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Paper 1

Iteratively decoded magic state distillation

Kwok Ho Wan

Year
2024
Journal
arXiv preprint
DOI
arXiv:2410.17992
arXiv
2410.17992

We present numerical simulation results for the 7-to-1 and 15-to-1 state distillation circuits, constructed using transversal CNOTs acting on multiple surface code patches. The distillation circuits are decoded iteratively using the method outlined in [arXiv:2407.20976]. We show that, with a re-configurable qubit architecture, we can perform fast magic state distillation in $\sim\mathcal{O}(1)$ code cycles. We confirm that both circuits suppress an injected input error rate $p$ to $\mathcal{O}(p^3)$ in the presence of additional circuit-level noise. We also outline how ZX-calculus and Pauli webs can be used to benchmark stabiliser proxies for these distillation circuits.

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Paper 2

Quantum Simulation of Nonlinear Dynamical Systems Using Repeated Measurement

Joseph Andress, Alexander Engel, Yuan Shi, Scott Parker

Year
2024
Journal
arXiv preprint
DOI
arXiv:2410.03838
arXiv
2410.03838

We present a quantum algorithm based on repeated measurement to solve initial-value problems for nonlinear ordinary differential equations (ODEs), which may be generated from partial differential equations in plasma physics. We map a dynamical system to a Hamiltonian form, where the Hamiltonian matrix is a function of dynamical variables. To advance in time, we measure expectation values from the previous time step, and evaluate the Hamiltonian function classically, which introduces stochasticity into the dynamics. We then perform standard quantum Hamiltonian simulation over a short time, using the evaluated constant Hamiltonian matrix. This approach requires evolving an ensemble of quantum states, which are consumed each step to measure required observables. We apply this approach to the classic logistic and Lorenz systems, in both integrable and chaotic regimes. Out analysis shows that solutions' accuracy is influenced by both the stochastic sampling rate and the nature of the dynamical system.

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