Quantum simulation holds promise of enabling a complete description of high-energy scattering processes rooted in gauge theories of the Standard Model. A first step in such simulations is preparation of interacting hadronic wave packets. To create the wave packets, one typically resorts to adiabatic evolution to bridge between wave packets in the free theory and those in the interacting theory, rendering the simulation resource intensive. In this work, we construct a wave-packet creation operator directly in the interacting theory to circumvent adiabatic evolution, taking advantage of resource-efficient schemes for ground-state preparation, such as variational quantum eigensolvers. By means of an ansatz for bound mesonic excitations in confining gauge theories, which is subsequently optimized using classical or quantum methods, we show that interacting mesonic wave packets can be created efficiently and accurately using digital quantum algorithms that we develop. Specifically, we obtain high-fidelity mesonic wave packets in the $Z_2$ and $U(1)$ lattice gauge theories coupled to fermionic matter in 1+1 dimensions. Our method is applicable to both perturbative and non-perturbative regimes of couplings. The wave-packet creation circuit for the case of the $Z_2$ lattice gauge theory is built and implemented on the Quantinuum $\texttt{H1-1}$ trapped-ion quantum computer using 13 qubits and up to 308 entangling gates. The fidelities agree well with classical benchmark calculations after employing a simple symmetry-based noise-mitigation technique. This work serves as a step toward quantum computing scattering processes in quantum chromodynamics.

中文翻译：

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规范理论中强子的散射波包：在量子计算机上进行准备


量子模拟有望实现对植根于标准模型的规范理论的高能散射过程的完整描述。这种模拟的第一步是准备相互作用的强子波包。为了创建波包，通常采用绝热演化来桥接自由理论中的波包和交互理论中的波包，从而使仿真资源密集。在这项工作中，我们直接在相互作用理论中构建了一个波包创建运算符，以规避绝热进化，利用资源高效的基态准备方案，例如变分量子特征求解器。通过限制规范理论中束缚介子激发的拟设，随后使用经典或量子方法进行优化，我们表明，使用我们开发的数字量子算法可以高效、准确地创建相互作用的介子波包。具体来说，我们在 $Z_2$ 和 $U（1）$ 晶格规范理论中获得了与 1+1 维费米子物质耦合的高保真介子波包。我们的方法适用于耦合的扰动和非扰动状态。$Z_2$ 晶格规范理论的波包创建电路是在 Quantinuum $\texttt{H1-1}$ 囚禁离子量子计算机上使用 13 个量子比特和多达 308 个纠缠门构建和实现的。这些保真度与采用基于对称的简单噪声缓解技术后的经典基准计算非常吻合。这项工作是朝着量子色动力学中量子计算散射过程迈出的一步。