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arXiv 2208.03053quant-phcond-mat.mes-hall
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揭示玻色子量子杂质的有限频率响应

Revealing the finite-frequency response of a bosonic quantum impurity

Sébastien Léger, Théo Sépulcre, Dorian Fraudet, Olivier Buisson, Cécile Naud, Wiebke Hasch-Guichard, Serge Florens, Izak Snyman, Denis M. Basko, Nicolas Roch

AI总结:

研究利用cQED工具构建边界sine-Gordon模型量子模拟器,首次完整绘制玻色子量子杂质的有限频率线性响应,揭示了边界非线性重整化与多体展宽,并推动多体量子电路进入需更先进理论建模的区间。

摘要:

量子杂质在凝聚态物理中无处不在,构成了多体问题最精简的实现。尽管测量其有限频率响应可以获取激发光谱或动力学特性等关键特征,但尽管对纳米电子量子点进行了二十多年的研究,这一目标仍然难以实现。必须同时满足极强耦合和极大测量带宽这两个相互冲突的实验约束条件。我们利用 cQED 工具绕过了这一问题,构建了一个经过精确表征的边界 sine-Gordon 模型量子模拟器,这是一个非平庸的玻色子杂质问题。我们成功完整绘制了该系统的有限频率线性响应图。其反应部分证明了边界处非线性存在强烈的重整化,与非微扰计算相符。其耗散部分揭示了多光子转换引起的剧烈多体展宽。实验结果与基于微观校准模型的重求和图解计算定量吻合。此外,我们将器件推入图解计算失效的区间,这需要更先进的理论工具来对多体量子电路进行建模。我们还批判性地考察了 cQED 平台在实现普适标度定律方面的技术局限性。这项工作为未来开启了令人兴奋的视角,例如量化量子临界点附近的量子纠缠,或获取非平庸多体问题的动力学特性。

英文摘要:

Quantum impurities are ubiquitous in condensed matter physics and constitute the most stripped-down realization of many-body problems. While measuring their finite-frequency response could give access to key characteristics such as excitations spectra or dynamical properties, this goal has remained elusive despite over two decades of studies in nanoelectronic quantum dots. Conflicting experimental constraints of very strong coupling and large measurement bandwidths must be met simultaneously. We get around this problem using cQED tools, and build a precisely characterized quantum simulator of the boundary sine-Gordon model, a non-trivial bosonic impurity problem. We succeeded to fully map out the finite frequency linear response of this system. Its reactive part evidences a strong renormalisation of the nonlinearity at the boundary in agreement with non-perturbative calculations. Its dissipative part reveals a dramatic many-body broadening caused by multi-photon conversion. The experimental results are matched quantitatively to a resummed diagrammatic calculation based on a microscopically calibrated model. Furthermore, we push the device into a regime where diagrammatic calculations break down, which calls for more advanced theoretical tools to model many-body quantum circuits. We also critically examine the technological limitations of cQED platforms to reach universal scaling laws. This work opens exciting perspectives for the future such as quantifying quantum entanglement in the vicinity of a quantum critical point or accessing the dynamical properties of non-trivial many-body problems.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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