In the present paper, we have proposed the experimentally achievable method for the characterization of the collective states of qubits in a linear chain. We study temporal dynamics of absorption of a single-photon pulse by three interacting qubits embedded in a one-dimensional waveguide. Numerical simulations were performed for a Gaussian-shaped pulse with different frequency detunings and interaction parameters between qubits. The dynamic behavior of the excitation probability for each qubit is investigated. It was shown that the maximum probability amplitudes of excitation of qubits are reached when the frequency of external excitation coincides with the frequency of excitation of the a corresponding eigenstate of the system. In this case, the the magnitude of the probability amplitude of each qubit in the chain unambiguously correlates with the contribution of this qubit to the corresponding collective state of the system, and the decay of these amplitudes are determined by the resonance width arising from the interaction of the qubit with the photon field of the waveguide. Therefore, we show that the pulsed harmonic probe can be used for the characterization of the energies, widths, and the wavefunctions of the collective states in a one-dimensional qubit chain.

中文翻译：

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三量子位系统中量子位集体状态的激发

在本文中，我们提出了一种可通过实验实现的方法，用于表征线性链中量子位的集体状态。我们研究了嵌入一维波导中的三个相互作用的量子位对单光子脉冲吸收的时间动力学。对具有不同频率失谐和量子位之间相互作用参数的高斯形脉冲进行了数值模拟。研究了每个量子位的激发概率的动态行为。结果表明，当外部激发频率与系统相应本征态的激发频率一致时，量子比特激发的最大概率幅度达到。在这种情况下，链中每个量子位的概率幅度的大小与该量子位对系统相应集体状态的贡献明确相关，并且这些幅度的衰减由量子位与量子位相互作用产生的共振宽度决定波导的光子场。因此，我们表明脉冲谐波探针可用于表征一维量子位链中集体态的能量、宽度和波函数。