Quantum 6, 670 (2022). https://doi.org/10.22331/q-2022-03-17-670 We propose to perform amplitude estimation with the help of constant-depth quantum circuits that variationally approximate states during amplitude amplification. In the context of Monte Carlo (MC) integration, we numerically […]
Quantum 6, 669 (2022). https://doi.org/10.22331/q-2022-03-17-669 We propose a quantum repeater architecture that can operate under ambient conditions. Our proposal builds on recent progress towards non-cryogenic spin-photon interfaces based on nitrogen-vacancy centers, which have excellent spin […]
Quantum 6, 668 (2022). https://doi.org/10.22331/q-2022-03-17-668 Valiant-Vazirani showed in 1985 [45] that solving NP with the promise that “yes” instances have only one witness is powerful enough to solve the entire NP class (under randomized reductions). […]
Quantum 6, 667 (2022). https://doi.org/10.22331/q-2022-03-11-667 Quantum error correcting codes (QECCs) are the means of choice whenever quantum systems suffer errors, e.g., due to imperfect devices, environments, or faulty channels. By now, a plethora of families […]
Quantum 6, 666 (2022). https://doi.org/10.22331/q-2022-03-11-666 In this paper we describe an algebraic/geometrical approach to quantum scrambling. Generalized quantum subsystems are described by an hermitian-closed unital subalgebra $cal A$ of operators evolving through a unitary channel. […]
Quantum 6, 665 (2022). https://doi.org/10.22331/q-2022-03-10-665 Multiparameter quantum estimation is made difficult by the following three obstacles. First, incompatibility among different physical quantities poses a limit on the attainable precision. Second, the ultimate precision is not […]
Quantum 6, 664 (2022). https://doi.org/10.22331/q-2022-03-03-664 This article proposes the first discrete-time implementation of Rydberg quantum walk in multi-dimensional spatial space that could ideally simulate different classes of topological insulators. Using distance-selective exchange-interaction between Rydberg excited […]
Quantum 6, 663 (2022). https://doi.org/10.22331/q-2022-03-01-663 The causal order of events need not be fixed: whether a bus arrives before or after another at a certain stop can depend on other variables – like traffic. Coherent […]
Quantum 6, 662 (2022). https://doi.org/10.22331/q-2022-03-01-662 For a classical channel, neither the Shannon ca-pa-city, nor the sum of conditional probabilities corresponding to the cases of successful transmission can be increased by the use of shared entanglement, […]
Quantum 6, 661 (2022). https://doi.org/10.22331/q-2022-02-24-661 We introduce the hemicubic codes, a family of quantum codes obtained by associating qubits with the $p$-faces of the $n$-cube (for $n>p$) and stabilizer constraints with faces of dimension $(ppm1)$. […]
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