High-efficiency Cooper pair splitting demonstrated by two-particle conductance resonance and positive noise cross-correlation

Abstract

Entanglement is at the heart of the Einstein-Podolsky-Rosen paradox, where the non-locality is a necessary ingredient. Cooper pairs in superconductors can be split adiabatically, thus forming entangled electrons. Here, we fabricate such an electron splitter by contacting an aluminium superconductor strip at the centre of a suspended InAs nanowire. The nanowire is terminated at both ends with two normal metallic drains. Dividing each half of the nanowire by a gate-induced Coulomb blockaded quantum dot strongly impeds the flow of Cooper pairs due to the large charging energy, while still permitting passage of single electrons. We provide conclusive evidence of extremely high efficiency Cooper pair splitting via observing positive two-particle correlations of the conductance and the shot noise of the split electrons in the two opposite drains of the nanowire. Moreover, the actual charge of the injected quasiparticles is verified by shot noise measurements.

Cooper Pair Splitting by Means of Graphene Quantum Dots

“…Consequently, for each conductance peak in g 1 , there will be a corresponding conductance peak in g 2 . This nonlocal positive conductance correlation is regarded as evidence of CPS [8][9][10].…”

“…DOI A Cooper pair, splitting from a superconductor into two different normal metal terminals [1,2], is a natural source of nonlocal entangled electrons, which is an essential resource for quantum information processing [3]. During the past decade, many efforts have been made to split Cooper pairs into metal [4][5][6][7], InAs nanowire [8][9][10], and carbon nanotube [11,12]. In a normal-superconductor-normal (NSN) type of metallic structure, evidence of entangled pairs has been reported using combined conductance and noise correlation measurements in two SN junctions [7].…”

Subgap structure in the conductance of a three-terminal Josephson junction

“…When two normal conductors are closely connected to a superconducting reservoir, Crossed Andreev Reflections (CAR) can inject two phase-correlated particles, one in each conductor, which amounts to split a Cooper pair into two entangled electrons [6][7][8][9][10][11][12][13][14][15]. This only occurs when the distance between the two normal conductors is smaller than the superconducting coherence length.…”

Majorana fermion induced nonlocal current correlations in spin-orbit coupled superconducting wires

“…1(a) has been fabricated recently 14,15,36 and the shot noise of the set up in the topologically trivial regime is measured. 36 Therefore, the measurements of the shot noise in the topologically nontrivial regime is experimentally feasible.…”