Native Gate Sets

A native gate set is the short list of operations a device's control electronics can physically execute; the compiler rewrites textbook gates such as CX into calibrated primitives, for example CZ sandwiched between Hadamards. Equivalent decompositions match mathematically but differ in physical pulse count and error, and the two-qubit pulses dominate the error budget.

Textbook gates vs hardware instructions

A device's native gate set is the short list of operations its control electronics can physically execute. Each native gate is backed by a calibrated pulse — a shaped microwave or laser signal, tuned until the physical operation matches the gate's mathematical definition. Everything else in your circuit is translated.

This is the same idea as a CPU's instruction set architecture (ISA): the list of supported operations, which operands they accept, and which qubit pairs they run on. Your source code says CX; the hardware may have no CX pulse at all. Superconducting devices commonly expose CZ or ECR (echoed cross-resonance, another microwave-driven entangling pulse) as the entangling primitive, and trapped-ion devices expose a two-qubit interaction of their own — the compiler builds CX out of whatever is there.

So a CX in a circuit listing is a claim about mathematics, not about pulses. The two runs below make that distinction measurable.