论文标题
任意等级的CNOT效率电路多体效率和量子激发
CNOT-Efficient Circuits for Arbitrary Rank Many-Body Fermionic and Qubit Excitations
论文作者
论文摘要
在嘈杂的中间量子量子设备上实现量子算法是必要的，有效的量子电路是必需的。输入单一耦合群集（UCC）Ansätze的费米子激发产生了包含cnot“楼梯”的量子电路，其数字以激发等级为例。最近，Yordanov等。 [物理。修订版A 102，062612（2020）;社区。物理。 4，228（2021）]为基于费米子（Fermionic-（Fermionic-（Fermionic）和基于Qubit-Excitation（QEB）（QEB）的单打和双打）构建了CNOT有效的量子回路，并说明了它们在适应性衍生化衍生化的伪造的伪造的变量量化量子eigaptial eigaptial eigaTemal eigaTsolver（Adapt-vqe）中的有用性。在这项工作中，我们将这些CNOT有效的量子电路扩展到任意激发等级。为了说明这些紧凑型2月和QEB量子电路的好处，我们使用最近开发的选定的投射量子量质量（SPQE）方法进行数值模拟，该方法依赖于自适应的UCC ANSATZ，该方法由任意级别的粒子孔孔孔激励算子构建。我们表明，2月和QEB-SPQE与传统的SPQE相比，CNOT门的数量减少了15个。与此同时，QEB-SPQE一般而言，通常要求的ANSATZ参数比Feb-SPQE多于Feb-SPQE，尤其是与更高的双重激励相对应的量子，从而导致量子循环较大的量子循环。尽管Adapt-VQE生成的CNOT的量子电路比SPQE少，但SPQE所需的数量级剩余元件评估比Adapt-VQE中的梯度元素评估少。
Efficient quantum circuits are necessary for realizing quantum algorithms on noisy intermediate-scale quantum devices. Fermionic excitations entering unitary coupled-cluster (UCC) ansätze give rise to quantum circuits containing CNOT "staircases" whose number scales exponentially with the excitation rank. Recently, Yordanov et al. [Phys. Rev. A 102, 062612 (2020); Commun. Phys. 4, 228 (2021)] constructed CNOT-efficient quantum circuits for both fermionic- (FEB) and qubit-excitation-based (QEB) singles and doubles and illustrated their usefulness in adaptive derivative-assembled pseudo-Trotterized variational quantum eigensolver (ADAPT-VQE) simulations. In this work, we extend these CNOT-efficient quantum circuits to arbitrary excitation ranks. To illustrate the benefits of these compact FEB and QEB quantum circuits, we perform numerical simulations using the recently developed selected projective quantum eigensolver (SPQE) approach, which relies on an adaptive UCC ansatz built from arbitrary-order particle-hole excitation operators. We show that both FEB- and QEB-SPQE decrease the number of CNOT gates compared to traditional SPQE by factors as large as 15. At the same time, QEB-SPQE requires, in general, more ansatz parameters than FEB-SPQE, in particular those corresponding to higher-than-double excitations, resulting in quantum circuits with larger CNOT counts. Although ADAPT-VQE generates quantum circuits with fewer CNOTs than SPQE, SPQE requires orders of magnitude less residual element evaluations than gradient element evaluations in ADAPT-VQE.
