紧束缚链中里维顿激发的产生与表征
Creation and characterization of leviton excitations in tight-binding chains
- Donostia International Physics Center (DIPC)（多诺斯蒂亚国际物理中心）
- IKERBASQUE, Basque Foundation for Science（伊克尔巴斯基克，巴斯克科学基金会）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文研究有限紧束缚链中洛伦兹脉冲产生里维顿的机制，发现中间脉冲速度区间可形成干净态，且洛伦兹脉冲优于非洛伦兹形状，为晶格平台相干电子输运提供微观框架。
AI中文摘要：
里维顿（Levitons）是由洛伦兹电压脉冲产生的最小激发电子波包，构成电子量子光学的核心资源。它们的产生和定义性质通常是在连续散射描述中表述的，而许多集成电子量子电路的候选平台是有限、离散且受晶格色散强烈影响的。我们研究了由时变电压脉冲驱动的有限一维非相互作用费米子紧束缚链中的里维顿产生。利用单粒子密度矩阵，我们解析了初始费米海之上的激发，并通过平均激发数及其涨落来量化其质量。我们发现，干净的类里维顿态仅出现在一个中间区域：脉冲足够慢以至于能被晶格上的动力学分辨，但又不能太慢以至于截断和有限尺寸效应在时域中扭曲洛伦兹轮廓。洛伦兹脉冲（即使被截断）在随系统尺寸增大而接近低噪声极限方面，系统性地优于非洛伦兹脉冲形状。我们进一步识别了与能带填充、脉冲幅度、线性电压降几何形状以及偏离连续整数电荷条件的残余偏差相关的有限晶格特征。这些结果为理解超越理想连续极限的里维顿形成以及评估基于晶格的相干少电子输运平台建立了微观框架。
英文摘要：
Levitons are minimal-excitation electronic wave packets generated by Lorentzian voltage pulses and constitute a central resource for electron quantum optics. Their creation and defining properties are usually formulated in continuum scattering descriptions, whereas many candidate platforms for integrated electronic quantum circuits are finite, discrete, and strongly shaped by lattice dispersion. We study leviton generation in finite one-dimensional tight-binding chains of non-interacting fermions driven by time-dependent voltage pulses. Using the single-particle density matrix, we resolve the excitation above the initial Fermi sea and quantify its quality through the average excitation number and its fluctuations. We find that clean leviton-like states emerge only in an intermediate regime where the pulse is slow enough to be resolved by the dynamics on the lattice, but not so slow that truncation and finite-size effects distort the Lorentzian profile in the time domain. Lorentzian pulses (even if truncated) systematically outperform non-Lorentzian pulse shapes in approaching the low-noise limit with increasing system size. We further identify finite-lattice signatures associated with band filling, pulse amplitude, linear voltage-drop geometry, and residual deviations from the continuum integer-charge condition. These results establish a microscopic framework for understanding leviton formation beyond the ideal continuum limit and for evaluating lattice-based platforms for coherent few-electron transport.
