A quantum emulator uses classical compute power to reproduce the behaviour of a quantum system or quantum computer with a small number of qubits. By running the underlying mathematics on conventional hardware, an emulator lets engineers benchmark, test, and validate quantum circuits without needing access to physical qubits.
Emulation is practical only up to a modest number of qubits. The resources required to track a quantum state on a classical machine grow exponentially with the number of qubits, so a few tens of qubits already push against the limits of even the largest supercomputers. This exponential cost is, in fact, one of the reasons quantum computers are worth building in the first place.
Emulators remain an essential tool for software development, algorithm design, and verifying that hardware behaves as intended. Quantum Motion uses classical emulation, including the open-source QuEST framework, to test and validate its systems as they scale.