Ding Lexin, Schilling Christian
Faculty of Physics, Arnold Sommerfeld Centre for Theoretical Physics (ASC), Ludwig-Maximilians-Universität München, Theresienstr. 37, 80333 München, Germany.
Wolfson College, University of Oxford, Linton Rd., Oxford OX2 6UD, United Kingdom.
J Chem Theory Comput. 2020 Jul 14;16(7):4159-4175. doi: 10.1021/acs.jctc.0c00054. Epub 2020 Jun 5.
The interplay between electron interaction and geometry in a molecular system can lead to rather paradoxical situations. The prime example is the dissociation limit of the hydrogen molecule. While a significant increase of the distance between the two nuclei marginalizes the electron-electron interaction, the exact ground state does, however, not take the form of a single Slater determinant. By first reviewing and then employing concepts from quantum information theory, we resolve this paradox and its generalizations to more complex systems in a quantitative way. To be more specific, we illustrate and prove that thermal noise due to finite, possibly even just infinitesimally low, temperature will destroy the entanglement beyond a critical separation distance () entirely. Our analysis is comprehensive in the sense that we simultaneously discuss both total correlation and entanglement in the particle picture as well as in the orbital/mode picture. Our results reveal a conceptually new characterization of static and dynamical correlation in ground states by relating them to the (non)robustness of correlation with respect to thermal noise.
分子系统中电子相互作用与几何结构之间的相互作用可能会导致相当矛盾的情况。典型的例子是氢分子的解离极限。虽然两个原子核之间距离的显著增加会使电子-电子相互作用边缘化，但精确的基态并非单个斯莱特行列式的形式。通过首先回顾然后运用量子信息论的概念，我们以定量的方式解决了这个悖论及其对更复杂系统的推广。更具体地说，我们说明并证明，由于有限温度（甚至可能只是极低的温度）引起的热噪声将在超过临界分离距离（）时完全破坏纠缠。我们的分析是全面的，因为我们同时在粒子图像以及轨道/模式图像中讨论了总相关性和纠缠。我们的结果通过将基态中的静态和动态相关性与热噪声相关性的（非）鲁棒性联系起来，揭示了一种概念上新的表征。
