Quantum tomography is a set of experimental techniques for reconstructing the full quantum state (state tomography), process (process tomography), or measurement (detector tomography) of a quantum system by performing many measurements from different angles or bases.
Why it matters. Tomography provides the most complete picture of what is happening inside a quantum processor. State tomography reconstructs the density matrix of a qubit or multi-qubit system, revealing not just the populations of the computational basis states but also the coherences (off-diagonal elements) that encode quantum information. Process tomography characterizes how a quantum gate transforms any input state, capturing all the ways the gate deviates from ideal behavior. These techniques are essential for diagnosing errors, validating gate implementations, and benchmarking processor performance. The main limitation is that full tomography requires a number of measurements that grows exponentially with the number of qubits, so it is typically applied to small subsystems rather than entire processors.
How it connects. Tomography experiments require precise state preparation across many different bases, followed by repeated measurement with high statistics. The Qblox Cluster supports this through its Q1 Sequence Processor (for efficient parameterized sweeps across preparation and measurement bases), on-board averaging in the readout modules (for rapid statistical accumulation), and the Qblox Scheduler (for defining and visualizing tomographic measurement protocols). Learn more about Qblox Scheduler.
