Tootfinder

On the CQC Conjecture
Hasan Iqbal
https://arxiv.org/abs/2509.08286 https://arxiv.org/pdf/2509.08286

On the CQC Conjecture
The CQC conjecture by Schneeloch et al. (Physical Review A 90.6, 2014) asserts that the sum of classical mutual information between two parties obtained by measuring individual systems in two mutually unbiased bases can not exceed their shared quantum mutual information. This remarkable conjecture, which deserves more work, still remains open. In this article, using a result by Coles and Piani (Physical Review A 89.2, 2014), we derive a sufficient condition for which the CQC conjecture holds. W…

Replaced article(s) found for cs.CR. https://arxiv.org/list/cs.CR/new
[1/1]:
- Robustness of Locally Differentially Private Graph Analysis Against Poisoning
Jacob Imola, Amrita Roy Chowdhury, Kamalika Chaudhuri

$\bf A^2$-robust superradiant phase transition in hybrid qubit-cavity optomechanics
Gang Liu, Wei Xiong
https://arxiv.org/abs/2508.08024 https://arxiv.org/…

$\bf A^2$-robust superradiant phase transition in hybrid qubit-cavity optomechanics
The $\mathbf{A}^2$ term presents a fundamental challenge to realizing the superradiant phase transition (SPT) in cavity quantum electrodynamics. Here, we propose a hybrid quantum system enabling SPT regardless of the presence of the $\mathbf{A}^2$ term. The system consisting of a qubit, a mechanical mode, and an optical cavity, where the qubit and mechanical mode constitute a quantum Rabi model, while the mechanical mode and cavity form an optomechanical system. Crucially, the auxiliary cavity …

Expanding a 4-qubit Dicke State a to 5-qubit Dicke State with Limited Qubit Access
Bibhuti Thapa, Oberon Moran, Duc-Kha Vu, Fatih Ozaydin
https://arxiv.org/abs/2508.07977 https:…

Expanding a 4-qubit Dicke State a to 5-qubit Dicke State with Limited Qubit Access
In scenarios where full access to all qubits of a multipartite quantum system is available and global operations can be implemented, the preparation of arbitrary entangled states - including multipartite Dicke states - is theoretically straightforward. However, practical constraints often limit direct control over all qubits. In this work, we first present an efficient method for preparing a four-qubit Dicke state, and then demonstrate how a four-qubit Dicke state can be expanded to a five-qubi…

Calculating the Projective Norm of higher-order tensors using a gradient descent algorithm
Aaditya Rudra, Maria Anastasia Jivulescu
https://arxiv.org/abs/2508.07933 https://

Calculating the Projective Norm of higher-order tensors using a gradient descent algorithm
Projective Norms are a class of tensor norms that map on the input and output spaces. These norms are useful for providing a measure of entanglement. Calculating the projective norms is an NP-hard problem, which creates challenges in computing due to the complexity of the exponentially growing parameter space for higher-order tensors. We develop a novel gradient descent algorithm to estimate the projective norm of higher-order tensors. The algorithm guarantees convergence to a minimum nuclear r…

Scheduling of syndrome measurements with a few ancillary qubits
Shintaro Sato, Yasunari Suzuki
https://arxiv.org/abs/2508.07913 https://arxiv.org/pdf/2508.…

Scheduling of syndrome measurements with a few ancillary qubits
Quantum error-correcting codes are a vital technology for demonstrating reliable quantum computation. They require data qubits for encoding quantum information and ancillary qubits for taking error syndromes necessary for error correction. The need for a large number of ancillary qubits is an overhead specific to quantum computing, and it prevents the scaling of quantum computers to a useful size. In this work, we propose a framework for generating efficient syndrome measurement circuits with a…

GPU-Accelerated Syndrome Decoding for Quantum LDPC Codes below the 63 $\mu$s Latency Threshold
Oscar Ferraz, Bruno Coutinho, Gabriel Falcao, Marco Gomes, Francisco A. Monteiro, Vitor Silva
https://arxiv.org/abs/2508.07879

GPU-Accelerated Syndrome Decoding for Quantum LDPC Codes below the 63 $μ$s Latency Threshold
This paper presents a GPU-accelerated decoder for quantum low-density parity-check (QLDPC) codes that achieves sub-$63$ $μ$s latency, below the surface code decoder's real-time threshold demonstrated on Google's Willow quantum processor. While surface codes have demonstrated below-threshold performance, the encoding rates approach zero as code distances increase, posing challenges for scalability. Recently proposed QLDPC codes, such as those by Panteleev and Kalachev, offer constant-rate encod…

Information Transport in Classic-Quantum Hybrid System
Julian Rapp, Radhika H. Joshi, Alwin van Steensel, Yuli V. Nazarov, Mohammad H. Ansari
https://arxiv.org/abs/2508.07870 ht…

Information Transport in Classic-Quantum Hybrid System
Many important quantities in quantum information science, such as entropy and entanglement, are non-linear functions of the density matrix and cannot be expressed as operator observables. Standard open-system approaches evolve only a single copy of the density matrix, making it impossible to track the dynamics of such quantities. A formalism proposed by some of the present authors addressed this challenge by evolving multiple virtual replicas, but was limited to the weak-coupling regime. Here, …

Master Equation for Quantum Self-Organization of Atoms and Molecules in Cavities
Tom Schmit, Catalin-Mihai Halati, Tobias Donner, Giovanna Morigi, Simon B. J\"ager
https://arxiv.org/abs/2508.07853

Master Equation for Quantum Self-Organization of Atoms and Molecules in Cavities
Quantum gases of atoms and molecules in optical cavities offer a formidable laboratory for studying the out-of-equilibrium dynamics of long-range interacting systems. Multiple scattering of cavity photons mediate interactions, and the emerging phases of matter are determined by the interplay of photon-mediated forces, dissipation, and quantum and thermal fluctuations. Control of these dynamics requires a detailed understanding of the mechanisms at play. Due to the number of degrees of freedom, …

Observation and Modulation of the Quantum Mpemba Effect on a Superconducting Quantum Processor
Yueshan Xu, Cai-Ping Fang, Bing-Jie Chen, Ming-Chuan Wang, Zi-Yong Ge, Yun-Hao Shi, Yu Liu, Cheng-Lin Deng, Kui Zhao, Zheng-He Liu, Tian-Ming Li, Hao Li, Ziting Wang, Gui-Han Liang, Da'er Feng, Xueyi Guo, Xu-Yang Gu, Yang He, Hao-Tian Liu, Zheng-Yang Mei, Yongxi Xiao, Yu Yan, Yi-Han Yu, Wei-Ping Yuan, Jia-Chi Zhang, Zheng-An Wang, Gangqin Liu, Xiaohui Song, Ye Tian, Yu-Ran Zhang, Shi-Xin …

Observation and Modulation of the Quantum Mpemba Effect on a Superconducting Quantum Processor
In non-equilibrium quantum many-body systems, the quantum Mpemba effect (QME) emerges as a counterintuitive phenomenon: systems exhibiting greater initial symmetry breaking restore symmetry faster than those with less. While theoretical exploration of QME has surged, experimental studies on its multidimensional modulation remain limited. Here, we report the observation and control of QME using a superconducting processor featuring a unique fully connected, tunable-coupling architecture that ena…

Steady state properties of periodically driven quantum systems
Milan \v{S}indelka, David Gelbwaser-Klimovsky
https://arxiv.org/abs/2508.07674 https://arxiv…

Steady state properties of periodically driven quantum systems
Periodic driving is used to steer physical systems to unique stationary states or nonequilibrium steady states (NESS), producing enhanced properties inaccessible to non-driven systems. For open quantum systems, characterizing the NESS is challenging and existing results are generally limited to specific types of driving and the Born-Markov approximation. Here we go beyond these limits by studying a generic periodically driven $ N$-level quantum system interacting with a low-density thermal gas.…

Estimating classical mutual information between quantum subsystems with neural networks
D. A. Konyshev, V. V. Mazurenko
https://arxiv.org/abs/2508.07652 https://

Estimating classical mutual information between quantum subsystems with neural networks
Characterizing correlations in a quantum system on the basis of the results of the projective measurements can be performed with different means including the calculation of the classical mutual information. Generally, estimating such information-entropy-based quantities requires having complete statistics of the system's states. Here we explore the possibility to reconstruct the classical mutual information and specific entropy of a quantum system with neural network approach on the basis of l…

Obfuscated Quantum and Post-Quantum Cryptography
Anju Rani, Xiaoyu Ai, Aman Gupta, Ravi Singh Adhikari, Robert Malaney
https://arxiv.org/abs/2508.07635 https://

Obfuscated Quantum and Post-Quantum Cryptography
In this work, we present an experimental deployment of a new design for combined quantum key distribution (QKD) and post-quantum cryptography (PQC). Novel to our system is the dynamic obfuscation of the QKD-PQC sequence of operations, the number of operations, and parameters related to the operations; coupled to the integration of a GPS-free quantum synchronization protocol within the QKD process. We compare the performance and overhead of our QKD-PQC system relative to a standard QKD system wi…

Tomography-assisted noisy quantum circuit simulator using matrix product density operators
Wei-guo Ma, Yun-Hao Shi, Kai Xu, Heng Fan
https://arxiv.org/abs/2508.07610 https://

Tomography-assisted noisy quantum circuit simulator using matrix product density operators
In recent years, efficient quantum circuit simulations incorporating ideal noise assumptions have relied on tensor network simulators, particularly leveraging the matrix product density operator (MPDO) framework. However, experiments on real noisy intermediate-scale quantum (NISQ) devices often involve complex noise profiles, encompassing uncontrollable elements and instrument-specific effects such as crosstalk. To address these challenges, we employ quantum process tomography (QPT) techniques …

Error-Resilient Fast Entangling Gates for Scalable Ion-Trap Quantum Processors
Isabelle Savill-Brown, Zain Mehdi, Alexander K. Ratcliffe, Varun D. Vaidya, Haonan Liu, Simon A. Haine, C. Ricardo Viteri, Joseph J. Hope
https://arxiv.org/abs/2508.07593

Error-Resilient Fast Entangling Gates for Scalable Ion-Trap Quantum Processors
Non-adiabatic two-qubit gate proposals for trapped-ion systems offer superior performance and flexibility over adiabatic schemes at the cost of increased laser control requirements. Existing fast gate schemes are limited by single-qubit transition errors, which constrain the total number of pulses in high-fidelity solutions. We introduce an improved gate search scheme that enables both local and non-local two-qubit gates in chains containing tens of ions. These protocols use a multi-objective m…

Graded Quantum Codes: From Weighted Algebraic Geometry to Homological Chain Complexes
Tony Shaska
https://arxiv.org/abs/2508.07542 https://arxiv.org/pdf/25…

Graded Quantum Codes: From Weighted Algebraic Geometry to Homological Chain Complexes
We introduce graded quantum codes, unifying two classes of quantum error-correcting codes. The first, quantum weighted algebraic geometry (AG) codes, derives from rational points on hypersurfaces in weighted projective spaces over finite fields. This extends classical AG codes by adding weighted degrees and singularities, enabling self-orthogonal codes via the CSS method with improved distances using algebraic structures and invariants like weighted heights.The second class arises from chain co…

A Method for Constructing Quasi-Random Peaked Quantum Circuits
O. G. Udalov
https://arxiv.org/abs/2508.07491 https://arxiv.org/pdf/2508.07491

A Method for Constructing Quasi-Random Peaked Quantum Circuits
An algorithm is proposed for constructing quasi-random "peaked" quantum circuits, i.e., circuits whose final qubit state exhibits a high probability concentration on a specific computational basis state. These circuits consist of random gates arranged in a brick-wall architecture. While the multiqubit state in the middle of the circuit can exhibit significant entanglement, the final state is, with high probability, a predetermined pure bitstring. A technique is introduced to obscure the final b…

PHIP Sequences and Dipolar Fields
Martin C. Korzeczek, Ilai Schwartz, Martin B. Plenio
https://arxiv.org/abs/2508.07488 https://arxiv.org/pdf/2508.07488

PHIP Sequences and Dipolar Fields
Para-hydrogen induced polarization (PHIP) achieves efficient hyperpolarisation of nuclear spins with the transfer of the singlet order of parahydrogen to target molecules through catalytic hydrogenation reactions and subsequent coherent control of the spin dynamics. However, in realistic conditions B0/B1 inhomogeneities lead to significant reduction in the polarization transfer efficiency. Moreover, in high-concentration samples, dipolar fields arising from the magnetisation of the sample can d…

Quanutm-State Texture as a Resource: Measures and Nonclassical Interdependencies
Yuntao Cui, Zhaobing Fan, Sunho Kim
https://arxiv.org/abs/2508.07481 https://

Quanutm-State Texture as a Resource: Measures and Nonclassical Interdependencies
Quantum-state texture is a newly recognized quantum resource that has garnered attention with the advancement of quantum theory. In this work, we discuss several main tasks concerning quantum-state texture resource theory, including quantum-state texture measure, quantum state transformation under free operations, and relations between quantum resources. We first provide two new quantum-state texture measures and propose specific form of function for constructing quantum-state texture measures …

Universally Robust Control of Open Quantum Systems
Lixiang Ding, Jingtao Fan, Xingze Qiu
https://arxiv.org/abs/2508.07379 https://arxiv.org/pdf/2508.07379

Universally Robust Control of Open Quantum Systems
Mitigating noise-induced decoherence is the central challenge in controlling open quantum systems. While existing robust protocols often require precise noise models, we introduce a universal framework for noise-agnostic quantum control that achieves high-fidelity operations without prior environmental noise characterization. This framework capitalizes on the dynamical modification of the system-environment coupling through control drives, an effect rigorously encoded in the dynamical equation.…

Integrating Quantum Computing with Multiconfiguration Pair-Density Functional Theory for Biological Electron Transfer
Yibo Chen, Zirui Sheng, Weitang Li, Yong Zhang, Xun Xu, Jun-Han Huang, Yuxiang Li
https://arxiv.org/abs/2508.07359

Integrating Quantum Computing with Multiconfiguration Pair-Density Functional Theory for Biological Electron Transfer
Accurate calculation of strongly correlated electronic systems requires proper treatment of both static and dynamic correlations, which remains challenging for conventional methods. To address this, we present VQE-PDFT, a quantum-classical hybrid framework that integrates variational quantum eigensolver with multiconfiguration pair-density functional theory (MC-PDFT). This framework strategically employs quantum circuits for multiconfigurational wavefunction representation while utilizing densi…

Quantum MIMO Diversity over Discrete-Variable Crosstalk Channels
Shehbaz Tariq, Junaid ur Rehman, Symeon Chatzinotas
https://arxiv.org/abs/2508.07344 https://

Quantum MIMO Diversity over Discrete-Variable Crosstalk Channels
Quantum communication plays a pivotal role in enabling distributed quantum computing and sensing. Diversity strategies can be used to increase the communication reliability (in the sense of output fidelity with respect to the input quantum state) when multiple communication channels are available. The current paper proposes a diversity strategy for quantum discrete variable (DV) multiple-input-multiple-output (MIMO) channels, utilizing approximate cloning to distribute information across multip…

The simplest Kochen-Specker set
Ad\'an Cabello
https://arxiv.org/abs/2508.07335 https://arxiv.org/pdf/2508.07335

The simplest Kochen-Specker set
Kochen-Specker (KS) sets are fundamental in physics. Every time nature produces bipartite correlations attaining the nonsignaling limit, or two parties always win a nonlocal game impossible to always win classically, is because the parties are measuring a KS set. The simplest quantum system in which all these phenomena occur is a pair of three-level systems. However, the simplest KS sets in dimension three known are asymmetrical and require a large number of bases (the current minimum is 16, se…

Information in quantum field theory simulators: Thin-film superfluid helium
Maciej T. Jarema, Cameron R. D. Bunney, Vitor S. Barroso, Mohammadamin Tajik, Chris Goodwin, Silke Weinfurtner
https://arxiv.org/abs/2508.07247

Information in quantum field theory simulators: Thin-film superfluid helium
Understanding quantum correlations through information-theoretic measures is fundamental to developments in quantum field theory, quantum information, and quantum many-body physics. A central feature in a plethora of systems is the area law, under which information scales with the size of the boundary of the system, rather than volume. Whilst many systems and regimes exhibiting an area law have been identified theoretically, experimental verification remains limited, particularly in continuous …

Squeezed Coherent States in Supersymmetric Quantum Mechanics with Position-Dependent Mass
Daniel Sabi Takou, Amidou Boukari, Assimiou Yarou Mora, Gabriel Y. H. Avossevou
https://arxiv.org/abs/2508.07228

Squeezed Coherent States in Supersymmetric Quantum Mechanics with Position-Dependent Mass
In this paper, we construct and analyze a class of squeezed coherent states within the framework of supersymmetric quantum mechanics (SUSYQM) involving a position-dependent mass (PDM). Using a deformed algebraic structure, we generalize the creation and annihilation operators to accommodate spatially varying mass profiles. The resulting states exhibit non-classical features, such as squeezing, coherence, and modified uncertainty relations, strongly influenced by both the deformation parameter…

Positive-divisibility of Subsystems in Quantum Dynamics
Anumita Mukhopadhyay, Praggnyamita Ghosh, Shibdas Roy
https://arxiv.org/abs/2508.07188 https://arxi…

Positive-divisibility of Subsystems in Quantum Dynamics
It is known that the existence of memory effect can revive quantum correlations in open system dynamics. In this regard, the backflow of information from environment to the system can be identified with Complete Positive (CP) indivisibility as well as Positive (P) indivisibility criteria. It is also known that if a quantum system is CP-divisible, it can also have memory effect which can be witnessed by P-indivisibility. Here, we have explored the relation of P-divisibility with unitality condit…

Bargmann invariants of Gaussian states
Jianwei Xu
https://arxiv.org/abs/2508.07155 https://arxiv.org/pdf/2508.07155…

Bargmann invariants of Gaussian states
Given a set of ordered quantum states, described by density operators $% \{ρ_{j}\}_{j=1}^{n}$, the Bargmann invariant of $\{ρ_{j}\}_{j=1}^{n}$ is defined as tr($ρ_{1}ρ_{2}...ρ_{n}$). Bargmann invariant serves as a fundamental concept for quantum mechanics and has diverse applications in quantum information science. Bosonic Gaussian states are a class of quantum states on infinite-dimensional Hilbert space, widely used in quantum optics and quantum information science. Bosonic Gaussian stat…

Optimal Quantum Estimation with Stabilizer-Based Local Measurements
Jia-Xuan Liu, Hai-Long Shi, Chunfeng Wu, Sixia Yu
https://arxiv.org/abs/2508.07150 https://

Optimal Quantum Estimation with Stabilizer-Based Local Measurements
A central challenge in quantum metrology is to identify optimal protocols under measurement constraints that reflect realistic experimental conditions, e.g., local measurements in multipartite scenarios. Here, we present a sufficient criterion for metrological schemes to saturate the quantum Cramér-Rao bound (QCRB) using local measurements, based on stabilizer formalism. In ideal settings, we show that graph states always admit local estimation protocols with an optimal estimation precision de…

Block encoding the 3D heterogeneous Poisson equation with application to fracture flow
Austin Pechan, John Golden, Daniel O'Malley
https://arxiv.org/abs/2508.07125 https://

Block encoding the 3D heterogeneous Poisson equation with application to fracture flow
Quantum linear system (QLS) algorithms offer the potential to solve large-scale linear systems exponentially faster than classical methods. However, applying QLS algorithms to real-world problems remains challenging due to issues such as state preparation, data loading, and efficient information extraction. In this work, we study the feasibility of applying QLS algorithms to solve discretized three-dimensional heterogeneous Poisson equations, with specific examples relating to groundwater flow …

Low Cost Bayesian Experimental Design for Quantum Frequency Estimation with Decoherence
Alexandra Ram\^oa, Lu\'is Paulo Santos, Akihito Soeda
https://arxiv.org/abs/2508.07120

Low Cost Bayesian Experimental Design for Quantum Frequency Estimation with Decoherence
A two-level quantum system evolving under a time-independent Hamiltonian produces oscillatory measurement probabilities. The estimation of the associated frequency is a cornerstone problem in quantum metrology, sensing, calibration and control. In this work, we tackle this task by introducing WES: a Window Expansion Strategy for low cost adaptive Bayesian experimental design. WES employs empirical cost-reduction techniques to keep the optimization overhead low, curb scaling problems, and enable…

QuProFS: An Evolutionary Training-free Approach to Efficient Quantum Feature Map Search
Yaswitha Gujju, Romain Harang, Chao Li, Tetsuo Shibuya, Qibin Zhao
https://arxiv.org/abs/2508.07104

QuProFS: An Evolutionary Training-free Approach to Efficient Quantum Feature Map Search
The quest for effective quantum feature maps for data encoding presents significant challenges, particularly due to the flat training landscapes and lengthy training processes associated with parameterised quantum circuits. To address these issues, we propose an evolutionary training-free quantum architecture search (QAS) framework that employs circuit-based heuristics focused on trainability, hardware robustness, generalisation ability, expressivity, complexity, and kernel-target alignment. By…

Geometry-Controlled Freezing and Revival of Bell Nonlocality through Environmental Memory
Mohamed Hatifi
https://arxiv.org/abs/2508.07046 https://arxiv.org…

Geometry-Controlled Freezing and Revival of Bell Nonlocality through Environmental Memory
We show that the distance between two qubits coupled to a structured reservoir acts as a single geometric control that can store, revive, or suppress Bell nonlocality. In a mirror-terminated guide, quantum correlations lost to the bath return at discrete recurrence times, turning a product state into a Bell-violating one without any entangling drive (only local basis rotations/readout). In the continuum limit, we derive closed-form criteria for the emergence of nonlocality from backflow, and in…

Bridging Classical and Quantum Computing for Next-Generation Language Models
Yi Pan, Hanqi Jiang, Junhao Chen, Yiwei Li, Huaqin Zhao, Lin Zhao, Yohannes Abate, Yingfeng Wang, Tianming Liu
https://arxiv.org/abs/2508.07026

Bridging Classical and Quantum Computing for Next-Generation Language Models
Integrating Large Language Models (LLMs) with quantum computing is a critical challenge, hindered by the severe constraints of Noisy Intermediate-Scale Quantum (NISQ) devices, including barren plateaus and limited coherence. Current approaches often fail due to static quantum-classical partitioning. We introduce Adaptive Quantum-Classical Fusion (AQCF), the first framework to bridge this gap through dynamic, quantum-classical co-design. AQCF's core principle is real-time adaptation: it analyzes…

A Quantum Walk-Driven Algorithm for the Minimum Spanning Tree Problem under a Maximal Degree Constraint
F. S. Luiz, F. F. Fanchini, Victor Hugo C. de Albuquerque, J. P. Papa, M. C. de Oliveira
https://arxiv.org/abs/2508.07007

A Quantum Walk-Driven Algorithm for the Minimum Spanning Tree Problem under a Maximal Degree Constraint
We present a novel quantum walk-based approach to solve the Minimum Spanning Tree (MST) problem under a maximal degree constraint (MDC). By recasting the classical MST problem as a quantum walk on a graph, where vertices are encoded as quantum states and edge weights are inverted to define a modified Hamiltonian, we demonstrate that the quantum evolution naturally selects the MST by maximizing the cumulative transition probability (and thus the Shannon entropy) over the spanning tree. Our metho…

Counter-propagating Entangled Photon Pairs from a Monolayer
Zhuoyuan Lu, Jiri Janousek, Syed M. Assad, Shuyao Qiu, Mayank Joshi, Yecheng Hu, Alex Y Song, Chuanyu Wang, Manuka Suriyage, Jie Zhao, Ping Koy Lam, Yuerui Lu
https://arxiv.org/abs/2508.06860

Counter-propagating Entangled Photon Pairs from a Monolayer
Non-phase-matched spontaneous parametric down-conversion (SPDC) in atomically thin materials provides new degrees of freedom and enhanced quantum information capacity compared to conventional phase-matched sources. These systems emerged as promising platforms for quantum computing, communication, and imaging, with the potential to support higher-order nonlinear processes. However, direct observation of photon-pair emission from a monolayer has remained experimentally challenging. In this work, …

Squeezed Magnons-Induced Nonreciprocal Entanglement in a Magnomechanical Cavity
Ziyad Imara, Khadija El Anouz, \.Ilkay Demir, Abderrahim El Allati
https://arxiv.org/abs/2508.06850

Squeezed Magnons-Induced Nonreciprocal Entanglement in a Magnomechanical Cavity
Magnomechanical cavities offer a new frontier in quantum electrodynamics that give rise to several significant theoretical and experimental results. In this paper, we propose a novel theoretical mechanism for achieving a nonreciprocal macroscopic entanglement between magnons, photons and phonons, based on the use of an alternative squeezed magnons method. Indeed, in contrast to conventional approaches, we show how precise control of the amplitude and phase of the squeezed mode allows to obtain …

Unambiguous discrimination of the change point for quantum channels
Kenji Nakahira
https://arxiv.org/abs/2508.06785 https://arxiv.org/pdf/2508.06785…

Unambiguous discrimination of the change point for quantum channels
Identifying the precise moment when a quantum channel undergoes a change is a fundamental problem in quantum information theory. We study how accurately one can determine the time at which a channel transitions to another. We investigate the quantum limit of the average success probability in unambiguous discrimination, in which errors are completely avoided by allowing inconclusive results with a certain probability. This problem can be viewed as a quantum process discrimination task, where th…

Rotation Errors Due to Field Quantization for Simultaneously Driven Atoms
Hunter Lindemann, Shanon Vuglar, Julio Gea-Banacloche
https://arxiv.org/abs/2508.06769 https://

Rotation Errors Due to Field Quantization for Simultaneously Driven Atoms
When an electromagnetic field in a coherent or quasiclassical (e.g., squeezed) state is used to simultaneously drive an ensemble of two-level atoms, the quantum nature of the field will, in general, cause the final state of the atoms to differ from the one predicted for a totally classical field. This is a potential source of error in quantum logic gates in which the gate is the rotation of the atoms by a laser. In this paper, we use second order perturbation theory to find how this error scale…

Continuous-Time Quantum Markov Chains And Discretizations Of p-Adic Schr\"odinger Equations: Comparisons And Simulations
W. A. Z\'u\~niga-Galindo, L. F. Chac\'on-Cort\'es
https://arxiv.org/abs/2508.06712

Continuous-Time Quantum Markov Chains And Discretizations Of p-Adic Schrödinger Equations: Comparisons And Simulations
The continuous-time quantum walks (CTQWs) are a fundamental tool in the development of quantum algorithms. Recently, it was shown that discretizations of p-adic Schrödinger equations give rise to continuous-time quantum Markov chains (CTQMCs); this type of Markov chain includes the CTQWs constructed using adjacency matrices of graphs as a particular case. In this paper, we study a large class of p-adic Schrödinger equations and the associated CTQMCs by comparing them with p-adic heat equation…

Interference Between Electromagnetic and Mechanical Waves
Alexandre Cesar Ricardo, Ciro Micheletti Diniz, Celso Jorge Villas-B\^oas
https://arxiv.org/abs/2508.06683 https://

Interference Between Electromagnetic and Mechanical Waves
Classically, wave interference is a phenomenon that can be explained by considering only the waves themselves, that is, without the need to consider the apparatus that monitors or observes them. Thus, in classical theories, interference can only occur between waves of the same nature. In quantum theory, the observed results require a description of the system and its measuring apparatus, which allows us to rethink the explanation of various natural phenomena. In this paper, we consider the ion-…

Reducing quantum resources for observable estimation with window-assisted coherent QPE
Harriet Apel, Cristian L. Cortes, Jessica Lemieux, Mark Steudtner
https://arxiv.org/abs/2508.06677

Reducing quantum resources for observable estimation with window-assisted coherent QPE
Quantum Phase Estimation (QPE) routines are known to fail probabilistically even with perfect gates and input states. This effect stems from an incompatibility of finite-sized quantum registers to capture a phase within QPE with phase angles of infinite precision, and the effect extend even beyond what would be reasonably expected from rounding. This effect can be partially mitigated by biasing the phase register with a window, or taper state, from classical signal processing. This paper focuse…

A scalable photonic quantum interconnect platform
Daniel Riedel, Teodoro Graziosi, Zhuoxian Wang, Chawina De-Eknamkul, Alex Abulnaga, Jonathan Dietz, Andrea Mucchietto, Michael Haas, Madison Sutula, Pierre Barral, Matteo Pompili, Carsten Robens, Jeonghoon Ha, Denis Sukachev, David Levonian, Mihir Bhaskar, Matthew Markham, Bartholomeus Machielse
https://

A scalable photonic quantum interconnect platform
Many quantum networking applications require efficient photonic interfaces to quantum memories which can be produced at scale and with high yield. Synthetic diamond offers unique potential for the implementation of this technology as it hosts color centers which retain coherent optical interfaces and long spin coherence times in nanophotonic structures. Here, we report a technique enabling wafer-scale processing of thin-film diamond that combines ion implantation and membrane liftoff, high-qual…

Observation of Metal-Insulator and Spectral Phase Transitions in Aubry-Andr\'e-Harper Models
Quan Lin, Christopher Cedzich, Qi Zhou, Peng Xue
https://arxiv.org/abs/2508.08255

Observation of Metal-Insulator and Spectral Phase Transitions in Aubry-André-Harper Models
Non-Hermitian extensions of the Aubry-André-Harper (AAH) model reveal a rich variety of phase transitions arising from the interplay of quasiperiodicity and non-Hermiticity. Despite their theoretical significance, experimental explorations remain challenging due to complexities in realizing controlled non-Hermiticity. Here, we present the first experimental realization of the unitary almost-Mathieu operator (UAMO) which simulates the AAH model by employing single-photon quantum walks. Through …

Composable Quantum Fault-Tolerance
Zhiyang He, Quynh T. Nguyen, Christopher A. Pattison
https://arxiv.org/abs/2508.08246 https://arxiv.org/pdf/2508.08246…

Composable Quantum Fault-Tolerance
Proving threshold theorems for fault-tolerant quantum computation is a burdensome endeavor with many moving parts that come together in relatively formulaic but lengthy ways. It is difficult and rare to combine elements from multiple papers into a single formal threshold proof, due to the use of different measures of fault-tolerance. In this work, we introduce composable fault-tolerance, a framework that decouples the probabilistic analysis of the noise distribution from the combinatorial analy…

Quantum-centric simulation of hydrogen abstraction by sample-based quantum diagonalization and entanglement forging
Tyler Smith, Tanvi P. Gujarati, Mario Motta, Ben Link, Ieva Liepuoniute, Triet Friedhoff, Hiromichi Nishimura, Nam Nguyen, Kristen S. Williams, Javier Robledo Moreno, Caleb Johnson, Kevin J. Sung, Abdullah Ash Saki, Marna Kagele
https://

Quantum-centric simulation of hydrogen abstraction by sample-based quantum diagonalization and entanglement forging
The simulation of electronic systems is an anticipated application for quantum-centric computers, i.e. heterogeneous architectures where classical and quantum processing units operate in concert. An important application is the computation of radical chain reactions, including those responsible for the photodegradation of composite materials used in aerospace engineering. Here, we compute the activation energy and reaction energy for hydrogen abstraction from 2,2-diphenyldipropane, used as a mi…

Photon Statistics for Fock and Coherent States Interfering in a Beamsplitter
Jhordan A. T. Santiago
https://arxiv.org/abs/2508.08223 https://arxiv.org/pdf/…

Photon Statistics for Fock and Coherent States Interfering in a Beamsplitter
We present a straightforward yet comprehensive theoretical study of different quantum states emerging from a bi-modal beamsplitter when various input states interfere. Specifically, we analyze the output states for different combinations of input fields, including Fock states $|n\rangle|m\rangle$, hybrid states $|n\rangle|α\rangle$, and coherent states $|α\rangle|β\rangle$. We derive explicit expressions for the output state vectors, calculate the mean photon nu…

Average Contraction Coefficients of Quantum Channels
Ruben Ibarrondo, Daniel Stilck Fran\c{c}a
https://arxiv.org/abs/2508.08214 https://arxiv.org/pdf/2508.…

Average Contraction Coefficients of Quantum Channels
The data-processing inequality ensures quantum channels reduce state distinguishability, with contraction coefficients quantifying optimal bounds. However, these can be overly optimistic and not representative of the usual behavior. We study how noise contracts distinguishability of `typical' states, beyond the worst-case. To that end, we introduce and study a family of moments of contraction for quantum divergences, which interpolate between the worst-case contraction coefficient of a channel …

Color it, Code it, Cancel it: k-local dynamical decoupling from classical additive codes
Minh T. P. Nguyen, Maximilian Rimbach-Russ, Stefano Bosco
https://arxiv.org/abs/2508.08213

Color it, Code it, Cancel it: k-local dynamical decoupling from classical additive codes
Dynamical decoupling is a central technique in quantum computing for actively suppressing decoherence and systematic imperfections through sequences of single-qubit operations. Conventional sequences typically aim to completely freeze system dynamics, often resulting in long protocols whose length scales exponentially with system size. In this work, we introduce a general framework for constructing time-optimal, selectively-tailored sequences that remove only specific local interactions. By com…

Pangenome-guided sequence assembly via binary optimisation
Josh Cudby, James Bonfield, Chenxi Zhou, Richard Durbin, Sergii Strelchuk
https://arxiv.org/abs/2508.08200 https://

Pangenome-guided sequence assembly via binary optimisation
De novo genome assembly is challenging in highly repetitive regions; however, reference-guided assemblers often suffer from bias. We propose a framework for pangenome-guided sequence assembly, which can resolve short-read data in complex regions without bias towards a single reference genome. Our method frames assembly as a graph traversal optimisation problem, which can be implemented on quantum computers. The pipeline first annotates pangenome graphs with estimated copy numbers for each node,…

Single-Shot Decoding and Fault-tolerant Gates with Trivariate Tricycle Codes
Abraham Jacob, Campbell McLauchlan, Dan E. Browne
https://arxiv.org/abs/2508.08191 https://

Single-Shot Decoding and Fault-tolerant Gates with Trivariate Tricycle Codes
While quantum low-density parity check (qLDPC) codes are a low-overhead means of quantum information storage, it is valuable for quantum codes to possess fault-tolerant features beyond this resource efficiency. In this work, we introduce trivariate tricycle (TT) codes, qLDPC codes that combine several desirable features: high thresholds under a circuit-level noise model, partial single-shot decodability for low-time-overhead decoding, a large set of transversal Clifford gates and automorphisms …

Characterization of syndrome-dependent logical noise in detector regions
Matthew Girling, Ben Criger, Cristina Cirstoiu
https://arxiv.org/abs/2508.08188 https://

Characterization of syndrome-dependent logical noise in detector regions
Characterizing how quantum error correction circuits behave under realistic hardware noise is essential for testing the premises that enable scalable fault tolerance. Logical error rates conditioned on syndrome outcomes are needed to enable noise-aware decoding and validate threshold-relevant assumptions. We introduce a protocol to directly estimate the logical Pauli channels (and pure errors) associated with detector regions formed of two or more syndrome extraction gadgets, conditioned on obs…

Fast and efficient long-distance quantum state transfer in long-range spin-$\frac{1}{2}$ models
F. Faria, C. C. Nelmes, T. J. G. Apollaro, T. P. Spiller, I. D'Amico
https://arxiv.org/abs/2508.08182

Fast and efficient long-distance quantum state transfer in long-range spin-$\frac{1}{2}$ models
Quantum state transfer is investigated beyond the nearest-neighbour coupling scheme in long spin-$\frac{1}{2}$ linear chains. Exploiting the properties of the next-nearest neighbour Hamiltonian's dispersion relation, it is shown that with minimal engineering, i.e., an on-site magnetic field on the two end sites and only a few symmetrically-modified end inter-site couplings, an average transfer fidelity above $99\%$ can be achieved. To leading order, the required time scales linearly with the le…

Quantum Circuit Complexity of Matrix-Product Unitaries
Georgios Styliaris, Rahul Trivedi, J. Ignacio Cirac
https://arxiv.org/abs/2508.08160 https://arxiv.o…

Quantum Circuit Complexity of Matrix-Product Unitaries
Matrix-product unitaries (MPUs) are many-body unitary operators that, as a consequence of their tensor-network structure, preserve the entanglement area law in 1D systems. However, it is unknown how to implement an MPU as a quantum circuit since the individual tensors describing the MPU are not unitary. In this paper, we show that a large class of MPUs can be implemented with a polynomial-depth quantum circuit. For an $N$-site MPU built from a repeated bulk tensor with open boundary, we explici…

Handling fabrication defects in hex-grid surface codes
Oscar Higgott, Benjamin Anker, Matt McEwen, Dripto M. Debroy
https://arxiv.org/abs/2508.08116 https://

Handling fabrication defects in hex-grid surface codes
Recent work has shown that a hexagonal grid qubit layout, with only three couplers per qubit, is sufficient to implement the surface code with performance comparable to that of a traditional four-coupler layout [McEwen et al., 2023]. In this work we propose a method for handling broken qubits and couplers even in hex-grid surface code architectures, using an extension of the LUCI framework [Debroy et al., 2024]. We show that for isolated broken qubits, the circuit distance drops by one, while f…

How Quantum Agents Can Change Which Strategies Are More Complex
Spiros Kechrimparis, Nix Barnett, Mile Gu, Hyukjoon Kwon
https://arxiv.org/abs/2508.08092 https://

How Quantum Agents Can Change Which Strategies Are More Complex
Whether winning blackjack or navigating busy streets, achieving desired outcomes requires agents to execute adaptive strategies, strategies where actions depend contextually on past events. In complexity science, this motivates memory as an operational quantifier of complexity: given two strategies, the more complex one demands the agent to track more about the past. Here, we show that conclusions about complexity fundamentally depend on whether agents can process and store quantum information.…

The role of Quantum Diffusion Flux in Super-Luminal Wave Packets
Charalampos Antonakos
https://arxiv.org/abs/2508.08065 https://arxiv.org/pdf/2508.08065

The role of Quantum Diffusion Flux in Super-Luminal Wave Packets
In this short-length paper, we will present some math that play a central role in quantum hydrodynamics and that were presented by Mita in the past. In this formulation of QM, a quantity is involved which is called the diffusion flux. As we will see, this quantity plays a crucial role on the evolution of wave packets. More specifically, we will initially briefly explain some results derived in Mita's papers, by analyzing Gaussian and soliton wave packets, while our main focus is on the role of …

Superresolution for two incoherent optical sources with arbitrary intensities in two dimensions
Junyan Li, Shengshi Pang
https://arxiv.org/abs/2508.08049 https://

Superresolution for two incoherent optical sources with arbitrary intensities in two dimensions
The Rayleigh criterion has long served as a fundamental limit for the resolution of classical optical imaging. However, recent advances in quantum metrology have led to the quantum superresolution technique that can break Rayleigh's curse and estimate the separation between a pair of incoherent point sources with nonvanishing precision. For two-dimensional optical systems, the precision limit of estimating the whole separation, i.e., the distance, between two point sources remains unknown so fa…

Replaced article(s) found for quant-ph. https://arxiv.org/list/quant-ph/new
[4/4]:
- Nonequilibrium Phase Transitions in Large $N$ Matrix Quantum Mechanics
Minjae Cho

Replaced article(s) found for quant-ph. https://arxiv.org/list/quant-ph/new
[3/4]:
- Charge sensitivity in the transmon regime
Rocio Gonzalez-Meza, Vito Iaia, Anika Zaman, Hiu-Yung Wong, Yujin Cho, Kristin Beck, Yaniv J. Rosen

Replaced article(s) found for quant-ph. https://arxiv.org/list/quant-ph/new
[2/4]:
- Heisenberg-limited calibration of entangling gates with robust phase estimation
Kenneth Rudinger, J. P. Marceaux, Akel Hashim, David I. Santiago, Irfan Siddiqi, Kevin C. Young

Replaced article(s) found for quant-ph. https://arxiv.org/list/quant-ph/new
[1/4]:
- The Algebra of the Pseudo-Observables I: Why Quantum Mechanics is the ultimate description of Rea...
Edoardo Piparo (Ministero dell'Istruzione dell'Universit\`a e della Ricerca)

Replaced article(s) found for quant-ph. https://arxiv.org/list/quant-ph/new
[3/3]:
- Principle of Diminishing Potentialities in Large N Algebras
Bik Soon Sia
h…

Replaced article(s) found for quant-ph. https://arxiv.org/list/quant-ph/new
[2/3]:
- Bipartite quantum states admitting a causal explanation
Minjeong Song, Arthur J. Parzygnat

Replaced article(s) found for quant-ph. https://arxiv.org/list/quant-ph/new
[1/3]:
- Tight Lieb-Robinson Bound for approximation ratio in Quantum Annealing
Arthur Braida, Simon Martiel, Ioan Todinca

Crosslisted article(s) found for quant-ph. https://arxiv.org/list/quant-ph/new
[1/1]:
- A Novel Theoretical Approach on Micro-Nano Robotic Networks Based on Density Matrices and Swarm Q...
Maria Mannone, Mahathi Anand, Peppino Fazio, Abdalla Swikir

QCardEst/QCardCorr: Quantum Cardinality Estimation and Correction
Tobias Winker, Jinghua Groppe, Sven Groppe
https://arxiv.org/abs/2509.08817 https://arxiv…

QCardEst/QCardCorr: Quantum Cardinality Estimation and Correction
Cardinality estimation is an important part of query optimization in DBMS. We develop a Quantum Cardinality Estimation (QCardEst) approach using Quantum Machine Learning with a Hybrid Quantum-Classical Network. We define a compact encoding for turning SQL queries into a quantum state, which requires only qubits equal to the number of tables in the query. This allows the processing of a complete query with a single variational quantum circuit (VQC) on current hardware. In addition, we compare mu…

A Pathway to Practical Quantum Advantage in Solving Navier-Stokes Equations
Xi-Ning Zhuang, Zhao-Yun Chen, Ming-Yang Tan, Jiaxuan Zhang, Chuang-Chao Ye, Tian-Hao Wei, Teng-Yang Ma, Cheng Xue, Huan-Yu Liu, Qing-Song Li, Tai-Ping Sun, Xiao-Fan Xu, Yun-Jie Wang, Yu-Chun Wu, Guo-Ping Guo
https://arxiv.org/abs/2509.08807

A Pathway to Practical Quantum Advantage in Solving Navier-Stokes Equations
The advent of fault-tolerant quantum computing (FTQC) promises to tackle classically intractable problems. A key milestone is solving the Navier-Stokes equations (NSE), which has remained formidable for quantum algorithms due to their high input-output overhead and nonlinearity. Here, we establish a full-stack framework that charts a practical pathway to a quantum advantage for large-scale NSE simulation. Our approach integrates a spectral-based input/output algorithm, an explicit and synthesiz…

Implementing a Universal Set of Geometric Quantum Gates through Dressed-State assisted STA
M. Estefan\'ia Rus, Alejandro Ferr\'on, Omar Osenda, Sergio S. Gomez
https://arxiv.org/abs/2509.08723 …

Implementing a Universal Set of Geometric Quantum Gates through Dressed-State assisted STA
Geometric quantum computation relies on the geometric phase that arises in adiabatic cyclic evolutions of non-degenerate quantum systems, enabling the design of robust quantum gates. However, the adiabatic condition requires long evolution times, making the system vulnerable to decoherence. In this work, we propose a scheme to realize fast and high-fidelity geometric quantum gates by applying the Superadiabatic Transitionless Driving (SATD) protocol within the dressed-state framework. We analyz…

Adaptive Quantum Computers: decoding and state preparation
Niels M. P. Neumann
https://arxiv.org/abs/2509.08718 https://arxiv.org/pdf/2509.08718

Adaptive Quantum Computers: decoding and state preparation
Interacting with a standard computer can enhance the capabilities of current quantum computers already today, particularly by offloading certain computations to the standard computer. Quantum computers that interact with standard computers to perform computations are called adaptive quantum computers. This work formalizes a model that describes these adaptive quantum computers. As quantum computers are still under development, this work focuses on computations that terminate after a fixed numbe…

Power and limitations of distributed quantum state purification
Benchi Zhao, Yu-Ao Chen, Xuanqiang Zhao, Chengkai Zhu, Giulio Chiribella, Xin Wang
https://arxiv.org/abs/2509.08691

Power and limitations of distributed quantum state purification
Quantum state purification, which mitigates noise by exploiting multiple noisy copies of unknown states, has applications in quantum communication and computation with imperfect devices. Despite its importance, the fundamental capabilities and limitations of purification in distributed quantum systems remain largely unexplored. Here, we systematically study distributed quantum state purification under local operations and classical communication (LOCC). We prove that no nontrivial two-to-one LO…

How to simulate magic state cultivation with around $8$ Clifford terms on average
Kwok Ho Wan, Zhenghao Zhong
https://arxiv.org/abs/2509.08658 https://arxi…

How to simulate magic state cultivation with around $8$ Clifford terms on average
Building upon [arXiv:2509.01224], we present a sketch on how to simulate the non-Clifford $d=5$ magic state cultivation circuits [arXiv:2409.17595] with a sum of $\approx 8$ Clifford ZX-diagrams on average, at $0.1\%$ noise. Compared to a magic cat state stabiliser decomposition of all $53$ non-Clifford spiders ($6{,}377{,}292$ terms required), this is more than $7 \times 10^{5}$ times reduction in the number of terms. Our stabiliser decomposition has the advantage of representing the final non…

Robust Belief-State Policy Learning for Quantum Network Routing Under Decoherence and Time-Varying Conditions
Amirhossein Taherpour, Abbas Taherpour, Tamer Khattab
https://arxiv.org/abs/2509.08654

Robust Belief-State Policy Learning for Quantum Network Routing Under Decoherence and Time-Varying Conditions
This paper presents a feature-based Partially Observable Markov Decision Process (POMDP) framework for quantum network routing, combining belief-state planning with Graph Neural Networks (GNNs) to address partial observability, decoherence, and scalability challenges in dynamic quantum systems. Our approach encodes complex quantum network dynamics, including entanglement degradation and time-varying channel noise, into a low-dimensional feature space, enabling efficient belief updates and scala…

Construction of Kochen-Specker Sets from Mutually Unbiased Bases
Mirko Navara, Karl Svozil
https://arxiv.org/abs/2509.08636 https://arxiv.org/pdf/2509.0863…

Construction of Kochen-Specker Sets from Mutually Unbiased Bases
We present a systematic, constructive analysis of Kochen-Specker contextuality, emphasizing the foundational importance of complete orthogonal bases (contexts). First, in three dimensions, we generate a complete inventory of 165 rays and 130 bases from mutually unbiased bases. This unified framework reveals that several known constructions are equivalent manifestations of a minimal 69-ray, 50-context Kochen--Specker nucleus and uncovers a striking 40-4-4 generative asymmetry among the mutual un…

No Bound Randomness in Quantum Nonlocality
Ravishankar Ramanathan, Yuan Liu, Yutian Wu, Stefano Pironio
https://arxiv.org/abs/2509.08623 https://arxiv.org/…

No Bound Randomness in Quantum Nonlocality
Recently it has been found that there exist maximally nonlocal quantum correlations that fail to certify randomness for any fixed input pair, rendering them useless for device-independent spot-checking randomness expansion schemes. Here we show that conversely, in DI randomness amplification protocols where all input pairs are used for randomness generation, any amount of quantum nonlocality is sufficient to certify randomness. This shows that no bound randomness exists in quantum nonlocality -…

Cat states in one- and two-mode $\mathbb{Z}_3$ Rabi models
Anatoliy I. Lotkov, Denis V. Kurlov, Valerii K. Kozin, Jelena Klinovaja, Daniel Loss
https://arxiv.org/abs/2509.08603 …

Cat states in one- and two-mode $\mathbb{Z}_3$ Rabi models
We investigate one- and two-mode variants of the $\mathbb{Z}_3$-symmetric quantum Rabi model, which describe the interaction of a qutrit with one or two bosonic modes and are directly relevant for circuit-QED and spin-qudit platforms. We find a canonical transformation that allows one to obtain the spectrum of the $\mathbb{Z}_3$ Rabi model using perturbation theory in a magnetic field. We show that in a certain parameter regime (deep-strong-coupling and a small magnetic field) the three lowest …

Computation of operator exponentials using the Dunford-Cauchy integral
Alexander Tsirulev
https://arxiv.org/abs/2509.08600 https://arxiv.org/pdf/2509.08600…

Computation of operator exponentials using the Dunford-Cauchy integral
We consider an n-qubit quantum system with a Hamiltonian, defined by an expansion in the Pauli basis, and propose a new algorithm for classical computing the exponential of the Hamiltonian. The algorithm is based on the representation of the exponential by the Dunford-Cauchy integral, followed by an efficient computation of the resolvent, and is suitable for Hamiltonians that are sparse in the Pauli basis. The practical efficiency of the algorithm is demonstrated by two illustrative examples.

Spectral Transitions of the Entanglement Hamiltonian in Monitored Free Fermions
Karim Chahine, Michael Buchhold
https://arxiv.org/abs/2509.08584 https://ar…

Spectral Transitions of the Entanglement Hamiltonian in Monitored Free Fermions
We numerically investigate measurement-induced phase transitions in monitored free fermions through the spectral and eigenstate properties of the entanglement Hamiltonian. By analyzing entanglement scaling, we identify three non-trivial fixed points, for which the entanglement follows exact analytical scaling forms: chaotic unitary dynamics at infinitesimal monitoring, characterized by a Gaussian Page law; a Fermi-liquid fixed point at moderate monitoring, defining a metallic phase with logarit…

Loss-tolerant parallelized Bell-state generation with a hybrid cat qudit
Z. M. McIntyre, W. A. Coish
https://arxiv.org/abs/2509.08577 https://arxiv.org/pdf…

Loss-tolerant parallelized Bell-state generation with a hybrid cat qudit
Having multiple Bell pairs shared by distant quantum registers provides a key resource for both quantum networks and distributed quantum computing. In this paper, we present a protocol for parallelized Bell-pair generation that uses the phase of a coherent light pulse to encode a qudit, enabling the simultaneous generation of multiple Bell pairs. By encoding a qudit in a basis of light-matter Schrödinger's cat states, the loss of a photon in transit can be detected through an $XX$ parity syndr…

Optimal detection of quantum states via projective measurements
Giuseppe Del Vecchio Del Vecchio, Satya N. Majumdar
https://arxiv.org/abs/2509.08556 https://

Optimal detection of quantum states via projective measurements
We consider the quantum dynamical evolution of a fully-connected quantum system subjected to random projective measurements and study the first detection time of an extended subspace of the Hilbert space. Exact analytical expressions are obtained for the mean first detection time and the full first detection probability distribution as functionals of the initial state $\ket{ψ_0}$ and the measurement rate $r$. Exact enumeration agrees perfectly with our analytical predictions.

Benchmarking Optimization Algorithms for Automated Calibration of Quantum Devices
Kevin Pack, Shai Machnes, Frank K. Wilhelm
https://arxiv.org/abs/2509.08555 https://

Benchmarking Optimization Algorithms for Automated Calibration of Quantum Devices
We present the results of a comprehensive study of optimization algorithms for the calibration of quantum devices. As part of our ongoing efforts to automate bring-up, tune-up, and system identification procedures, we investigate a broad range of optimizers within a simulated environment designed to closely mimic the challenges of real-world experimental conditions. Our benchmark includes widely used algorithms such as Nelder-Mead and the state-of-the-art Covariance Matrix Adaptation Evolution …

Demonstration of a Compatibility-Based Childcare Support Service using Quantum Annealing
Yuuma Matsumoto, Taisei Takabayashi, Rima Sato, Rumiko Honda, Masayuki Ohzeki
https://arxiv.org/abs/2509.08520

Demonstration of a Compatibility-Based Childcare Support Service using Quantum Annealing
In contemporary Japan, isolated parenting has become a serious social issue, increasing psychological stress on parents and potentially affecting children's development. Existing childcare support services tend to focus on physical assistance, while psychological support and community connections remain insufficient. To address this gap, we developed a service that connects parents with senior community members who have parenting experience, aiming to provide psychological support and foster in…

Parametric resonance and nonlinear dynamics in a coupled double-pendulum system
Yusheng Niu, Yixian Liu, Hongyan Fan, Zhenqi Bai, Yichi Zhang
https://arxiv.org/abs/2509.08509 ht…

Parametric resonance and nonlinear dynamics in a coupled double-pendulum system
Nonlinear dynamics plays a significant role in interdisciplinary fields spanning biology, engineering, mathematics, and physics. Under small-amplitude approximations, certain nonlinear systems can be effectively described by the linear Mathieu equation, which is widely recognized for modeling the response of systems with periodically modulated parameters. Here we investigated a collision-coupled double pendulum system within the framework of Lagrangian mechanics, further explored the nonlinear …

A relational critique of Bell locality
Jan van Neerven, Marijn Waaijer
https://arxiv.org/abs/2509.08487 https://arxiv.org/pdf/2509.08487

A relational critique of Bell locality
This paper provides a systematic analysis of Bell experiments from the relational perspective, demonstrating that the apparent ``nonlocality'' of quantum mechanics stems from a problematic application of relativistic principles rather than mysterious space-like influences. We show that when Bell experiments are properly analysed through individual observer accounts, all measurements remain strictly local. Alice's and Bob's local measurements can be fully understood in terms of variables from th…

Robustness of quantum algorithms: Worst-case fidelity bounds and implications for design
Julian Berberich, Tobias Fellner, Robert L. Kosut, Christian Holm
https://arxiv.org/abs/2509.08481

Robustness of quantum algorithms: Worst-case fidelity bounds and implications for design
Errors occurring on noisy hardware pose a key challenge to reliable quantum computing. Existing techniques such as error correction, mitigation, or suppression typically separate the error handling from the algorithm analysis and design. In this paper, we develop an alternative, algorithm-centered framework for understanding and improving the robustness against errors. For a given quantum algorithm and error model, we derive worst-case fidelity bounds which can be explicitly computed to certify…

Frequency drift corrected ultra-stable laser through phase-coherent fiber producing a quantum channel
Stanley Johnson, Sandeep Mishra, Anirban Pathak, Subhadeep De
https://arxiv.org/abs/2509.08419

Frequency drift corrected ultra-stable laser through phase-coherent fiber producing a quantum channel
Phase coherent fibers (PCF) are essential to distribute nearly monochromatic photons, ultra-stable in their frequency and phases, which have demanding requirements for state-of-the-art networked experiments, quantum as well as very high-speed communications. We report the development of a novel system that produces PCF links, also actively corrects the unavoidable slow frequency drift of the source laser. The PCF follows white phase noise limited $σ_o \times τ^{-1}$ stability behavior having …

Realizing the Haldane Model in Thermal Atoms
Jiefei Wang, Jianhao Dai, Ruosong Mao, Yunzhou Lu, Xiao Liu, Huizhu Hu, Shi-Yao Zhu, Xingqi Xu, Han Cai, Da-Wei Wang
https://arxiv.org/abs/2509.08411

Realizing the Haldane Model in Thermal Atoms
Topological materials hold great promise for developing next-generation devices with transport properties that remain resilient in the presence of local imperfections. However, their susceptibility to thermal noise has posed a major challenge. In particular, the Haldane model, a cornerstone in topological physics, generally requires cryogenic temperatures for experimental realization, limiting both the investigation of topologically robust quantum phenomena and their practical applications. In …

Addressing requirements for crosstalk-free quantum-gate operation in many-body nanofiber cavity QED systems
Tim Keller, Seigo Kikura, Rui Asaoka, Yasunari Suzuki, Yuuki Tokunaga, Takao Aoki
https://arxiv.org/abs/2509.08408

Addressing requirements for crosstalk-free quantum-gate operation in many-body nanofiber cavity QED systems
A distributed network architecture in which flying photons connect individual modules containing stationary atomic qubits is a promising approach for scaling up neutral-atom based quantum-computing platforms. We consider an all-fiber based platform consisting of nanofiber cavity QED systems interconnected via conventional optical fibers. Each nanofiber cavity is strongly coupled to multiple atoms through its evanescent field, and atom pairs within one cavity (local) or two distant cavities (rem…

LLM-Guided Ans\"atze Design for Quantum Circuit Born Machines in Financial Generative Modeling
Yaswitha Gujju, Romain Harang, Tetsuo Shibuya
https://arxiv.org/abs/2509.08385

LLM-Guided Ansätze Design for Quantum Circuit Born Machines in Financial Generative Modeling
Quantum generative modeling using quantum circuit Born machines (QCBMs) shows promising potential for practical quantum advantage. However, discovering ansätze that are both expressive and hardware-efficient remains a key challenge, particularly on noisy intermediate-scale quantum (NISQ) devices. In this work, we introduce a prompt-based framework that leverages large language models (LLMs) to generate hardware-aware QCBM architectures. Prompts are conditioned on qubit connectivity, gate error…

From Physical to Logical: Graph-State-Based Connectivity in Quantum Networks
Mateo M. Blanco, Manuel Fern\'andez-Veiga, Ana Fern\'andez-Vilas, Rebeca P. D\'iaz-Redondo
https://arxiv.org/abs/2509.08384

From Physical to Logical: Graph-State-Based Connectivity in Quantum Networks
Entanglement is a key resource in quantum communication, but bipartite schemes are often insufficient for advanced protocols like quantum secret sharing or distributed computing. Graph states offer a flexible way to represent and manage multipartite entanglement in quantum networks, enabling logical connectivity through local operations and classical communication (LOCC). In this work, we extend existing approaches based on bi-star configurations to more complex multi-star topologies. We analyz…

Persistent-DPO: A novel loss function and hybrid learning for generative quantum eigensolver
Junya Nakamura, Shinichiro Sanji
https://arxiv.org/abs/2509.08351 https://

Persistent-DPO: A novel loss function and hybrid learning for generative quantum eigensolver
We study the generative quantum eigensolver (GQE)~\cite{nakaji2024generative}, which trains a classical generative model to produce quantum circuits with desired properties such as describing molecular ground states. We introduce two methods to improve GQE. First, we identify a limitation of direct preference optimization (DPO) when used as the loss function in GQE, and propose Persistent-DPO (P-DPO) as a solution to this limitation. Second, as a method to improve the online learning during the…

Atomic diffraction by patterned holes in hexagonal boron nitride: a comparison between semi-classical and quantum computational models
Eivind Kristen Osestad, Ekaterina Zossimova, Michael Walter, Johannes Fiedler
https://arxiv.org/abs/2509.08336

Atomic diffraction by patterned holes in hexagonal boron nitride: a comparison between semi-classical and quantum computational models
The diffraction of atoms and molecules through tiny, sub-nanometre holes in atomically thin membranes is a promising approach for advancing atom interferometry sensing and atomic holography. However, dispersion interactions, such as the Casimir-Polder force, pose a significant challenge by attracting diffracting particles to the membrane, limiting the minimum hole size. This paper presents a numerical simulation of helium matter-wave diffraction through sub-nanometre holes in hexagonal boron ni…

Towards solving industrial integer linear programs with Decoded Quantum Interferometry
Francesc Sabater, Ouns El Harzli, Geert-Jan Besjes, Marvin Erdmann, Johannes Klepsch, Jonas Hiltrop, Jean-Francois Bobier, Yudong Cao, Carlos A. Riofrio
https://arxiv.org/abs/2509.08328

Towards solving industrial integer linear programs with Decoded Quantum Interferometry
Optimization via decoded quantum interferometry (DQI) has recently gained a great deal of attention as a promising avenue for solving optimization problems using quantum computers. In this paper, we apply DQI to an industrial optimization problem in the automotive industry: the vehicle option-package pricing problem. Our main contributions are 1) formulating the industrial problem as an integer linear program (ILP), 2) converting the ILP into instances of max-XORSAT, and 3) developing a detaile…

The Born rule as a natural transformation of functors
Boyu Yang, James Fullwood
https://arxiv.org/abs/2509.08323 https://arxiv.org/pdf/2509.08323

The Born rule as a natural transformation of functors
In this work, we show that the quantum mechanical notions of density operator, positive operator-valued measure (POVM), and the Born rule, are all simultaneously encoded in the categorical notion of a natural transformation of functors. In particular, we show that given a fixed quantum system, there exists an explicit bijection from the set of density operators on the associated Hilbert space to the set of natural transformations between the canonical measurement and probability functors associ…

Practical robust Bayesian spin-squeezing-enhanced quantum sensing under noises
Jinye Wei, Jungeng Zhou, Yi Shen, Jiahao Huang, Chaohong Lee
https://arxiv.org/abs/2509.08316 http…

Practical robust Bayesian spin-squeezing-enhanced quantum sensing under noises
Spin-squeezed states constitute a valuable entanglement resource capable of surpassing the standard quantum limit (SQL). However, spin-squeezed states only enable sub-SQL uncertainty within a narrow parametric window near some specific points. Identifying optimal measurement protocols for spin-squeezed states remains an outstanding challenge. Here we present an adaptive Bayesian quantum estimation protocol that achieves optimal measurement precision with spin-squeezed states under noises. Our p…

Symmetry-protected many-body Ramsey spectroscopy: precision scaling and robustness
Sijie Chen, Jiahao Huang, Min Zhuang, Chaohong Lee
https://arxiv.org/abs/2509.08291 https://…

Symmetry-protected many-body Ramsey spectroscopy: precision scaling and robustness
Quantum entanglement is a powerful quantum resource for enhancing measurement precision beyond classical limit. % Here we propose an entanglement-enhanced symmetry-protected destructive many-body Ramsey interferometry for precise parameter estimation. % Through matching the symmetry of input states and Hamiltonian, the spectral shift of Ramsey spectroscopy caused by interparticle interaction, noise, decoherence and experimental imperfection can be mitigated for both time-independent and time-de…

Ramsey Spectroscopy via Symmetry-Protected Destructive Many-Body Interferometry
Sijie Chen, Jiahao Huang, Min Zhuang, Chaohong Lee
https://arxiv.org/abs/2509.08288 https://

Ramsey Spectroscopy via Symmetry-Protected Destructive Many-Body Interferometry
Ramsey spectroscopy, a fundamental tool in both basic science and practical applications, is inevitably subject to several detrimental effects. % Here we propose a symmetry-protected destructive many-body interferometry (SPDMBI) for Ramsey spectroscopy, which successfully mitigates the spectral shift caused by interparticle interaction, noise, decoherence and experimental imperfection. % Through matching the symmetry of the input states and the Hamiltonian, the SPDMBI-based Ramsey spectroscopy …

Comparing incompatibility from an operational perspective
Kensei Torii, Ryo Takakura, Ryotaro Imamura
https://arxiv.org/abs/2509.08284 https://arxiv.org/pd…

Comparing incompatibility from an operational perspective
To effectively utilize quantum incompatibility as a resource in quantum information processing, it is crucial to evaluate how incompatible a set of devices is. In this study, we propose an ordering to compare incompatibility and reveal its various properties based on the operational intuition that larger incompatibility can be detected with fewer states. We especially focus on typical class of incompatibility exhibited by mutually unbiased qubit observables and numerically demonstrate that the …

FeynmanDD: Quantum Circuit Analysis with Classical Decision Diagrams
Ziyuan Wang, Bin Cheng, Longxiang Yuan, Zhengfeng Ji
https://arxiv.org/abs/2509.08276 https://

FeynmanDD: Quantum Circuit Analysis with Classical Decision Diagrams
Applications of decision diagrams in quantum circuit analysis have been an active research area. Our work introduces FeynmanDD, a new method utilizing standard and multi-terminal decision diagrams for quantum circuit simulation and equivalence checking. Unlike previous approaches that exploit patterns in quantum states and operators, our method explores useful structures in the path integral formulation, essentially transforming the analysis into a counting problem. The method then employs effi…

Scalable Network of Mach-Zehnder Interferometers with a Single Entangled Resource
Zhihui Yan, Yanni Feng, Luca Pezze, Zhaoqing Zeng, Jingxu Ma, Xiaoyu Zhou, Augusto Smerzi, Xiaojun Jia, Kunchi Peng
https://arxiv.org/abs/2509.08230

Scalable Network of Mach-Zehnder Interferometers with a Single Entangled Resource
Distributed quantum sensing exploits entanglement to enhance the estimation of multiple parameters across a network of spatially-separated sensors, achieving sensitivities beyond the classical limit. Potential applications cover a plethora of technologies, from precision navigation to biomedical imaging and environmental monitoring. However, practical implementations are challenged by the complex optimal distribution of entanglement throughout the sensing nodes, which affects scalability and ro…

Enhancing Sum Capacity via Quantum and No-Signaling Cooperation Between Transmitters
Seung-Hyun Nam, Hyun-Young Park, Jiyoung Yun, Ashutosh Rai, Si-Hyeon Lee, Joonwoo Bae
https://arxiv.org/abs/2509.08219

Enhancing Sum Capacity via Quantum and No-Signaling Cooperation Between Transmitters
We consider a communication scenario over a discrete memoryless interference channel or multiple access channel without feedback, where transmitters exploit classical, quantum, or no-signaling cooperation. In this scenario, several previous works have shown that the sum capacities of channels involving pseudo-telepathy games can be enhanced by quantum or no-signaling cooperation. However, a full characterization of which channels admit such an improvement remains open. By focusing on the common…