Paper Orthonormal bases of extreme quantumness Marcin Rudziński, Adam Burchardt, and Karol Życzkowski, Quantum 8, 1234 (2024). Spin anticoherent states acquired recently a lot of attention as the most "quantum" states. Some coherent and anticoherent spin states are known as optimal quantum rotosensors. In this work,…
Paper Entanglement Purification with Quantum LDPC Codes and Iterative Decoding Narayanan Rengaswamy, Nithin Raveendran, Ankur Raina, and Bane Vasić, Quantum 8, 1233 (2024). Recent constructions of quantum low-density parity-check (QLDPC) codes provide optimal scaling of the number of logical qubits and the minimum distance in terms of the code length, thereby o…
Paper A new quantum machine learning algorithm: split hidden quantum Markov model inspired by quantum conditional master equation Xiao-Yu Li, Qin-Sheng Zhu, Yong Hu, Hao Wu, Guo-Wu Yang, Lian-Hui Yu, and Geng Chen, Quantum 8, 1232 (2024). The Hidden Quantum Markov Model (HQMM) has significant potential for analyzing time-series data and studying stochastic processes in the quantum domain as an upgrading option with potential…
Paper Parameter Setting in Quantum Approximate Optimization of Weighted Problems Shree Hari Sureshbabu, Dylan Herman, Ruslan Shaydulin, Joao Basso, Shouvanik Chakrabarti, Yue Sun, and Marco Pistoia, Quantum 8, 1231 (2024). Quantum Approximate Optimization Algorithm (QAOA) is a leading candidate algorithm for solving combinatorial optimization problems on quantum computers. However, in many cases QAOA requires…
Paper Quantum Kolmogorov complexity and quantum correlations in deterministic-control quantum Turing machines Mariano Lemus, Ricardo Faleiro, Paulo Mateus, Nikola Paunković, and André Souto, Quantum 8, 1230 (2024). This work presents a study of Kolmogorov complexity for general quantum states from the perspective of deterministic-control quantum Turing Machines (dcq-TM). We extend the dcq-TM model to i…
Paper Measurement-induced multipartite-entanglement regimes in collective spin systems Pablo M. Poggi and Manuel H. Muñoz-Arias, Quantum 8, 1229 (2024). We study the competing effects of collective generalized measurements and interaction-induced scrambling in the dynamics of an ensemble of spin-1/2 particles at the level of quantum trajecto…
Paper Parallel Quantum Algorithm for Hamiltonian Simulation Zhicheng Zhang, Qisheng Wang, and Mingsheng Ying, Quantum 8, 1228 (2024). We study how parallelism can speed up quantum simulation. A parallel quantum algorithm is proposed for simulating the dynamics of a large class of Hamiltonians with good sparse structures, c…
Paper Microcanonical windows on quantum operators Silvia Pappalardi, Laura Foini, and Jorge Kurchan, Quantum 8, 1227 (2024). We discuss the construction of a microcanonical projection WOW of a quantum operator O induced by an energy window filter W, its spectrum, and the retrieval of canonical many-time correlatio…
Paper Block-encoding structured matrices for data input in quantum computing Christoph Sünderhauf, Earl Campbell, and Joan Camps, Quantum 8, 1226 (2024). The cost of data input can dominate the run-time of quantum algorithms. Here, we consider data input of arithmetically structured matrices via $\textit{block encoding}$ circuits, the input mod…
Paper The complexity of quantum support vector machines Gian Gentinetta, Arne Thomsen, David Sutter, and Stefan Woerner, Quantum 8, 1225 (2024). Quantum support vector machines employ quantum circuits to define the kernel function. It has been shown that this approach offers a provable exponential speedup compared to any known classi…
Paper Witnessing environment dimension through temporal correlations Lucas B. Vieira, Simon Milz, Giuseppe Vitagliano, and Costantino Budroni, Quantum 8, 1224 (2024). We introduce a framework to compute upper bounds for temporal correlations achievable in open quantum system dynamics, obtained by repeated measurements on the system. As these correlations…
Paper Energy densities in quantum mechanics V. Stepanyan and A.E. Allahverdyan, Quantum 8, 1223 (2024). Quantum mechanics does not provide any ready recipe for defining energy density in space, since the energy and coordinate do not commute. To find a well-motivated energy density, we start fr…
Paper Resource engines Hanna Wojewódka-Ściążko, Zbigniew Puchała, and Kamil Korzekwa, Quantum 8, 1222 (2024). In this paper we aim to push the analogy between thermodynamics and quantum resource theories one step further. Previous inspirations were based predominantly on thermodynamic considerations…
Paper Efficient Verification of Ground States of Frustration-Free Hamiltonians Huangjun Zhu, Yunting Li, and Tianyi Chen, Quantum 8, 1221 (2024). Ground states of local Hamiltonians are of key interest in many-body physics and also in quantum information processing. Efficient verification of these states are crucial to many applicatio…
Paper Multivariate trace estimation in constant quantum depth Yihui Quek, Eneet Kaur, and Mark M. Wilde, Quantum 8, 1220 (2024). There is a folkloric belief that a depth-$\Theta(m)$ quantum circuit is needed to estimate the trace of the product of $m$ density matrices (i.e., a multivariate trace), a subroutine crucial to…
Paper A full circuit-based quantum algorithm for excited-states in quantum chemistry Jingwei Wen, Zhengan Wang, Chitong Chen, Junxiang Xiao, Hang Li, Ling Qian, Zhiguo Huang, Heng Fan, Shijie Wei, and Guilu Long, Quantum 8, 1219 (2024). Utilizing quantum computer to investigate quantum chemistry is an important research field nowadays. In addition to the ground-state problems that have been widely studied, the determination…
