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| Main Authors: | , |
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| Format: | Preprint |
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2024
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| Online Access: | https://arxiv.org/abs/2404.16594 |
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| _version_ | 1866910829519044608 |
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| author | Wu, Jun-Yi Wu, Shin-Tza |
| author_facet | Wu, Jun-Yi Wu, Shin-Tza |
| contents | We propose a linear-optical scheme that allows encoding grid-state quantum bits (qubits) into a bosonic mode using cat state and post-selection as sources of non-Gaussianity in the encoding. As a linear-optical realization of the quantum-walk encoding scheme in [Lin {\em et al.}, Quantum Info. Processing {\bf 19}, 272 (2020)], we employ the cat state as a quantum coin that enables encoding approximate Gottesman-Kitaev-Preskill (GKP) qubits through quantum walk of a squeezed vacuum state in phase space. We show that the conditional phase-space displacement necessary for the encoding can be realized through a Mach-Zehnder interferometer (MZI) assisted with ancillary cat-state input under appropriate parameter regimes. By analyzing the fidelity of the MZI-based displacement operation, we identify the region of parameter space over which the proposed linear-optical scheme can generate grid-state qubits with high fidelity. With adequate parameter setting, our proposal should be accessible to current optical and superconducting-circuit platforms in preparing grid-state qubits for bosonic modes in the, respectively, optical and microwave domains. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2404_16594 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Linear-optical approach to encoding qubits into harmonic-oscillator modes via quantum walks Wu, Jun-Yi Wu, Shin-Tza Quantum Physics We propose a linear-optical scheme that allows encoding grid-state quantum bits (qubits) into a bosonic mode using cat state and post-selection as sources of non-Gaussianity in the encoding. As a linear-optical realization of the quantum-walk encoding scheme in [Lin {\em et al.}, Quantum Info. Processing {\bf 19}, 272 (2020)], we employ the cat state as a quantum coin that enables encoding approximate Gottesman-Kitaev-Preskill (GKP) qubits through quantum walk of a squeezed vacuum state in phase space. We show that the conditional phase-space displacement necessary for the encoding can be realized through a Mach-Zehnder interferometer (MZI) assisted with ancillary cat-state input under appropriate parameter regimes. By analyzing the fidelity of the MZI-based displacement operation, we identify the region of parameter space over which the proposed linear-optical scheme can generate grid-state qubits with high fidelity. With adequate parameter setting, our proposal should be accessible to current optical and superconducting-circuit platforms in preparing grid-state qubits for bosonic modes in the, respectively, optical and microwave domains. |
| title | Linear-optical approach to encoding qubits into harmonic-oscillator modes via quantum walks |
| topic | Quantum Physics |
| url | https://arxiv.org/abs/2404.16594 |