25.12.2024 - The Hindu

First proposed

In 1982, Richard Feyman proposed the idea of developing a computer that could simulate both quantum and classical physics.

Basics of Quantum and Classical computers

Classical computers work on the principles of classical physics. Their fundamental computing unit is the bit. Each bit represents one piece of information with two possible values, 0 or 1. Quantum computers rely on quantum bits, or qubits. Qubits can exist in the states 0, 1 or in a state that’s partly 0 and partly 1. The 2 principles involved are superposition and entanglement.

Superposition

The ability of qubits to be in 2 states.

Entanglement

This phenomenon allows qubits to be intrinsically linked no matter how far apart they physically are. Measuring the state of one of the qubits will immediately yield information about the state of the other.

Bell Lab's super computer

In 1994, Bell Labs computer scientist Peter Shor created the Shor’s algorithm. It could find the factors of large numbers. This has major implications for data security. Current methods to secure data involve locking the data and hiding the key in the solution of a difficult mathematical problem. By using Shor’s algorithm, a quantum computer could quickly get the key and open the locks.

Commercial quantum computer

In 2019, IBM unveiled the world’s first circuit-based commercial quantum computer, Q System One.

Google's WILLOW

Google unveiled a quantum chip called Willow, purportedly the world’s first quantum processor in which error-corrected qubits improve as they scale. Quantum states are easily prone to errors due to interactions with the environment, so quantum computers need error correction to hold information long enough to perform useful calculations with them.

Challenges

The chief concern is that building quantum computers remains expensive and complex. Keeping many qubits stable is also difficult because of error rates and decoherence (when a qubit loses superposition because of noise from its surroundings). The problems for which we really need quantum computers — like discovering new drugs or cracking mysteries in astronomy — also require millions of qubits.

Scope

The problems for which we really need quantum computers — like discovering new drugs or cracking mysteries in astronomy — also require millions of qubits.

National Quantum Mission, 2023

Rs 6000 crore for 8 years to develop quantum computers.

February 2025

Microsoft's Majorana vs Chinese chip

• While Microsoft announced “Majorana”, Peking University professors published a paper in Nature with a different approach.
• The Chinese scientists unveiled the world’s first large-scale quantum entanglement on an optical chip.
• The Chinese chip is smaller than Microsoft’s and uses light-based photonic technology that operates at room temperature.
• In contrast, the Majorana 1 relies on superconducting materials that require extremely low temperatures to function