可调双位点Hubbard分子的熵谱学
Entropy spectroscopy of a tunable two-site Hubbard molecule
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中文总结 AI 辅助
本文提出双量子点熵测量协议，测量GaAs可调双位点Hubbard分子总熵，揭示隧穿与相互作用决定热激活态，与模型定量一致。
中文摘要 AI 辅助
在隧穿与相互作用相互竞争时，确定哪些微观态保持热激活是Hubbard物理中的一个核心问题。在此，我们为双量子点开发了一种熵测量协议，扩展了为单量子点建立的基于电荷的方法，并测量了在GaAs双点中实现的可调双位点Hubbard分子的总熵。通过在固定失谐下同时移动两个点能级，仅使用单个电荷传感器即可正确探测熵。随着点间隧穿增加，系统从两个类原子点经过杂化分子态演化为合并的单点。在整个演化过程中，熵减小，因为隧穿诱导的能级分裂超过热能并抑制了高能态的占据。测量解析了反键态贡献的减弱以及杂化单重态和三重态热贡献的变化，与双位点Hubbard模型定量一致。通过区分具有相同电荷构型但不同轨道和自旋内容的态，熵揭示了隧穿和相互作用如何决定最小Hubbard系统的热激活态。
英文摘要
Determining which microscopic states remain thermally active when tunneling and interactions compete is a central question in Hubbard physics. Here we develop an entropy measurement protocol for a double quantum dot, extending the charge-based approach established for a single dot, and measure the total entropy of a tunable two-site Hubbard molecule realized in a GaAs double dot. By shifting both dot levels together at fixed detuning, the entropy is correctly probed with only a single charge sensor. As interdot tunneling increases, the system evolves from two atomic-like dots through hybridized molecular states to a merged single dot. Across this evolution, the entropy decreases as tunnel-induced energy splitting exceeds the thermal energy and suppresses the occupation of higher-energy states. The measurements resolve the diminishing contribution of antibonding states and the changing thermal contributions of hybridized singlet and triplet states, in quantitative agreement with a two-site Hubbard model. By distinguishing states with the same charge configuration but different orbital and spin content, entropy reveals how tunneling and interactions determine the thermally active states of the minimal Hubbard system.
发表机构
- Jeonbuk National University（全北国立大学）
- KAIST（韩国科学技术院）
- POSTECH（浦项科技大学）
- Weizmann Institute of Science（魏茨曼科学研究所）
- Pusan National University（釜山国立大学）
机构由 AI 辅助整理，请以论文原文为准。
