Entropy and algorithmic complexity in quantum information theory

Umesh V. Vazirani

Fabio Benatti, Tyll Krueger, Markus P. Müller +2 more

In classical information theory, entropy rate and algorithmic complexity per symbol are related by a theorem of Brudno. In this paper, we prove a quantum version of this theorem, connecting the von Neumann entropy rate and two notions of quantum algorithmic complexity, both based on the shortest qubit descriptions of qubit strings that, run by a universal quantum Turing machine, reproduce them as outputs.

Nilanjana Datta

Jincheng Zhang

This paper explores the application of quantum information entropy to the theory of computational complexity. We posit that quantum information entropy can serve as a novel metric for quantifying the complexity of quantum algorithms and their associated resource requirements. The core argument is that traditional measures of computational complexity, such as circuit depth or quantum gate count, often fail to fully capture the inherent challenges posed by quantum systems. By leveraging entropy, we aim to provide a more nuanced and potentially more accurate assessment of the difficulty of quantum computations. This work introduces a framework for analyzing quantum algorithms through the lens of information entropy, exploring relationships between algorithmic complexity, entropy generation, and the resources needed to execute these algorithms. Specifically, we examine how entropy can be used to characterize the 'quantumness' of an algorithm and its impact on the overall computational cost. The ultimate goal is to develop a more robust and predictive model for quantum computation, leading to improved algorithm design and resource allocation. ---

Fabio Benatti

We review the basics of classical algorithmic complexity theory and two of its quantum extensions that have been prompted by the foreseeable existence of quantum computing devices. In particular, we will examine the relations between these extensions and the von Neumann entropy rate of generic quantum information sources of ergodic type.

Guillaume Aubrun, Stanisław Szarek