Quantum 9, 1940 (2025). https://doi.org/10.22331/q-2025-12-11-1940 (i) We point out that every local unitary circuit of depth smaller than the linear system size is easily distinguished from a global Haar random unitary if there is a […]
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Quantum 9, 1939 (2025). https://doi.org/10.22331/q-2025-12-11-1939 We propose a Bell test experiment using momentum-entangled atom pairs of different masses, specifically metastable helium isotopes ${}^{3}He^{*}$ and ${}^{4}He^{*}$, though the method extends to other atom species. Entanglement is […]
Quantum 9, 1938 (2025). https://doi.org/10.22331/q-2025-12-11-1938 The detection and quantification of non-Markovianity, a.k.a. memory, in quantum systems is a central problem in the theory of open quantum systems. There memory is as a result of the […]
Quantum 9, 1937 (2025). https://doi.org/10.22331/q-2025-12-11-1937 We present a finite-size security proof of the decoy-state BB84 QKD protocol against coherent attacks, using entropic uncertainty relations, for imperfect detectors. We apply this result to the case of […]
Quantum 9, 1936 (2025). https://doi.org/10.22331/q-2025-12-11-1936 Recently, usage of detecting regions facilitated the discovery of new circuits for fault-tolerantly implementing the surface code. Building on these ideas, we present LUCI, a framework for constructing fault-tolerant circuits […]
Quantum 9, 1935 (2025). https://doi.org/10.22331/q-2025-12-10-1935 Quantum groups have been widely explored as a tool to encode possible nontrivial generalisations of reference frame transformations, relevant in quantum gravity. In quantum information, it was found that the […]
Quantum 9, 1934 (2025). https://doi.org/10.22331/q-2025-12-10-1934 Conditional displacement with a qubit ancilla is a critical component in continuous-variable error correction protocols. We present the generalized conditional displacement operator, conditioned on a qudit ancilla, and explore potential […]
Quantum 9, 1933 (2025). https://doi.org/10.22331/q-2025-12-10-1933 We analyze the existence and degeneracies of quantum exceptional, diabolical, and hybrid points in simple bosonic systems – comprising up to six modes with damping and/or amplification – under two […]
Quantum 9, 1932 (2025). https://doi.org/10.22331/q-2025-12-10-1932 The existence and degeneracies of quantum exceptional, diabolical, and hybrid (i.e., diabolically degenerated exceptional) singularities of simple bosonic systems composed of up to five modes with damping and/or amplification are […]
Quantum 9, 1931 (2025). https://doi.org/10.22331/q-2025-12-05-1931 To achieve quantum fault tolerance with lower overhead, quantum low-density parity-check (QLDPC) codes have emerged as a promising alternative to topological codes such as the surface code, offering higher code […]
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