Question

what are merit and demerit of election? explain......

Answer 1

The on-demand generation and separation of entangled photon pairs are key components of quantum information processing in quantum optics1,2,3. In an electronic analogue, the decomposition of electron pairs represents an essential building block for using the quantum state of ballistic electrons in electron quantum optics4,5,6,7. The scattering of electrons has been used to probe the particle statistics of stochastic sources in Hanbury Brown and Twiss experiments8,9 and the recent advent of on-demand sources further offers the possibility to achieve indistinguishability between multiple sources in Hong–Ou–Mandel experiments10,11,12,13,14,15. Cooper pairs impinging stochastically at a mesoscopic beamsplitter have been successfully partitioned, as verified by measuring the coincidence of arrival16,17,18,19,20,21. Here, we demonstrate the splitting of electron pairs generated on demand. Coincidence correlation measurements allow the reconstruction of the full counting statistics, revealing regimes of statistically independent, distinguishable or correlated partitioning, and have been envisioned as a source of information on the quantum state of the electron pair22,23,24,25,26. The high pair-splitting fidelity opens a path to future on-demand generation of spin-entangled electron pairs from a suitably prepared two-electron quantum-dot ground state.