We report on a quantum–classical simulation of the single-band Hubbard model using two-site dynamical mean-field theory (DMFT). Our approach uses IBM’s superconducting qubit chip to compute the zero-temperature impurity Green’s function in the time domain and a classical computer to fit the measured Green’s functions and extract their frequency domain parameters. We find that the quantum circuit synthesis (Trotter) and hardware errors lead to incorrect frequency estimates, and subsequently to an inaccurate quasiparticle weight when calculated from the frequency derivative of the self-energy. These errors produce incorrect hybridization parameters that prevent the DMFT algorithm from converging to the correct self-consistent solution. To avoid this pitfall, we compute the quasiparticle weight by integrating the quasiparticle peaks in the spectral function. This method is much less sensitive to Trotter errors and allows the algorithm to converge to self-consistency for a half-fill...

中文翻译：

---

噪声量子硬件的两点动力学平均场理论的量子经典模拟

我们报告了使用两点动态平均场理论（DMFT）的单频带Hubbard模型的量子经典模拟。我们的方法使用IBM的超导qubit芯片在时域中计算零温度杂质Green的函数，并使用经典计算机拟合测得的Green的函数并提取其频域参数。我们发现，从自能的频率导数计算时，量子电路合成（Trotter）和硬件错误会导致错误的频率估计，并随后导致不正确的准粒子权重。这些错误会产生错误的杂交参数，从而阻止DMFT算法收敛到正确的自洽解。为了避免这种陷阱，我们通过在光谱函数中积分准粒子峰来计算准粒子权重。这种方法对Trotter错误的敏感度要低得多，并且允许算法收敛到自洽半填充。