01652nas a2200157   4500000000100000008004100001260001500042100002600057700001900083700002200102700002200124245007000146856003700216300000700253520123400260       2026                            d  c05/29/20261 aLudmiła Marcinkowska1 aŁukasz Pawela1 aMarcin Markiewicz1 aZbigniew Puchała00aAsymptotic distinguishability of Haar-averaged measurement models  uhttps://arxiv.org/abs/2605.31168  a493 aWe study discrimination problems generated by the same basic Haar-random measurement mechanism at two observational levels. First, we derive an explicit expression for the type-II error in the task of discriminating a Haar-random measure-and-prepare channel from the identity channel I, using a coherence-sensitive entangled tester. Second, after passing to the induced classical measurement records, we compare two random measurement models: one induced by a single collective unitary of the form U^⊗(n₁+n₂) with U ∈ U(d), and another induced by independent local unitaries U₁^⊗n₁ ⊗ U₂^⊗n₂. For the associated Haar-averaged aggregate histogram laws, in which the block of origin of each count is not retained, we obtain closed-form formulas and quantify their discrepancy through the total variation distance. We derive asymptotic expressions in the fixed-N, large-d regime, the fixed-d, large-N regime, the sparse joint-scaling regime N = o(√d), and the critical scaling regime N/√d → c. We also identify the block-resolved pair-of-histograms law, showing that the aggregate total variation distance is a coarse-grained lower bound on the distinguishability available when block labels are retained.01819nas a2200157   4500000000100000008004100001260001500042100002200057700001900079700002200098245009800120856003700218300000700255520135800262022004101620       2026                            d  c25/02/20261 aMarcin Markiewicz1 aŁukasz Pawela1 aZbigniew Puchała00aChoi-level twirling of quantum channels: finite constructions and non-compact transformations  uhttps://arxiv.org/abs/2512.23586  a153 aTwirling, i.e. averaging over symmetry actions, is a standard tool for reducing quantum states and channels to a symmetry-invariant form. We study channel twirling from the perspective of the channel–state duality and provide a constructive Choi-level description of the averaging map induced by arbitrary input/output representations. Our main technical result concerns the collective setting: for π in(U) = U ⊗tin and π out(U) = U ⊗tout , we introduce a partial-transpose reduction that removes the contragredient action and converts the mixed (walled Brauer) channel twirl into an ordinary Schur–Weyl twirl of the partially transposed Choi operator under U ⊗(tin+tout) , enabling explicit permutation-based formulas without constructing walled Brauer idempotents or mixed Schur transforms. Beyond compact symmetries, we extend channel twirling to reductive, generally non-unitary groups via Cartan decomposition and obtain an invariant-sector decomposition of the averaged Choi operator with weights determined solely by the Abelian Cartan component. Finally, we provide two finite realizations of channel averaging: a “dual” implementation as a convex mixture of unitary-1-design channels acting on invariant sectors, and a design-like reconstruction showing that weighted group t-designs induce channel t-designs for t = tin + tout.  a1751-8121 (online), 1751-8113 (druk)00672nas a2200133   4500000000100000008004100001100002200042700001900064700002200083245007100105856005500176520029300231022001400524       2026                            d1 aMarcin Markiewicz1 aŁukasz Pawela1 aZbigniew Puchała00aSingle-shot comparison of random quantum channels and measurements  uhttps://www.nature.com/articles/s41598-026-70695-z3 aIn this work we provide an efficiency analysis of the problem of discrimination of two randomly chosen unknown quantum operations in the single-shot regime. We provide tight bounds for the success probability of such a protocol for arbitrary quantum channels and generalized measurements.  a2045-232200269nas a2200109   4500000000100000008004100001260001200042100002000054700002200074245005600096490000700152       2025                            d  c11/20251 aPaweł Błasiak1 aMarcin Markiewicz00aIdentical particles as a genuine non-local resource0 v1101272nas a2200133   4500000000100000008004100001260001200042100001700054700002200071700002000093245007800113490000700191520094000198       2025                            d  c03/20251 aJay Lawrence1 aMarcin Markiewicz1 aMarek Żukowski00aRelational quantum mechanics is still incompatible with quantum mechanics0 v153 aWe showed in a recent article (Lawrence et al. 2023. Quantum, 7, 1015), that relative facts (outcomes), a central concept in Relational Quantum Mechanics, are inconsistent with Quantum Mechanics. We proved this by constructing a Wigner-Friend type sequential measurement scenario on a Greenberger-Horne-Zeilinger (GHZ) state of three qubits, and making the following assumption: “if an interpretation of quantum theory introduces some conceptualization of outcomes of a measurement, then probabilities of these outcomes must follow the quantum predictions as given by the Born rule.” Our work has been criticized by Cavalcanti et al. (2023. European Journal for Philosophy of Science, 13(4),55). In this note we show that their critique, based on their own reformulation of our argument, does not apply to our paper. It also raises questions of principle which are not answered within the framework of Relational Quantum Mechanics.00319nas a2200121   4500000000100000008004100001260001200042100001700054700002200071700002000093245007700113490000700190       2024                            d  c07/20241 aJay Lawrence1 aMarcin Markiewicz1 aMarek Żukowski00aComment on Aurélien Drezet’s Defense of Relational Quantum Mechanics.0 v5401232nas a2200181   4500000000100000008004100001100002200042700002400064700002200088700001900110700001700129700002200146245009300168856004700261300001100308490000700319520072400326       2018                            d1 aMarcin Markiewicz1 aAdrian Kolodziejski1 aZbigniew Puchała1 aAdam Rutkowski1 aTomasz Tylec1 aWieslaw Laskowski00aUnified approach to geometric and positive-map-based non-linear entanglement identifiers  uhttps://doi.org/10.1103/PhysRevA.97.042339  a0423390 v973 aDetecting quantumness of correlations (especially entanglement) is a very hard task even in the simplest case, i.e., two-partite quantum systems. Here we provide an analysis of whether there exists a relation between two of the most popular types of entanglement identifiers: the first one based on positive maps and not directly applicable in the laboratory and the second one a geometric entanglement identifier which is based on specific Hermiticity-preserving maps. We show a profound relation between those two types of entanglement criteria. Hereunder we have proposed a general framework of nonlinear functional entanglement identifiers which allows us to construct experimentally friendly entanglement criteria.01143nas a2200157   4500000000100000008004100001100002200042700002200064700001900086700002300105700002200128245005700150856004700207490000700254520072400261       2017                            d1 aMarcin Markiewicz1 aZbigniew Puchała1 aAnna de Rosier1 aWiesław Laskowski1 aKarol Życzkowski00aQuantum noise generated by local random Hamiltonians  uhttps://doi.org/10.1103/PhysRevA.95.0323330 v953 aWe investigate the impact of a local random unitary noise on multipartite quantum states of arbitrary dimension. We follow the dynamical approach, in which the single-particle unitaries are generated by local random Hamiltonians. Assuming short evolution time we derive an upper bound on the fidelity between an initial and the final state transformed by this type of noise. This result is based on averaging the Tamm-Mandelstam bound and holds for a wide class of distributions of random Hamiltonians fulfilling specific symmetry conditions. It is showed that the sensitivity of a given pure quantum state to the discussed type of noise depends only on the properties of a single-particle and bipartite reduced states.00286nas a2200097   4500000000100000008004100001260001200042100002000054700002200074245009200096                                       d  c09/20241 aMarek Żukowski1 aMarcin Markiewicz00aAgainst (unitary) interpretation (of quantum mechanics): removing the metaphysical load00899nas a2200097   4500000000100000008004100001100002200042700002400064245005500088520065800143                                       d1 aMarcin Markiewicz1 aKonrad Schlichtholz00aUnitary operator bases as universal averaging sets3 aWe provide a generalization of the idea of unitary designs to cover finite averaging over much more general operations on quantum states. Namely, we construct finite averaging sets for averaging quantum states over arbitrary reductive Lie groups, on condition that the averaging is performed uniformly over the compact component of the group. Our construction comprises probabilistic mixtures of unitary 1-designs on specific operator subspaces. Provided construction is very general, competitive in the size of the averaging set when compared to other known constructions, and can be efficiently implemented in the quantum circuit model of computation.