Quantum phase estimation in the language of digital signal processing
Sukin Sim (Dylan)
PsiQuantum
Quantum phase estimation (QPE) is a central subroutine in many quantum algorithms and applications. Accordingly, QPE has been extensively studied and improved across several disciplines, including quantum algorithms, metrology, and signal processing. However, under the traditional formulation and programming paradigm for QPE, it remains difficult to integrate and unify these advances without re-implementing code, often with limited extensibility. This motivates the need for a more general conceptual framework for QPE. In this talk, we reintroduce QPE through the language of digital signal processing. From this perspective—perhaps implicit in several prior works—we show how a wide range of improvements across different disciplines, including window functions, bidirectional phase kickback, and qubitization, can be understood and incorporated more naturally. Through this pedagogical presentation, we aim to highlight the value of reframing quantum algorithms, particularly in the context of programming and deploying quantum applications.
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