New quantum method slashes resource demands for entanglement measurement

Researchers at Peking University have developed a new method for measuring partial-transpose moments in quantum systems. The breakthrough reduces the quantum resources needed for this key task. Junxiang Huang and colleagues designed the approach to improve the efficiency of quantum technologies. Partial-transpose moments act as a mathematical fingerprint for the strength of quantum entanglement between particles. The team’s method now estimates these moments with fewer resources than before. It requires only 2n+1 active qubits, regardless of the moment order.

The current technique works with explicit two-qubit systems. It also advances the estimation of nonlinear functions for partial-transpose spectral data. The approach achieves uniform additive error with a copy complexity of O(K log K/ε²). Strong converse bounds suggest the scaling is near optimal, differing only by a logarithmic factor.

Future work will likely expand the method to systems with more than two qubits. This could further enhance its utility in quantum computing. The new method cuts the resource demands for quantifying entanglement strength. This reduction is a critical step for scaling up quantum technologies. The advance brings more efficient quantum devices closer to reality.