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The quantum walk formalism is a widely used and highly successful framework for modeling quantum systems, such as simulations of the Dirac equation, different dynamics in both the low and high energy regime, and for developing a wide range of quantum algorithms. Here we present the circuit-based implementation of a discrete-time quantum walk in position space on a five-qubit trapped-ion quantum processor. We encode the space of walker positions in particular multi-qubit states and program the system to operate with different quantum walk parameters, experimentally realizing a Dirac cellular automaton with tunable mass parameter. The quantum walk circuits and position state mapping scale favorably to a larger model and physical systems, allowing the implementation of any algorithm based on discrete-time quantum walks algorithm and the dynamics associated with the discretized version of the Dirac equation.
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http://dx.doi.org/10.1038/s41467-020-17519-4 | DOI Listing |
Cognition
September 2025
Department of Cognitive Science, Indiana University Bloomington, United States of America. Electronic address:
We propose a novel quantum walk framework for modeling serial reproduction, designed to effectively capture the transmission of inherently vague concepts, such as emotions and ideas, through quantum superpositions and controlled unitary operations. In a comprehensive comparison with Bayesian models using the largest dataset of reproduced narratives to date, our framework demonstrates superior predictive accuracy, surpassing Bayesian approaches in modeling non-linear relationships and multimodal distributions in emotion transmission. Furthermore, it successfully replicates recent key findings on emotion transmission in serial reproduction.
View Article and Find Full Text PDFQuantum gates are crucial for processing quantum information, but implementing them in a photonic platform poses unique challenges due to the peculiar way photons propagate and interfere. Here, we propose quantum photonic gates that utilize continuous time two-dimensional random walking photons. These gates can be implemented using the inverse design method, where photons randomly walk in a two-dimensional silicon host medium embedded with silicon dioxide scatterers.
View Article and Find Full Text PDFMultiphoton interference is crucial to many photonic quantum technologies. In particular, interference forms the basis of optical quantum information processing platforms and can lead to significant computational advantages. It is therefore interesting to study the interference arising from various states of light in large interferometric networks.
View Article and Find Full Text PDFAchieving both reconfigurability and stable output signals is a critical challenge in the development of integrated photonic circuits for large-scale optical quantum information processing. This has led to the creation of multimode photonic processors, also known as reconfigurable multimode interferometers, which have wide-ranging applications in quantum and classical information processing. However, maintaining phase stability in multiport input signals remains a significant hurdle, particularly due to the phase instabilities introduced by active cooling systems and temperature drifts in the photonic processor.
View Article and Find Full Text PDFEntropy (Basel)
June 2025
Graduate School of Environment and Information Sciences, Yokohama National University, Hodogaya, Yokohama 240-8501, Japan.
We propose a model that interpolates between quantum walks and persistent (correlated) random walks using one parameter on the one-dimensional lattice. We show that the limit distribution is described by the normal variance mixture with the arcsine law.
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