EAGER: Chemically-Inspired, Tunable Quantum Computing Architectures for Dynamics of Molecular Systems

在化学系化学理论、模型和计算方法项目的支持下，印第安纳州大学的Philip Richerme和Srinivasan Iyengar正在开发受量子化学动力学研究启发的量子器件。Richerme和Iyengar研究的化学过程在大多数生物，材料和大气系统的反应化学中起着核心作用。例如，量子化学动力学可能是具有全球重要性的催化转化的基础，包括减少二氧化碳，这对于将这种温室气体转化为有用的原料，人工光合作用和固氮至关重要。对这些过程进行建模的经典方法一直不成功，因为它们需要指数级的计算资源来准确描述系统中大量的量子力学电子和原子核。相反，Richerme和Iyengar将从根本上使用量子硬件，其设计反映了所研究分子的几何形状，以模拟这些化学系统的动力学。这可能使他们能够直接计算这些系统的波包动力学和振动光谱，而无需门模型量子计算的显着开销。此外，该项目将为实验和理论研究生提供丰富的培训环境-无论是在MS和博士水平-并将使量子化学轨道内的印第安纳州大学量子硕士学位课程的发展，在全国范围内，认识到需要在量子信息科学领域的劳动力发展。Richerme和Iyengar将开发一种新的方法来映射从化学系统的微观量子相互作用到工程量子硬件。他们的核心观点是，量子物体的相对几何形状驱动了它们的连通性，从而驱动了它们的行为，并在设计量子硬件以模拟自然过程时提供了显着的简化。从分子本身的几何形状中汲取灵感，他们安排了捕获离子量子比特阵列的几何形状，以自然地复制各种核自由度之间纠缠传播的相互作用和时间尺度。这种方法的动机是观察到紧密间隔的捕获离子量子比特强烈相互作用，而随着离子-离子距离的增加，相互作用迅速衰减。从相对离子位置出现的耦合强度的这种差异提供了一个框架，在该框架中，在多个紧密间隔的离子组内并行模拟多个核维度;然后，这些离子簇之间的弱耦合在有效的核自由度之间产生相关性。通过改变施加到离子阱电极的约束电压，离子簇之间的间距可控制到亚微米精度，类似于控制阱电压以实现等间距离子串的现有工作。一旦通过系统几何结构对这些原生相互作用进行编码，模拟量子模拟方法应该能够在系统中传播分子动力学和提取振动频率，而不需要指数数量的量子门。 该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry, Philip Richerme and Srinivasan Iyengar of Indiana University, are developing quantum devices inspired by and for the study of quantum chemical dynamics. The chemical processes studied by Richerme and Iyengar play central roles in the reactive chemistry of most biological, materials, and atmospheric systems. For instance, quantum chemical dynamics likely underlie catalytic transformations of global importance, including the reduction of CO2, which is critical to converting this greenhouse gas to useful feedstocks, artificial photosynthesis, and nitrogen fixation. Classical approaches toward modeling these processes have been unsuccessful, since they would require exponentially large computing resources to accurately describe the large numbers of quantum-mechanical electrons and nuclei within the system. Instead, Richerme and Iyengar will use fundamentally quantum hardware, whose design mirrors the geometry of the molecules under study, to emulate the dynamics of these chemical systems. This may allow them to directly calculate wavepacket dynamics and vibrational spectra for these systems without the significant overhead of gate-model quantum computation. In addition, this project will provide a rich training environment for experimental and theory graduate students – both at the MS and PhD levels – and will enable the development of a Quantum Chemistry track within the Indiana University Quantum Master’s degree program, addressing the nationally-recognized need for workforce development in the area of Quantum Information Science.Richerme and Iyengar will develop a new approach to mapping the microscopic quantum interactions of chemical systems to engineered quantum hardware. Their central insight is that the relative geometry of quantum objects drives their connectivity, and hence, behavior and offers significant simplifications when designing quantum hardware to emulate natural processes. Drawing inspiration from the geometry of the molecules themselves, they arrange the geometry of trapped-ion qubit arrays to natively replicate the interactions and timescales of entanglement propagation between the various nuclear degrees of freedom. This approach is motivated by the observation that closely-spaced trapped-ion qubits interact strongly, while interactions decay quickly as the ion-ion distance is increased. This difference in coupling strengths, emerging from the relative ion positions, provides a framework in which multiple nuclear dimensions are simulated in parallel within multiple closely-spaced groups of ions; weak couplings across these ion clusters then generates correlations among the effective nuclear degrees of freedom. The spacing between ion clusters is controllable to sub-micron precision by changing the confinement voltages applied to ion-trap electrodes, similar to prior work which controls the trap voltages to achieve equally-spaced ion strings. Once these native interactions are encoded through the system geometry, analog quantum simulation methods should enable propagation of the molecular dynamics and extraction of the vibrational frequencies in the system, without requiring exponential numbers of quantum gates. Success in this approach has the potential to be transformational in the fields of quantum dynamics and vibrational spectroscopy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.