Quantum 9, 1923 (2025). https://doi.org/10.22331/q-2025-12-02-1923 Over the past decade, a number of quantum processes have been proposed which are logically consistent, yet feature a cyclic causal structure. However, there is no general formal method to […]
Quantum 9, 1922 (2025). https://doi.org/10.22331/q-2025-12-02-1922 Quantum random-access memory (QRAM) is a mechanism to access data (quantum or classical) based on addresses which are themselves a quantum state. QRAM has a long and controversial history, and […]
Quantum 9, 1921 (2025). https://doi.org/10.22331/q-2025-12-02-1921 The Pauli exclusion principle is fundamental to understanding electronic quantum systems. It namely constrains the expected occupancies $n_i$ of orbitals $varphi_i$ according to $0 leq n_i leq 2$. In this […]
Quantum 9, 1920 (2025). https://doi.org/10.22331/q-2025-11-27-1920 We propose a model for quantum computing with long chains of trapped ions and we design quantum error correction schemes for this model. The main components of a quantum error […]
Quantum 9, 1919 (2025). https://doi.org/10.22331/q-2025-11-20-1919 Sequential methods for quantum hypothesis testing offer significant advantages over fixed-length approaches, which rely on a predefined number of state copies. Despite their potential, these methods remain underexplored for unambiguous […]
Quantum 9, 1918 (2025). https://doi.org/10.22331/q-2025-11-20-1918 The spectral variant of the quantum marginal problem asks: Given prescribed spectra for a set of overlapping quantum marginals, does there exist a compatible joint state? The main idea of […]
Quantum 9, 1917 (2025). https://doi.org/10.22331/q-2025-11-20-1917 We study a qDRIFT-type randomized method to simulate Lindblad dynamics by decomposing its generator into an ensemble of Lindbladians, $mathcal{L} = sum_{a in mathcal{A}} mathcal{L}_a$, where each $mathcal{L}_a$ comprises a […]
Quantum 9, 1916 (2025). https://doi.org/10.22331/q-2025-11-20-1916 To better understand quantum computation we can search for its limits or no-gos, especially if analogous limits do not appear in classical computation. Classical computation easily implements and extensively employs […]
Quantum 9, 1915 (2025). https://doi.org/10.22331/q-2025-11-17-1915 Loop-based boson samplers interfere photons in the time degree of freedom using a sequence of delay lines. Since they require few hardware components while also allowing for long-range entanglement, they […]
Quantum 9, 1914 (2025). https://doi.org/10.22331/q-2025-11-17-1914 An important class of fermionic observables, relevant in tasks such as fermionic partial tomography and estimating energy levels of chemical Hamiltonians, are the binary measurements obtained from the product of […]
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