A team of scientists at the Indian Institute of Science (IISc) and the Tata Institute of Fundamental Research (TIFR) has successfully demonstrated a 20-qubit superconducting quantum processor with a novel error correction mechanism. The breakthrough positions India among a handful of nations with indigenous quantum computing capability.

🔹 The 20-qubit milestone

The processor, named 'Siddhi-20', achieves a coherence time of 100 microseconds and gate fidelity above 99%. It uses a flip-chip architecture to reduce crosstalk between qubits. The team also demonstrated a 5-qubit error correction code that suppresses errors by a factor of 8, a critical step toward fault-tolerant quantum computing.

Lead researcher

"This is our 'Sputnik moment' in quantum tech. We have indigenously designed and fabricated the chip in India, including the control electronics. The next step is scaling to 50 qubits within two years." – Prof. Arindam Ghosh, IISc.

How it works

The processor uses transmon qubits made from niobium, cooled to 15 millikelvin in a dilution refrigerator. Control signals are generated by custom RFSoC boards developed at IIT Madras. The system can run quantum algorithms like Grover's search and quantum Fourier transform.

20qubits
99%gate fidelity
100μscoherence time

🔹 Error correction breakthrough

Quantum computers are notoriously error-prone due to decoherence. The team implemented a 'surface code' variant on a 5-qubit lattice that detects and corrects bit-flip and phase-flip errors in real time. This is the first such demonstration in India and one of the few globally outside major tech labs.

Software stack

Alongside the hardware, the team developed 'QSim' – a quantum simulator and compiler that supports OpenQASM and can map algorithms to the qubit topology. It is now available on the National Quantum Mission cloud platform for researchers and students.

🔹 National Quantum Mission boost

This breakthrough comes under the ₹6,000 crore National Quantum Mission (NQM) launched in 2023. The mission aims to build intermediate-scale quantum computers with 50-100 qubits by 2026. Four 'Thematic Hubs' (IISc, IIT Bombay, IIT Madras, and TIFR) are working on superconducting, photonic, and trapped-ion qubits.

Government response

"India is now in the top league of quantum research. This achievement will accelerate applications in cryptography, drug discovery, and materials science." – Dr. Jitendra Singh, Minister of State for Science & Technology.

Applications on the horizon

  • Cryptography: Developing quantum-resistant algorithms for secure communications.
  • Drug discovery: Simulating molecular structures for new pharmaceuticals.
  • Optimization: Solving complex logistics and financial modelling problems.
  • Climate modeling: More accurate simulations of climate systems.

🔹 Global context

India joins the US (IBM, Google), China (USTC), and Europe in the race for quantum supremacy. While China recently demonstrated a 66-qubit processor, India's focus on error correction and indigenous fabrication is seen as a strategic advantage. The Siddhi-20 will be open for academic collaborations through a 'quantum cloud' later this year.