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Coherent Measuring and Data Processing Methods and Devices

Valery I. Mandrosov

Published Sep 1, 1993• 1 citation
OpenAlex

Related papers

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Learning problems involving quantum data are natural candidates for demonstrating an advantage in quantum machine learning. Recent results indicate that, for certain tasks and under noiseless conditions, coherent processing of quantum data outperforms fixed-measurement schemes followed by classical processing. It remained uncertain whether this performance gap persists at a finite scale, and in the presence of noise that is unavoidable with current quantum devices. In this work, we present simulations and analysis of the performance of existing hardware on a learning problem known to exhibit asymptotic advantage, now subjected to noisy quantum data. Comparing coherent quantum processing directly against fixed-measurement schemes, our results demonstrate a clear performance separation at a scale of just 30 to 40 noisy qubits. Already at this scale, the fundamental bottleneck is no longer classical computation but data acquisition; matching the noisy coherent protocol with measure-first strategies would still require months or even years of measurements. By systematically evaluating hardware constraints such as state preparation, gate errors, readout errors, connectivity, and coherence times, we provide evidence that a demonstration of such a strong learning advantage is accessible on near-term devices.

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Abstract In the protocols of device-independent quantum random number generator, it is essential to certify the randomness of the generated numbers. However, statistical fluctuations in measurement data might break the nosignaling conditions, making those data unphysical. In this letter, we proposed to circumvent this problem by using the standard constrained least-squares method. As examples, we apply our present approach on post-processing two different experimental data by utilizing either CHSH correlations or complete measurement statistics, and do comparisons with the original distribution. The post-processing results not only prove the effectiveness of our work to solve the unphysical problem, but also show that randomness certified by processing complete measurement statistics is always larger than through Bell-like inequalities.

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Experimental Apparatus and Techniques

Yuma Nakamura

Springer theses•Jan 1, 2026•0 citations
Measurements in the quantum domain can exceed classical notions. This concerns fundamental questions about the nature of the measurement process itself, as well as applications, such as their function as building blocks of quantum information processing protocols. In this paper we explore the notion of entanglement for detection devices in theory and experiment. A method is devised that allows one to determine nonlocal quantum coherence of positive-operator-valued measures via negative contributions in a joint distribution that fully describes the measurement apparatus under study. This approach is then applied to experimental data for detectors that ideally project onto Bell states. In particular, we describe the reconstruction of the aforementioned entanglement quasidistributions from raw data and compare the resulting negativities with those expected from theory. Therefore, our method provides a versatile toolbox for analyzing measurements regarding their quantum-correlation features for quantum science and quantum technology.
Learning problems involving quantum data are natural candidates for demonstrating an advantage in quantum machine learning. Recent results indicate that, for certain tasks and under noiseless conditions, coherent processing of quantum data outperforms fixed-measurement schemes followed by classical processing. It remained uncertain whether this performance gap persists at a finite scale, and in the presence of noise that is unavoidable with current quantum devices. In this work, we present simulations and analysis of the performance of existing hardware on a learning problem known to exhibit asymptotic advantage, now subjected to noisy quantum data. Comparing coherent quantum processing directly against fixed-measurement schemes, our results demonstrate a clear performance separation at a scale of just 30 to 40 noisy qubits. Already at this scale, the fundamental bottleneck is no longer classical computation but data acquisition; matching the noisy coherent protocol with measure-first strategies would still require months or even years of measurements. By systematically evaluating hardware constraints such as state preparation, gate errors, readout errors, connectivity, and coherence times, we provide evidence that a demonstration of such a strong learning advantage is accessible on near-term devices.
Abstract In the protocols of device-independent quantum random number generator, it is essential to certify the randomness of the generated numbers. However, statistical fluctuations in measurement data might break the nosignaling conditions, making those data unphysical. In this letter, we proposed to circumvent this problem by using the standard constrained least-squares method. As examples, we apply our present approach on post-processing two different experimental data by utilizing either CHSH correlations or complete measurement statistics, and do comparisons with the original distribution. The post-processing results not only prove the effectiveness of our work to solve the unphysical problem, but also show that randomness certified by processing complete measurement statistics is always larger than through Bell-like inequalities.