Roca-Jerat Sebastián, Macaluso Emilio, Chiesa Alessandro, Santini Paolo, Carretta Stefano
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, Zaragoza 50009, Spain.
Departamento de Física de la Materia Condensada, Universidad de Zaragoza, Zaragoza 50009, Spain.
Mater Horiz. 2025 Jun 3;12(11):3918-3928. doi: 10.1039/d4mh01512f.
Noise affecting quantum processors still limits quantum simulations to a small number of units and operations. This is especially true for the simulation of open quantum systems, which involve additional units and operations to map environmental degrees of freedom. Hence, finding efficient approaches for the simulation of open quantum systems is an open issue. In this work, we demonstrate how using units with > 2 levels (qudits) results in a reduction of up to two orders of magnitude in the number of operations (gates) required to implement state-of-the-art algorithms. We explore two conceptually distinct families of these algorithms that were initially designed for qubits and discuss the gate complexity scaling that different platforms (qubit-based qudit-based) offer. Additionally, we present realistic simulations of an experimental platform based on molecular spin qudits coupled to superconducting resonators, where the main hardware error sources are included. We show that, in all cases considered, the use of qudits leads to a remarkable reduction in circuit complexity and that molecular nanomagnets are ideal qudit hosts.
影响量子处理器的噪声仍然将量子模拟限制在少量的单元和操作上。对于开放量子系统的模拟来说尤其如此，开放量子系统涉及额外的单元和操作来映射环境自由度。因此，找到用于模拟开放量子系统的有效方法是一个悬而未决的问题。在这项工作中，我们展示了使用具有大于2个能级的单元（量子位）如何使实现最先进算法所需的操作（门）数量减少多达两个数量级。我们探索了最初为量子比特设计的这两类概念上不同的算法，并讨论了不同平台（基于量子比特的和基于量子位的）所提供的门复杂度缩放。此外，我们给出了基于与超导谐振器耦合的分子自旋量子位的实验平台的实际模拟，其中包括了主要的硬件误差源。我们表明，在所考虑的所有情况下，使用量子位会显著降低电路复杂度，并且分子纳米磁体是理想的量子位宿主。
