A key component of variational quantum algorithms (VQAs) is the choice of classical optimizer employed to update the parameterization of an ansatz. It is well recognized that quantumalgorithms will, for the foreseeab...
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A key component of variational quantum algorithms (VQAs) is the choice of classical optimizer employed to update the parameterization of an ansatz. It is well recognized that quantumalgorithms will, for the foreseeable future, necessarily be run on noisy devices with limited fidelities. Thus, the evaluation of an objective function (e.g., the guiding function in the quantum approximate optimization algorithm (QAOA) or the expectation of the electronic Hamiltonian in variationalquantum eigensolver (VQE)) required by a classical optimizer is subject not only to stochastic error from estimating an expected value but also to error resulting from intermittent hardware noise. Model-based derivative-free optimization methods have emerged as popular choices of a classical optimizer in the noisy VQA setting, based on empirical studies. However, these optimization methods were not explicitly designed with the consideration of noise. In this work we adapt recent developments from the "noise-aware numerical optimization" literature to these commonly used derivative-free model-based methods. We introduce the key defining characteristics of these novel noise-aware derivative-free model-based methods that separate them from standard model-based methods. We study an implementation of such noise-aware derivative-free model-based methods and compare its performance on demonstrative VQA simulations to classical solvers packaged in scikit-quant.
variational quantum algorithms (VQAs) demonstrate potential advantages on noisy intermediate-scale quantum (NISQ) devices, particularly in applications for quantum machine learning (QML). However, due to the high cost...
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variational quantum algorithms (VQAs) demonstrate potential advantages on noisy intermediate-scale quantum (NISQ) devices, particularly in applications for quantum machine learning (QML). However, due to the high cost and limited availability of quantum resources, delegating VQAs through cloud networks offers a practical solution for clients with limited quantum capabilities. Recently, Shingu et al. proposed a variational secure cloud quantum computing protocol that employs ancilla-driven quantum computation (ADQC) to facilitate cloud-based VQAs while minimizing quantum resource consumption. Nonetheless, their protocol lacks verifiability, rendering it susceptible to potential malicious interference by the server or unintended deviations that could result in corrupted output states. Furthermore, channel loss necessitates frequent re- delegation, complicating the verification process as the size of the delegated variational circuit increases. This paper introduces a novel protocol that addresses these challenges by incorporating both verifiability and high tolerance to channel loss in cloud-based VQAs. Our approach emphasizes the critical integration of ADQC with robust security measures to ensure computational integrity, even in less controlled cloud networks.
quantum computing is a new discipline combining quantum mechanics and computer science, which is expected to solve technical problems that are difficult for classical computers to solve efficiently. At present, quantu...
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quantum computing is a new discipline combining quantum mechanics and computer science, which is expected to solve technical problems that are difficult for classical computers to solve efficiently. At present, quantumalgorithms and hardware continue to develop at a high speed, but due to the serious constraints of quantum devices, such as the limited numbers of qubits and circuit depth, the fault-tolerant quantum computing will not be available in the near future. variational quantum algorithms(VQAs) using classical optimizers to train parameterized quantum circuits have emerged as the main strategy to address these constraints. However, VQAs still have many challenges, such as trainability, hardware noise, expressibility and entangling capability. The fundamental concepts and applications of VQAs are reviewed. Then, strategies are introduced to overcome the challenges of VQAs and the importance of further researching VQAs is highlighted.
variational quantum algorithms (VQA) combine the advantages of classical and near-term quantum computation for solving problems on today's noisy quantum devices. variationalquantum Eigensolver (VQE) is one of the...
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ISBN:
(纸本)9798331541378
variational quantum algorithms (VQA) combine the advantages of classical and near-term quantum computation for solving problems on today's noisy quantum devices. variationalquantum Eigensolver (VQE) is one of the widely used VQAs, which aims to find the approximate ground state energy of a given Hamiltonian. While traditional VQE implementation is promising for ansatz-based trial state preparation, it requires an initial fiducial state or a reference state, which can be infeasible for large quantum systems. In this paper, we propose a novel approach for trial state preparation in VQE algorithms. This method leverages passive steering, a circuit-based approach with repeated measurements, eliminating the need for an initial fiducial state or a reference state. Experimental results demonstrate that passive steering-based state preparation provides improved accuracy and scalability of VQE compared to traditional ansatz-based solutions. Our proposed solution can also be effectively combined with the existing ansatz-based methods, where passive steering prepares the reference state while ansatz prepares the trial state, facilitating a robust and scalable state preparation for variational quantum algorithms.
The quantum processors' performance is predicted to surpass the application of variational quantum algorithms in finance has proven to be instrumental in addressing crucial challenges. From enhancing security thro...
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ISBN:
(纸本)9789819733019;9789819733026
The quantum processors' performance is predicted to surpass the application of variational quantum algorithms in finance has proven to be instrumental in addressing crucial challenges. From enhancing security through anomaly detection and fraud indicator identification to optimizing credit scoring and improving stock price prediction, VQAs demonstrate their versatility and potential to revolutionize the financial industry's analytical capabilities. As quantum computing continues to advance, the integration of VQAs is expected to play an increasingly pivotal role in shaping the future of financial technology. In this paper, we review variational quantum algorithms in anomaly detection and fraud indicator systems, credit scoring, and stock price prediction.
The quantum processors' performance is predicted to surpass the traditional systems during this decade in computational performance and capabilities. This disruptive technology can significantly impact many indust...
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ISBN:
(纸本)9789819732982;9789819732999
The quantum processors' performance is predicted to surpass the traditional systems during this decade in computational performance and capabilities. This disruptive technology can significantly impact many industrial sectors in the long term. Other than communication and mathematics, we expect the finance sector to be one of the first to receive the prosperity of this new cutting-edge technology. This paper provides a review of the current progress on quantumalgorithms for financial applications, specifically focusing on the use cases that can be addressed through machine learning.
quantum computing is a game-changing technology for global academia,research centers and industries including computational science,mathematics,finance,pharmaceutical,materials science,chemistry and *** it has seen a ...
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quantum computing is a game-changing technology for global academia,research centers and industries including computational science,mathematics,finance,pharmaceutical,materials science,chemistry and *** it has seen a major boost in the last decade,we are still a long way from reaching the maturity of a full-fledged quantum *** said,we will be in the noisy-intermediate scale quantum(NISQ)era for a long time,working on dozens or even thousands of qubits quantum computing *** outstanding challenge,then,is to come up with an application that can reliably carry out a nontrivial task of interest on the near-term quantum devices with non-negligible quantum *** address this challenge,several near-term quantum computing techniques,including variational quantum algorithms,error mitigation,quantum circuit compilation and benchmarking protocols,have been proposed to characterize and mitigate errors,and to implement algorithms with a certain resistance to noise,so as to enhance the capabilities of near-term quantum devices and explore the boundaries of their ability to realize useful ***,the development of near-term quantum devices is inseparable from the efficient classical sim-ulation,which plays a vital role in quantum algorithm design and verification,error-tolerant verification and other *** review will provide a thorough introduction of these near-term quantum computing techniques,report on their progress,and finally discuss the future prospect of these techniques,which we hope will motivate researchers to undertake additional studies in this field.
In this paper, we investigate the use of variational quantum algorithms for simulating the thermodynamic properties of dinuclear metal complexes. Our study highlights the potential of quantum computing to transform ad...
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In this paper, we investigate the use of variational quantum algorithms for simulating the thermodynamic properties of dinuclear metal complexes. Our study highlights the potential of quantum computing to transform advanced simulations and provide insights into the physical behavior of quantum systems. The results demonstrate the effectiveness of variational quantum algorithms in simulating thermal states and exploring the thermodynamic properties of low-dimensional molecular magnetic systems. The findings from this research contribute to broadening our understanding of quantum systems and pave the way for future advancements in materials science through quantum computing.
Estimating the difference between quantum data is crucial in quantum computing. However, as typical characterizations of quantum data similarity, the trace distance and quantum fidelity are believed to be exponentiall...
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Estimating the difference between quantum data is crucial in quantum computing. However, as typical characterizations of quantum data similarity, the trace distance and quantum fidelity are believed to be exponentially-hard to evaluate in general. In this work, we introduce hybrid quantum-classical algorithms for these two distance measures on near-term quantum devices where no assumption of input state is required. First, we introduce the variational trace distance estimation (VTDE) algorithm. We in particular provide the technique to extract the desired spectrum information of any Hermitian matrix by local measurement. A novel variational algorithm for trace distance estimation is then derived from this technique, with the assistance of a single ancillary qubit. Notably, VTDE could avoid the barren plateau issue with logarithmic depth circuits due to a local cost function. Second, we introduce the variational fidelity estimation algorithm. We combine Uhlmann's theorem and the freedom in purification to translate the estimation task into an optimization problem over a unitary on an ancillary system with fixed purified inputs. We then provide a purification subroutine to complete the translation. Both algorithms are verified by numerical simulations and experimental implementations, exhibiting high accuracy for randomly generated mixed states.
quantum machine learning-and specifically variational quantum algorithms (VQAs)-offers a powerful, flexible paradigm for programming near-term quantum computers, with applications in chemistry, metrology, materials sc...
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quantum machine learning-and specifically variational quantum algorithms (VQAs)-offers a powerful, flexible paradigm for programming near-term quantum computers, with applications in chemistry, metrology, materials science, data science, and mathematics. Here, one trains an ansatz, in the form of a parameterized quantum circuit, to accomplish a task of interest. However, challenges have recently emerged suggesting that deep ansatzes are difficult to train, due to flat training landscapes caused by randomness or by hardware noise. This motivates our work, where we present a variable structure approach to build ansatzes for VQAs. Our approach, called VAns (Variable Ansatz), applies a set of rules to both grow and (crucially) remove quantum gates in an informed manner during the optimization. Consequently, VAns is ideally suited to mitigate trainability and noise-related issues by keeping the ansatz shallow. We employ VAns in the variationalquantum eigensolver for condensed matter and quantum chemistry applications, in the quantum autoencoder for data compression and in unitary compilation problems showing successful results in all cases.
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