Jia-Xin Liu

The exact information cost of randomized measurements in quantum metrology

Randomized measurements provide state-independent readout for multiparameter quantum sensing. Although 3-designs retain a constant fraction of the quantum Fisher information (QFI) for every pure state, we show that 2-designs need not. In dimension \(d\), complete mutually unbiased bases (MUBs) retain exactly \(1/(d+1)\...