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Replication of quantum factorisation records with an 8-bit home computer, an abacus, and a dog.
https://eprint.iacr.org/2025/1237
saved 2025-07-18

Replication of Quantum Factorisation Records with an 8-bit Home Computer, an Abacus, and a Dog
This paper presents implementations that match and, where possible, exceed current quantum factorisation records using a VIC-20 8-bit home computer from 1981, an abacus, and a dog. We hope that this work will inspire future efforts to match any further quantum factorisation records, should they arise.

On the convergence of the variational quantum eigensolver and quantum optimal control
Marco Wiedmann, Daniel Burgarth, Gunther Dirr, Thomas Schulte-Herbr\"uggen, Emanuel Malvetti, Christian Arenz
https://arxiv.org/abs/2509.05295

On the convergence of the variational quantum eigensolver and quantum optimal control
When does a variational quantum algorithm converge to a globally optimal problem solution? Despite the large literature around variational approaches to quantum computing, the answer is largely unknown. We address this open question by developing a convergence theory for the variational quantum eigensolver (VQE). By leveraging the terminology of quantum control landscapes, we prove a sufficient criterion that characterizes when convergence to a ground state of a Hamiltonian can be guaranteed fo…

On the Classical Hardness of the Semidirect Discrete Logarithm Problem in Finite Groups
Mohammad Ferry Husnil Arif, Muhammad Imran
https://arxiv.org/abs/2508.05048 https://

On the Classical Hardness of the Semidirect Discrete Logarithm Problem in Finite Groups
The semidirect discrete logarithm problem (SDLP) in finite groups was proposed as a foundation for post-quantum cryptographic protocols, based on the belief that its non-abelian structure would resist quantum attacks. However, recent results have shown that SDLP in finite groups admits efficient quantum algorithms, undermining its quantum resistance. This raises a fundamental question: does the SDLP offer any computational advantages over the standard discrete logarithm problem (DLP) against cl…

Pathfinding Quantum Simulations of Neutrinoless Double-$\beta$ Decay
Ivan A. Chernyshev, Roland C. Farrell, Marc Illa, Martin J. Savage, Andrii Maksymov, Felix Tripier, Miguel Angel Lopez-Ruiz, Andrew Arrasmith, Yvette de Sereville, Aharon Brodutch, Claudio Girotto, Ananth Kaushik, Martin Roetteler
https://arxiv.org/abs/2506.057…

Pathfinding Quantum Simulations of Neutrinoless Double-$β$ Decay
We present results from co-designed quantum simulations of the neutrinoless double-$β$ decay of a simple nucleus in 1+1D quantum chromodynamics using IonQ's Forte-generation trapped-ion quantum computers. Electrons, neutrinos, and up and down quarks are distributed across two lattice sites and mapped to 32 qubits, with an additional 4 qubits used for flag-based error mitigation. A four-fermion interaction is used to implement weak interactions, and lepton-number violation is induced by a neutr…

Scalable parallel simulation of quantum circuits on CPU and GPU systems
Guolong Zhong, Yi Fan, Zhenyu Li
https://arxiv.org/abs/2509.04955 https://arxiv.org…

Scalable parallel simulation of quantum circuits on CPU and GPU systems
Quantum computing enables parallelism through superposition and entanglement and offers advantages over classical computing architectures. However, due to the limitations of current quantum hardware in the noisy intermediate-scale quantum (NISQ) era, classical simulation remains a critical tool for developing quantum algorithms. In this research, we present a comprehensive parallelization solution for the Q$^2$Chemistry software package, delivering significant performance improvements for the f…

Current comparator for both AC and DC ratio measurements with 10-8-level accuracy
Hidekazu Muramatsu, Yuta Kainuma, Hiromitsu Kato, Norihiko Sakamoto, Tatsuji Yamada, Chiharu Urano, Hiroshi Abe, Shinobu Onoda, Takeshi Ohshima, Yuji Hatano, Mutsuko Hatano, Nobu-Hisa Kaneko, Yasutaka Amagai, Takayuki Iwasaki
https://arxiv.org/abs/2508.05140

Current comparator for both AC and DC ratio measurements with 10-8-level accuracy
Accurate measurements of alternating current (AC) and direct current(DC) ratios are fundamental to electric power metrology. However, conventional current comparators for AC and DC typically rely on distinct technologies-electromagnetic induction for AC and superconducting quantum interference devices for DC. This technological divide leads to a fragmented and complex traceability system. Bridging this gap is critical for developing unified current standards that meet the demands of emerging po…

Optically accessible high-finesse millimeter-wave resonator for cavity quantum electrodynamics with atom arrays
Tony Zhang, Michelle Wu, Sam R. Cohen, Lin Xin, Debadri Das, Kevin K. S. Multani, Nolan Peard, Anne-Marie Valente-Feliciano, Paul B. Welander, Amir H. Safavi-Naeini, Emilio A. Nanni, Monika Schleier-Smith
https://arxiv…

Optically accessible high-finesse millimeter-wave resonator for cavity quantum electrodynamics with atom arrays
Cavity quantum electrodynamics (QED) is a powerful tool in quantum science, enabling preparation of non-classical states of light and scalable entanglement of many atoms coupled to a single field mode. While the most coherent atom-photon interactions have been achieved using superconducting millimeter-wave cavities coupled to Rydberg atoms, these platforms so far lack the optical access required for trapping and addressing individual atomic qubits. We present a millimeter-wave Fabry-Pérot cavi…

Geometric Invariants of Quantum Metrology
Christopher Wilson, John Drew Wilson, Luke Coffman, Shah Saad Alam, Murray J. Holland
https://arxiv.org/abs/2507.06128

Geometric Invariants of Quantum Metrology
We establish a previously unexplored conservation law for the Quantum Fisher Information Matrix (QFIM) expressed as follows; when the QFIM is constructed from a set of observables closed under commutation, i.e., a Lie algebra, the spectrum of the QFIM is invariant under unitary dynamics generated by these same operators. Each Lie algebra therefore endows any quantum state with a fixed "budget" of metrological sensitivity -- an intrinsic resource that we show, like optical squeezing in interfero…

Challenges in Applying Variational Quantum Algorithms to Dynamic Satellite Network Routing
Phuc Hao Do, Tran Duc Le
https://arxiv.org/abs/2508.04288 https://

Challenges in Applying Variational Quantum Algorithms to Dynamic Satellite Network Routing
Applying near-term variational quantum algorithms to the problem of dynamic satellite network routing represents a promising direction for quantum computing. In this work, we provide a critical evaluation of two major approaches: static quantum optimizers such as the Variational Quantum Eigensolver (VQE) and the Quantum Approximate Optimization Algorithm (QAOA) for offline route computation, and Quantum Reinforcement Learning (QRL) methods for online decision-making. Using ideal, noise-free sim…

Beyond the Projection Postulate and Back: Quantum Theories with Generalised State-Update Rules
Vincenzo Fiorentino, Stefan Weigert
https://arxiv.org/abs/2506.06207

Beyond the Projection Postulate and Back: Quantum Theories with Generalised State-Update Rules
Are there consistent and physically reasonable alternatives to the projection postulate? Does it have unique properties compared to acceptable alternatives? We answer these questions by systematically investigating hypothetical state-update rules for quantum systems that nature could have chosen over the Lüders rule. Among other basic properties, any prospective rule must define unique post-measurement states and not allow for superluminal signalling. Particular attention will be paid to consi…