论文标题
量子点分子中单线量子Qubit的光学控制中的相干限制
Coherence limitations in the optical control of the singlet-triplet qubit in a quantum dot molecule
论文作者
论文摘要
我们分析了在自组装的量子点分子中两电子状态的单线 - 三态子空间上实现的量子空间的光学驱动动力学。我们通过两个频谱分离的激光脉冲或单个频谱较宽的脉冲研究了两个可能的对照方案，基于与激发（四粒子）状态的耦合（四粒子）状态。与理想的$λ$ - 系统中理想的绝热拉曼职业转移相比，我们定量地表征了由非绝热进化和实际系统中有限的光谱选择性产生的量子操作的缺陷。接下来，我们研究与周围晶体晶格的声子和辐射重组所诱导的破坏性的影响。结果，我们能够确定不同错误来源之间的优化权衡，并指出了两个光学控制方案中对单线量子Qubit的量子控制最有利的条件。
We analyze the optically driven dynamics of a qubit implemented on a singlet-triplet subspace of two-electron states in a self-assembled quantum dot molecule. We study two possible control schemes based on the coupling to an excited (four-particle) state either by two spectrally separated laser pulses or by a single spectrally broad pulse. We quantitatively characterize the imperfections of the qubit operation resulting from non-adiabatic evolution and from limited spectral selectivity in a real system, as compared to the ideal adiabatic Raman transfer of occupation in the $Λ$-system. Next, we study the effects of decoherence induced by the coupling to the phonons of the surrounding crystal lattice and by radiative recombination. As a result, we are able to identify the optimization trade-offs between different sources of errors and indicate the most favorable conditions for quantum control of the singlet-triplet qubit in the two optical control schemes.
