论文标题
价值键固体的变分量子模拟
Variational Quantum Simulation of Valence-Bond Solids
论文作者
论文摘要
我们引入了一种混合量子型经典变分算法，以模拟热力学极限中沮丧的量子自旋模型的地面相图。该方法基于群集gutzwiller ansatz，其中群集的波函数由参数化的量子电路提供，其关键成分是两个Qubit的真实XY Gate，允许在最近的邻居量子骨上有效地产生价值键。附加可调的单量子Z和两数Qubit的ZZ旋转门可以描述磁有序和顺磁性相，同时将变异优化限制为U（1）子空间。我们在方格上对J1-J2 Heisenberg模型进行基准测试，并揭示其相图，该方法具有远距离有序的Neel和柱状抗铁磁性相，以及以2x2强相关的Plaquettes的周期性模式来表征的中等价值键相。我们的结果表明，该算法的收敛性是由远距离顺序的开始的指导，开辟了一种有希望的途径，以合成实现沮丧的量子磁体及其量子相变为顺磁价键固体，并具有当前开发的超导电路电路设备。
We introduce a hybrid quantum-classical variational algorithm to simulate ground-state phase diagrams of frustrated quantum spin models in the thermodynamic limit. The method is based on a cluster-Gutzwiller ansatz where the wave function of the cluster is provided by a parameterized quantum circuit whose key ingredient is a two-qubit real XY gate allowing to efficiently generate valence-bonds on nearest-neighbor qubits. Additional tunable single-qubit Z- and two-qubit ZZ-rotation gates allow the description of magnetically ordered and paramagnetic phases while restricting the variational optimization to the U(1) subspace. We benchmark the method against the J1-J2 Heisenberg model on the square lattice and uncover its phase diagram, which hosts long-range ordered Neel and columnar anti-ferromagnetic phases, as well as an intermediate valence-bond solid phase characterized by a periodic pattern of 2x2 strongly-correlated plaquettes. Our results show that the convergence of the algorithm is guided by the onset of long-range order, opening a promising route to synthetically realize frustrated quantum magnets and their quantum phase transition to paramagnetic valence-bond solids with currently developed superconducting circuit devices.
