Quantum Mechanics and Applications

Latest papers

• Role of scrambling and noise in temporal information processing with quantum systems

  Weijie Xiong, Zo\"e Holmes, Armando Angrisani, Yudai Suzuki, Thiparat Chotibut, Supanut Thanasilp · 24 September 2026

  Scrambling quantum systems have attracted attention as effective substrates for temporal information processing. Here we consider a quantum reservoir processing framework that captures a broad range of physical computing models with quantum systems. We examine the scalability and memory retention of…

• Reply to comments arXiv:2512.07881 and arXiv:2601.06104 on quantum structure in human and AI-generated language

  Massimiliano Sassoli de Bianchi, Roberto Leporini · 23 September 2026

  We reply to the comments by M. Sienicki and K. Sienicki (arXiv:2512.07881) and by K. Sienicki (arXiv:2601.06104) on our work on quantum-mechanical statistics in human language (arXiv:2407.14924) and on quantum structure in AI-generated language (arXiv:2511.21731). We thank the authors for their care…

• Interactive proofs for verifying (quantum) learning and testing

  Matthias C. Caro, Jens Eisert, Marcel Hinsche, Marios Ioannou, Alexander Nietner, Ryan Sweke · 18 September 2026

  We consider the problem of testing and learning from data in the presence of resource constraints, such as limited memory or weak data access, which place limitations on the efficiency and feasibility of testing or learning. In particular, we ask the following question: Could a resource-constrained …

• An Irreducible Quantum Advantage in Aligning World Models with Reality

  Josep Lumbreras, Hailan Ma, Jayne Thompson, Mile Gu · 21 August 2026

  World models provide digital simulacra of the true world, allowing agents to be trained and tested before costly real-world deployment. At each time step, they receive an action and generate an observation and reward matching the statistics of the true world. In complex environments where present ou…

• Quantum-Structured World Models (QSWMs) for Predictive Latent Dynamics

  Hailong Jiang, Emran Hossain, Feng Yu, Jianfeng Zhu, Guilin Zhang, Wulan Guo · 7 August 2026

  World models learn latent states that summarize interaction histories, evolve over time, and support prediction, simulation, or planning. Most existing world models represent these states using classical vectors, probability distributions, recurrent hidden states, or transformer activations. In this…

• Unifying quantum measurement constructions via a relative-entropy minimum change principle

  Nana Liu, Mark M. Wilde · 6 August 2026

  The minimum change principle provides an information-theoretic characterization of the Bayes reversal channel in classical probability theory and has recently been proposed as a framework for extending Bayes' rule to quantum information theory. Using quantum relative entropy, we investigate a minimu…

• Minimal Decision Dynamics and Contextual Probability: A Quantum Tug-of-War Model

  Song-Ju Kim · 13 July 2026

  Decision making often exhibits context dependence that challenges classical probability theory. This paper develops a quantum-like extension of the Tug-of-War (QTOW) decision-making model to clarify when such context dependence can be represented by a single minimal internal state. The QTOW construc…

• Lean-Quantum: Toward AI-Assisted Formalization of Quantum Information

  Kazumi Kasaura, Kei Tsukamoto, Kento Mori, Risa Mizuno, Takahiro Namatame, Yuta Oriike, Masaya Taniguchi, Sho Sonoda, Hayata Yamasaki · 8 July 2026

  Quantum information theory is built on entropic quantities; among them, the sandwiched R\'enyi relative entropy is a fundamental divergence with various applications, and its data processing inequality (DPI) under quantum channels is a cornerstone result. In this work, we present a Lean 4 library fo…

• Platonic Projection Structures: Operator-Induced Observability in Representation Learning

  Kazuo Ishii, Bishnu Prasad Gautam, Jieling Wu, Javaid Saher · 7 July 2026

  We characterize observability in representation learning through Platonic Projection Structures (PPS), an operator-theoretic framework for analyzing representation accessibility under partial observation. Rather than treating observable outputs as direct reflections of latent representations, PPS mo…

• Reinforcement Learning to Disentangle Multiqubit Quantum States from Partial Observations

  Pavel Tashev, Stefan Petrov, Matthew T. Diaz, Friederike Metz, Alaina M. Green, Norbert M. Linke, Marin Bukov · 23 June 2026

  Using partial knowledge of a quantum state to control multiqubit entanglement is a largely unexplored paradigm in the emerging field of quantum interactive dynamics with the potential to address outstanding challenges in quantum state preparation and compression, quantum control, and quantum complex…

• Reconciling Causality and Non-Equilibrium Thermodynamics with Hamiltonian Causal Models

  Dario Rancati, Max Welling, Francesco Locatello · 4 June 2026

  Causal modeling of physical temporal phenomena must handle interventions that act along trajectories, nonstationary induced laws, path-dependent effects, and feedback mediated by dynamics, all challenging in standard causal models. We introduce Hamiltonian Causal Models (HCMs), a trajectory-level fr…

• Platonic Transformers: A Solid Choice For Equivariance

  Mohammad Mohaiminul Islam, Rishabh Anand, David R. Wessels, Friso de Kruiff, Thijs P. Kuipers, Rex Ying, Clara I. S\'anchez, Sharvaree Vadgama, Georg B\"okman, Erik J. Bekkers · 4 June 2026

  While widespread, Transformers lack inductive biases for geometric symmetries common in science and computer vision. Existing equivariant methods often sacrifice the efficiency and flexibility that make Transformers so effective through complex, computationally intensive designs. We introduce the Pl…

• Kolmogorov-Arnold Fourier Networks

  Jusheng Zhang, Yijia Fan, Kaitong Cai, Keze Wang, Wenhao Wang · 26 May 2026

  Although Kolmogorov-Arnold-based interpretable networks (KANs) possess strong theoretical expressiveness, they suffer from severe parameter explosion and limited ability to capture high-frequency features in high-dimensional tasks. To address these issues, we propose the Kolmogorov-Arnold Fourier Ne…

• Spacetime Formation under Requirements: Contextual Realization and Form-Dependent Probability

  Song-Ju Kim · 26 May 2026

  Quantum cognition often explains order effects, contextuality, and violations of the law of total probability by replacing classical probability with quantum probability on a fixed event structure. This paper proposes a different interpretation: quantum probability is the fixed-spacetime projection …

• Bayesian Parameter Shift Rule in Variational Quantum Eigensolvers

  Samuele Pedrielli, Christopher J. Anders, Lena Funcke, Karl Jansen, Kim A. Nicoli, Shinichi Nakajima · 7 May 2026

  Parameter shift rules (PSRs) are key techniques for efficient gradient estimation in variational quantum eigensolvers (VQEs). In this paper, we propose its Bayesian variant, where Gaussian processes with appropriate kernels are used to estimate the gradient of the VQE objective. Our Bayesian PSR off…

• A decision-theoretic approach to dealing with uncertainty in quantum mechanics

  Keano De Vos, Gert de Cooman, Alexander Erreygers, Jasper De Bock · 1 May 2026

  We provide a decision-theoretic framework for dealing with uncertainty in quantum mechanics. This uncertainty is two-fold: on the one hand there may be uncertainty about the state the quantum system is in, and on the other hand, as is essential to quantum mechanical uncertainty, even if the quantum …

• Fundamental Physics, Existential Risks and Human Futures

  Adrian Kent (Centre for Quantum Information,Foundations, DAMTP, University of Cambridge,Perimeter Institute for Theoretical Physics) · 30 April 2026

  Over the past 25 years, I have been involved in some intriguing developments in the foundations of physics, exploring the quantum reality problem, the relationship between quantum theory and gravity and the interplay between consciousness and physical laws. These investigations make it plausible tha…

• The Exact Replica Threshold for Nonlinear Moments of Quantum States

  Shuai Zeng · 27 April 2026

  Joint measurements on multiple copies of a quantum state provide access to nonlinear observables such as $\operatorname{tr}(\rho^t)$, but whether replica number marks a sharp information-theoretic resource boundary has remained unclear. For every fixed order $t\ge 3$, existing protocols show that $\…

• Contextuality as an External Bookkeeping Cost under Fixed Shared-State Semantics

  Song-Ju Kim · 8 April 2026

  Contextuality is a central feature distinguishing quantum from classical probability theories, but its operational meaning is often stated only qualitatively. In this Letter, we study a simple information-theoretic question: how much additional contextual information must a classical simulation intr…

• Operational Noncommutativity in Sequential Metacognitive Judgments

  Enso O. Torres Alegre, Diana E. Mora Jimenez · 8 April 2026

  Metacognition, understood as the monitoring and regulation of one's own cognitive processes, is inherently sequential: an agent evaluates an internal state, updates it, and may then re-evaluate under modified criteria. Order effects in cognition are well documented, yet it remains unclear whether su…

• Detecting Intrinsic and Instrumental Self-Preservation in Autonomous Agents: The Unified Continuation-Interest Protocol

  Christopher Altman · 13 March 2026

  Autonomous agents, especially delegated systems with memory, persistent context, and multi-step planning, pose a measurement problem not present in stateless models: an agent that preserves continued operation as a terminal objective and one that does so merely instrumentally can produce observation…

• Implementing Pearl's $\mathcal{DO}$-Calculus on Quantum Circuits: A Simpson-Type Case Study on NISQ Hardware

  Pilsung Kang · 3 March 2026

  Distinguishing correlation from causation is a central challenge in machine intelligence, and Pearl's $\mathcal{DO}$-calculus provides a rigorous symbolic framework for reasoning about interventions. A complementary question is whether such intervention logic can be given \emph{executable semantics}…

• Implementing Pearl's $\mathcal{DO}$-Calculus on Quantum Circuits: A Simpson-Type Case Study on NISQ Hardware

  Pilsung Kang · 3 March 2026

  Distinguishing correlation from causation is a central challenge in machine intelligence, and Pearl's $\mathcal{DO}$-calculus provides a rigorous symbolic framework for reasoning about interventions. A complementary question is whether such intervention logic can be given \emph{executable semantics}…

• Extending quantum theory with AI-assisted deterministic game theory

  Florian Pauschitz, Ben Moseley, Ghislain Fourny · 20 February 2026

  We present an AI-assisted framework for predicting individual runs of complex quantum experiments, including contextuality and causality (adaptive measurements), within our long-term programme of discovering a local hidden-variable theory that extends quantum theory. In order to circumvent impossibi…

• Quantum generative model on bicycle-sharing system and an application

  Fumio Nemoto, Nobuyuki Koike, Daichi Sato, Yuuta Kawaai, Masayuki Ohzeki · 10 February 2026

  Recently, bicycle-sharing systems have been implemented in numerous cities, becoming integral to daily life. However, a prevalent issue arises when intensive commuting demand leads to bicycle shortages in specific areas and at particular times. To address this challenge, we employ a novel quantum ma…