论文标题
超导量子量子计算机上的hartree-fock
Hartree-Fock on a superconducting qubit quantum computer
论文作者
论文摘要
随着搜索继续寻找嘈杂的中间量表量子设备的有用应用，费米子系统的各种模拟仍然是最有前途的方向之一。在这里，我们对化学进行了一系列量子模拟，其中最大的涉及十几个量子位，78个两倍的门和114个四分之一的门。我们对$ {\ rm h} _6 $，$ {\ rm h} _8 $，$ {\ rm h} _ {10} $和$ {\ rm h} _ {12} $链的绑定能量建模。我们还基于$ n $表达性来证明减轻错误策略，从而极大地改善了我们实验的有效保真度。我们的参数化ANSATZ电路实现了无与伦比的Fermion Evolution的Givens旋转方法，我们在变化中进行了优化以准备Hartree-Fock波函数。这种普遍存在的算法原始性对应于轨道基础的旋转，许多提案要求分子和哈伯德模型的相关模拟。由于非相互作用的费米昂演变在经典上是可以模拟的，但仍会在计算基础上产生高度纠缠的状态，因此我们使用这些实验来对硬件的性能进行基准测试，同时建立基础，以扩大更复杂的化学量子量子模拟。
As the search continues for useful applications of noisy intermediate scale quantum devices, variational simulations of fermionic systems remain one of the most promising directions. Here, we perform a series of quantum simulations of chemistry the largest of which involved a dozen qubits, 78 two-qubit gates, and 114 one-qubit gates. We model the binding energy of ${\rm H}_6$, ${\rm H}_8$, ${\rm H}_{10}$ and ${\rm H}_{12}$ chains as well as the isomerization of diazene. We also demonstrate error-mitigation strategies based on $N$-representability which dramatically improve the effective fidelity of our experiments. Our parameterized ansatz circuits realize the Givens rotation approach to non-interacting fermion evolution, which we variationally optimize to prepare the Hartree-Fock wavefunction. This ubiquitous algorithmic primitive corresponds to a rotation of the orbital basis and is required by many proposals for correlated simulations of molecules and Hubbard models. Because non-interacting fermion evolutions are classically tractable to simulate, yet still generate highly entangled states over the computational basis, we use these experiments to benchmark the performance of our hardware while establishing a foundation for scaling up more complex correlated quantum simulations of chemistry.
