Quantum Journal

When Symmetry Suppresses Magic

Nonstabilizerness is a critical resource for quantum advantage, but evaluating it, especially for mixed states, requires superexponentially many samples in system size, making the problem NP-hard. While symmetries are known to reduce this complexity, it is unclear whether they also restrict the amount of magic. In this work, we provide an explicit example of such a symmetry by proving that the Robustness of Magic (RoM) for N-qubit X-states is at...

Exponential strong converse for blind quantum data compression

We establish exponential strong converse theorems for blind quantum data compression of finite-dimensional mixed-state sources, with and without entanglement assistance. Blind compression is a fundamental quantum information processing task in which the sender aims to transmit quantum states without direct access to the classical label. Strong converse is a notable aspect of data compression: the accuracy of the compression abruptly drops down t...

Machine Learning Fine-Tunes the Quantum Math Behind Real Transmon Qubits - Bioengineer.org

D-Wave Quantum Bets on Dual-Rail Architecture to Cut Error-Correction Costs - ad-hoc-news.de