Molecular Ions: an Hybrid Atom-Ion Platform to Generate Quantum States

信息技术的最新发展对社会产生了巨大的影响。新技术爆炸式增长的一个因素是计算能力的快速增长，摩尔定律描述了这一点：处理器能力每18个月翻一番。这伴随着处理器尺寸的减小。在不久的将来，基于经典信息处理的实际处理器将达到量子极限；量子力学的测不准原理将发挥作用。量子信息科学（QIS）是利用量子力学规律研究信息科学的新途径。量子信息的新进展表明，基于基本量子原理的设备，如干涉和纠缠，可以比任何经典计算机更有效地执行某些任务。在量子信息处理方面的努力导致了量子密码学和量子算法的协议。许多平台已经被用于QIS的研究，如俘获离子、中性原子、里德伯原子、晶体中的原子、粒子的自旋、腔量子电动力学（QED）或非线性光学装置中的光子、介观系综和极性分子。随着量子信息科学领域的成熟，它的目标也越来越成熟。人们正在寻找更现实的、更好的可扩展系统，寻找新的应用领域，并与物理学的其他领域进行更强的交叉施肥。将研究基于分子离子的产生量子态和量子信息处理的混合平台，着眼于可行性、可扩展性以及与物理学其他子领域的连接。这个混合平台分享了其他平台的优点；中性原子的长相干时间和捕获离子的强相互作用。这些系统所需的特性将被研究，以确定分子离子中的最佳候选者，这些候选者将允许原子之间的库仑相互作用被关闭和打开。这将有助于指导设计新的量子信息处理实验装置。主要的工作涉及量子信息科学，即量子态的可能产生，以及相位门的实现。首先，将探索利用分子离子作为使能剂来设计非平凡状态，例如非局部原子。将研究特定种类、碱+碱土和同核碱土双原子分子离子，并计算它们的性质（能面、跃迁矩、超精细结构等）。其次，中性原子和捕获离子阵列可以用来有效地产生强的远程相互作用，可以通过使用分子离子作为介质来开启和关闭，从而实现纠缠，系统将被研究，例如钠（Na）和钙（Ca）， Na + Ca+或Ca+ Ca+的组合。这些新系统将通过仔细计算的实际参数进行探索，以帮助理解复杂的物理系统，并预测新的现象和产生新的理论概念。分子离子量子计算的探索性研究有望将量子信息系统和原子、分子、光学物理的范围扩大到介观系统和凝聚态物理。

The recent developments in information technology are having a large impact on the society. One factor in the explosion of new technologies is the rapid increase in computing power, described by Moore's law: processor power doubles every 18 months. This is accompanied by a reduction in the size of the processors. In the near future, the actual processors based on classical treatment of information will reach the quantum limit; the uncertainty principle of quantum mechanics will come into play. Quantum Information Science (QIS) is a new approach to information science that takes advantage of laws of quantum mechanics. New advances in quantum information indicate that devices based on fundamental quantum principles, such as interference and entanglement, can perform certain tasks considerably more efficiently than any classical computer. Efforts in quantum information processing have led to protocols for quantum cryptography, and quantum algorithms. Many platforms have been studied for QIS, such as trapped ions, neutral atoms, Rydberg atoms, atoms in crystals, spin of particles, photons in cavity quantum electrodynamics (QED) or nonlinear optical setups, mesoscopic ensembles, and polar molecules.As the field of quantum information science matures, so do its goals. There is a search for more realistic and better scalable systems, for novel areas of application and stronger cross-fertilization with other areas in physics. A hybrid platform for generating quantum states and for quantum information processing, based on molecular ions will be studied, with an eye towards feasibility, scalability, and connection with other subfields in physics. This hybrid platform shares the advantages of other platforms; the long coherence times of neutral atoms, and strong interactions of trapped ions. The required properties of these systems will be studied in order to identify the best candidates among molecular ions that will allow the Coulomb interactions between atoms to be switched off and on. This will help guide efforts in designing new experimental apparatus for quantum information processing.The main effort relates to quantum information science, namely the possible generation of quantum states, and the implementation of phase gates. First, the use of molecular ions as enablers to design non-trivial states, such as non-local atoms will be explored. Specific species, alkali+alkaline earth and homonuclear alkaline earth diatomic molecular ions will be studied and their properties (energy surfaces, transition moments, hyperfine structure, etc.) computed. Second, arrays of neutral atoms and trapped ions that could be used to effectively create strong long-range interactions that can be switched on and off by using molecular ions as mediators to enable entanglement will be studied, systems, such as combinations of sodium (Na) and calcium (Ca), Na + Ca+, or Ca + Ca+. These new systems will be explored using realistic parameters from careful calculations, to help in understanding complex physical systems, and to predict new phenomena and to generate new theoretical concepts. The exploratory research on quantum computing with molecular ions promises to broaden the scope of QIS and atomic, molecular and optical physics to mesoscopic systems, and condensed matter physics.