Enregistré dans:
| Auteur principal: | |
|---|---|
| Format: | Preprint |
| Publié: |
2025
|
| Sujets: | |
| Accès en ligne: | https://arxiv.org/abs/2503.01797 |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866908572478078976 |
|---|---|
| author | Woods, Benjamin D. |
| author_facet | Woods, Benjamin D. |
| contents | The exchange interaction $J$ offers a powerful tool for quantum computation based on semiconductor spin qubits. However, the exchange interaction in two-electron systems in the absence of a magnetic field is usually constrained to be non-negative $J \geq 0$, which inhibits the construction of various dynamically corrected exchange-based gates. In this work, we show that negative exchange $J < 0$ can be realized in two-electron Si quantum dot arrays in the absence of a magnetic field due to the presence of the valley degree of freedom. Here, valley phase differences between dots produce a non-trivial $\mathbb{Z}_2$ gauge field in the low-energy effective theory, which in turn can lead to a negative exchange interaction. In addition, we show that this $\mathbb{Z}_2$ gauge field can break Nagaoka ferromagnetism and be engineered by altering the occupancy of the dot array. Therefore, our work uncovers new tools for exchange-based quantum computing and a novel setting for studying quantum magnetism. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_01797 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Negative exchange interaction in Si quantum dot arrays via valley-phase induced $\mathbb{Z}_2$ gauge field Woods, Benjamin D. Mesoscale and Nanoscale Physics Quantum Physics The exchange interaction $J$ offers a powerful tool for quantum computation based on semiconductor spin qubits. However, the exchange interaction in two-electron systems in the absence of a magnetic field is usually constrained to be non-negative $J \geq 0$, which inhibits the construction of various dynamically corrected exchange-based gates. In this work, we show that negative exchange $J < 0$ can be realized in two-electron Si quantum dot arrays in the absence of a magnetic field due to the presence of the valley degree of freedom. Here, valley phase differences between dots produce a non-trivial $\mathbb{Z}_2$ gauge field in the low-energy effective theory, which in turn can lead to a negative exchange interaction. In addition, we show that this $\mathbb{Z}_2$ gauge field can break Nagaoka ferromagnetism and be engineered by altering the occupancy of the dot array. Therefore, our work uncovers new tools for exchange-based quantum computing and a novel setting for studying quantum magnetism. |
| title | Negative exchange interaction in Si quantum dot arrays via valley-phase induced $\mathbb{Z}_2$ gauge field |
| topic | Mesoscale and Nanoscale Physics Quantum Physics |
| url | https://arxiv.org/abs/2503.01797 |