Publications

@article{Wei2010,

title = {Positive noise cross-correlation in hybrid superconducting and normal-metal three-terminal devices},

author = {Jian Wei and Venkat Chandrasekhar},

url = {https://www.nature.com/articles/nphys1669},

doi = {https://doi.org/10.1038/nphys1669},

year  = {2010},

date = {2010-05-16},

journal = {Nature Physics},

volume = {6},

pages = {494-498},

abstract = {Non-local entanglement is a key ingredient to quantum information processing. For photons, entanglement has been demonstrated, but it is more difficult to observe for electrons. One approach is to use a superconductor, where electrons form spin-entangled Cooper pairs, which is a natural source for entangled electrons. For a three-terminal device consisting of a superconductor sandwiched between two normal metals, it has been predicted that Cooper pairs can split into spin-entangled electrons flowing in the two spatially separated normal metals resulting in a negative non-local resistance and a positive current–current correlation. The former prosperity has been observed, but not the latter. Here we show that both characteristics can be observed, consistent with Cooper-pair splitting. Moreover, the splitting efficiency can be tuned by independently controlling the energy of the electrons passing the two superconductor/normal-metal interfaces, which may lead to better understanding and control of non-local entanglement.},

keywords = {Andreev reflection, crossed andreev reflection, Proximity effect, Superconductivity},

pubstate = {published},

tppubtype = {article}

}

@article{Cadden-Zimansky2009,

title = {Cooper-pair-mediated coherence between two normal metals},

author = {Paul Cadden-Zimansky and Jian Wei and Venkat Chandrasekhar},

url = {https://www.nature.com/articles/nphys1252?foxtrotcallback=true},

doi = {https://doi.org/10.1038/nphys1252},

year  = {2009},

date = {2009-04-26},

journal = {Nature Physics},

volume = {5},

pages = {393–397},

abstract = {Two electrons bound in a singlet state have long provided a conceptual and pedagogical framework for understanding the non-local nature of entangled quantum objects. As bound singlet electrons separated by a coherence length of up to several hundred nanometres occur naturally in conventional Bardeen–Cooper–Schrieffer superconductors in the form of Cooper pairs, recent theoretical investigations have focused on whether electrons in spatially separated normal-metal probes placed within a coherence length of each other on a superconductor can be quantum mechanically coupled by the singlet pairs. This coupling is predicted to occur through the non-local processes of elastic cotunnelling and crossed Andreev reflection. In crossed Andreev reflection, the constituent electrons of a Cooper pair are sent into different normal probes while retaining their mutual coherence. In elastic cotunnelling, a sub-gap electron approaching the superconductor from one normal probe undergoes coherent, long-range tunnelling to the second probe that is mediated by the Cooper pairs in the condensate. Here, we present experimental evidence for coherent, non-local coupling between electrons in two normal metals linked by a superconductor. The coupling is observed in non-local resistance oscillations that are periodic in an externally applied magnetic flux.},

keywords = {Andreev reflection, crossed andreev reflection, Proximity effect, Superconductivity},

pubstate = {published},

tppubtype = {article}

}

@article{cadden-zimansky_charge_2007,

title = {Charge imbalance, crossed Andreev reflection and elastic co-tunnelling in ferromagnet/superconductor/normal-metal structures},

author = { P Cadden-Zimansky and Z Jiang and V Chandrasekhar},

url = {http://stacks.iop.org/1367-2630/9/i=5/a=116?key=crossref.a335a730aad5102879358913893f090a},

doi = {10.1088/1367-2630/9/5/116},

issn = {1367-2630},

year  = {2007},

date = {2007-01-01},

urldate = {2015-10-23},

journal = {New Journal of Physics},

volume = {9},

number = {5},

pages = {116--116},

keywords = {Andreev reflection, charge imbalance, crossed andreev reflection, Magnetism, nanomagnets, spin transport},

pubstate = {published},

tppubtype = {article}

}

@article{cadden-zimansky_nonlocal_2006,

title = {Nonlocal Correlations in Normal-Metal Superconducting Systems},

author = { P. Cadden-Zimansky and V. Chandrasekhar},

url = {http://link.aps.org/doi/10.1103/PhysRevLett.97.237003},

doi = {10.1103/PhysRevLett.97.237003},

issn = {0031-9007, 1079-7114},

year  = {2006},

date = {2006-12-01},

urldate = {2016-12-29},

journal = {Physical Review Letters},

volume = {97},

number = {23},

keywords = {Andreev reflection, charge imbalance, crossed andreev reflection, Superconductivity},

pubstate = {published},

tppubtype = {article}

}