论文标题
用于模拟晶格Schwinger模型的量子算法
Quantum Algorithms for Simulating the Lattice Schwinger Model
论文作者
论文摘要
Schwinger模型(1+1维中的量子电动力学)是用于研究量子仪表理论的测试床。我们提供可扩展的,显式的数字量子算法,以模拟NISQ和耐故障设置中的晶格Schwinger模型。特别是,我们使用最近派生的换向器边界对Schwinger模型的低阶Trotter公式模拟进行了严格的分析,并在两种情况下都为模拟所需的资源提供了上限。在晶格单元中,我们在$ n/2 $的物理站点上找到一个schwinger型号,耦合常数$ x^{ - 1/2} $和电场截止$ x^{ - 1/2}λ$可以在量子计算机上模拟,以$ 2 $的量子计算机在量子计算机上使用$ t $ t $ - gates或cnots $ t $ - gate或cnots $ cnots $ - gate或cnots $ \ widetieldeLdeLdeDildeLdeLdeLdeLdeLdeLdeLdeDildede}(3/3/ t^{3/2} \ sqrt {x}λ)$用于固定操作员错误。使用截断$λ$的缩放比Qubitifate或QDRIFT等算法预期的缩放量要好。此外,我们通过假设一个简单的目标可观察到的平均成对密度来提供可观察到的可观察到可观察到的可观察到的可观察到的可观察结果。最后,我们绑定了根平方的误差,以通过模拟估算可观察到的理想和实际CNOT通道之间的钻石距离的函数。这项工作提供了模拟Schwinger模型的严格分析,同时还提供了基准,可以对此进行测试。
The Schwinger model (quantum electrodynamics in 1+1 dimensions) is a testbed for the study of quantum gauge field theories. We give scalable, explicit digital quantum algorithms to simulate the lattice Schwinger model in both NISQ and fault-tolerant settings. In particular, we perform a tight analysis of low-order Trotter formula simulations of the Schwinger model, using recently derived commutator bounds, and give upper bounds on the resources needed for simulations in both scenarios. In lattice units, we find a Schwinger model on $N/2$ physical sites with coupling constant $x^{-1/2}$ and electric field cutoff $x^{-1/2}Λ$ can be simulated on a quantum computer for time $2xT$ using a number of $T$-gates or CNOTs in $\widetilde{O}( N^{3/2} T^{3/2} \sqrt{x} Λ)$ for fixed operator error. This scaling with the truncation $Λ$ is better than that expected from algorithms such as qubitization or QDRIFT. Furthermore, we give scalable measurement schemes and algorithms to estimate observables which we cost in both the NISQ and fault-tolerant settings by assuming a simple target observable---the mean pair density. Finally, we bound the root-mean-square error in estimating this observable via simulation as a function of the diamond distance between the ideal and actual CNOT channels. This work provides a rigorous analysis of simulating the Schwinger model, while also providing benchmarks against which subsequent simulation algorithms can be tested.