Few measurements now predict a qubit’s power for quantum tasks

Researchers have demonstrated that assessing a qubit’s power for quantum tasks may require fewer measurements than previously thought. The team, including members from the Federal University of Rio Grande do Norte and the Technical University of Denmark, found that quantifying a key resource for universal quantum computation can be achieved using any set of m n-qubit Pauli measurements, so long as the set includes anti-commuting pairs. The work establishes that “nonstabilizerness is, to a large extent, in the eyes of the beholder,” meaning the chosen measurement method significantly impacts the quantification. This new approach offers a way to estimate quantum magic with a runtime exponential in the number of measurements but polynomial in the number of qubits, a marked improvement over existing methods requiring doubly exponential classical post-processing. Assessing a qubit’s capacity for quantum computation no longer demands an exponentially growing number of measurements. This…