Quantum supremacy is the point at which a quantum computer can perform a calculation that is impossible or impractical for any classical computer to achieve within a reasonable period. This concept highlights the potential power of quantum computing compared to traditional computing systems. Specifically, it suggests that there are certain types of problems, often related to quantum mechanics, where a quantum computer can outperform the best classical computers available today.
To illustrate this, consider the problem of factoring very large numbers, which is critical for encryption methods used in internet security. Classical algorithms struggle with this task as the number size increases, typically requiring an impractical amount of time to solve them. In contrast, a quantum computer could utilize algorithms like Shor's algorithm to factor these numbers much faster. In 2019, Google claimed to achieve quantum supremacy when their 53-qubit quantum processor, Sycamore, completed a specific problem in just 200 seconds, which they estimated would take the fastest classical supercomputers approximately 10,000 years to solve. This comparison highlighted the gap between quantum and classical capabilities.
While achieving quantum supremacy is a significant milestone for the field, it is essential to recognize that practical applications may still be in development. Many problems suitable for quantum computing remain theoretical or require further research to translate into real-world solutions. However, the concept serves as a benchmark to measure progress in quantum computing, pushing researchers and developers to continue exploring new algorithms and hardware designs. As quantum technology matures, it holds the promise of solving complex problems in various fields such as cryptography, drug discovery, and materials science, proving its value beyond mere theoretical considerations.