Experimental realization of sequential weak measurements of non-commuting Pauli observables

Abstract

Sequential weak measurements of non-commuting observables is not only fundamentally interesting in quantum measurement but also shown potential in various applications. The previous reported methods, however, can only realize limited sequential weak measurements experimentally. In this Letter, we propose the realization of sequential measurements of arbitrary observables and experimentally demonstrate for the first time the measurement of sequential weak values of three non-commuting Pauli observables by using genuine single photons. The results presented here will not only improve our understanding of quantum measurement, e.g. testing quantum contextuality, macroscopic realism, and uncertainty relation, but also have many applications such as realizing counterfactual computation, direct process tomography, direct measurement of the density matrix and unbounded randomness certification.

Experimental test of sequential weak measurements for certified quantum randomness extraction

“…[24]), we shall focus on the use of the weak measurement [25]. Throughout the last three decades, this tool has found many diverse applications, from the amplification of feeble quantities [26][27][28], to the measurement of incompatible observables [29][30][31], through quantum state reconstruction [32][33][34][35]. Recently, it has been exploited for sequential protocols, in which a system undergoes multiple measurements without ever completely collapsing or losing its useful quantum features, which can be harvested repeatedly.…”

Ability of unbounded pairs of observers to achieve quantum advantage in random access codes with a single pair of qubits

“…This idea of sharing quantum correlations by multiple sequential observers has been extended in different contexts as well [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42]. The applications of sequential sharing of quantum correlations in different quantum information processing tasks have also been demonstrated [16,[43][44][45][46][47][48][49][50]. In most of these studies, multiple sequential observers at only one wing have been considered, whereas the present study contemplates multiple sequential observers at each of the wings.…”

Experimental Test of Sequential Weak Measurements for Certified Quantum Randomness Extraction

“…[22]), we shall focus on the use of the weak measurement [23]. Throughout the last three decades, this tool has found many diverse applications, from the amplification of feeble quantities [24][25][26], to the measurement of incompatible observables [27][28][29], through quantum state reconstruction [30][31][32][33]. Recently, it has been exploited for sequential protocols, in which a system undergoes multiple measurements without ever completely collapsing or losing its useful quantum features, which can be harvested repeatedly.…”