Quantum

Paper

Hexagons govern three-qubit contextuality

Metod Saniga, Frédéric Holweck, Colm Kelleher, Axel Muller, Alain Giorgetti, and Henri de Boutray,

Quantum 9, 1601 (2025).

Split Cayley hexagons of order two are distinguished finite geometries living in the three-qubit symplectic polar space in two different forms, called classical and skew. Although neither of…

Paper

Sparse Blossom: correcting a million errors per core second with minimum-weight matching

Oscar Higgott and Craig Gidney,

Quantum 9, 1600 (2025).

In this work, we introduce a fast implementation of the minimum-weight perfect matching (MWPM) decoder, the most widely used decoder for several important families of quantum error correctin…

Paper

Bipartite polygon models: entanglement classes and their nonlocal behaviour

Mayalakshmi Kolangatt, Thigazholi Muruganandan, Sahil Gopalkrishna Naik, Tamal Guha, Manik Banik, and Sutapa Saha,

Quantum 9, 1599 (2025).

Hardy's argument constitutes an elegantly logical test for identifying nonlocal features of multipartite correlations. In this paper, we investigate Hardy's nonlocal behavior within a broad…

Paper

Can QBism exist without Q? Morphophoric measurements in generalised probabilistic theories

Anna Szymusiak and Wojciech Słomczyński,

Quantum 9, 1598 (2025).

In a Generalised Probabilistic Theory (GPT) equipped additionally with some extra geometric structure we define the morphophoric measurements as those for which the measurement map sending s…

Paper

Efficient Learning of Long-Range and Equivariant Quantum Systems

Štěpán Šmíd and Roberto Bondesan,

Quantum 9, 1597 (2025).

In this work, we consider a fundamental task in quantum many-body physics – finding and learning ground states of quantum Hamiltonians and their properties. Recent works have studied the tas…

Paper

Private and Robust States for Distributed Quantum Sensing

Luís Bugalho, Majid Hassani, Yasser Omar, and Damian Markham,

Quantum 9, 1596 (2025).

Distributed quantum sensing enables the estimation of multiple parameters encoded in spatially separated probes. While traditional quantum sensing is often focused on estimating a single par…

Paper

Efficient discrimination between real and complex quantum theories

Josep Batle, Tomasz Białecki, Tomasz Rybotycki, Jakub Tworzydło, and Adam Bednorz,

Quantum 9, 1595 (2025).

We improve the test to show the impossibility of a quantum theory based on real numbers by a larger ratio of complex-to-real bound on a Bell-type parameter. In contrast to previous theoretic…

Paper

Recursive Quantum Relaxation for Combinatorial Optimization Problems

Ruho Kondo, Yuki Sato, Rudy Raymond, and Naoki Yamamoto,

Quantum 9, 1594 (2025).

Quantum optimization methods use a continuous degree-of-freedom of quantum states to heuristically solve combinatorial problems, such as the MAX-CUT problem, which can be attributed to vario…

Paper

Lower bounds for quantum-inspired classical algorithms via communication complexity

Nikhil S. Mande and Changpeng Shao,

Quantum 9, 1593 (2025).

Quantum-inspired classical algorithms provide us with a new way to understand the computational power of quantum computers for practically-relevant problems, especially in machine learning.…

Paper

Response to “The measurement postulates of quantum mechanics are not redundant”

Lluís Masanes, Thomas D. Galley, and Markus P. Müller,

Quantum 9, 1592 (2025).

Adrian Kent has recently presented a critique [1] of our paper [2] in which he claims to refute our main result: the measurement postulates of quantum mechanics can be derived from the rest…

Paper

A hierarchy of semidefinite programs for generalised Einstein-Podolsky-Rosen scenarios

Matty J. Hoban, Tom Drescher, and Ana Belén Sainz,

Quantum 9, 1591 (2025).

Correlations in Einstein-Podolsky-Rosen (EPR) scenarios, captured by $assemblages$ of unnormalised quantum states, have recently caught the attention of the community, both from a foundational…

Paper

Unlocking Heisenberg Sensitivity with Sequential Weak Measurement Preparation

T. B. Lantaño, Dayou Yang, K. M. R. Audenaert, S. F. Huelga, and M. B. Plenio,

Quantum 9, 1590 (2025).

We propose a state preparation protocol based on sequential measurements of a central spin coupled with a spin ensemble, and investigate the usefulness of the generated multi-spin states for…

Paper

A graph-state based synthesis framework for Clifford isometries

Timothée Goubault de Brugière, Simon Martiel, and Christophe Vuillot,

Quantum 9, 1589 (2025).

We tackle the problem of Clifford isometry compilation, i.e, how to synthesize a Clifford isometry into an executable quantum circuit. We propose a simple framework for synthesis that only e…

Paper

Des-q: a quantum algorithm to provably speedup retraining of decision trees

Niraj Kumar, Romina Yalovetzky, Changhao Li, Pierre Minssen, and Marco Pistoia,

Quantum 9, 1588 (2025).

Decision trees are widely adopted machine learning models due to their simplicity and explainability. However, as training data size grows, standard methods become increasingly slow, scaling…

Paper

Out-of-time-ordered correlators of mean-field bosons via Bogoliubov theory

Marius Lemm and Simone Rademacher,

Quantum 9, 1587 (2025).

Quantum many-body chaos concerns the scrambling of quantum information among large numbers of degrees of freedom. It rests on the prediction that out-of-time-ordered correlators (OTOCs) of t…

Paper

Fast algorithms for classical specifications of stabiliser states and Clifford gates

Nadish de Silva, Wilfred Salmon, and Ming Yin,

Quantum 9, 1586 (2025).

The stabiliser formalism plays a central role in quantum computing, error correction, and fault tolerance. Conversions between and verifications of different specifications of stabiliser sta…

Category: Paper