论文标题
Inasp量子点阵列中拓扑保护的单线量子Qubit的微观设计
Microscopic design of a topologically protected singlet-triplet qubit in an InAsP quantum dot array
论文作者
论文摘要
我们在这里介绍了使嵌入INP纳米线中的Inasp量子点阵列中拓扑保护的单线量子Qubit的显微镜设计的步骤。量子位是用两个haldane旋转的 - $ \ frac {1} {2} $ quasiparticles中的合成自旋一链。量子位通过两腿多轨哈伯kanamori（HK）模型描述，其参数是从一个单个和双量子点中多达八个电子的显微镜计算获得的参数。在这种描述量子点长阵列的HK模型中，使用精确的对角线化和矩阵乘积状态（MPS）工具，我们演示了一个四倍的准生长基态基态与激发态通过类似于Haldane相的Heisenberg Spin-1链的有限能量差异。我们通过观察低能谱的磁场依赖性作为应用磁场的函数，证明了自旋 - $ \ frac {1} {2} $ quasiparticles在链的边缘的存在。应用的磁场还可以将单线分离出来，$ s^z = 0 $ triplet状态与其他三重态组件，允许这些状态用作量子。最重要的是，在参数空间中，多轨哈伯德链的低能光谱产生了Heisenberg Spin-1链频谱。由于有限的能量差距，该量子位有可能受到保护免受扰动的潜力。
We present here the steps enabling the microscopic design of a topologically protected singlet-triplet qubit in an InAsP quantum dot array embedded in an InP nanowire. The qubit is constructed with two Haldane spin-$\frac{1}{2}$ quasiparticles in a synthetic spin one chain. The qubit is described by a two-leg multi-orbital Hubbard Kanamori (HK) model with parameters obtained from the microscopic calculations of up to eight electrons in a single and double quantum dot. In this HK model describing long arrays of quantum dots, using both exact diagonalization and matrix product state (MPS) tools, we demonstrate a four-fold quasidegenerate ground state separated from excited states by a finite energy gap similar to a Heisenberg spin-1 chain in the Haldane phase. We demonstrate the existence of spin-$\frac{1}{2}$ quasiparticles at the edges of the chain by observing the magnetic field dependence of the low energy spectrum as a function of applied magnetic field. The applied magnetic field also isolates the singlet and $S^z=0$ triplet states from the other triplet components allowing these states to serve as a qubit basis. Most importantly, the regions in parameter space where the low energy spectrum of the multi-orbital Hubbard chain yields a Heisenberg spin-1 chain spectrum are mapped out. Due to the finite energy gap, this qubit has the potential to be protected against perturbations.
