Low-dimensional copper oxide lattices naturally manifest electronic states with strong short range quantum entanglement, which are known to lead to remarkable emergent material properties. However the nanometer scale many-body wavefunction is challenging to measure or manipulate in a simple way. In this study, X-ray induced dd electronic transitions are used to suppress spin entanglement across a single lattice site in the spin-1/2 antiferromagnetic chain compound SrCuO2, revealing a class of cuprate magnetic excitations that result from breaking the spin chain. These measurements are the first to employ two closely spaced X-ray resonances of copper (M2 and M3) as a form of natural 2-slit interferometer to distinguish between different types of electronic transition and resolve how they influence the dynamics of nearby spin-entangled electrons.
@article{arxiv.1203.2397,
title = {Disentangling a quantum antiferromagnet with resonant inelastic X-ray scattering},
author = {L. Andrew Wray and Ignace Jarrige and Kazuhiko Ikeuchi and Kenji Ishii and Yuri Shvyd'ko and Yuqi Xia and M. Zahid Hasan and Charles Mathy and Hiroshi Eisaki and Jinsheng Wen and Zhijun Xu and Genda Gu and Zahid Hussain and Yi-De Chuang},
journal= {arXiv preprint arXiv:1203.2397},
year = {2012}
}