Quantum dynamics in electron-nuclei coupled spin system in quantum dots: Bunching, revival, and quantum correlation in electron-spin measurements

摘要

We investigate quantum dynamics in the electron-nuclei coupled spin system inquantum dots and clarify the fundamental features of quantum correlationinduced via successive electron spin measurements. This quantum correlationleads to interesting phenomena such as the bunching of outcomes in the electronspin measurements and the revival of an arbitrary initial electron spin state.The nuclear spin system is also affected by the quantum correlation and is infact squeezed via conditional measurements or postselection. This squeezing isconfirmed by calculating the increase in the purity of the nuclear spin system.Thus the successive electron spin measurements provide a probabilistic methodto squeeze the nuclear spin system. These new features are predicted not onlyfor the case of a double quantum dots occupied by a pair of electrons but alsofor the case of a single quantum dot occupied by a single electron or a pair ofelectrons.