Context
Google’s Quantum Processor,‘Willow’, unveiled by Google, showcases significant advancements in quantum computing.
About Willow Quantum Processor
- Specifications:
- 105 physical qubits (50+ for data, others for error correction).
- Operates at temperatures near absolute zero (-273.15°C).
- Employs superconducting qubits for high precision.
- Error Mitigation:
- Leakage Errors: Reserved qubits prevent interferences.
- Coherence Time: ~100 microseconds due to advanced correction protocols.
- Error Rate Reduction:
- Achieved lower error rates despite adding more qubits (below-threshold capability).
Random Circuit Sampling (RCS) Task
- Task: Calculates probability of strings of 0s and 1s under random gate operations.
- Performance:
- Willow: Few minutes.
- Classical Supercomputers: Estimated 10 septillion years.
- Significance: Demonstrated superiority for computationally hard tasks.
- Potential Applications of Quantum Computing
- Scientific Research: Drug design, material science, climate modelling, optimisation problems.
- Societal Impact: Unravelling natural phenomena and tackling complex computational problems.
Bit vs. Qubit
- Classical Bits: Represent information as 0s and 1s; controlled by gate operations like AND, OR.
- Quantum Bits (Qubits):
- Represent 0, 1, and combinations of both (Quantum Superposition).
- Information representation grows exponentially with qubits (e.g., 10 qubits = 2¹⁰ numbers).
- Basis of the enhanced efficiency and power of quantum computers.
Challenges in Quantum Computing
- Fragility of Qubits:
- Sensitive to disturbances; limits information retention and scalability.
- Errors include bit flip errors and phase flip errors.
- Error Correction Protocols:
- Classical Correction: Triple redundancy (e.g., 0 = 000).
- Quantum Correction: Requires extra qubits; uses surface code (data + measurement qubits).
- No-Cloning Theorem: Prevents exact duplication of qubit states.
Source: TH
Previous Year Question
Which one of the following is the context in which the term “qubit” is mentioned?
[UPSC Civil Services Exam – 2022 Prelims]
(a) Cloud Services
(b) Quantum Computing
(c) Visible Light Communication Technologies
(d) Wireless Communication Technologies
Answer: (b)