Quantum supremacy is the point at which a quantum computer performs a computation that is practically impossible for even the most powerful classical supercomputers. It doesn’t necessarily mean solving a useful or commercial problem—it simply marks a clear computational advantage.
Key Concept:
Quantum computers leverage quantum bits (qubits), which can exist in superpositions and become entangled, allowing them to explore vast solution spaces simultaneously. This can lead to exponential speedups for specific tasks.
Historic Demonstration:
In 2019, Google claimed to have achieved quantum supremacy with its 53-qubit processor “Sycamore” by completing a random quantum circuit sampling task in about 200 seconds. The same task, they estimated, would take a classical supercomputer thousands of years.
Important Clarifications:
- Quantum supremacy does not mean quantum computers are better at everything.
- The demonstrated problems may not have practical applications.
- It’s a milestone showing that quantum hardware has reached a regime where it can outperform classical hardware in at least one domain.
Why It Matters:
Quantum supremacy confirms that quantum processors can outpace classical limits, validating decades of theoretical research. It’s a crucial step toward building quantum systems that could eventually tackle real-world problems like cryptography, drug discovery, and complex optimization.