Measurement-based quantum computation in finite one-dimensional systems: string order implies computational power
1Leibniz University Hannover, Hannover, Germany
2Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, Canada
3School of Physics, Nankai University, Tianjin, China
4Department of Physics and Astronomy, University of British Columbia, Vancouver, Canada
| Published: | 2023-12-28, volume 7, page 1215 |
| Eprint: | arXiv:2210.05089v4 |
| Doi: | https://doi.org/10.22331/q-2023-12-28-1215 |
| Citation: | Quantum 7, 1215 (2023). |
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Abstract
We present a new framework for assessing the power of measurement-based quantum computation (MBQC) on short-range entangled symmetric resource states, in spatial dimension one. It requires fewer assumptions than previously known. The formalism can handle finitely extended systems (as opposed to the thermodynamic limit), and does not require translation-invariance. Further, we strengthen the connection between MBQC computational power and string order. Namely, we establish that whenever a suitable set of string order parameters is non-zero, a corresponding set of unitary gates can be realized with fidelity arbitrarily close to unity.

Featured image: Representations of the symmetry group involved in the description of MBQC on symmetric states: linear representations (blue) and projective representations (red and green). For more information, see the caption of Fig. 6.
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