Quantum Algorithms for Quantum Molecular Systems: A Survey

WIREs Computational Molecular Science Wiley 15:3 (2025)

Authors:

Yukun Zhang, Xiaoming Zhang, Jinzhao Sun, Heng Lin, Yifei Huang, Dingshun Lv, Xiao Yuan

Abstract:

ABSTRACTSolving quantum molecular systems presents a significant challenge for classical computation. The advent of early fault‐tolerant quantum computing devices offers a promising avenue to address these challenges, leveraging advanced quantum algorithms with reduced hardware requirements. This review surveys the latest developments in quantum computing algorithms for quantum molecular systems in the fault‐tolerant quantum computing era, covering encoding schemes, advanced Hamiltonian simulation techniques, and ground‐state energy estimation methods. We highlight recent progress in overcoming practical barriers, such as reducing circuit depth and minimizing the use of ancillary qubits. Special attention is given to the potential quantum advantages achievable through these algorithms, as well as the limitations imposed by dequantization and classical simulation techniques. The review concludes with a discussion of future directions, emphasizing the need for optimized algorithms and experimental validation to bridge the gap between theoretical developments and practical implementation for quantum molecular systems.

Reply to comment on: Observation of the quantum equivalence principle for matter-waves

(2025)

Authors:

Or Dobkowski, Barak Trok, Peter Skakunenko, Yonathan Japha, David Groswasser, Maxim Efremov, Chiara Marletto, Ivette Fuentes, Roger Penrose, Vlatko Vedral, Wolfgang P Schleich, Ron Folman

Conditions for Unitarity in Timeless Quantum Theory

ArXiv 2504.01579 (2025)

Quantum causal inference with extremely light touch

npj Quantum Information Nature Research 11:1 (2025) 54

Authors:

Xiangjing Liu, Yixian Qiu, Oscar Dahlsten, Vlatko Vedral

Abstract:

We give a causal inference scheme using quantum observations alone for a case with both temporal and spatial correlations: a bipartite quantum system with measurements at two times. The protocol determines compatibility with five causal structures distinguished by the direction of causal influence and whether there are initial correlations. We derive and exploit a closed-form expression for the spacetime pseudo-density matrix (PDM) for many times and qubits. This PDM can be determined by light-touch coarse-grained measurements alone. We prove that if there is no signalling between two subsystems, the reduced state of the PDM cannot have negativity, regardless of initial spatial correlations. In addition, the protocol exploits the time asymmetry of the PDM to determine the temporal order. The protocol succeeds for a state with coherence undergoing a fully decohering channel. Thus coherence in the channel is not necessary for the quantum advantage of causal inference from observations alone.

Efficient noise tailoring and detection of hypergraph states using Clifford circuits

ArXiv 2503.1287 (2025)

Authors:

Guedong Park, Jinzhao Sun, Hyunseok Jeong