Zhu Xing-Yu, Tu Tao, Guo Ao-Lin, Zhou Zong-Quan, Li Chuan-Feng, Guo Guang-Can
Key Lab of Quantum Information, Chinese Academy of Sciences, University of Science and Technology of China, Hefei, 230026, China.
Department of Physics and Astronomy, University of California at Los Angeles, California, 90095, USA.
Sci Rep. 2018 Oct 25;8(1):15761. doi: 10.1038/s41598-018-34108-0.
The hybrid system of electron spins and resonator photons is an attractive architecture for quantum computing owing to the long coherence times of spins and the promise of long-distance coupling between arbitrary pairs of qubits via photons. For the device to serve as a building block for a quantum processer, it is also necessary to readout the spin qubit state. Here we analyze in detail the measurement process of an electron spin singlet-triplet qubit in quantum dots using a coupled superconducting resonator. We show that the states of the spin singlet-triplet qubit lead to readily observable features in the spectrum of a microwave field through the resonator. These features provide useful information on the hybrid system. Moreover, we discuss the working points which can be implemented with high performance in the current state-of-the-art devices. These results can be used to construct the high fidelity measurement toolbox in the spin-circuit QED system.
电子自旋与谐振器光子的混合系统是一种颇具吸引力的量子计算架构，这得益于自旋的长相干时间以及通过光子在任意量子比特对之间实现长距离耦合的前景。要使该器件成为量子处理器的构建模块，读出自旋量子比特状态也是必要的。在此，我们详细分析了利用耦合超导谐振器对量子点中电子自旋单重态 - 三重态量子比特的测量过程。我们表明，自旋单重态 - 三重态量子比特的状态会通过谐振器在微波场频谱中产生易于观测的特征。这些特征为混合系统提供了有用信息。此外，我们还讨论了在当前最先进的器件中能够以高性能实现的工作点。这些结果可用于构建自旋电路量子电动力学系统中的高保真测量工具箱。
