LEAPS-MPS: Multiqubit Entangling Gates for Solid-State Qubit Systems

量子信息科学和量子计算已成为未来科学技术的前沿。量子计算有望实现从经典计算能力到量子计算能力的飞跃。然而，目前的量子硬件只有少量的量子比特(单个设备中有数百个量子比特)，而且相干有限，这使得它很难用于实际问题。在这个项目中，PI将通过研究在量子硬件上实现量子操作的替代方法来解决上面的一些限制，方法是在两个以上的量子比特之间创建纠缠-量子计算的基本资源-比标准方法更有效。这种方法可以减少量子电路的深度，扩展有限的量子硬件的有用性。这种新的方法将被应用于一些混合的量子经典算法，许多人认为这些算法在不久的将来将成为量子计算机的领先实际应用。随着量子技术的进步及其重要性的增加，更多的量子劳动力将是保持竞争优势的关键，重要的是让代表不足的人口群体参与量子科学和技术。该项目将为德克萨斯大学埃尔帕索分校的研究生和本科生提供宝贵的研究经验，他们将加入学术界、行业和国家实验室的量子劳动力大军。量子计算需要使用量子比特之间的纠缠门来创建纠缠，以产生高度纠缠的多量子比特态。实现量子电路的标准方法是使用单量子比特门和两量子比特门，原则上可以产生任何量子电路。然而，对于任何实际的量子电路，仅使用两个量子比特门创建纠缠通常会导致非常长的量子门序列。本项目研究半导体自旋量子比特和超导量子比特的固态量子比特平台中两个以上量子比特的可能的多量子比特纠缠门。这个项目将考虑两种方案来产生多量子比特门：(I)同时应用量子比特之间的成对相互作用和(Ii)由公共总线调节的多量子比特相互作用，其中两个以上的量子比特同时连接。对物理量子比特平台的理论分析，以及整个项目中量子门和量子电路的数值模拟，将有助于揭示由多量子比特门组成的量子电路在实现量子算法，特别是变分量子本征解算器等混合量子算法方面的效率。该项目开发的新方法可以使目前可用的量子计算设备在实际问题中得到有用的应用，例如模拟超出经典计算能力的复杂量子系统。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Quantum information science and quantum computing have become the forefront of future science and technology. Quantum computing promises a great leap forward from classical computing capabilities. However, the current quantum hardware has only a modest number of qubits (hundreds of qubits in a single device) and limited coherence, making it difficult to use for practical problems. In this project, the PI will address some of the above limitations by investigating alternative ways to implement quantum operations on quantum hardware by creating entanglement - an essential resource for quantum computation - between more than two qubits more efficiently than the standard approach. This approach can reduce the depth of the quantum circuits and extend the usefulness of the limited quantum hardware. This new method will be applied to some hybrid quantum-classical algorithms that many consider the leading practical applications of quantum computers in the near future. As quantum technology progresses and its importance increases, a larger quantum workforce will be essential for maintaining the competitive edge, and it is important to engage underrepresented demographic groups in quantum science and technology. This project will provide valuable research experiences to graduate and undergraduate students at the University of Texas at El Paso who will join the quantum workforce in academia, industries, and national labs. Quantum computation requires creating entanglement using entangling gates between qubits to generate highly entangled many-qubit states. The standard approach for implementing quantum circuits is to use single- and two-qubit gates that can generate any quantum circuits in principle. However, creating entanglement only using two-qubit gates typically results in a very long sequence of quantum gates for any practical quantum circuits. This project investigates possible multiqubit entangling gates for more than two qubits in solid-state-based qubit platforms of semiconductor spin qubits and superconducting qubits. This project will consider two schemes to generate multiqubit gates: (i) simultaneous application of pairwise interactions between qubits and (ii) multiqubit interactions mediated by a common bus where more than two qubits are connected simultaneously. Theoretical analysis of the physical qubit platforms and numerical simulation of the quantum gates and quantum circuits throughout the project will shed light on the efficiency of quantum circuits made of multiqubit gates in implementing quantum algorithms, especially hybrid quantum algorithms such as variational quantum eigensolver. The new approach developed in this project can lead to useful applications of the currently available quantum computing devices for practical problems, such as simulating complex quantum systems beyond the capability of classical computation.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.