A 100-qubit quantum computer has the potential to perform a vast number of simultaneous calculations, far exceeding the capabilities of classical computers for certain problems. However, it's important to note that the impact of quantum computers is not as straightforward as solving all computational tasks. While quantum computers excel in certain areas, there are still tasks that are unlikely to be efficiently solved by any computer, classical or quantum, in the foreseeable future. Here are a few examples:
Solving NP-complete problems: NP-complete problems are a class of computational problems for which no efficient classical algorithms are known. They are considered computationally difficult, and solving them typically requires exponential time. While quantum computers can provide exponential speedup for some problems, it does not mean they can solve all NP-complete problems efficiently. Currently, there are no known quantum algorithms that can solve NP-complete problems in polynomial time.
Cryptography: Quantum computers have the potential to break many of the cryptographic protocols used in modern computer security. As quantum computers are designed to efficiently solve certain mathematical problems, such as factoring large numbers, they could undermine the security of widely used encryption algorithms like RSA and elliptic curve cryptography. However, post-quantum cryptography is an active research area aiming to develop quantum-resistant cryptographic algorithms.
Simulating complex quantum systems: While quantum computers can efficiently simulate certain quantum systems, simulating large-scale quantum systems, especially those with strong interactions and complex dynamics, remains a challenging task. This limitation makes it difficult to fully explore and understand the behavior of complex molecules, materials, or chemical reactions using quantum computers alone.
General-purpose problem solving: While quantum computers excel in solving specific problems such as optimization, factorization, or quantum simulations, they may not necessarily outperform classical computers in general-purpose problem solving tasks that don't benefit from quantum algorithms. For many everyday tasks like word processing, web browsing, or general data analysis, classical computers will likely remain efficient and sufficient.
In summary, while a 100-qubit quantum computer could potentially perform an enormous number of simultaneous calculations for specific problems, there are still computational tasks that are inherently challenging and unlikely to be efficiently solved by any type of computer in the near future. The capabilities of quantum computers are complementary to classical computers, and both will continue to play important roles in solving different types of problems.