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Paper 1
Layered Decoding of Quantum LDPC Codes
Julien Du Crest, Francisco Garcia-Herrero, Mehdi Mhalla, Valentin Savin, Javier Valls
- Year
- 2023
- Journal
- arXiv preprint
- DOI
- arXiv:2308.13377
- arXiv
- 2308.13377
We address the problem of performing message-passing-based decoding of quantum LDPC codes under hardware latency limitations. We propose a novel way to do layered decoding that suits quantum constraints and outperforms flooded scheduling, the usual scheduling on parallel architectures. A generic construction is given to construct layers of hypergraph product codes. In the process, we introduce two new notions, t-covering layers which is a generalization of the usual layer decomposition, and a new scheduling called random order scheduling. Numerical simulations show that the random ordering is of independent interest as it helps relieve the high error floor typical of message-passing decoders on quantum codes for both layered and serial decoding without the need for post-processing.
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Spatial inversion symmetry breaking of vortex current in biased-ladder superfluid
Weijie Huang, Yao Yao
- Year
- 2023
- Journal
- arXiv preprint
- DOI
- arXiv:2307.15889
- arXiv
- 2307.15889
We investigate the quench dynamics of interacting bosons on a two-leg ladder in presence of a uniform Abelian gauge field. The model hosts a variety of emergent quantum phases, and we focus on the superfluid biased-ladder phase breaking the $Z_{2}$ symmetry of two legs. We observe an asymmetric spreading of vortex current and particle density, i.e., the current behaves particle-like on the right and wave-like on the left, indicating spontaneous breaking of the spatial inversion symmetry. By decreasing the repulsion strength, it is found the particle-like current is more robust than the wave-like one. The evolution of entanglement entropy manifests logarithmic growth with time suggesting many-body localization matters.
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