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| Main Authors: | , , , |
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| Format: | Preprint |
| Published: |
2025
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2504.18281 |
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| _version_ | 1866915585781137408 |
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| author | Rodríguez, Mauricio J. Rodríguez-Mena, Esteban A. Kalo, Ahmad Fouad Niquet, Yann-Michel |
| author_facet | Rodríguez, Mauricio J. Rodríguez-Mena, Esteban A. Kalo, Ahmad Fouad Niquet, Yann-Michel |
| contents | We discuss the microscopic modeling of exchange interactions between double semiconductor quantum dots used as spin qubits. Starting from a reference full configuration interaction (CI) calculation for the two-particle wave functions, we build a reduced basis set of dressed states that can describe the ground-state singlets and triplets over the whole operational range with as few as one hundred basis functions (as compared to a few thousands for the full CI). This enables fast explorations of the exchange interactions landscape as well as efficient time-dependent simulations. We apply this methodology to a double hole quantum dot in germanium, and discuss the physics of exchange interactions in this system. We show that the net exchange splitting results from a complex interplay between inter-dot tunneling, Coulomb exchange and correlations. We analyze, moreover, the effects of confinement, strains and Rashba interactions on the anisotropic exchange and singlet-triplet mixings at finite magnetic field. We finally illustrate the relevance of this methodology for time-dependent calculations on a singlet-triplet qubit. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2504_18281 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Dressed basis sets for the modeling of exchange interactions in double quantum dots Rodríguez, Mauricio J. Rodríguez-Mena, Esteban A. Kalo, Ahmad Fouad Niquet, Yann-Michel Mesoscale and Nanoscale Physics We discuss the microscopic modeling of exchange interactions between double semiconductor quantum dots used as spin qubits. Starting from a reference full configuration interaction (CI) calculation for the two-particle wave functions, we build a reduced basis set of dressed states that can describe the ground-state singlets and triplets over the whole operational range with as few as one hundred basis functions (as compared to a few thousands for the full CI). This enables fast explorations of the exchange interactions landscape as well as efficient time-dependent simulations. We apply this methodology to a double hole quantum dot in germanium, and discuss the physics of exchange interactions in this system. We show that the net exchange splitting results from a complex interplay between inter-dot tunneling, Coulomb exchange and correlations. We analyze, moreover, the effects of confinement, strains and Rashba interactions on the anisotropic exchange and singlet-triplet mixings at finite magnetic field. We finally illustrate the relevance of this methodology for time-dependent calculations on a singlet-triplet qubit. |
| title | Dressed basis sets for the modeling of exchange interactions in double quantum dots |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2504.18281 |