PhD Researcher · Scientific Machine Learning · Johns Hopkins University

I teach machines the
physics of the real world.

Neural operators, differentiable control of PDEs, and high-performance scientific computing — from turbulence to fracture, from the brain to the supercomputer.

Baltimore, MD · droysar1@jh.edu

scroll
01 — The Throughline

From concrete to computation.

I began by learning to build with concrete and steel in a small town in Assam. Somewhere along the way I fell for the equations underneath the structures — and then for teaching computers to solve them faster than we ever could by hand. This is that trajectory.

2016 — 2022Kokrajhar, Assam · India

The foundations, literally.

Diploma and B.Tech in Civil Engineering at the Central Institute of Technology, Kokrajhar (9.2 & 8.98 CGPA). Concrete, surveying, structures — I learned how the physical world is held up, and where it fails.

2022 — 2024IIT Madras · Chennai

Falling for the mathematics.

M.Tech at IIT Madras — top 5% of my class (CGPA 9.22), GATE top 3% nationwide. Numerical methods, optimization, data science. I stopped seeing beams and started seeing boundary-value problems. My first PINNs paper for inverse problems in heterogeneous media.

2024 — nowJohns Hopkins University · Baltimore

Teaching operators to learn physics.

PhD in Civil & Systems Engineering with Dr. Somdatta Goswami. Deep operator networks that learn hidden physics to 95% accuracy, differentiable predictive control of PDEs, neural surrogates for traumatic-brain-injury modeling and fracture.

2025 — nowArgonne ALCF · UT Austin

Scaling to the national labs.

Multi-GPU neural-operator training on Argonne's Polaris (two Director's Discretionary Awards, 5,600 node-hours; 83% faster). Chishiki AI Fellow at UT Austin. 1st place, global Tesseract differentiable-simulation hackathon.

2026 — nowLawrence Livermore National Laboratory

Interfaces, at the Livermore scale.

Graduate research intern at the Data Science Institute — building agentic workflows for materials-science applications and geometry-aware neural operators for moving-interface problems.

02 — What I Work On

Four questions I keep chasing.

\(\mathcal{G}_\theta\)

Neural Operators

Learning maps between infinite-dimensional function spaces — \(\mathcal{G}_\theta : a(x)\!\mapsto\! u(x)\) — DeepONets and FNOs that replace expensive solvers and generalize across geometries and parameters.

DeepONet · FNO · JAX
\(\min_{f} J\)

Differentiable PDE Control

Steering physical systems in real time. Differentiable predictive control with time-integrated operators, robust to noise, delay, and the sim-to-real gap.

DPC · MPC · Control
\(\nabla_a\mathcal{L}\)

Inverse Problems & Hidden Physics

Recovering material properties and governing parameters from sparse, noisy data by minimizing \(\mathcal{L}=\lVert b - F(\hat a)\rVert^2\) with interface-aware networks.

PINNs · I-PINNs · Inversion
\(\textstyle\sum_{\text{GPU}}\)

HPC & Scale

Distributed multi-GPU training of high-dimensional operators on leadership-class supercomputers — because physics doesn't fit on one card.

CUDA · MPI · Polaris
03 — The Live Lab

Simulations, running in your browser.

Every panel below integrates a real governing equation, live, on your device — no videos, no pre-baked frames. Drag the parameters and watch the physics respond. These interactive demos mirror the systems I accelerate with neural operators in my research (see the real results ↓).

Fig. 01 — Hyperbolic PDE
live

Wave Equation

\[ \frac{\partial^2 u}{\partial t^2} = c^2\nabla^2 u \;-\; \gamma\,\frac{\partial u}{\partial t} \]

A vibrating membrane integrated by explicit finite differences and rendered as a live 3D wireframe. A driven source ripples outward; the damping term \(\gamma\) bleeds energy away.

Fig. 02 — Phase field
live

Allen–Cahn Phase Separation

\[ \frac{\partial u}{\partial t} = \varepsilon^2\nabla^2 u + u - u^3 \]

Spinodal decomposition: a uniform mixture spontaneously separates into two phases and coarsens, minimizing interface energy. The same physics behind alloys, foams, and the moving interfaces I model at Livermore.

Fig. 03 — Incompressible flow
move / drag your cursor across the field

Turbulence & Smoke

\[ \frac{\partial \mathbf{u}}{\partial t} + (\mathbf{u}\!\cdot\!\nabla)\mathbf{u} = -\nabla p + \nu\nabla^2\mathbf{u},\quad \nabla\!\cdot\!\mathbf{u}=0 \]

A genuine incompressible fluid solver (Stam's stable-fluids method): semi-Lagrangian advection, diffusion, and a pressure projection that keeps the flow divergence-free. Push it and watch vortices shed and tangle.

Fig. 04 — Feedback control
live

Learning to Control a PDE

\[ \frac{\partial u}{\partial t} = \alpha\,\frac{\partial^2 u}{\partial x^2} + f(x,t),\quad f = K\big(u^{*}(x,t)-u\big) \]

A heated rod that must track a moving target profile \(u^{*}\) (dashed). Distributed actuators inject and remove heat; a feedback policy drives the error to zero. A toy of my differentiable predictive control work — accepted at IEEE CDC 2026.

04 — Research in Motion

The real thing.

The interactive demos above are teaching tools. These are actual outputs from my papers — neural-operator controllers, learned surrogates, and high-fidelity solvers, straight from the experiments.

Uncontrolled European power-grid frequency deviation spreading after a fault, uncontrolled
→
Controlled (DPC) European power-grid frequency stabilized by differentiable predictive control
GreenHack 2026 · Power-Grid Frequency Control

Stabilizing the European power grid after a fault

\( M_i\,\dot{\omega}_i = P_i - D_i\,\omega_i - \sum_j B_{ij}\sin(\delta_i-\delta_j),\quad \dot{\delta}_i=\omega_i \)

A 900 MW generation loss in Greece sends a frequency-deviation \(|\Delta f|\) wave across the continent. Left: uncontrolled, the disturbance propagates. Right: differentiable predictive control drives every node's frequency back to nominal in real time.

ICML 2026 · CINOC  ·  🥇 Tesseract Hackathon (Multi-Agent DPC)

2D Navier–Stokes density transport

\( \partial_t \omega + (\mathbf{u}\!\cdot\!\nabla)\omega = \nu\nabla^2\omega \)

Cardinality-invariant neural-operator policies (CINOC) for multi-agent control of incompressible flow — scalable to any number of actuators and sensors. The differentiable-simulation pipeline that won 1st place at the global Tesseract hackathon.

FKPP travelling-wave front under control
IEEE CDC 2026 · Differentiable Predictive Control

Controlling a 1D reaction–diffusion front

\( \partial_t u = D\,\partial_{xx} u + r\,u(1-u) \)

Differentiable predictive control on a time-integrated neural operator drives the state \(u(x,t)\) to a target profile \(u^{*}\) with distributed actuators — accepted at IEEE CDC 2026.

Phase-field solidification microstructure evolving
Moving interfaces · LLNL

Phase-field solidification

\( \partial_t \phi = -M\,\frac{\delta \mathcal{F}}{\delta \phi} \)

Dendritic microstructure growth — the class of geometry-aware moving-interface problems I build neural operators for at Lawrence Livermore.

TI-DON vs FDM prediction benchmark with relative L2 error histogram
IEEE CDC 2026 · Time-Integrated DeepONet

Operator surrogate vs. the ground-truth solver

Across 3,000 unseen samples the time-integrated DeepONet matches the finite-difference solver to a median relative \(L_2\) error of 1.11% — while running orders of magnitude faster, which is what makes real-time control tractable.

05 — Selected Work

Where the equations meet the world.

Inverse problem forward-modeling loop schematic
Inverse · Hidden Physics

Learning Hidden Physics & Parameters

Deep operator networks that recover governing parameters from data — \(\hat a \leftarrow \hat a - \gamma\nabla\mathcal{L}\) — to 95% accuracy. Published in CMAME.

Control · ICML 2026

CINOC — Cardinality-Invariant Operator Policies

Scalable PDE control policies invariant to the number of actuators and sensors. Accepted at ICML 2026.

Biomechanics · Award finalist

Real-Time Traumatic Brain Injury Modeling

Multimodal neural operators for real-time TBI biomechanics — toward personalized protective-gear design. WSE Trainee Award finalist.

LLM · RAG · Deployed

ARIA — AI Teaching Assistant

A multimodal RAG assistant for Statics & Mechanics, deployed to 90 students in production on Streamlit.

HPC · Argonne Polaris

Scalable Multi-GPU Operator Training

Distributed CUDA + MPI training of high-dimensional PDE operators — 83% faster, 5,600 awarded node-hours on Polaris.

Fracture control pipeline schematic
Neural Operators · FEM

Hybrid Neural–FEM Fracture Simulation

A neural-operator + finite-element hybrid that accelerates crack propagation while preserving accuracy, with an RL agent steering the crack. Built with FEniCSx.

06 — Publications

The full list.

Every paper, preprint, and work in review — across ML venues, computational-mechanics journals, and controls conferences. Also on my Google Scholar.

07 — Recognition

Some things that went right.

Chishiki AI Graduate FellowshipSCIPE · UT Austin · 2026–27
1st — Tesseract HackathonGlobal · differentiable simulation
2× Director's Discretionary AwardArgonne ALCF · 5,600 node-hours
3rd — NASA & DNV ChallengeOptimization under uncertainty
WSE Trainee Award FinalistTBI modeling · JHU 2025
Creel Family FellowshipJohns Hopkins · 2024–25
GATE 2022 · Top 3%96.96 percentile nationwide
TATA Motors Excellence ScholarshipAcademic performance
09 — Let's build something

Working on operators, control, or SciML at scale?
I'd love to talk.