Superconducting Spin-Singlet QuBit in a Triangulene Spin Chain
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arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866914315080040448 |
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| author | Huang, Chen-How Ortuzar, Jon Cazalilla, M. A. |
| author_facet | Huang, Chen-How Ortuzar, Jon Cazalilla, M. A. |
| contents | Chains of triangular nanographene (triangulene), recently identified as realizing the valence-bond solid phase of a spin-1 chain, offer a promising platform for quantum information processing. We propose a spin-singlet qubit based on these chains grown on a superconducting substrate. Using the numerical renormalization group (NRG), we identify a manifold consisting of the two lowest-lying, spin-singlet states isolated from doublet states of opposite fermion parity, which undergo an avoided crossing. A qubit utilizing these states is thus protected from random Zeeman and/or spin-orbit coupling. Despite the unavoidable effect of quasiparticle poisoning on qubit performance, the isolation of the singlet states offers additional protection. In addition, we introduce a mesoscopic device architecture, based on a triple quantum dot coupled to a superconducting junction, that quantum simulates the spin chain and enables control and readout of the qubit. An effective two-level description of the device is validated using time-dependent NRG. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2503_23928 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Superconducting Spin-Singlet QuBit in a Triangulene Spin Chain Huang, Chen-How Ortuzar, Jon Cazalilla, M. A. Mesoscale and Nanoscale Physics Superconductivity Chains of triangular nanographene (triangulene), recently identified as realizing the valence-bond solid phase of a spin-1 chain, offer a promising platform for quantum information processing. We propose a spin-singlet qubit based on these chains grown on a superconducting substrate. Using the numerical renormalization group (NRG), we identify a manifold consisting of the two lowest-lying, spin-singlet states isolated from doublet states of opposite fermion parity, which undergo an avoided crossing. A qubit utilizing these states is thus protected from random Zeeman and/or spin-orbit coupling. Despite the unavoidable effect of quasiparticle poisoning on qubit performance, the isolation of the singlet states offers additional protection. In addition, we introduce a mesoscopic device architecture, based on a triple quantum dot coupled to a superconducting junction, that quantum simulates the spin chain and enables control and readout of the qubit. An effective two-level description of the device is validated using time-dependent NRG. |
| title | Superconducting Spin-Singlet QuBit in a Triangulene Spin Chain |
| topic | Mesoscale and Nanoscale Physics Superconductivity |
| url | https://arxiv.org/abs/2503.23928 |