Quantum computing is highly sensitive to environmental noise, leading to quantum errors—defined as deviations between measured and expected outcomes. To mitigate these errors, various Quantum Error Mitigation (QEM) methods have been proposed; however, they show limited performance in complex quantum circuits due to error-propagation caused by entanglement. In this paper, we propose a novel entanglement-aware QEM method that simultaneously considers circuit architecture and entanglement information. Our method achieves high QEM performance by encoding entanglement strength as self-attention bias and edge features, thus effectively capturing error-propagation patterns. Experimental results on complex quantum circuits demonstrate that the proposed method outperforms existing QEM approaches and achieves effective error mitigation across various noise types.
Quantum computing is highly sensitive to environmental noise, leading to quantum errors—defined as deviations between measured and expected outcomes. To mitigate these errors, various Quantum Error Mitigation (QEM) methods have been proposed; however, they show limited performance in complex quantum circuits due to error-propagation caused by entanglement. In this paper, we propose a novel entanglement-aware QEM method that simultaneously considers circuit architecture and entanglement information. Our method achieves high QEM performance by encoding entanglement strength as self-attention bias and edge features, thus effectively capturing error-propagation patterns. Experimental results on complex quantum circuits demonstrate that the proposed method outperforms existing QEM approaches and achieves effective error mitigation across various noise types.
Quantum error mitigation (QEM) is a crucial area of research for realizing fault-tolerant quantum computation. While various QEM techniques have been developed, many rely on classical post-processing of quantum measurements, which can introduce their own biases and limitations. This paper proposes a novel hardware error mitigation strategy leveraging the inherent properties of quantum entanglement and its susceptibility to environmental decoherence. The core idea is to actively suppress quantum decoherence, specifically targeting the entanglement that contributes significantly to error propagation in quantum computations. We formulate a control scheme that precisely modulates environmental parameters to minimize the detrimental effects of entanglement-induced decoherence. The effectiveness of this approach is demonstrated through a theoretical analysis, outlining the potential for significant error reduction without relying on complex post-processing algorithms. The key benefit lies in a proactive, hardware-level approach to mitigating errors, offering a potentially more robust and efficient solution compared to post-processing methods. This work establishes a foundational framework for future research in entanglement-aware QEM.
Near-term quantum computers have been built as intermediate-scale quantum devices and are fragile against quantum noise effects, namely, NISQ devices. Traditional quantum-error-correcting codes are not implemented on such devices and to perform quantum computation in good accuracy with these machines we need to develop alternative approaches for mitigating quantum computational errors. In this work, we propose quantum error mitigation (QEM) scheme for quantum computational errors which occur due to couplings with environments during gate operations, i.e., decoherence. To establish our QEM scheme, first we estimate the quantum noise effects on single-qubit states and represent them as groups of quantum circuits, namely, quantum-noise-effect circuit groups. Then our QEM scheme is conducted by subtracting expectation values generated by the quantum-noise-effect circuit groups from those obtained by the quantum circuits for the quantum algorithms under consideration. As a result, the quantum noise effects are reduced, and we obtain approximately the ideal expectation values via the quantum-noise-effect circuit groups and the numbers of elementary quantum circuits composing them scale polynomial with respect to the products of the depths of quantum algorithms and the numbers of register bits. To numerically demonstrate the validity of our QEM scheme, we run noisy quantum simulations of qubits under amplitude damping effects for four types of quantum algorithms. Furthermore, we implement our QEM scheme on IBM Q Experience processors and examine its efficacy. Consequently, the validity of our scheme is verified via both the quantum simulations and the quantum computations on the real quantum devices. Our QEM scheme is solely composed of quantum-computational operations (quantum gates and measurements), and thus, it can be conducted by any type of quantum device. In addition, it can be applied to error mitigation for many other types of quantum noise effects as well as noisy quantum computing of long-depth quantum algorithms.
We present a simple, malleable and low-overhead approach for improving generic biased quantum error mitigation (QEM) methods, achieving up to 15% fidelity improvements over standard QEM on 100-qubit circuits with up to 2000 entangling gates. We do so by constructing verifiable benchmark circuits which mirror the application circuit's native-gate structure and thus noise profile. These circuits can be used to benchmark and mitigate the bias of the underlying error mitigation method, requiring only the application circuit and hardware native gate set. We present two methods for generating benchmark circuits; one is agnostic to the target hardware at the expense of a small overhead of single-qubit gates, while the other is specific to the IBM superconducting hardware and has no gate overhead. As a corollary, we introduce benchmarked-noise zero-noise extrapolation (bnZNE) as a simple adaptation of zero-noise extrapolation (ZNE), one of the most popular error mitigation methods. We consider as an example the bias-mitigated ZNE and bnZNE of Trotterized Hamiltonian simulations, observing that our approaches outperform standard ZNE using both small-scale classical simulations and 100-qubit utility-scale experiments on the IBM superconducting hardware. We consider the measurement of both single-site observables as well as two-site correlations along a one-dimensional qubit chain. We also provide a software package for implementing the error mitigation techniques used in this research.
Quantum technologies work by utilizing properties inherent in quantum systems such as quantum coherence and quantum entanglement and are expected to be superior to classical counterparts for solving certain problems in science and engineering. The quantum technologies are, however, fragile against an interaction with an environment (decoherence) and in order to utilize them with high accuracy we need to develop error mitigation techniques which reduce decoherence effects. In this work, we analyze quantum error mitigation (QEM) protocol for quantum metrology in the presence of quantum noise. We demonstrate the effectiveness of our QEM protocol by analyzing three types of quantum Fisher information (QFI), ideal (error-free) QFI, noisy (erroneous) QFI, and quantum-error-mitigated QFI, and show both analytically and numerically that the scaling behaviors of quantum-error-mitigated QFI with respect to the number of probes become restored to the those exhibited in the ideal quantum metrology. Our QEM protocol is constructed by an ensemble of quantum circuits, namely QEM circuit groups, and has advantages such that it can be applied to noisy quantum metrology for any type of initial state as well as any type of the probe-system Hamiltonian, and it can be physically implemented in any type of quantum device. Furthermore, the quantum-error-mitigated QFI become approximately equal to the ideal QFI for almost any values of physical quantities to be sensed. Our protocol enables us to use quantum entanglement as a resource to perform high-sensitive quantum metrology even under the influence of quantum noise.
This paper explores a novel approach to quantum error correction (QEC) centered around the deliberate incorporation of entanglement-based redundancy directly within the design of quantum circuits. Current QEC strategies often rely on external, post-processing correction stages, which introduce significant overhead and complexity. We argue that a more efficient and intrinsically robust solution lies in building self-correcting circuits where redundancy is woven into the circuit's architecture itself, utilizing entangled qubits to detect and mitigate errors in real-time. This approach shifts the paradigm from correction *after* computation to correction *during* computation. The core mechanism involves encoding logical information across multiple physical qubits through carefully designed entangled states, creating a network capable of detecting errors via measurement and then implementing corrective operations through controlled interactions. We present a theoretical framework for designing such circuits, detailing the key considerations for state preparation, entanglement distribution, and error detection/correction protocols. We demonstrate, through mathematical analysis and circuit design principles, that this entanglement-based redundancy can substantially improve the resilience of quantum computations against various noise sources. The proposed method offers a potentially transformative pathway towards fault-tolerant quantum computing, reducing the overall complexity and resource requirements associated with error correction.
Error correction is a fundamental challenge in quantum computing, hindering the ability to perform complex calculations. Current error correction techniques rely on decoding, which is computationally intensive and requires a full readout of the computation. This paper explores a novel quantum error mitigation protocol that utilizes quantum entanglement to detect and correct errors without the need for full decoding, offering a potential paradigm shift in the field. We propose a protocol where entangled qubits are strategically positioned to detect and correct errors in a quantum circuit, minimizing the computational burden while maintaining high fidelity. The core mechanism involves creating entanglement between qubits, enabling the detection of errors as deviations from expected entanglement states. This paper details the protocol's design, analysis of its potential benefits, and initial experimental validation demonstrating its effectiveness in mitigating errors.