Quantum Research

arXiv:2604.22568v1 Announce Type: new Abstract: We study truncations of hierarchical equations of motion (HEOM) for finite-dimensional open quantum systems. We prove that for finite-dimensional approximations constructed with a Schur-complement type of terminator, the spectrum converges to that of

arXiv:2604.22588v1 Announce Type: new Abstract: We develop analytical and algorithmic techniques that enable efficient simulation of a broad class of noisy stabilizer circuits. We derive closed-form expressions of expectation values for tensor product of Paulis in circuits with non-deterministic Pa

arXiv:2604.22593v1 Announce Type: new Abstract: Proposed experiments for gravitationally induced entanglement (GIE) typically suppress direct electromagnetic interactions between two massive particles by inserting a conducting Faraday shield. For superconducting particles, their large diamagnetism

arXiv:2604.22627v1 Announce Type: new Abstract: Joint measurements on multiple copies of a quantum state provide access to nonlinear observables such as $\operatorname{tr}(\rho^t)$, but whether replica number marks a sharp information-theoretic resource boundary has remained unclear. For every fixe

arXiv:2604.22664v1 Announce Type: new Abstract: Near-term hardware is constrained by high error rates, small qubit counts, and relatively low output fidelity, making the execution of large, high performance quantum circuits difficult. Circuit partitioning (or circuit cutting) has emerged as a promi

arXiv:2604.22704v1 Announce Type: new Abstract: Precise and autonomous clocks are of fundamental interest and central importance to both foundational studies and practical applications. Here, we construct a blueprint for a quantum clock governed by time-independent interactions. By carefully-engine

arXiv:2604.22751v1 Announce Type: new Abstract: Symmetry-resolved spectroscopies, such as angle-resolved photoemission spectroscopy and polarization-resolved Raman, are central for quantum material characterization, yet remain challenging at nanoscale dimensions and low frequencies. Here, we propos

arXiv:2604.19707v2 Announce Type: cross Abstract: In quadratic gravity, with a positive Weyl squared coefficient, the extra spin-2 sector is shown to correspond to a dual inverted harmonic oscillator, instead of a ghost. Using the Wightman spectrum condition, we prove that the associated K\"{a}ll\'

arXiv:2604.21992v1 Announce Type: cross Abstract: We investigate the effect of a periodic electric field drive on the generalized Aubry-Andr\'e model, also known as the Ganeshan-Pixley-Das Sarma (GPD) model, which is well known as a host of mobility edges. Our study of the Floquet spectrum of the d

arXiv:2604.22112v1 Announce Type: cross Abstract: Tantalum is a promising platform for superconducting quantum circuits, yet coherence times remain limited by dielectric losses from interfacial two-level systems (TLS), exacerbated by native oxide regrowth. Here, we implement molecular surface passi

arXiv:2604.22336v1 Announce Type: cross Abstract: We propose a quantum-enhanced sensing scheme for the detection of wave-like dark matter and high-frequency gravitational waves using two-dimensional ion crystals in a Penning trap. The protocol employs spin-motion squeezed states to improve the sign

arXiv:2604.22537v1 Announce Type: cross Abstract: This work describes a few-body dynamics method based on the Faddeev integral equations in momentum space for determining the total cross sections of fusion and breakup reactions with two- and three-body final channels in the continuum, employing a c

arXiv:2604.22553v1 Announce Type: cross Abstract: Proximity-induced superconductivity in low-dimensional systems offers a powerful pathway to engineer topological superconducting phases in, otherwise, non-superconducting systems. These exotic phases are of fundamental and technological interest due

arXiv:2604.22600v1 Announce Type: cross Abstract: Active matter is driven out of equilibrium by a local influx of energy. While classical active matter has been extensively studied, the extension of active matter concepts to quantum systems has been explored far less. In this work we develop a full

arXiv:2604.22718v1 Announce Type: cross Abstract: We describe a numerical many-body technique that is based on both tensor networks and quantum Monte Carlo. The variational ansatz is a tensor network that can harvest volume-law entanglement. It is constructed from a tensor train to which one applie

arXiv:2208.06471v5 Announce Type: replace Abstract: In the classic multi-stage Stern$-$Gerlach experiment conducted by Frisch and Segr\`e, the Majorana (Landau$-$Zener) and Rabi formulae diverge afar from the experimental observation while the physical mechanism for electron-spin collapse remains u

arXiv:2402.17007v2 Announce Type: replace Abstract: In this paper, we develop the resource theory of quantum secret key. Operating under the assumption that entangled states with zero distillable key do not exist, we define the key cost of a quantum state, and device. We study its properties throug

arXiv:2408.09850v2 Announce Type: replace Abstract: This study explores the dual role of a squeezed reservoir in controlling the quantum phase synchronization of a driven two-level system. We first demonstrate, through a Liouvillian eigen-spectrum analysis, that the squeezed reservoir can induce a

arXiv:2411.09256v2 Announce Type: replace Abstract: We study higher order quantum maps in the context of a *-autonomous category of affine subspaces. We show that types of higher order maps can be identified with certain Boolean functions that we call type functions. By an extension of this identif

arXiv:2412.11778v4 Announce Type: replace Abstract: We introduce a classical computational method for quantum dynamics that relies on a global-in-time variational principle. Unlike conventional time-stepping approaches, our scheme computes the entire state trajectory over a finite time window by mi

arXiv:2412.15665v2 Announce Type: replace Abstract: Motivated by recent progress in quantum hardware and algorithms researchers have developed quantum heuristics for optimization problems, aiming for advantages over classical methods. To date, quantum hardware is still error-prone and limited in si

arXiv:2501.16335v4 Announce Type: replace Abstract: Quantum information scrambling (QIS) describes the rapid spread of initially localized information across an entire quantum many-body system through entanglement generation. Once scrambled, the original local information becomes encoded globally,

arXiv:2502.02491v2 Announce Type: replace Abstract: We consider the quantum analog of the generalized Zernike systems given by the Hamiltonian: $$\hat{\mathcal{H}}_N =\hat{p}_1^2+\hat{p}_2^2+\sum_{k=1}^N \gamma_k (\hat{q}_1 \hat{p}_1+\hat{q}_2 \hat{p}_2)^k ,$$ with canonical operators $\hat{q}_i,\,

arXiv:2503.11785v3 Announce Type: replace Abstract: Quantum error mitigation (QEM) has emerged as a powerful tool for the extraction of useful quantum information from quantum devices. Here, we introduce the Subspace Noise Tailoring (SNT) algorithm, which efficiently combines the cheap cost of Symm

arXiv:2505.19723v4 Announce Type: replace Abstract: Superposed coherent states are central to quantum technologies, yet their reliable identification remains a challenge, especially in noisy or resource-constrained settings. We introduce a novel, directly measurable criterion for detecting cat-like

arXiv:2507.07249v2 Announce Type: replace Abstract: The fluctuation-dissipation theorem (FDT) is a fundamental result in statistical mechanics. It stipulates that, if perturbed out of equilibrium, a system responds at a rate proportional to a thermal-equilibrium property. Applications range from pa

arXiv:2507.23787v2 Announce Type: replace Abstract: We prove that the generic quantum speedups for brute-force search and counting only hold when the process we apply them to can be efficiently inverted. The algorithms speeding up these problems, amplitude amplification and amplitude estimation, as

arXiv:2508.00055v2 Announce Type: replace Abstract: Many quantum algorithms, to compute some property of a unitary $U$, require access not just to $U$, but to $cU$, the unitary with a control qubit. We show that having access to $cU$ does not help for a large class of quantum problems. For a quantu

arXiv:2508.10660v2 Announce Type: replace Abstract: We explore the potential application of quantum annealing to address the protein structure problem. To this end, we compare several proposed ab initio protein folding models for quantum computers and analyze their scaling and performance for class

arXiv:2508.14583v2 Announce Type: replace Abstract: The quantum theory of relativistic particles, based on the first quantization technique similar to that used by Schroedinger and Dirac in formulating quantum mechanics, is reconsidered on the basis of a photon-like dispersion relation correspondin

arXiv:2508.18147v2 Announce Type: replace Abstract: Molecular docking is a critical computational method in drug discovery used to predict the binding conformation and orientation of a ligand within a protein's binding site. Mapping this challenge onto a graph-based problem, specifically the Maximu

arXiv:2509.06873v3 Announce Type: replace Abstract: Quantum Machine Learning (QML) has emerged as a promising framework for exploring how quantum dynamics may enhance data processing tasks. Here we investigate Quantum Extreme Learning Machines (QELMs), a quantum analogue of classical Extreme Learni

arXiv:2509.15483v2 Announce Type: replace Abstract: Extracting momentum-resolved excitation spectra in strongly correlated quantum systems remains a major challenge, especially beyond one spatial dimension. We present an efficient tensor-network approach to compute dispersion relations via imaginar

arXiv:2510.20046v3 Announce Type: replace Abstract: Solvable bosonic models provide a fundamental framework for describing light propagation in nonlinear media, including optical down-conversion processes that generate squeezed states of light and their higher-order generalizations. In quantum opti

arXiv:2511.19687v2 Announce Type: replace Abstract: Absorption spectroscopy is a fundamental tool for probing molecular structure. However, performing absorption spectroscopy on individual molecules is challenging due to the low signal-to-noise ratio. Here, we report on a nondestructive absorption

arXiv:2511.20026v2 Announce Type: replace Abstract: Fast coherent state transport is essential to quantum computation and quantum information processing. While an adiabatic transport of atomic qubits guarantees a high fidelity of the state preparation, it requires a long timescale that defies effic

arXiv:2512.09007v2 Announce Type: replace Abstract: In this paper, a method is developed for the study of a generic small central quantum system, which is locally coupled to an environment as a many-body quantum chaotic system that satisfies the eigenstate thermalization hypothesis (ETH) ansatz. Th

arXiv:2512.14302v2 Announce Type: replace Abstract: Multipartite nonlocality has been extensively investigated within one-dimensional quantum lattices. Previous research has primarily focused on the nonlocality measure $S$, which quantifies the violation of Bell-type inequalities. However, the opti

arXiv:2512.16197v2 Announce Type: replace Abstract: Color centers hosted in hexagonal boron nitride have emerged as a highly promising platform for single-photon emission and spin-photon technologies relevant to quantum communication and quantum networking. As a wide-bandgap van der Waals material,

arXiv:2601.03230v2 Announce Type: replace Abstract: We show that excitons coupled to cavity photons and phonons admit a generalized Bloch theorem when formulated for the conserved total crystal momentum. In minimal-coupling and Fr\"ohlich representations, the interchange of momenta between fermions

arXiv:2603.15190v2 Announce Type: replace Abstract: We study the error-correction properties of multi-mode Fock-state codes under amplitude-damping (AD) noise, focusing on the asymptotic regime in which the total excitation of the code states grows without limit and the number of photon losses indu

arXiv:2603.15515v3 Announce Type: replace Abstract: Solving large-scale sparse linear systems is a challenging computational task due to the introduction of non-zero elements, or "fill-in." The Graph Partitioning Problem (GPP) arises naturally when minimizing fill-in and accelerating solvers. In th

arXiv:2603.24237v2 Announce Type: replace Abstract: Atom loss is a dominant error source in neutral-atom quantum processors, yet its correlated structure remains largely unexploited by existing quantum error correction decoders. We analyze the performance of the surface code equipped with teleporta

arXiv:2603.29439v4 Announce Type: replace Abstract: Superconducting quantum processor units (QPUs) are incapable of producing massive datasets for quantum error correction (QEC) because of hardware limitations. Thus, QEC decoders heavily depend on synthetic data from qubit error models. Classic dep

arXiv:2604.06461v2 Announce Type: replace Abstract: We introduce a systematic protocol for constructing quantum Hilbert-space-fragmented Hamiltonians, whose Krylov-sector structure, unlike in classically fragmented models, can be fully resolved only in an entangled basis. The protocol takes as inpu

arXiv:2604.08367v2 Announce Type: replace Abstract: The Quantum Approximate Optimization Algorithm (QAOA) has emerged as a promising approach for addressing combinatorial optimization problems on near-term quantum hardware. In this work, we conduct an empirical evaluation of QAOA on the Max-Cut pro

arXiv:2604.09196v3 Announce Type: replace Abstract: The standard stimulated Raman adiabatic passage (STIRAP) protocol enables high-fidelity quantum state transfer in an ideal three-level system via adiabatic following of a dark state evolution. However, in practical systems with more energy levels,

arXiv:2604.09775v2 Announce Type: replace Abstract: Distributed quantum computing offers a promising approach to scaling quantum devices by networking multiple quantum processors. We present a quantum state tomography protocol tailored for distributed quantum computers that avoids assuming remote e

arXiv:2604.14224v2 Announce Type: replace Abstract: A time-integrated measure of complexity is proposed for diagnosing the degree of quantum ergodicity. The scrambling dynamics of maximally entangled states within the ensemble of unitary evolutions are quantified by applying numerical bootstrapped

arXiv:2604.20838v2 Announce Type: replace Abstract: We construct a quantum low-density parity-check code family from a length-$512$ Calderbank--Shor--Steane base matrix pair. The base pair is permutation-equivalent to the known SPC(3) product CSS code, and the present affine-coset description gives

arXiv:2604.21594v2 Announce Type: replace Abstract: Systematic control errors remain a primary obstacle to realizing high-fidelity single-qubit gates. We introduce composite pulse sequences that implement X and Hadamard gates while simultaneously compensating amplitude (Rabi-frequency), detuning (f

arXiv:2412.19780v2 Announce Type: replace-cross Abstract: Tensor networks are a tool first employed in the context of many-body quantum physics that now have a wide range of uses across the computational sciences, from numerical methods to machine learning. Methods integrating tensor networks into

arXiv:2503.15811v2 Announce Type: replace-cross Abstract: The variational determination of the two-boson reduced density matrix is described for a one-dimensional system of $N$ (where $N$ ranges from $2$ to $10^4$) harmonically trapped bosons interacting via contact interaction. The ground-state en

arXiv:2503.21437v2 Announce Type: replace-cross Abstract: Technological understanding is not a singular concept but varies depending on context. Building on De Jong and De Haro's (2025) notion of technological understanding as the ability to realise an aim through the use of a technological artefac

arXiv:2505.16913v3 Announce Type: replace-cross Abstract: We consider a free quantum particle in one dimension whose mass profile exhibits jump discontinuities. The corresponding Hamiltonian is a self-adjoint realisation of the kinetic-energy operator, with the specific realisation determined by th

arXiv:2510.05242v3 Announce Type: replace-cross Abstract: Bound electron-hole pairs in semiconductors known as excitons are the subject of intense research due to their potential for optoelectronic devices and applications, especially in the realm of two-dimensional materials. While the properties

arXiv:2512.02798v2 Announce Type: replace-cross Abstract: Single-photon sources based on neutral or charged excitons in a semiconductor quantum dot are attractive resources for photonic quantum computers and simulators. To obtain indistinguishable photons, the source is pumped on resonance with pol

arXiv:2602.20376v2 Announce Type: replace-cross Abstract: We approach the Max-3-Cut problem through the lens of maximizing complex-valued quadratic forms and demonstrate that low-rank structure in the objective matrix can be exploited, leading to alternative algorithms to classical semidefinite pro

arXiv:2602.21468v5 Announce Type: replace-cross Abstract: The spin-$1/2$ $J_1$-$J_2$ Heisenberg model on the square lattice exhibits a debated intermediate phase between N\'eel antiferromagnetic and stripe ordered regimes, with competing theories proposing plaquette valence bond, nematic, and quant

arXiv:2603.19381v2 Announce Type: replace-cross Abstract: Modulated symmetries are internal symmetries that act in a spatially non-uniform manner. Consequently, when a modulated symmetry $G_{\text{int}}$ is combined with a spatial symmetry $G_{\text{sp}}$, the total symmetry group takes the form of

arXiv:2604.00037v2 Announce Type: replace-cross Abstract: Tensor trains (TTs), also known as matrix product states (MPS), are compressed representations of high-dimensional data that can be efficiently manipulated to perform calculations on the data. In many applications, such as TT-based solvers f

arXiv:2604.03669v2 Announce Type: replace-cross Abstract: The statistics of gaps between quantum energy levels is a hallmark criterion in quantum chaos and quantum integrability studies. The relevant distributions corresponding to exactly integrable vs. fully chaotic systems are universal and descr

arXiv:2604.11596v2 Announce Type: replace-cross Abstract: A spectrally isolated quartet can admit a local two-qubit description at each point in parameter space and still acquire a loop holonomy outside the local subgroup $\mathrm{U}(2)\otimes\mathrm{U}(2)$. We study this question in three localize

arXiv:2604.21857v2 Announce Type: replace-cross Abstract: New sources of charge-parity (CP) violation beyond those described in the Standard Model (SM) are required to explain the observed matter--antimatter asymmetry of the Universe. The Standard Model Effective Field Theory (SMEFT) provides a fra

npj Quantum Information, Published online: 24 April 2026; doi:10.1038/s41534-026-01242-xEfficient post-selection for general quantum LDPC Codes

npj Quantum Information, Published online: 24 April 2026; doi:10.1038/s41534-026-01243-wPlacing and routing quantum LDPC codes in multilayer superconducting hardware

npj Quantum Information, Published online: 24 April 2026; doi:10.1038/s41534-026-01248-5Near-term fermionic simulation with subspace noise tailored quantum error mitigation

npj Quantum Information, Published online: 22 April 2026; doi:10.1038/s41534-026-01241-ySurface-code hardware Hamiltonian

npj Quantum Information, Published online: 21 April 2026; doi:10.1038/s41534-026-01247-6Distributed quantum inner product estimation with structured random circuits

npj Quantum Information, Published online: 21 April 2026; doi:10.1038/s41534-026-01221-2Two-qubit gates using on-demand single-photons from ordered shape and size controlled large-volume superradiant quantum dots

npj Quantum Information, Published online: 17 April 2026; doi:10.1038/s41534-026-01228-9Collective purification of interacting quantum networks beyond symmetry constraints

npj Quantum Information, Published online: 17 April 2026; doi:10.1038/s41534-026-01229-8Quantum reservoir computing induced by controllable damping