论文标题
通过量子变异本素量量化状态制备的效率
Quantifying the efficiency of state preparation via quantum variational eigensolvers
论文作者
论文摘要
最近，使用低深度量子电路（例如量子近似优化算法（QAOA））对复杂量子状态的有效制备引起了很多兴趣。虽然已经证明，这种算法以惊人的精度准备了某些相关的量子旋转状态，但缺乏量化QAOA效率的系统方法。在这里，我们提出，QAOA在准备有序状态的成功与目标状态的相互作用距离有关，该距离衡量了该状态在单个粒子模式的任意基础上与所有高斯州的多种歧视相关。我们在数字上验证了这一点，以验证几个不可融合量子模型的示例，包括具有两种和三旋转相互作用的ISING模型以及在外部场中的群集模型。我们的结果表明，纠缠频谱的结构，与相互作用距离见证，与QAOA状态制备的成功相关，并且该相关性还包含有关模型中存在不同阶段的信息。我们得出的结论是，QAOA通常会找到一个解决方案，该解决方案围绕最近的自由雕刻状态。
Recently, there has been much interest in the efficient preparation of complex quantum states using low-depth quantum circuits, such as Quantum Approximate Optimization Algorithm (QAOA). While it has been numerically shown that such algorithms prepare certain correlated states of quantum spins with surprising accuracy, a systematic way of quantifying the efficiency of QAOA in general classes of models has been lacking. Here, we propose that the success of QAOA in preparing ordered states is related to the interaction distance of the target state, which measures how close that state is to the manifold of all Gaussian states in an arbitrary basis of single-particle modes. We numerically verify this for several examples of non-integrable quantum models, including Ising models with two- and three-spin interactions and the cluster model in an external field. Our results suggest that the structure of the entanglement spectrum, as witnessed by the interaction distance, correlates with the success of QAOA state preparation, and that this correlation also contains information about different phases present in the model. We conclude that QAOA typically finds a solution that perturbs around the closest free-fermion state.
