标题： 变分制备超导transmon量子比特系统中的纠缠态 显示英文标题

标题： Variational preparation of entangled states in a system of transmon qubits

摘要： 在量子比特系统中生成纠缠态的传统方法依赖于精确的两量子比特纠缠门以及单量子比特旋转的结合。然而，实现高保真纠缠需要两量子比特操作具有很高的精度，这要求复杂的校准协议。 在这项工作中，我们使用了一个经过最少校准的类似iSwap的两量子比特门，并通过简单的参数优化（通量脉冲幅度和持续时间）来准备两个和三个transmon量子比特系统中的贝尔态和GHZ态。通过将这个门集成到变分量子算法（VQA）中，我们在无需复杂校准的情况下保持了高保真度。 我们提出的方法利用变分量子算法（VQAs）通过不完美的多量子比特操作来创建目标量子态。此外，我们还实验性地证明了贝尔态对Clauser-Horne-Shimony-Holt（CHSH）不等式的违背，确认了它们的高保真制备。 显示英文摘要

摘要： The conventional method for generating entangled states in qubit systems relies on applying precise two-qubit entangling gates alongside single-qubit rotations. However, achieving high-fidelity entanglement demands high accuracy in two-qubit operations, requiring complex calibration protocols. In this work, we use a minimally calibrated two-qubit iSwap-like gate, tuned via straightforward parameter optimization (flux pulse amplitude and duration), to prepare Bell states and GHZ states experimentally in systems of two and three transmon qubits. By integrating this gate into a variational quantum algorithm (VQA), we bypass the need for intricate calibration while maintaining high fidelity. Our proposed methodology employs variational quantum algorithms (VQAs) to create the target quantum state through imperfect multiqubit operations. Furthermore, we experimentally demonstrate a violation of the Clauser-Horne-Shimony-Holt (CHSH) inequality for Bell states, confirming their high fidelity of preparation.