Abstract Superconducting qubits can be sensitive to energy deposits caused by cosmic rays and ambient radioactivity. While previous studies have explored correlated effects in time and space due to cosmic ray interactions, we present the first direct comparison of a transmon qubit’s performance measured at two distinct sites: the above-ground SQMS facility (Fermilab, US) and the deep-underground Gran Sasso Laboratory (Italy). Despite the stark difference in radiation levels, we observe a similar average qubit relaxation time of approximately 80 microseconds at both locations. To investigate radiation-induced events, we employ a fast decay detection protocol, comparing the relative rates of events between the two environments. Although intrinsic noise remains the dominant source of errors in superconducting qubits, our analysis revealed a significant excess of radiation-induced events for high-coherence transmon qubits operated above-ground. Finally, using γ -ray sources with increasing activity levels, we evaluate the qubit response in a controlled low-background environment.

We study the theory of, and propose an experimental design for, a Sagnac tractor atom interferometer based on a photonic integrated circuit (PIC). The atoms are trapped in counter-rotating azimuthal optical lattices, formed by interfering evanescent fields of laser modes injected into circular PIC waveguides. We develop quantum models for the radial and azimuthal dynamics of the interfering atoms in adiabatic frames, which provide computational efficiency. The theory is applied to an exemplary PIC, for which we first compute field modes and atom trapping potentials for 87Rb. We then evaluate non-adiabaticity, fidelity, and sensitivity of the exemplary PIC.

Circuit-based quantum computing (CBQC), also known as the gate model, is currently regarded as the leading paradigm for performing quantum computation and has garnered widespread interest due to its relatively better-established implementation and close intuitive resemblance to classical computation. However, an alternative model that solely utilizes single-qubit measurements on entangled states to perform computation, namely the measurement-based quantum computing (MBQC), has started to attract further research interest as it is deemed more naturally suited for certain quantum hardware architectures, though its actual implementation remains largely underexplored. Recently, there have been preliminary efforts to characterize the specific regimes in which MBQC may potentially be more advantageous compared to CBQC. Nevertheless, a more systematic assessment is necessary to assess the suitability of each model across a broader range of more practical cases. In this work, we present a detailed comparative analysis of CBQC and MBQC, beginning with reviewing the theoretical foundations of each model before highlighting its distinguishing features that set the two paradigms apart. Furthermore, building on previous work, we propose a generalized regime analysis that more accurately captures the conditions under which a given quantum algorithm is more favorably executed in MBQC or CBQC. Subsequently, we identify critical parameters that likely determine whether a quantum algorithm is better suited to CBQC or MBQC, categorizing detailed key factors and performance metrics into layers of quantum computation. Next, we propose a decision flow that, given specific hardware constraints and algorithm requirements, guides the selection to the most appropriate model, discussing suitability in two representative worked examples of quantum algorithm applications: Quantum Fourier Transform (QFT) and Variational Quantum Algorithm (VQE). Last, we discuss the potential to combine both models as a hybrid approach to leverage the best of both worlds and explore its benefits for practical quantum computing applications.

Convex hull computation is a fundamental problem in secure multi-party computational geometry (SMCG), classified under secure multi-party computation (SMC) for finding the convex hull of a set of points. Existing quantum solutions largely depend on quantum homomorphic encryption (QHE), which introduces significant computational overhead due to frequent key updates by a trusted third party (TTP). Furthermore, most current protocols lack a mechanism for input commitment, making them vulnerable to post-computation input tampering or denial by the TTP. To overcome these limitations, we propose an efficient convex hull protocol that utilizes quantum secret commitment (QSC) as a more secure alternative to QHE. Our protocol enables a designated party (the committer) to securely commit to input values in a manner that guarantees both binding (no post-hoc alteration) and hiding (input secrecy). We introduce a novel value comparison protocol within an Ideal Quantum K-Party model, ensuring privacy-preserving convex hull computation without reliance on QHE. Rigorous security analysis demonstrates significant improvements in computational efficiency and resilience against quantum adversaries. Our protocol represents a pivotal advancement for quantum-secure multi-party computations and lays the groundwork for scalable, future-proof privacy-preserving geometry in quantum computing contexts.

Abstract Quantum computing (QC) advances will help solve high complexity challenges that classical system architectures cannot solve. This report examines the philosophical foundation for QC research using a PRISMA-compliant systematic literature review and bibliometric analysis. This review emphasizes business applications of QC, including optimization, cryptography and cybersecurity, machine learning, financial modeling and forecasting, supply chain management, healthcare and analytics, and materials design, showing how QC can improve prediction and forecast accuracy, data physicalness, large-scale optimization, and more. The research will also identify execution constraints such hardware readiness, qubit capacity, development and operation expenses, personnel availability, and regulatory and commercial governance. Bibliometric data showed a focus on foundational quantum theoretical contributions and algorithms, with multidisciplinary and practical work emerging. Scaled algorithms, quantum-resistant standards, and any solutions industry nexus to enterprise are among the research opportunities. The literature evaluation will also identify ethical, policy, and sustainability issues related to quantum benefits. The paper helps businesspeople understand QC’s current and future opportunities, including a research-based assessment of where we’ve come, common themes in the literature, and strategic domains for scaling QC as a research agenda from laboratory experiments to enriching the service experience as commercial utility.

In distributed quantum computing, the final solution of a problem is usually achieved by catenating these partial solutions resulted from different computing nodes, but intolerable errors likely yield in this catenation process. In this paper, we propose a universal error correction scheme to reduce errors and obtain effective solutions. Then, we apply this error correction scheme to designing a distributed phase estimation algorithm that presents a basic tool for studying distributed Shor’s algorithm and distributed discrete logarithm algorithm as well as other distributed quantum algorithms. Our method may provide a universal strategy of error correction for a kind of distributed quantum computing.

We investigate lattice scalar field theory in two-dimensional Euclidean space via a quantum annealer. To accommodate the quartic interaction terms, we introduce three schemes for rewriting them as quadratic polynomials through the use of auxiliary qubits. These methods are applied on D-Wave quantum annealer, and their effectiveness is assessed by examining the annealer-generated distributions. Using these distributions, we perform Monte Carlo sampling via the Metropolis-Hastings algorithm and compare the outcomes with those from classical local Metropolis simulations.

Quantum networks aim to facilitate the fault-tolerant and secure transmission of quantum states across distant devices. The widely adopted quantum teleportation scheme requires multiple rounds of entanglement swapping and purification, leading to significant resource overhead and operational complexity. In this study, we propose a novel fault-tolerant and secure quantum communication scheme based on uncorrectable error injection. Our method exploits a quantum state encoding scheme based on quantum error correction codes, which strategically introduces uncorrectable errors to enhance security. It eliminates the need for entanglement distribution while reducing resource requirements. The injected errors protect against eavesdropping by preventing unauthorized parties from retrieving meaningful information. Security analysis shows that as the data length and encoded message size increase, information leakage becomes negligible relative to the size of the total message. Comparative performance analysis with existing approaches indicates that our method reduces transmission overhead while maintaining comparable fidelity in low-error regimes. These findings suggest that the proposed method offers a scalable and practical alternative for secure long-distance quantum communication, distributed quantum computing, and future quantum internet applications.

Tian et al. (EPJ Quantum Technol 11(1):35, 2024) proposed three semi-quantum summation protocols that enable resource-limited participants to securely compute the sum of their private inputs with assistance from a semi-honest third party (TP). In these protocols, participants do not need quantum measurement devices to achieve secure computation. Although the protocols have been analyzed against common attacks to demonstrate their robustness, this study identifies two significant issues in Tian et al.’s work: a security loophole and a design flaw. The security loophole permits a malicious participant to steal another participant’s private input without detection, while the design flaw prevents participants from obtaining the correct summation result when the number of participants is odd. To address these issues, this study proposes improved semi-quantum summation protocols under the same assumptions and environment.