Ancilla-free implementation of generalized measurements for qubits embedded in a qudit space

Understand

Informationally complete (IC) positive operator-valued measures (POVMs) are generalized quantum measurements that offer advantages over the standard computational basis readout of qubits.

• For instance, IC-POVMs enable efficient extraction of operator expectation values, a crucial step in many quantum algorithms.
• POVM measurements are typically implemented by coupling one additional ancilla qubit to each logical qubit, thus imposing high demands on the device size and connectivity.
• Here, we show how to implement a general class of IC-POVMs without ancilla qubits.