Extracting Entropy from Quantum Computers

Masanori Ohya, Dėnes Petz

Andrew M. Steane

Quantum error correction (QEC) and fault tolerant quantum computing are introduced. The basic theory of an important class of quantum error correcting codes, the stabilizer codes, is given. Fault tolerance is described very briefly. The whole fault-tolerant correction process can usefully be described in thermodynamic language, as a special form of heat engine which extracts entropy from a collection of qubits without fully measuring their state. QEC is useful both for stabilizing quantum computers and for detecting small many-body correlated effects which would otherwise be swamped by (uncorrelated) noise.

Jincheng Zhang

Quantum entanglement, a fundamental phenomenon in quantum mechanics, holds the potential for revolutionary computational capabilities. This paper explores the application of entanglement-based information entropy to a novel adaptive computing approach. We propose a method that leverages the unique properties of entangled quantum states to achieve precise computations and information extraction across a broader range of quantum systems. This work investigates the design of a specialized calculation model based on entangled states, emphasizing the extraction and analysis of entangled states. The core claim is that this approach offers significantly enhanced computational efficiency and precision compared to traditional methods, particularly for complex quantum states. The research will demonstrate the feasibility of scaling this approach to more complex sub-systems.

Nilanjana Datta

Noam Avidan, Rotem Arnon-Friedman

Computational entropies provide a framework for quantifying uncertainty and randomness under computational constraints. They play a central role in classical cryptography, underpinning the analysis and construction of primitives such as pseudo-random generators, leakage-resilient cryptography, and randomness extractors. However, in the quantum setting, computational analogs of entropy remain largely unexplored. In this work, we initiate the study of quantum computational entropy by definingquantum computational unpredictability entropy, a natural generalization of classical unpredictability entropy to the quantum setting. Our definition builds on the operational interpretation of quantum min-entropy as the optimal guessing probability, while restricting the adversary to efficient guessing strategies. We prove that this entropy satisfies several fundamental properties, including a leakage chain rule that holds even in the presence of unbounded prior quantum side-information. We also show that unpredictability entropy enables pseudo-randomness extraction against quantum adversaries with bounded computational power. Together, these results lay a foundation for developing cryptographic tools that rely on min-entropy in the quantum computational setting.

Subhash C. Kak