IIT Guwahati

Department of Physics

Atom Based Quantum Technologies Lab

Research Overview

Our group works at the intersection of atomic physics, quantum optics, and quantum information science. The central goal is to build a scalable neutral-atom quantum computing and simulation platform using laser-cooled Ytterbium (Yb) and Rubidium (Rb) atoms held in optical tweezer arrays.

Achieving this requires mastering a chain of challenging steps: laser cooling atoms from room temperature down to a few microkelvin, trapping single atoms in tightly focused optical tweezers, arranging them into defect-free arrays using holographic techniques, driving high-fidelity single- and multi-qubit gate operations, and harnessing the enormous interaction strength of Rydberg states to entangle neighboring atoms.

In parallel we pursue shorter-term projects in atomic coherence, electromagnetically induced transparency (EIT), magnetometry, and optical-frequency metrology - areas that sharpen our experimental toolbox and yield independent scientific contributions.


Research Areas

Laser Cooling & Trapping

We cool Rb and Yb atoms from room temperature to a few microkelvin using Zeeman slowers, magneto-optical traps (MOTs), and sub-Doppler cooling techniques. Achieving deep cooling is the essential first step for all downstream quantum control experiments.

MOT Zeeman Slower Sub-Doppler Cooling Rb & Yb

Optical Tweezer Arrays

Individual atoms are trapped in diffraction-limited optical tweezers formed by tightly focused laser beams. Using spatial light modulators (SLMs) and acousto-optic deflectors we generate reconfigurable arrays and sort atoms into defect-free registers - the hardware backbone of our quantum processor.

SLM Single Atom Imaging Array Reconfiguration

Single-Qubit Operations

Hyperfine ground states of 87Rb serve as the qubit basis. We drive high-fidelity single-qubit rotations using precisely controlled microwave and optical Raman pulses, characterising gate performance through randomised benchmarking and process tomography.

Microwave Pulses Raman Transitions Randomised Benchmarking

Rydberg Excitation & Blockade

Exciting atoms to high-n Rydberg states produces enormous dipole-dipole interactions that can suppress double excitation within a blockade radius - the key mechanism for two-qubit entangling gates. We study blockade dynamics, gate fidelity, and decoherence in the Rydberg manifold.

Rydberg Blockade CZ Gate Dipole–Dipole Interaction

Atomic Coherence & EIT

We exploit quantum coherence effects such as electromagnetically induced transparency, coherent population trapping, and slow/stored light to study light-matter interaction at the quantum level and explore applications in quantum memory and precision sensing.

EIT CPT Slow Light Quantum Memory

Spectroscopy & Metrology

High-resolution saturated absorption spectroscopy, frequency stabilisation via the Pound-Drever-Hall technique, and optical frequency metrology of narrow atomic transitions in Rb and Yb provide ultra-stable laser references for our experiments and contribute to precision measurement science.

PDH Locking Saturated Absorption Frequency Metrology Magnetometry

Key Experimental Techniques

High-Coherence Laser Systems

ECDLs locked via PDH to high-finesse cavities; EOMs and AOMs for precise frequency control.

Ultra-High Vacuum Technology

Custom UHV chambers operating below 10-10 Torr for long atomic coherence times.

FPGA-Based Experimental Control

ARTIQ/Sinara and Red Pitaya platforms for sub-microsecond timing sequences across all lab hardware.

Single-Atom Fluorescence Imaging

sCMOS and EMCCD cameras with high-NA objectives for quantum-state-resolved atom detection.

Holographic Beam Shaping

Spatial light modulators and WGS algorithms to generate and reconfigure arbitrary tweezer arrays.

Quantum Simulation & Analysis

Python (NumPy, QuTiP, Qiskit) for master-equation and MCWF simulations of qubit dynamics.