul Thakur | Scale resolved structure of quantum information under random quantum dynamics. | Quantum information plays a central role in many aspects of many-body quantum dynamics. I will give a brief review of the current understanding of universal features of entanglement growth and information scrambling in random quantum circuits, which serve as toy models for locally interacting quantum systems. Quantum entanglement is inherently non-local, which implies that information is also encoded non-locally and may not be recovered using just local probes. Understanding of the structure of many body entanglement as a hierarchy of length scales at which information is encoded is one way of bringing out this inherent non-locality. This can be achieved using the recently introduced notion of the "Information lattice". I will discuss how this scale-resolved picture can add to our understanding of (i) unitary random circuits and (ii) random circuits interspersed with projective measurements which induce a non-equilibrium phase transition in the entanglement structure. |
| 14:45 | Ramananda Santra | Non-thermal perspective of merging galaxy clusters in the SKA Era | Galaxy clusters host diffuse radio halos that trace relativistic electrons and magnetic fields in the intracluster medium (ICM), providing a direct probe of non-thermal processes such as turbulence, shocks, and particle (re-)acceleration. Recent observations with LOFAR, uGMRT, MeerKAT, and VLA have begun to reveal the complex spectral and morphological structure of these halos, offering new constraints on competing models for their origin, including turbulent re-acceleration and hadronic scenarios. In this talk, I will present a multi-frequency radio and X-ray study of three massive merging clusters: Abell 2163 (z = 0.203), MACS J0417.5−1154 (z = 0.45), and Abell 2219 (z = 0.225). Combining uGMRT, MeerKAT, and VLA data with XMM-Newton and Chandra observations, we investigate the coupling between thermal gas and non-thermal components. All three systems show disturbed morphologies, extended radio halos, and spatially varying spectral indices associated with merger-driven turbulence and shocks. We find a strong spatial correlation between radio and X-ray emission, supporting a close link between thermal energy dissipation and relativistic particle populations. Notably, MACS J0417 presents a rare case of a giant radio halo in a cool-core system, posing challenges to standard merger-driven scenarios. I will discuss how these results inform current theoretical models of particle acceleration and magnetic field amplification in the ICM, and how the Square Kilometre Array (SKA) will enable decisive tests by probing faint emission, spectral curvature, and magnetic field structure across cosmic time. |
| 15:00 | Krishnadev V | Chiral beating patterns and collective dynamics of nodal cilia | Motile cilia are thin, hair-like cellular projections that serve as fundamental building blocks of locomotion and material transport in many eukaryotes. Each cilium is an active machine driven by thousands of internal nanaometric molecular motors that collectively conspire to produce whip-like oscillations along its ∼10 μm length. It is well known that often beating patterns of a cilium are chiral, meaning that their beating has a preferred handedness. A canonical example of which is the nodal cilia that play a crucial role in early embryonic development. In this work, we aim to understand the mechanistic origin of such chiral beating patterns and the ensuing collective hydrodynamics in a lattice of such cilia. We first develop a bottom-up, 3D biophysical model of the evolutionarily conserved axoneme that generates the beating of a cilium. The center-line of the axoneme is modeled as a Kirchhoff rod that accounts for the bending and twisting modes of deformation, and we additionally account for the internal active processes that involve: (a) force generation by molecular machines, (b) geometric feedback from deformation that regulates the activity of molecular motors, (c) internal dissipation, and (d) hydrodynamical stresses. This detailed chemo-mechanical model exhibits a Hopf bifurcation beyond a critical activity, giving rise to spontaneous oscillations. Crucially, we find that in the presence of an intrinsic twist, the emergent dynamics is chiral, which we further illustrate by performing a linear stability analysis. Building on this model, we then probe the collective dynamics of such hydrodynamically interacting active filaments. Using direct numerical simulations and reduced order models, our work reveals how fluid-mediated long-range interaction leads to synchronization and large-scale fluid pumping in a lattice of such chiral cilia. Our results have implications for understanding transport in arrays of nodal cilia and their role in left-right symmetry breaking in vertebrates. |
| TEA BREAK+POSTER(15:15-15:45) | |||
| Session 4(15:45-16:30), Session Chair: Anjali Bhatter | |||
| 15:45 | Indranil Mukherjee | Microscopic and hydrodynamic correlation in 1d hard rod gas | We provide exact analytical calculations of the microscopic correlation. For the correlation at macroscopic scale, we utilize Ballistic Macroscopic Fluctuation Theory (BMFT) to derive an explicit expression for the correlations of a coarse-grained mass density, which reveals the emergence of long-range correlations on the Euler space-time scale. By performing a systematic coarse-graining of our exact microscopic results, we establish a micro-macro correspondence and demonstrate that the resulting macroscopic correlations agree precisely with the predictions of BMFT. This analytical verification provides a concrete validation of the underlying assumptions of hydrodynamic theory in the context of hard rod gas. |
| 16:00 | Arnab Paul | A preliminary study of the sedimentation of fibres | A huge class of microscopic objects found in the ocean can be modeled as fibres. Now although at shallow depth the ocean flow is turbulent, at high depth the flow is slow enough that it falls in the viscous regime. Thus it is important to study the sedimentation of fibres. We study the sedimentation of such fibres by simplifying them as freely jointed chains. This is specifically helpful in modelling cloth fibres in the ocean which are highly flexible. |
| 16:15 | Tirthankar Mondal | A Phase-Space Perspective on Free-Fermion Dynamics | We study the dynamics of spinless free fermions starting with a domain wall configuration under a tight binding hamiltonian on a ring. We look into the evolution of some properties in the initial occupying subsystem like local Number density and Number Fluctuations(related to bipartite entanglement). We use wigner functions to look at this evolution in a (x,p) space, and see what contributes to density and number fluctuation there. In the continuum limit this allows us to get analytical results for these properties. |
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Performance by Jangama Collective (6pm Onwards)
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ICTS In-House Banquet Dinner (7:30pm Onwards)
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