Tootfinder

Efficient Quantum Information-Inspired Ansatz for Variational Quantum Eigensolver Algorithm: Applications to Atomic Systems
Abdul Kalam, Prasenjit Deb, Akitada Sakurai, B. K. Sahoo, V. S. Prasannaa, B. P. Das
https://arxiv.org/abs/2508.10593

Efficient Quantum Information-Inspired Ansatz for Variational Quantum Eigensolver Algorithm: Applications to Atomic Systems
We present a quantum information-inspired ansatz for the variational quantum eigensolver (VQE) and demonstrate its efficacy in calculating ground-state energies of atomic systems. Instead of adopting a heuristic approach, we start with an approximate multi-qubit target state and utilize two quantum information-theoretic quantities, i.e., von Neumann entropy and quantum mutual information, to construct our ansatz. The quantum information encoded in the target state helps us to design unique bloc…

Quantum register based on double quantum dots in semiconductor nanowires
Vladimir Vyurkov, Leonid Fedichkin, Igor Semenikhin, Denis Drozhzhin, Konstantin Rudenko, Vladimir Lukichev
https://arxiv.org/abs/2507.08485

Quantum register based on double quantum dots in semiconductor nanowires
An implementation of a universal solid-state quantum register based on electron space states in field-defined double quantum dots (DQD possesses one electron in two adjacent tunnel bound dots) in an ultrathin semiconductor nanowire is discussed. To some extent, the structure resembles that of a field-effect transistor with multiple controlling electrodes (gates). Scalability is audible and it opens up a possibility of large-scale quantum computer fabricated by advanced silicon technology. Moreo…

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 …

Pretty good state transfer in Grover walks on abelian Cayley graphs
Koushik Bhakta, Bikash Bhattacharjya
https://arxiv.org/abs/2508.09711 https://arxiv.org…

Pretty good state transfer in Grover walks on abelian Cayley graphs
In this paper, we study pretty good state transfer (PGST) in Grover walks on graphs. We consider transfer of quantum states that are localized at the vertices of a graph and we use Chebyshev polynomials to analyze PGST between such states. In general, we find a necessary and sufficient condition for the occurrence of PGST on graphs. We then focus our analysis on abelian Cayley graphs and derive a necessary and sufficient condition for the occurrence of PGST on such graphs. Consequently, we obta…

Observing Spacetime
Vijay Balasubramanian, Tom Yildirim
https://arxiv.org/abs/2509.09763 https://arxiv.org/pdf/2509.09763

Observing Spacetime
Complex states of quantum gravity in flat and AdS gravity can have features that are inaccessible to classical asymptotic observers. The missing information appears to such observers to be hidden behind a horizon or in a baby universe. Here we use the gravitational path integral to ask whether quantum observables can access the hidden data. We show that generic probes give a universal result and contain no information about the state. However, a probe appropriately fine-tuned to the state can g…

Machine-Learning-enabled ab initio study of quantum phase transitions in SrTiO$_3$
Jonathan Schmidt, Nicola A. Spaldin
https://arxiv.org/abs/2508.10735 https://

Machine-Learning-enabled ab initio study of quantum phase transitions in SrTiO$_3$
We use the self-consistent harmonic approximation (SSCHA) with machine learning interatomic potentials to calculate the effect of $^{18}$O substitution on the properties of quantum paraelectric SrTiO$_3$ (STO). We find that calculations including both quantum and anharmonic effects are able to reproduce the experimentally observed isotope effect, in which replacement of $^{16}$O by $^{18}$O induces the ferroelectric state, and demonstrate that the ferroelectric phase transition in ST$^{18}$O ca…

Quantum statistics of single-mode radiation emitted by superradiant Dicke states
A. Yadav, D. D. Yavuz
https://arxiv.org/abs/2508.09962 https://arxiv.org/p…

Quantum statistics of single-mode radiation emitted by superradiant Dicke states
We study the quantum statistics of single-mode radiation emitted by an atomic ensemble when the ensemble is initially prepared in a superradiant Dicke state. We show that while the radiation is well approximated by the Glauber coherent state at early times in the evolution, the emission can be truly quantum at later times. In particular, one can observe a large amount of photon-number squeezing in the emission under certain conditions; even a Fock state can be produced. We discuss the quantum s…

On quantum creation of a toroidal universe
Alan H. Guth, Alexander Vilenkin
https://arxiv.org/abs/2508.08747 https://arxiv.org/pdf/2508.08747

On quantum creation of a toroidal universe
We consider the quantum creation of a universe with flat spatial sections and the topology of a 3-torus, taking into account the effect of Casimir energy. We show that the corresponding instantons are singular. Since these instantons describe universes originating in a state of infinite energy, we argue that they cannot be interpreted as quantum creation from `nothing'. If quantum corrections to the energy-momentum tensor are neglected, the spacetime of the toroidal universe reduces to de Sitte…

Baryon-baryon, meson-meson, and meson-baryon interactions in nonrelativistic QCD
Beno\^it Assi, Anthony Grebe, Michael Wagman
https://arxiv.org/abs/2508.10090 https://

Baryon-baryon, meson-meson, and meson-baryon interactions in nonrelativistic QCD
Van der Waals potentials describing interactions between color-singlet mesons and/or baryons vanish at leading order in potential nonrelativistic quantum chromodynamics (pNRQCD). This result and constraints from Gauss's law are used to prove that weakly-coupled pNRQCD van der Waals potentials in generic non-Abelian gauge theories with only heavy quarks are too weak to form bound states whose color state is a product of color-singlets. Quantum Monte Carlo calculations of four, five, and six quar…

Nonequilibrium steady state in Lindblad dynamics for infinite quantum spin systems
Kenji Shimomura, Nagisa Hara, Seiichiro Kusuoka
https://arxiv.org/abs/2508.07448 https://

Nonequilibrium steady state in Lindblad dynamics for infinite quantum spin systems
We consider Lindblad dynamics of quantum spin systems on infinite lattices and define a nonequilibrium steady state (NESS) and a time-averaged nonequilibrium steady state (TANESS) on the basis of $C^*$-algebraic formalism. Generically, the NESS on an infinite system does not equal the thermodynamic limit of NESSs on finite systems. We give a sufficient condition that they coincide with each other, in terms of both a condition number, which quantifies the normality of a Liouvillian, and some spe…

Generation of a CW anti-bunched photon field from a thin-film PPLN waveguide by two-photon interference with a weak coherent state
Yue Li, Haochuan Li, Yuhang Lei, Xiaoting Li, Jianmin Wang, Xuan Tang, Mu Ku Chen, E. Y. B. Pun, Cheng Wang, Z. Y. Ou
https://arxiv.org/abs/2508.10135

Generation of a CW anti-bunched photon field from a thin-film PPLN waveguide by two-photon interference with a weak coherent state
An anti-bunched photon field is produced from a thin-film ppln waveguide by mixing the on-chip two-photon state with a weak but matched coherent state. This is achieved by taking out the two-photon part of the coherent state via a destructive two-photon interference with the on-chip two-photon state. We achieve a photon rate of 100 kHz with a g2-value of 0.35. This anti-bunched light field will have applications in high-resolution quantum imaging such as long baseline quantum telescopy for enha…

On the Generalization Limits of Quantum Generative Adversarial Networks with Pure State Generators
Jasmin Frkatovic, Akash Malemath, Ivan Kankeu, Yannick Werner, Matthias Tsch\"ope, Vitor Fortes Rey, Sungho Suh, Paul Lukowicz, Nikolaos Palaiodimopoulos, Maximilian Kiefer-Emmanouilidis
https://arxiv.org/abs/2508.09844

On the Generalization Limits of Quantum Generative Adversarial Networks with Pure State Generators
We investigate the capabilities of Quantum Generative Adversarial Networks (QGANs) in image generations tasks. Our analysis centers on fully quantum implementations of both the generator and discriminator. Through extensive numerical testing of current main architectures, we find that QGANs struggle to generalize across datasets, converging on merely the average representation of the training data. When the output of the generator is a pure-state, we analytically derive a lower bound for the di…

Quantum Inspired Legal Tech Environmental Integration for Emergency Pharmaceutical Logistics with Entropy Modulated Collapse and Multilevel Governance
Ruicheng Li, Jingxu Wu
https://arxiv.org/abs/2508.08286

Quantum Inspired Legal Tech Environmental Integration for Emergency Pharmaceutical Logistics with Entropy Modulated Collapse and Multilevel Governance
Emergency pharmaceutical logistics during rapid-onset disasters must balance timeliness, legal compliance, and environmental uncertainty. We present a hybrid framework that co-designs quantum-inspired decision dynamics, embedded legal constraints, and blockchain-verified environmental feedback. Candidate routes are modeled as a superposed state whose collapse is governed by entropy modulation-delaying commitment under ambiguity and accelerating resolution when coherent signals emerge. Legal sta…

Emergent Hydrodynamics in an Exclusion Process with Long-Range Interactions
Ali Zahra, Jerome Dubail, Gunter M. Sch\"utz
https://arxiv.org/abs/2508.09879 https://

Emergent Hydrodynamics in an Exclusion Process with Long-Range Interactions
We study the symmetric Dyson exclusion process (SDEP) - a lattice gas with exclusion and long-range, Coulomb-type interactions that emerge both as the maximal-activity limit of the symmetric exclusion process and as a discrete version of Dyson's Brownian motion on the unitary group. Exploiting an exact ground-state (Doob) transform, we map the stochastic generator of the SDEP onto the spin-$1/2$ XX quantum chain, which in turn admits a free-fermion representation. At macroscopic scales we conje…

A Novel Theoretical Approach on Micro-Nano Robotic Networks Based on Density Matrices and Swarm Quantum Mechanics
Maria Mannone, Mahathi Anand, Peppino Fazio, Abdalla Swikir
https://arxiv.org/abs/2509.08002

A Novel Theoretical Approach on Micro-Nano Robotic Networks Based on Density Matrices and Swarm Quantum Mechanics
In a robotic swarm, parameters such as position and proximity to the target can be described in terms of probability amplitudes. This idea led to recent studies on a quantum approach to the definition of the swarm, including a block-matrix representation. Here, we propose an advancement of the idea, defining a swarm as a mixed quantum state, to be described with a density matrix, whose size does not change with the number of robots. We end the article with some directions for future research.

Reversing adiabatic state preparation
L. Romanato, N. Eshaqi-Sani, L. Lepori, T. Kirova, E. Arimondo, S. Wimberger
https://arxiv.org/abs/2507.08439 https:/…

Reversing adiabatic state preparation
We present a detailed study of an adiabatic state preparation in an effective three-level quantum system. States can be prepared with high speed and fidelity by adding a counterdiabatic quantum control protocol. As a second step, we invert the preparation protocol to get back to the initial state. This describes an overall cyclic evolution in state space. Using counterdiabatic terms, the resulting composed fast evolution can be repeated many times. We then analyze the control of Berry's phase a…

Gauging the variational optimization of projected entangled-pair states
Wei Tang, Laurens Vanderstraeten, Jutho Haegeman
https://arxiv.org/abs/2508.10822 https://

Gauging the variational optimization of projected entangled-pair states
Projected entangled-pair states (PEPS) constitute a powerful variational ansatz for capturing ground state physics of two-dimensional quantum systems. However, accurately computing and minimizing the energy expectation value remains challenging, in part because the impact of the gauge degrees of freedom that are present in the tensor network representation is poorly understood. We analyze the role of gauge transformations for the case of a U(1)-symmetric PEPS with point group symmetry, thereby …

Edge Reconstruction in a Quantum Spin Hall Insulator
Rahul Soni, Matthias Thamm, Gonzalo Alvarez, Bernd Rosenow, Adrian Del Maestro
https://arxiv.org/abs/2508.10726 https://

Edge Reconstruction in a Quantum Spin Hall Insulator
We study interaction-driven edge reconstruction in a quantum spin Hall insulator described by the Bernevig-Hughes-Zhang model with Kanamori-Hubbard interactions using the real-space density matrix renormalization group method in both the grand-canonical and canonical ensembles. For a two-dimensional cylinder with a smooth edge, we identify discrete particle-number transitions that lead to a spin-polarized edge state stabilized by an emergent ferromagnetic exchange interaction. The reconstructio…

Bianchi-I cosmology with scale dependent $G$ and $\Lambda$ in asymptotically safe gravity
Chiang-Mei Chen, Akihiro Ishibashi, Rituparna Mandal, Nobuyoshi Ohta
https://arxiv.org/abs/2509.09759

Bianchi-I cosmology with scale dependent $G$ and $Λ$ in asymptotically safe gravity
We study anisotropic Bianchi-I (BI) cosmology, incorporating quantum gravitational corrections into the Einstein equation through the scale-dependent Newton coupling and cosmological term, as determined by the flow equation of the effective action for gravity. For the cosmological term $Λ_0=0$, we derive the quantum-corrected power-series solution for a general equation-of-state parameter $w$ in the range $-1

Quantum recurrences and the arithmetic of Floquet dynamics
Amit Anand, Dinesh Valluri, Jack Davis, Shohini Ghose
https://arxiv.org/abs/2508.09933 https://a…

Quantum recurrences and the arithmetic of Floquet dynamics
The Poincaré recurrence theorem shows that conservative systems in a bounded region of phase space eventually return arbitrarily close to their initial state after a finite amount of time. An analogous behavior occurs in certain quantum systems where quantum states can recur after sufficiently long unitary evolution, a phenomenon known as quantum recurrence. Periodically driven (i.e. Floquet) quantum systems in particular exhibit complex dynamics even in small dimensions, motivating the study …

Surpassing the PLOB bound in continuous-variable quantum secret sharing using a state-discrimination detector
Qin Liao, Chong Tang, Qingquan Peng, Chao Ding, Lingjin Zhu, Yijun Wang, Xiquan Fu
https://arxiv.org/abs/2508.09445

Surpassing the PLOB bound in continuous-variable quantum secret sharing using a state-discrimination detector
Continuous-variable quantum secret sharing (CVQSS) is a promising approach to ensuring multi-party information security. While CVQSS offers practical ease of implementation, its present performance remains limited. In this paper, we propose a novel CVQSS protocol integrated with a state-discrimination detector (SDD), dubbed SDD-CVQSS. In particular, we first develop the detailed procedure of SDD-CVQSS, which replaces the traditional coherent detector with an SDD and eliminates the long-standing…

QB Ground State Energy Estimation Benchmark
Nicole Bellonzi, Joshua T. Cantin, Mohammad Reza Jangrouei, Alexander Kunitsa, Jason Necaise, Nam Nguyen, John Penuel, Maxwell D. Radin, Jhonathan Romero Fontalvo, Rashmi Sundareswara, Linjun Wang, Thomas Watts, Yanbing Zhou, Michael C. Garrett, Adam Holmes, Artur F. Izmaylov, Matthew Otten
https://

QB Ground State Energy Estimation Benchmark
Ground State Energy Estimation (GSEE) is a central problem in quantum chemistry and condensed matter physics, demanding efficient algorithms to solve complex electronic structure calculations. This work introduces a structured benchmarking framework for evaluating the performance of both classical and quantum solvers on diverse GSEE problem instances. We assess three prominent methods -- Semistochastic Heat-Bath Configuration Interaction (SHCI), Density Matrix Renormalization Group (DMRG), and …

Rigged Hilbert Space Formulation of Quantum Thermo Field Dynamics and Mapping to Rigged Liouville Space
Junichi Takahashi, Shousuke Ohmori
https://arxiv.org/abs/2508.06923 https…

Rigged Hilbert Space Formulation of Quantum Thermo Field Dynamics and Mapping to Rigged Liouville Space
The rigged Hilbert space, a triplet extension of the Hilbert space, provides a mathematically rigorous foundation for quantum mechanics by extending the Hilbert space to accommodate generalized eigenstates. In this paper, we construct a triplet structure for the thermal space arising in Thermo Field Dynamics with the aid of the tensor product formulation of rigged Hilbert spaces, a formalism that reformulates thermal averages as pure-state expectation values in a doubled Hilbert space. We then …

Emergent gauge flux in QED$_3$ with flavor chemical potential: application to magnetized U(1) Dirac spin liquids
Chuang Chen, Urban F. P. Seifert, Kexin Feng, Oleg A. Starykh, Leon Balents, Zi Yang Meng
https://arxiv.org/abs/2508.08528

Emergent gauge flux in QED$_3$ with flavor chemical potential: application to magnetized U(1) Dirac spin liquids
We design a lattice model of non-compact U(1) gauge field coupled to fermions with a flavor chemical potential and solve it with large-scale determinant quantum Monte Carlo simulations. For zero flavor chemical potential, the model realizes three-dimensional quantum electrodynamics (QED$_3$) which has been argued to describe the ground state and low-energy excitations of the Dirac spin liquid phase of quantum antiferromagnets. At finite flavor chemical potential, corresponding to a Zeeman field…

Quantum Wavefront Correction via Machine Learning for Satellite-to-Earth CV-QKD
Nathan K. Long, Ziqing Wang, Benjamin P. Dix-Matthews, Alex Frost, John Wallis, Kenneth J. Grant, Robert Malaney
https://arxiv.org/abs/2508.10326

Quantum Wavefront Correction via Machine Learning for Satellite-to-Earth CV-QKD
State-of-the-art free-space continuous-variable quantum key distribution (CV-QKD) protocols use phase reference pulses to modulate the wavefront of a real local oscillator at the receiver, thereby compensating for wavefront distortions caused by atmospheric turbulence. It is normally assumed that the wavefront distortion in these phase reference pulses is identical to the wavefront distortion in the quantum signals, which are multiplexed during transmission. However, in many real-world deployme…

Readout of multi-level quantum geometry from electronic transport
Raffael L. Klees, M\'onica Benito
https://arxiv.org/abs/2508.08239 https://arxiv.org/…

Readout of multi-level quantum geometry from electronic transport
The quantum geometric tensor (QGT) of a quantum system in a given parameter space captures both the geometry of the state manifold and the topology of the system. While the local QGT elements have been successfully measured in various platforms, the challenge of detecting them in electronic transport systems - such as tunnel or molecular junctions - has yet to be resolved. To fill this gap, we propose a measurement protocol based on weak and resonant parameter modulations, and theoretically dem…

Magic Steady State Production: Non-Hermitian and Stochastic pathways
Pablo Martinez-Azcona, Matthieu Sarkis, Alexandre Tkatchenko, Aur\'elia Chenu
https://arxiv.org/abs/2507.08676

Magic Steady State Production: Non-Hermitian and Stochastic pathways
Universal quantum computers require states with both entanglement and non-stabilizerness, the latter property being commonly known as \textit{quantum magic}. Here, we introduce a protocol that prepares magic steady states by leveraging non-Hermitian dynamics, which, contrary to unitary dynamics, can host pure-state attractors. We investigate the dissipative qubit, in which we find the optimal parameters to prepare $|H\rangle$ and $|T\rangle$ states. Interestingly, this approach does n…

Saturable Quantum Speed Limits for Imaginary-Time Evolution
Kohei Kobayashi
https://arxiv.org/abs/2508.10361 https://arxiv.org/pdf/2508.10361

Saturable Quantum Speed Limits for Imaginary-Time Evolution
We derive a Geometric quantum speed limit (QSL) for imaginary-time evolution, where the dynamics is governed by a non-unitary Schrödinger equation. By introducing a cost function based on the angular distance between the normalized evolving state and the initial state, we obtain a lower bound on the evolution time expressed as the ratio between this angle and the time-averaged energy dispersion. Our bound is analytical, general, and applicable to arbitrary time-independent Hamiltonians. We ana…

Light Storage and Retrieval in an Atomic Tripod System
Shan Zhong, A. J. Sudler, D. Blume, Alberto M. Marino
https://arxiv.org/abs/2508.10220 https://arxiv…

Light Storage and Retrieval in an Atomic Tripod System
Highly-efficient quantum memories are essential for advancing quantum information processing technologies, including scalable quantum computing and quantum networks. We experimentally demonstrate a light storage and retrieval protocol in a tripod system using an ensemble of laser-cooled $^{87}$Rb atoms. The tripod system, which consists of three ground states and an excited state, offers rich dynamics: its use to coherently store and retrieve a weak probe pulse in the $^{87}$Rb $F=1$ ground sta…

Quantized Charge Accumulation in a Quantum Anomalous Hall System
Yuanze Li (State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China), Jiahao Chen (State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, China), Renfei Wang (International Center for Quantum Materials, Peking University, Beijing, China), Yifan Zhang (School of Information Science and Technology, ShanghaiTech …

Quantized Charge Accumulation in a Quantum Anomalous Hall System
We report the first experimental observation of magnetic-field-induced quantized charge accumulation in a quantum anomalous Hall (QAH) system -- a phenomenon originating from the intrinsic two-dimensional surface state and fundamentally distinct from conventional edge-dependent transport phenomena. Our approach employs a novel out-of-plane capacitive detection method to directly probe this charge accumulation, revealing its distinction and correlation with other surface state properties, such a…

Bayesian Interpretation of Husimi Function and Wehrl Entropy
Chen Xu, Yiqi Yu, Peng Zhang
https://arxiv.org/abs/2507.08600 https://ar…

Bayesian Interpretation of Husimi Function and Wehrl Entropy
Husimi function (Q-function) of a quantum state is the distribution function of the density operator in the coherent state representation. It is widely used in theoretical research, such as in quantum optics. The Wehrl entropy is the Shannon entropy of the Husimi function, and is non-zero even for pure states. This entropy has been extensively studied in mathematical physics. Recent research also suggests a significant connection between the Wehrl entropy and many-body quantum entanglement in s…

Variational Time Evolution Compression for Solving Impurity Models on Quantum Hardware
Stefan Wolf, Martin Eckstein, Michael J. Hartmann
https://arxiv.org/abs/2508.10526 https:/…

Variational Time Evolution Compression for Solving Impurity Models on Quantum Hardware
Dynamical mean-field theory (DMFT) is a useful tool to analyze models of strongly correlated fermions like the Hubbard model. In DMFT, the lattice of the model is replaced by a single impurity site embedded in an effective bath. The resulting single impurity Anderson model (SIAM) can then be solved self-consistently with a quantum-classical hybrid algorithm. This procedure involves repeatedly preparing the ground state on a quantum computer and evolving it in time to measure the Greens function…

Fault tolerant Operations in Majorana-based Quantum Codes: Gates, Measurements and High Rate Constructions
Maryam Mudassar, Alexander Schuckert, Daniel Gottesman
https://arxiv.org/abs/2508.09928

Fault tolerant Operations in Majorana-based Quantum Codes: Gates, Measurements and High Rate Constructions
Majorana-based quantum computation in nanowires and neutral atoms has gained prominence as a promising platform to encode qubits and protect them against noise. In order to run computations reliably on such devices, a fully fault-tolerant scheme is needed for state preparation, gates, and measurements. However, current fault-tolerant schemes have either been limited to specific code families or have not been developed fully. In this work, we develop a general framework for fault-tolerant comput…

The Role of Symmetry in Generalized Hong-Ou-Mandel Interference and Quantum Metrology
\'Eloi Descamps, Arne Keller, P\'erola Milman
https://arxiv.org/abs/2508.09887 http…

The Role of Symmetry in Generalized Hong-Ou-Mandel Interference and Quantum Metrology
The Hong-Ou-Mandel interferometer is a foundational tool in quantum optics, with both fundamental and practical significance. Earlier works identified that input-state symmetry under exchange of the two spatial modes is fundamental in the understanding of the Hong-Ou-Mandel effect. We now show that this notion of symmetry is central to generalizing this effect. In particular, this point of view enables the construction of extensions beyond the standard two single-photon case to arbitrary input …

Edge State Selective Measurement of Quantum Hall Dispersions
Henok Weldeyesus, Taras Patlatiuk, Qianqian Chen, Christian P. Scheller, Amir Yacoby, Loren N. Pfeiffer, Ken W. West, Dominik M. Zumb\"uhl
https://arxiv.org/abs/2507.07905

Edge State Selective Measurement of Quantum Hall Dispersions
Edge states reflect the key physical properties yet are difficult to probe individually, particularly when several states are present at an edge. We present momentum resolved tunneling spectroscopy between a quantum well and a quantum wire to extract the dispersions of the quantum Hall edge states. Momentum and energy selective tunneling allows to separately address the different states even if they are spatially overlapping. This delivers the edge state velocities over broad ranges of magnetic…

Measurement-Based Quantum Diffusion Models
Xinyu Liu, Jingze Zhuang, Wanda Hou, Yi-Zhuang You
https://arxiv.org/abs/2508.08799 https://arxiv.org/pdf/2508.0…

Measurement-Based Quantum Diffusion Models
We introduce measurement-based quantum diffusion models that bridge classical and quantum diffusion theory through randomized weak measurements. The measurement-based approach naturally generates stochastic quantum trajectories while preserving purity at the trajectory level and inducing depolarization at the ensemble level. We address two quantum state generation problems: trajectory-level recovery of pure state ensembles and ensemble-average recovery of mixed states. For trajectory-level reco…

Direct Nuclear-Level Qubits using Trapped Th-229 Ions: A Platform for Entanglement and Universal Quantum Information Processing
Jingbo Wang, Haixing Miao, Shiqian Ding, Dong E. Liu
https://arxiv.org/abs/2508.10626

Direct Nuclear-Level Qubits using Trapped Th-229 Ions: A Platform for Entanglement and Universal Quantum Information Processing
The low-energy isomeric transition in Thorium-229 offers a unique interface between nuclear and atomic physics, presenting a resource for quantum technologies that is notably resilient to environmental decoherence. While early experiments focused on nuclei in solid-state crystals, the recent advent of a continuous-wave vacuum ultraviolet laser at 148.4~nm now enables direct coherent control of individual trapped Th-229 ions. Building on this breakthrough, we present a theoretical framework for …

Dicke-Stark model, coherent state space, superradiant phase transition, equilibrium state, quantum entanglement
Weilin Wang, Ronghai Liu, Fangcheng Qiu, Mingshu Zhao, Jinying Ma, Zhanyuan Yan
https://arxiv.org/abs/2508.08860

Dicke-Stark model, coherent state space, superradiant phase transition, equilibrium state, quantum entanglement
In this study, the energy spectrum and thermal equilibrium states of the finite-size Dicke-Stark model were numerically obtained within the extended coherent state space by solving the dressed master equation for strongly coupled light-atom systems. The critical point of the superradiant phase transition in the infinite-size Dicke-Stark model was analytically derived using the mean-field approach and confirmed with numerical calculation. Under thermal equilibrium conditions, analyses of the neg…

Quantum Hall Resistance and Quantum Hall Plateaus from Edge State Quantization
Pedro Pereyra
https://arxiv.org/abs/2508.05912 https://arxiv.org/pdf/2508.05…

Quantum Hall Resistance and Quantum Hall Plateaus from Edge State Quantization
Despite the extensive literature on the quantum Hall effect (QHE), a direct derivation of the phenomenological formula $ρ_{xy} = h/e^2ν$ from first principles has remained elusive. In this work, we revisit the Landau and Landauer-Büttiker formalisms and impose hard-wall boundary conditions on the wavefunction, an essential but often overlooked constraint. This condition quantizes the guiding center position and the longitudinal wave number $k_x$, leading naturally to a discrete number of edg…

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…

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…

Instrument-based quantum resources: quantification, hierarchies and towards constructing resource theories
Jatin Ghai, Arindam Mitra
https://arxiv.org/abs/2508.09134 https://

Instrument-based quantum resources: quantification, hierarchies and towards constructing resource theories
Quantum resources are certain features of the quantum world that provide advantages in certain information-theoretic, thermodynamic, or any other useful operational tasks that are outside the realm of what classical theories can achieve. Quantum resource theories provide us with an elegant framework for studying these resources quantitatively and rigorously. While numerous state-based quantum resource theories have already been investigated, and to some extent, measurement-based resource theori…

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…

Quantum-Guided Cluster Algorithms for Combinatorial Optimization
Peter J. Eder, Aron Kerschbaumer, Jernej Rudi Fin\v{z}gar, Raimel A. Medina, Martin J. A. Schuetz, Helmut G. Katzgraber, Sarah Braun, Christian B. Mendl
https://arxiv.org/abs/2508.10656

Quantum-Guided Cluster Algorithms for Combinatorial Optimization
Finding the ground state of Ising spin glasses is notoriously difficult due to disorder and frustration. Often, this challenge is framed as a combinatorial optimization problem, for which a common strategy employs simulated annealing, a Monte Carlo (MC)-based algorithm that updates spins one at a time. Yet, these localized updates can cause the system to become trapped in local minima. Cluster algorithms (CAs) were developed to address this limitation and have demonstrated considerable success …

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…

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.…

Time correlations from steady-state expectation values
Wojciech G\'orecki, Simone Felicetti, Lorenzo Maccone, Roberto Di Candia
https://arxiv.org/abs/2507.08661

Time correlations from steady-state expectation values
Recovering properties of correlation functions is typically challenging. On one hand, experimentally, it requires measurements with a temporal resolution finer than the system's dynamics. On the other hand, analytical or numerical analysis requires solving the system evolution. Here, we use recent results of quantum metrology with continuous measurements to derive general lower bounds on the relaxation and second-order correlation times that are both easy to calculate and measure. These bounds …

Hybrid Optomechanical Cooling with Kerr Magnons and Squeezed Vacuum
Xiao-Hong Fan, Qin-Geng Chen, Jiaojiao Chen, Wei Xiong
https://arxiv.org/abs/2508.09725 https://

Hybrid Optomechanical Cooling with Kerr Magnons and Squeezed Vacuum
Ground-state cooling is essential for accessing the quantum regime and enabling quantum control of macroscopic systems. However, achieving optomechanical cooling in the unresolved-sideband regime ($ω_b < κ$) remains challenging. In this Letter, we propose an efficient cooling strategy based on a hybrid optomechanical system incorporating a yttrium iron garnet (YIG) sphere embedded in an optomechanical cavity. Under strong cavity driving, the Kerr nonlinearity of the magnons hosted in the YIG …

Entanglement certification from moments of positive maps
Qing-Hua Zhang, Xiaoyu Ma, Shao-Ming Fei
https://arxiv.org/abs/2508.09766 https://arxiv.org/pdf/25…

Entanglement certification from moments of positive maps
Entanglement certification is crucial in physical experiments, particularly when only partial knowledge of the quantum state is available. In this context, we present an entanglement criterion based on positive but not completely positive maps, which eliminates the need to identify eigenvalues of the output state. Notably, the Faddeev-LeVerrier algorithm establishes a relationship between the coefficients of characteristic polynomials and the moments of a matrix. This enables the existence of n…

State-adaptive quantum error correction and fault-tolerant quantum computing
D. -S. Wang
https://arxiv.org/abs/2508.06011 https://arxiv.org/pdf/2508.06011

State-adaptive quantum error correction and fault-tolerant quantum computing
We present a theoretical framework for state-adaptive quantum error correction (SAQEC) that bridges the gap between quantum computing and error correction paradigms. By incorporating knowledge of quantum states into the error correction process, we establish a new capacity regime governed by quantum mutual information rather than coherent information. This approach reveals a fundamental connection to entanglement-assisted protocols. We demonstrate practical applications in fault-tolerant quantu…

Metrological power of single-qubit dynamical Casimir effect in circuit QED
A. P. Costa, H. R. Schelb, A. V. Dodonov
https://arxiv.org/abs/2508.10182 https://

Metrological power of single-qubit dynamical Casimir effect in circuit QED
We consider a nonstationary circuit QED system described by the quantum Rabi model, in which an artificial two-level atom with a tunable transition frequency is coupled to a single-mode resonator. We focus on regimes where the external modulation takes the form $\sin[η(t) t]$, with the modulation frequency $η(t)$ varying slowly and linearly in time near $2ν$ and $4ν$, $ν$ being the resonator frequency. Starting from the vacuum state, we numerically compute the Quantum Fisher Information fo…

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 …

Coherent control of interacting solid-state spins below the diffraction limit
Haitong Xu, Mehmet T. Uysal, Lukasz Dusanowski, Adam Turflinger, Ashwin Boddeti, Joseph Alexander, Jeff D. Thompson
https://arxiv.org/abs/2508.09122

Coherent control of interacting solid-state spins below the diffraction limit
Optically addressed atomic defects in the solid-state are widely used as single-photon sources and memories for quantum network applications. The solid-state environment allows for a high density of electron and nuclear spins with the potential to form registers for coherent information processing. However, it is challenging to reliably address individual spins at nanometer separations where interactions are large. Rare-earth ions offer a unique solution, as their narrow homogeneous optical lin…

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…

Online Quantum State Tomography via Stochastic Gradient Descent
Jian-Feng Cai, Yuling Jiao, Yinan Li, Xiliang Lu, Jerry Zhijian Yang, Juntao You
https://arxiv.org/abs/2507.07601

Online Quantum State Tomography via Stochastic Gradient Descent
We initiate the study of online quantum state tomography (QST), where the matrix representation of an unknown quantum state is reconstructed by sequentially performing a batch of measurements and updating the state estimate using only the measurement statistics from the current round. Motivated by recent advances in non-convex optimization algorithms for solving low-rank QST, we propose non-convex mini-batch stochastic gradient descent (SGD) algorithms to tackle online QST, which leverage the l…

Scalable Quantum State Preparation for Encoding Genomic Data with Matrix Product States
Floyd M. Creevey, Hitham T. Hassan, James McCafferty, Lloyd C. L. Hollenberg, Sergii Strelchuk
https://arxiv.org/abs/2508.06184

Scalable Quantum State Preparation for Encoding Genomic Data with Matrix Product States
As quantum computing hardware advances, the need for algorithms that facilitate the loading of classical data into the quantum states of these devices has become increasingly important. This study presents a method for producing scalable quantum circuits to encode genomic data using the Matrix Product State (MPS) formalism. The method is illustrated by encoding the genome of the bacteriophage $ΦX174$ into a 15-qubit state, and analysing the trade-offs between MPS bond dimension, reconstruction…

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…

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…

Shortcuts to adiabaticity with a quantum control field
Emma C. King, Giovanna Morigi, Rapha\"el Menu
https://arxiv.org/abs/2508.06304 https://arxiv.or…

Shortcuts to adiabaticity with a quantum control field
Quantum adiabatic dynamics is the crucial element of adiabatic quantum computing and quantum annealing. Shortcuts to adiabaticity enable acceleration of the computational time by suppressing unwanted non-adiabatic processes with designed classical fields. Here, we consider quantum state transfer in the Landau-Zener model, which exemplifies the key elements of quantum adiabatic dynamics. We argue that non-adiabatic transitions can be suppressed by autonomous quantum dynamics, which involves coup…

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…

Diagonalizing large-scale quantum many-body Hamiltonians using variational quantum circuit and tensor network
Peng-Fei Zhou, Shuang Qiao, An-Chun Ji, Shi-Ju Ran
https://arxiv.org/abs/2508.06159

Diagonalizing large-scale quantum many-body Hamiltonians using variational quantum circuit and tensor network
Exact diagonalization (ED) is an essential tool for exploring quantum many-body physics but is fundamentally limited by the exponentially-scaled computational complexity. Here, we propose tensor network variational diagonalization (TNVD), which encodes the full eigenenergy spectrum of a quantum many-body Hamiltonian into a matrix product state, and encodes the eigenstates as the evolutions of product states using variational quantum circuit (VQC). Thereby, TNVD reduces the computational complex…

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 penalty-free quantum algorithm to find energy eigenstates
Nannan Ma, Heng Dai, Jiangbin Gong
https://arxiv.org/abs/2509.09148 https://arxiv.org/pdf/2509.…

A penalty-free quantum algorithm to find energy eigenstates
Finding eigenstates of a given many-body Hamiltonian is a long-standing challenge due to the perceived computational complexity. Leveraging on the hardware of a quantum computer accommodating the exponential growth of the Hilbert space size with the number of qubits, more quantum algorithms to find the eigenstates of many-body Hamiltonians will be of wide interest with profound implications and applications. In this work, we advocate a quantum algorithm to find the ground state and excited stat…

Classical simulation of noisy quantum circuits via locally entanglement-optimal unravelings
Simon Cichy, Paul K. Faehrmann, Lennart Bittel, Jens Eisert, Hakop Pashayan
https://arxiv.org/abs/2508.05745 …

Classical simulation of noisy quantum circuits via locally entanglement-optimal unravelings
Classical simulations of noisy quantum circuits is instrumental to our understanding of the behavior of real world quantum systems and the identification of regimes where one expects quantum advantage. In this work, we present a highly parallelizable tensor-network-based classical algorithm -- equipped with rigorous accuracy guarantees -- for simulating $n$-qubit quantum circuits with arbitrary single-qubit noise. Our algorithm represents the state of a noisy quantum system by a particular ense…

Special Issue: Commemorating the 110th Anniversary of TANG Au-chin's Birthday Calculation of the Green's function on near-term quantum computers via Cartan decomposition
Lingyun Wan, Jie Liu, Jinlong Yang
https://arxiv.org/abs/2509.09248

Special Issue: Commemorating the 110th Anniversary of TANG Au-chin's Birthday Calculation of the Green's function on near-term quantum computers via Cartan decomposition
Accurate computation of the Green's function is crucial for connecting experimental observations to the underlying quantum states. A major challenge in evaluating the Green's function in the time domain lies in the efficient simulation of quantum state evolution under a given Hamiltonian-a task that becomes exponentially complex for strongly correlated systems on classical computers. Quantum computing provides a promising pathway to overcome this barrier by enabling efficient simulation of quan…

Model-based framework for automated quantification of error sources in quantum state tomography
Junpei Oba, Hsin-Pin Lo, Yasuhiro Yamada, Takayuki Matsui, Takuya Ikuta, Yuya Yonezu, Toshimori Honjo, Seiji Kajita, Hiroki Takesue
https://arxiv.org/abs/2508.05538

Model-based framework for automated quantification of error sources in quantum state tomography
High-quality quantum state generation is essential for advanced quantum information processing, including quantum communication, quantum sensing, and quantum computing. In practice, various error sources degrade the quality of quantum states, and quantum state tomography (QST) is a standard diagnostic tool. However, in QST, multiple error sources gather in a single density matrix, making it difficult to identify individual error sources. To address this problem, we propose an automated method f…

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…

Quantum State Preparation Of Multiconfigurational States For Quantum Chemistry
Gabriel Greene-Diniz, Georgia Prokopiou, David Zsolt Manrique, David Mu\~noz Ramo
https://arxiv.org/abs/2508.05390

Quantum State Preparation Of Multiconfigurational States For Quantum Chemistry
The ability to prepare states for quantum chemistry is a promising feature of quantum computers, and efficient techniques for chemical state preparation is an active area of research. In this paper, we implement and investigate two methods of quantum circuit preparation for multiconfigurational states for quantum chemical applications. It has previously been shown that controlled Givens rotations are universal for quantum chemistry. To prepare a selected linear combination of Slater determinant…

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…

Structural Perspectives from Quantum States and Measurements in Optimal State Discrimination
Hyunho Cha, Jungwoo Lee
https://arxiv.org/abs/2507.05778 https…

Structural Perspectives from Quantum States and Measurements in Optimal State Discrimination
Quantum state discrimination is a fundamental concept in quantum information theory, which refers to a class of techniques to identify a specific quantum state through a positive operator-valued measure. In this work, we investigate how structural information about either the quantum states or the measurement operators can influence our ability to determine or bound the optimal discrimination probability. First, we observe that for single-qubit states, pairwise fidelities are sufficient to comp…

Experimental Ground-State Energy of a 125-Site Flat Kagome Antiferromagnet via Hamiltonian Engineering on Quantum Computer
Muhammad Ahsan
https://arxiv.org/abs/2507.06361

Experimental Ground-State Energy of a 125-Site Flat Kagome Antiferromagnet via Hamiltonian Engineering on Quantum Computer
We present an instance of utility-grade quantum computation by calculating the ground-state energy of a 125-site flat Kagome lattice under the antiferromagnetic Heisenberg model (KAFH), using IBM's Falcon and Hummingbird quantum processors. For spin-1/2 KAFH, our best per-site ground-state energy estimate reaches -0.417J, and after applying open-boundary corrections, it closely approaches the established thermodynamic value of -0.438J. To achieve this, we propose a hybrid approach that splits t…

Behind the scenes of the Quantum Extreme Learning Machines
A. De Lorenzis, M. P. Casado, N. Lo Gullo, T. Lux, F. Plastina, A. Riera
https://arxiv.org/abs/2509.06873 https://

Behind the scenes of the Quantum Extreme Learning Machines
In recent years, Quantum Machine Learning (QML) has grown rapidly, emerging as a promising approach to make quantum computing implementation competitive. In this work, we investigate Quantum Extreme Learning Machines (QELM), a quantum variant of Extreme Learning Machines where training is restricted to the output layer. The proposed architecture combines dimensionality reduction (via PCA or Autoencoders), quantum state encoding, evolution under an XX Hamiltonian, and measurement, providing feat…

Noise-Canceling Quantum Feedback: non-Hermitian Dynamics with Applications to State Preparation and Magic State Distillation
Tathagata Karmakar, Philippe Lewalle, Yipei Zhang, K. Birgitta Whaley
https://arxiv.org/abs/2507.05611

Noise-Canceling Quantum Feedback: non-Hermitian Dynamics with Applications to State Preparation and Magic State Distillation
Time-continuous quantum measurement allows for the tracking of a quantum system in real time via sequences of short, and individually weak, measurement intervals. Such measurements are necessarily invasive, imparting backaction to the system, and allowing the observer to update their state estimate based on stochastic measurement outcomes. Feedback control then involves real-time interventions by an observer, conditioned on the time-continuous measurement signal that they receive. We here consi…

Quasi-stationary normal states for quantum Markov semigroups
Ameur Dhahri, Franco Fagnola, Federico Girotti, Hyun Jae Yoo
https://arxiv.org/abs/2508.06396 https://

Quasi-stationary normal states for quantum Markov semigroups
We introduce the notion of Quasi-Stationary State (QSS) in the context of quantum Markov semigroups that generalizes the one of quasi-stationary distribution in the case of classical Markov chains. We provide an operational interpretation of QSSs using the theory of direct and indirect quantum measurements. Moreover, we prove that there is a connection between QSSs and spectral properties of the quantum Markov semigroup. Finally, we discuss some examples which, despite their simplicity, already…

Quantum Wall States for Noise Mitigation and Eternal Purity Bounds
Miguel Casanova, Francesco Ticozzi
https://arxiv.org/abs/2507.07944 https://

Quantum Wall States for Noise Mitigation and Eternal Purity Bounds
The present work analyzes state-stabilization techniques for decoupling a subsystem from environmental interactions. The proposed framework uses analytical and numerical tools to find an approximate decoherence-free subspace (DFS) with enhanced passive noise isolation. Active state-stabilizing control on a subsystem mediating dominant environmental interactions, which we call wall subsystem, creates an effective quantum wall state. The proposed method controls only the wall subsystem, leaving t…

Role of Plaquette Term in Genuine $2 1$D String Dynamics on Quantum Simulators
Yizhuo Tian, N. S. Srivatsa, Kaidi Xu, Jesse J. Osborne, Umberto Borla, Jad C. Halimeh
https://arxiv.org/abs/2508.05736

Role of Plaquette Term in Genuine $2+1$D String Dynamics on Quantum Simulators
With the advent of quantum simulators of $2+1$D lattice gauge theories (LGTs), a fundamental open question is under what circumstances the observed physics is genuinely $2+1$D rather than effectively $1+1$D. Here, we address this question in the ongoing strong effort to quantum-simulate string dynamics in $2+1$D LGTs on state-of-the-art quantum hardware. Through tensor network simulations and analytic derivations, we show that the plaquette term, which represents a magnetic field and only emerg…

Quantum sensing with a spin ensemble in a two-dimensional material
Souvik Biswas, Giovanni Scuri, Noah Huffman, Eric I. Rosenthal, Ruotian Gong, Thomas Poirier, Xingyu Gao, Sumukh Vaidya, Abigail J. Stein, Tsachy Weissman, James H. Edgar, Tongcang Li, Chong Zu, Jelena Vu\v{c}kovi\'c, Joonhee Choi
https://arxiv.org/abs/2509.08984…

Quantum sensing with a spin ensemble in a two-dimensional material
Quantum sensing with solid-state spin defects has transformed nanoscale metrology, offering sub-wavelength spatial resolution with exceptional sensitivity to multiple signal types. Maximizing these advantages requires minimizing both the sensor-target separation and detectable signalthreshold. However, leading platforms such as nitrogen-vacancy (NV) centers in diamond suffer performance degradation near surfaces or in nanoscale volumes, motivating the search for optically addressable spin senso…

Instance-Optimal Quantum State Certification with Entangled Measurements
Ryan O'Donnell, Chirag Wadhwa
https://arxiv.org/abs/2507.06010 https://…

Instance-Optimal Quantum State Certification with Entangled Measurements
We consider the task of quantum state certification: given a description of a hypothesis state $σ$ and multiple copies of an unknown state $ρ$, a tester aims to determine whether the two states are equal or $ε$-far in trace distance. It is known that $Θ(d/ε^2)$ copies of $ρ$ are necessary and sufficient for this task, assuming the tester can make entangled measurements over all copies [CHW07,OW15,BOW19]. However, these bounds are for a worst-case $σ$, and it is not known what the optimal…

Extracting and charging energy into almost unknown quantum states
Andrea Canzio, Vasco Cavina, Roberto Menta, Vittorio Giovannetti
https://arxiv.org/abs/2509.08899 https://

Extracting and charging energy into almost unknown quantum states
In this work, we investigate the amount of energy that can be extracted or charged through unitary operations when only minimal information about the state is known. Assuming knowledge of only the mean energy of the state, we start by developing optimal upper bounds for the work that can be unitarily extracted or charged in this scenario. In deriving these upper bounds, we provide a complete characterization of the minimum ergotropy and anti-ergotropy for density matrices with fixed average ene…

Exponential Lindbladian fast forwarding and exponential amplification of certain Gibbs state properties
Zhong-Xia Shang, Dong An, Changpeng Shao
https://arxiv.org/abs/2509.09517

Exponential Lindbladian fast forwarding and exponential amplification of certain Gibbs state properties
We investigate Lindbladian fast-forwarding and its applications to estimating Gibbs state properties. Fast-forwarding refers to the ability to simulate a system of time $t$ using significantly fewer than $t$ queries or circuit depth. While various Hamiltonian systems are known to circumvent the no fast-forwarding theorem, analogous results for dissipative dynamics, governed by Lindbladians, remain largely unexplored. We first present a quantum algorithm for simulating purely dissipative Lindbla…

Matrix-product entanglement characterizing the optimality of state-preparation quantum circuits
Shuo Qi, Wen-Jun Li, Gang Su, Shi-Ju Ran
https://arxiv.org/abs/2507.05989

Matrix-product entanglement characterizing the optimality of state-preparation quantum circuits
Multipartite entanglement offers a powerful framework for understanding the complex collective phenomena in quantum many-body systems that are often beyond the description of conventional bipartite entanglement measures. Here, we propose a class of multipartite entanglement measures that incorporate the matrix product state (MPS) representation, enabling the characterization of the optimality of quantum circuits for state preparation. These measures are defined as the minimal distances from a t…

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.

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…

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…

Towards Nonlinear Quantum Thermodynamics
Gershon Kurizki, Nilakantha Meher, Avijit Misra, Durga Bhaktavatsala Rao Dasari, Tomas Opatrny
https://arxiv.org/abs/2507.07537

Towards Nonlinear Quantum Thermodynamics
We have recently put forth several schemes of unconventional, nonlinearly-enabled thermodynamic (TD) devices that can operate in either the classical or the quantum domain by transforming thermal-state input in multiple uncorrelated modes into non-gaussian state output in selected modes: a four-mode Kerr-nonlinear interferometer that acts as a heat engine; two coupled Kerr-nonlinear Mach-Zehnder interferometers that act as a phase microscope with unprecedented phase resolution; and a noise sens…

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…

Speeding up Pontus-Mpemba effects via dynamical phase transitions
Andrea Nava, Reinhold Egger, Bidyut Dey, Domenico Giuliano
https://arxiv.org/abs/2509.09366 https://

Speeding up Pontus-Mpemba effects via dynamical phase transitions
We demonstrate that open quantum systems exhibiting dynamical phase transitions (DPTs) allow for highly efficient protocols implementing the Pontus-Mpemba effect. The relaxation speed-up toward a predesignated target state is tied to the existence of a long metastable time window preceding the DPT and can be exploited in applications to systematically optimize quantum protocols. As paradigmatic example for the connection between DPTs and quantum Mpemba effects, we study one-dimensional (1D) int…

Optimality of universal conclusive entanglement purification protocols
Alexandre C. Orthey, Aby Philip, Tulja Varun Kondra, Alexander Streltsov
https://arxiv.org/abs/2509.09423 …

Optimality of universal conclusive entanglement purification protocols
Entanglement purification is essential for quantum technologies; yet, rigorous bounds on the success probability for universal protocols -- those requiring no prior knowledge about the input state -- have remained underexplored. We establish such fundamental limits for conclusive protocols distilling perfect Bell states from a pure two-qubit states by deriving the optimal success probability starting with: two copies of a state with known Schmidt basis, and four copies of a state with unknown S…

Efficient Convex Optimization for Bosonic State Tomography
Shengyong Li, Yanjin Yue, Ying Hu, Rui-Yang Gong, Qianchuan Zhao, Zhihui Peng, Pengtao Song, Zeliang Xiang, Jing Zhang
https://arxiv.org/abs/2509.06305

Efficient Convex Optimization for Bosonic State Tomography
Quantum states encoded in electromagnetic fields, also known as bosonic states, have been widely applied in quantum sensing, quantum communication, and quantum error correction. Accurate characterization is therefore essential yet difficult when states cannot be reconstructed with sparse Pauli measurements. Tomography must work with dense measurement bases, high-dimensional Hilbert spaces, and often sample-based data. However, existing convex optimization-based techniques are not efficient enou…

Quantum Walks for Chemical Reaction Networks
Seenivasan Hariharan, Sebastian Zur, Sachin Kinge, Lucas Visscher, Kareljan Schoutens, Stacey Jeffery
https://arxiv.org/abs/2509.07890

Quantum Walks for Chemical Reaction Networks
We lay the foundation for a quantum algorithmic framework to analyse fixed-structure chemical reaction networks (CRNs) using quantum random walks (QRWs) via electrical circuit theory. We model perturbations to CRNs, such as, species injections that shift steady-state concentrations, while keeping the underlying species-reaction graph fixed. Under physically meaningful mass-action constraints, we develop quantum algorithms that (i) decide reachability of target species after perturbation, (ii) s…

Quantum chemistry with provable convergence via randomized sample-based quantum diagonalization
Samuele Piccinelli, Alberto Baiardi, Max Rossmannek, Almudena Carrera Vazquez, Francesco Tacchino, Stefano Mensa, Edoardo Altamura, Ali Alavi, Mario Motta, Javier Robledo-Moreno, William Kirby, Kunal Sharma, Antonio Mezzacapo, Ivano Tavernelli
https://

Quantum chemistry with provable convergence via randomized sample-based quantum diagonalization
Sample-based quantum diagonalization (SQD) is a recently proposed algorithm to approximate the ground-state wave function of many-body quantum systems on near-term and early-fault-tolerant quantum devices. In SQD, the quantum computer acts as a sampling engine that generates the subspace in which the Hamiltonian is classically diagonalized. A recently proposed SQD variant, Sample-based Krylov Quantum Diagonalization (SKQD), uses quantum Krylov states as circuits from which samples are collected…

Controlling quantum entanglement with classical non-separable light
R. F. Barros, A. L. S. Santos Junior, A. Z. Khoury, R. Fickler
https://arxiv.org/abs/2507.06462

Controlling quantum entanglement with classical non-separable light
Here we investigate the quantum frequency conversion of entangled photons driven by a classically non-separable laser beam. We show that the frequency conversion dynamics is described by a quantum channel that stems from the classical drive field through the channel-state duality - the quantum channel is dual to the classical coherence matrix of the drive field. This implies that the evolution of entanglement in the conversion process is bound by the classical non-separability of the drive fiel…

Process Tensor Approaches to Non-Markovian Quantum Dynamics
Jonathan Keeling, E. Miles Stoudenmire, Mari-Carmen Ba\~nuls, David R. Reichman
https://arxiv.org/abs/2509.07661 http…

Process Tensor Approaches to Non-Markovian Quantum Dynamics
The paradigm of considering open quantum systems -- i.e. focusing only on the system of interest, and treating the rest of the world as an effective environment -- has proven to be a highly effective way to understand a range of quantum systems, across areas of study such as quantum optics, cold atoms, superconducting qubits, and impurities in solid-state systems. A common approach in many of these contexts has been to consider simplified approaches based on the Born and Markov approximations. …

Quantum state reconstruction with variational quantum circuit
Shabnam Jabeen, Dmytro Kurdydyk, Aadi Palnitkar, Mihir Talati, Jeffrey Yan, Jinghong Yang
https://arxiv.org/abs/2507.01246

Quantum state reconstruction with variational quantum circuit
Reconstructing quantum states from measurement data represents a formidable challenge in quantum information science, especially as system sizes grow beyond the reach of traditional tomography methods. While recent studies have explored quantum machine learning (QML) for quantum state tomography (QST), nearly all rely on idealized assumptions, such as direct access to the unknown quantum state as quantum data input, which are incompatible with current hardware constraints. In this work, we pres…

Quantum state-transfer and periodicity in discrete-time quantum walk under non-Markovian noise
Monika Rani, Supriyo Dutta, Subhashish Banerjee
https://arxiv.org/abs/2506.24066

Quantum state-transfer and periodicity in discrete-time quantum walk under non-Markovian noise
In quantum communication, quantum state transfer from one location to another in a quantum network plays a prominent role, where the impact of noise could be crucial. The idea of state transfer can be fruitfully associated with quantum walk on graphs. We investigate the consequences of non-Markovian quantum noises on periodicity and state transfer induced by a discrete-time quantum walk on graphs, governed by the Grover coin operator. Different bipartite graphs, such as the path graph, cycle gr…

Resource-Efficient Synthesis of Sparse Quantum States
Renaud Vilmart, Sunheang Ty, Chetra Mang
https://arxiv.org/abs/2508.05386 https://arxiv.org/pdf/2508.…

Resource-Efficient Synthesis of Sparse Quantum States
Preparing a quantum circuit that implements a given sparse state is an important building block that is necessary for many different quantum algorithms. In the context of fault-tolerant quantum computing, the so-called non-Clifford gates are much more expensive to perform than the Clifford ones. We hence provide an algorithm for synthesizing sparse quantum states with a special care for quantum resources. The circuit depth, ancilla count, and crucially non-Clifford count of the circuit produced…

Hybrid Quantum--Classical Machine Learning Potential with Variational Quantum Circuits
Soohaeng Yoo Willow, D. ChangMo Yang, Chang Woo Myung
https://arxiv.org/abs/2508.04098 htt…

Hybrid Quantum--Classical Machine Learning Potential with Variational Quantum Circuits
Quantum algorithms for simulating large and complex molecular systems are still in their infancy, and surpassing state-of-the-art classical techniques remains an ever-receding goal post. A promising avenue of inquiry in the meanwhile is to seek practical advantages through hybrid quantum-classical algorithms, which combine conventional neural networks with variational quantum circuits (VQCs) running on today's noisy intermediate-scale quantum (NISQ) hardware. Such hybrids are well suited to NIS…

Quantum Zeno effect versus adiabatic quantum computing and quantum annealing
Naser Ahmadiniaz, Dennis Kraft, Gernot Schaller, Ralf Sch\"utzhold
https://arxiv.org/abs/2509.04057

Quantum Zeno effect versus adiabatic quantum computing and quantum annealing
For the adiabatic version of Grover's quantum search algorithm as proposed by Roland and Cerf, we study the impact of decoherence caused by a rather general coupling to some environment. For quite generic conditions, we find that the quantum Zeno effect poses strong limitations on the performance (quantum speed-up) since the environment effectively measures the state of the system permanently and thereby inhibits or slows down quantum transitions. Generalizing our results, we find that analogou…

An Ultra-Cold Mechanical Quantum Sensor for Tests of New Physics
Andraz Omahen, Simon Storz, Marius Bild, Dario Scheiwiller, Matteo Fadel, Yiwen Chu
https://arxiv.org/abs/2507.02653

An Ultra-Cold Mechanical Quantum Sensor for Tests of New Physics
Initialization of mechanical modes in the quantum ground state is crucial for their use in quantum information and quantum sensing protocols. In quantum processors, impurity of the modes' initial state affects the infidelity of subsequent quantum algorithms. In quantum sensors, excitations out of the ground state contribute to the noise of the detector, and their prevalence puts a bound on rare events that deposit energy into the mechanical modes. In this work, we measure the excited-state popu…

Quantum Annealing for the Set Splitting Problem
Sean Borneman
https://arxiv.org/abs/2508.06410 https://arxiv.org/pdf/2508.06410

Quantum Annealing for the Set Splitting Problem
I present a novel use of quantum annealing to solve the Set Splitting Problem using (QUBO) problem formulation. The contribution of the work is in formulating penalty functions that ensure the ground state of the QUBO Hamiltonian corresponds to valid solutions that split the input subsets. This approach scales linearly in terms of the number of logical qubits relative to problem size. Empirical tests of the proposed solution show convergence to globally optimal solutions, with high accuracy rat…