Why build quantum computers if you can simulate them?
Classical computers can simulate small quantum systems but become exponentially slower as qubits increase, making simulation of practical quantum computers impossible. This is why building physical quantum computers is necessary for solving complex problems beyond classical reach.
Background
- Quantum computers use qubits that can be in a "superposition" of 0 and 1 simultaneously, unlike classical bits. This lets them explore many possibilities at once, making them theoretically much faster than classical computers for certain problems (e.g., cryptography, drug discovery).
- "Simulating" a quantum computer means using a classical computer to model what a quantum computer would do. This is possible for very small quantum systems (a few qubits), but quickly becomes impossible as qubits increase because the calculations grow exponentially — e.g., simulating 50 qubits requires memory beyond what any classical computer has.
- The article argues that the real point of building quantum hardware is to solve problems we *cannot* simulate classically — so the fact that we can simulate tiny quantum systems is irrelevant to the case for building larger ones.