IISc Bangalore Develops Six-Qubit Photonic Quantum Device
IISc's Six-Qubit Photonic System Helps India Reach Quantum Milestone.
IISc Bangalore
A six-qubit photonic device from the Indian Institute of Science (IISc) advanced India's quantum quest. This breakthrough involves designing and implementing universal quantum gates using single photon manipulation.
The research aims to produce powerful quantum computers that can be widely used, like classical computers. Around November 1, 2025, the Indian Institute of Science Office of Communications' KERNEL features featured the scientific announcement.
Unleash Quantum Phenomena
Quantum computers outperform ordinary computers due to superposition and entanglement. Quantum computers use qubits, while classical use ON/OFF bits.
Superposition gives a qubit a quantum advantage by being ON and OFF. When two or more particles are sufficiently closely connected that an impact on one instantly affects the other, even when they are far apart, entanglement occurs. These systems can calculate faster than conventional machines because qubits can superpose.
Six-Qubit Photonic System Architecture
The team led by IISc Department of Electronic Systems Engineering and Instrumentation and Applied Physics researcher C M Chandrashekar made this finding. Their research focused on encoding information as qubits using photons, light packets.
Scientists modified photons to work as three qubits in this combination. Every photon has two polarisation states, which create an intrinsic qubit. Researchers encoded more qubits using route encoding, an advanced method. While in superposition, a travelling photon is split into two spatial pathways. After two passes, the pathways are recombined. This gave the photon three qubits: two from route encoding and one from polarisation states.
The researchers created a six-qubit entangled state by entangled two photons with the same configuration.
Building Universal Quantum Gates
Quantum computers use quantum gates, which are like classical computers' AND, OR, and NOT gates. The IISc team created these quantum gates utilising their revolutionary six-qubit technology.
The building was built via a series of quantum walks, a precise method that allows a particle to move under control. This photon-based experiment required linear optical components like waveplates, beam splitters, and mirrors. By methodically tweaking these pieces, the scientists created the full set of universal quantum gates for quantum computation.
Benefits and Prospects
This achievement relies on photonic qubit selection. Photonic qubits are suited for real-world quantum computing because they function at ambient temperature and resist environmental noise.
The study shows experimentally how single photons can deterministically generate multi-qubit gates and encode multiple qubits. The deterministic implementation of these gates was an advance over photon-based approaches.
Based on foundational research at IISc, reported in KERNEL, this demonstration shows a clear path to publically accessible quantum computers. India's quantum computing efforts took a major turn with this six-qubit machine.
