Paper Learning Quantum Processes with Quantum Statistical Queries Chirag Wadhwa and Mina Doosti, Quantum 9, 1739 (2025). In this work, we initiate the study of learning quantum processes from quantum statistical queries. We focus on two fundamental learning tasks in this new access model: shadow tomography of…
Paper Non-onsite symmetries and quantum teleportation in split-index matrix product states David T. Stephen, Quantum 9, 1738 (2025). We describe a class of spin chains with new physical and computational properties. On the physical side, the spin chains give examples of symmetry-protected topological phases that are defin…
Paper A Quadratic Speedup in Finding Nash Equilibria of Quantum Zero-Sum Games Francisca Vasconcelos, Emmanouil-Vasileios Vlatakis-Gkaragkounis, Panayotis Mertikopoulos, Georgios Piliouras, and Michael I. Jordan, Quantum 9, 1737 (2025). Recent developments in domains such as non-local games, quantum interactive proofs, and quantum generative adversarial networks have renewed interest in quantum game theory and, specifically…
Paper Quantum network-entanglement measures Zhen-Peng Xu, Julio I. de Vicente, Liang-Liang Sun, and Sixia Yu, Quantum 9, 1736 (2025). Quantum networks are of high interest nowadays and a quantum internet has been long envisioned. Network-entanglement adapts the notion of entanglement to the network scenario and network-ent…
Paper Memory attacks in network nonlocality and self-testing Mirjam Weilenmann, Costantino Budroni, and Miguel Navascues, Quantum 9, 1735 (2025). We study what can or cannot be certified in communication scenarios where the assumption of independence and identical distribution (iid) between experimental rounds fails. In this respect,…
Paper An Effective Way to Determine the Separability of Quantum State Ma-Cheng Yang and Cong-Feng Qiao, Quantum 9, 1734 (2025). We propose in this work a practical approach to address the longstanding and challenging problem of quantum separability, leveraging the correlation matrices of generic observables. General…
Paper Multidimensional Electrical Networks and their Application to Exponential Speedups for Graph Problems Jianqiang Li and Sebastian Zur, Quantum 9, 1733 (2025). Recently, Apers and Piddock [TQC '23] strengthened the connection between quantum walks and electrical networks via Kirchhoff's Law and Ohm's Law. In this work, we develop a new multidimensi…
Paper Accurately Simulating the Time Evolution of an Ising Model with Echo Verified Clifford Data Regression on a Superconducting Quantum Computer Tim Weaving, Alexis Ralli, Peter J. Love, Sauro Succi, and Peter V. Coveney, Quantum 9, 1732 (2025). We present an error mitigation strategy composed of Echo Verification (EV) and Clifford Data Regression (CDR), the combination of which allows one to learn the effect of the quantum noise ch…
Paper Speeding up Quantum Annealing with Engineered Dephasing Mykolas Sveistrys, Josias Langbehn, Raphaël Menu, Steve Campbell, Giovanna Morigi, and Christiane P. Koch, Quantum 9, 1731 (2025). Building on the insight that engineered noise, specifically, engineered dephasing can enhance the adiabaticity of controlled quantum dynamics, we investigate how a dephasing-generating coupl…
Paper Pauli path simulations of noisy quantum circuits beyond average case Guillermo González-García, J. Ignacio Cirac, and Rahul Trivedi, Quantum 9, 1730 (2025). For random quantum circuits on $n$ qubits of depth $\Theta(\log n)$ with depolarizing noise, the task of sampling from the output state can be efficiently performed classically using a Pauli pat…
Paper A geometrical description of non-Hermitian dynamics: speed limits in finite rank density operators Niklas Hörnedal, Oskar A. Prośniak, Adolfo del Campo, and Aurélia Chenu, Quantum 9, 1729 (2025). Non-Hermitian dynamics in quantum systems preserves the rank of the state density operator. Using this insight, we develop a geometric framework to describe its time evolution. In particular…
Paper Hierarchical memories: Simulating quantum LDPC codes with local gates Christopher A. Pattison, Anirudh Krishna, and John Preskill, Quantum 9, 1728 (2025). Constant-rate low-density parity-check (LDPC) codes are promising candidates for constructing efficient fault-tolerant quantum memories. However, if physical gates are subject to geometric-l…
Paper Improving the efficiency of learning-based error mitigation Piotr Czarnik, Michael McKerns, Andrew T. Sornborger, and Lukasz Cincio, Quantum 9, 1727 (2025). Error mitigation will play an important role in practical applications of near-term noisy quantum computers. Current error mitigation methods typically concentrate on correction quality at t…
Paper Partitioned Quantum Subspace Expansion Tom O’Leary, Lewis W. Anderson, Dieter Jaksch, and Martin Kiffner, Quantum 9, 1726 (2025). We present an iterative generalisation of the quantum subspace expansion algorithm used with a Krylov basis. The iterative construction connects a sequence of subspaces via their lowest ener…
Paper Measuring quantum relative entropy with finite-size effect Masahito Hayashi, Quantum 9, 1725 (2025). We study the estimation of relative entropy $D(\rho\|\sigma)$ when $\sigma$ is known. We show that the Cramér-Rao type bound equals the relative varentropy. Our estimator attains the Cramér-Rao…
Paper Efficient separate quantification of state preparation errors and measurement errors on quantum computers and their mitigation Hongye Yu and Tzu-Chieh Wei, Quantum 9, 1724 (2025). Current noisy quantum computers have multiple types of errors, which can occur in the state preparation, measurement/readout, and gate operation, as well as intrinsic decoherence and relaxat…
