What is quantum computing?

Sub: Sci

Sec: Computer and IT

Quantum Computers:

Quantum computers are revolutionary devices that leverage the principles of quantum mechanics to solve complex problems faster than classical computers.
Proposed by Richard Feynman in 1982, the idea arose from the realization that classical computers struggle to simulate quantum systems.

Basics of Quantum Computing:

Classical Computers:
- Operate on bits (0 or 1).
- Use the binary system to represent information.
Quantum Computers:
- Use qubits, which can exist in states 0, 1, or a mix of both simultaneously (superposition).
Rely on two fundamental principles:
Superposition:
- Allows qubits to hold multiple states at once.
- For example, it is like a spinning coin that is both heads and tails until measured.
Entanglement:
- Links qubits so the state of one instantly reveals the state of another, regardless of distance.
- Example: Like knowing the pair of a glove in another box once one is opened.
These principles enable quantum computers to perform multiple computations simultaneously and solve problems faster than classical computers.

Progress in Quantum Computing:

1994: Shor’s Algorithm: Demonstrated quantum computers’ ability to factor large numbers quickly, with implications for data security.
2019: IBM’s Q System One: The first circuit-based commercial quantum computer, using quantum gates to manipulate qubits.
- Google’s Sycamore Processor: Achieved quantum supremacy, solving a problem in 200 seconds that would take a supercomputer 10,000 years.
2023: Google’s Willow Quantum Chip:
- Introduced error-corrected qubits that improve with scaling.
- Completed a calculation in 5 minutes that would take a supercomputer 10 trillion trillion years.

Present Limitations:

Cost and Complexity: Building quantum computers is expensive and technologically challenging.
Stability Issues:
- Qubits are prone to errors and decoherence (loss of superposition due to environmental noise).
- Error correction remains a significant hurdle.
Scale Requirements: Practical applications like drug discovery or astrophysics require millions of qubits, which are currently unfeasible.

India’s Quantum Mission:

Recognizing the potential of quantum computing, India launched the National Quantum Mission (2023), allocating ₹6,000 crore over eight years.

Key Objectives of NQM

Development of Quantum Technologies:
- Build quantum computers with 50-1,000 physical qubits over the next 8 years.
- Focus on scalable quantum hardware and error correction mechanisms.
Quantum Communication:
- Create a secure quantum communication network between strategic locations.
- Develop satellite-based quantum key distribution (QKD) systems for enhanced data security.
Quantum Materials and Sensors:
- Design and fabricate quantum materials for advanced applications.
- Develop sensors for precision measurements in areas like meteorology, healthcare, and navigation.
Quantum Algorithms and Applications:
- Research quantum algorithms for optimization problems, cryptography, and artificial intelligence.
- Apply quantum solutions to drug discovery, climate modelling, and financial modelling.

Source: TH