Paper Discrete-variable quantum key distribution with homodyne detection Ignatius William Primaatmaja, Cassey Crystania Liang, Gong Zhang, Jing Yan Haw, Chao Wang, and Charles Ci-Wen Lim, Quantum 6, 613 (2022). Most quantum key distribution (QKD) protocols can be classified as either a discrete-variable (DV) protocol or continuous-variable (CV) protocol, based on how classical information is being…
Paper Symmetry-protected sign problem and magic in quantum phases of matter Tyler D. Ellison, Kohtaro Kato, Zi-Wen Liu, and Timothy H. Hsieh, Quantum 5, 612 (2021). We introduce the concepts of a symmetry-protected sign problem and symmetry-protected magic to study the complexity of symmetry-protected topological (SPT) phases of matter. In particular, w…
Paper Graph Picture of Linear Quantum Networks and Entanglement Seungbeom Chin, Yong-Su Kim, and Sangmin Lee, Quantum 5, 611 (2021). The indistinguishability of quantum particles is widely used as a resource for the generation of entanglement. Linear quantum networks (LQNs), in which identical particles linearly evolve to…
Paper Lieb’s Theorem and Maximum Entropy Condensates Joseph Tindall, Frank Schlawin, Michael Sentef, and Dieter Jaksch, Quantum 5, 610 (2021). Coherent driving has established itself as a powerful tool for guiding a many-body quantum system into a desirable, coherent non-equilibrium state. A thermodynamically large system will, how…
Paper The Efficient Preparation of Normal Distributions in Quantum Registers Arthur G. Rattew, Yue Sun, Pierre Minssen, and Marco Pistoia, Quantum 5, 609 (2021). The efficient preparation of input distributions is an important problem in obtaining quantum advantage in a wide range of domains. We propose a novel quantum algorithm for the efficient pre…
Paper Squeezing-enhanced communication without a phase reference Marco Fanizza, Matteo Rosati, Michalis Skotiniotis, John Calsamiglia, and Vittorio Giovannetti, Quantum 5, 608 (2021). We study the problem of transmitting classical information using quantum Gaussian states on a family of phase-noise channels with a finite decoherence time, such that the phase-reference is…
Paper Dynamical second-order noise sweetspots in resonantly driven spin qubits Jordi Picó-Cortés and Gloria Platero, Quantum 5, 607 (2021). Quantum dot-based quantum computation employs extensively the exchange interaction between nearby electronic spins in order to manipulate and couple different qubits. The exchange interactio…
Paper Improved upper bounds on the stabilizer rank of magic states Hammam Qassim, Hakop Pashayan, and David Gosset, Quantum 5, 606 (2021). In this work we improve the runtime of recent classical algorithms for strong simulation of quantum circuits composed of Clifford and T gates. The improvement is obtained by establishing a n…
Paper A Fault-Tolerant Honeycomb Memory Craig Gidney, Michael Newman, Austin Fowler, and Michael Broughton, Quantum 5, 605 (2021). Recently, Hastings & Haah introduced a quantum memory defined on the honeycomb lattice. Remarkably, this honeycomb code assembles weight-six parity checks using only two-local measurements.…
Paper On tensor network representations of the (3+1)d toric code Clement Delcamp and Norbert Schuch, Quantum 5, 604 (2021). We define two dual tensor network representations of the (3+1)d toric code ground state subspace. These two representations, which are obtained by initially imposing either family of stabili…
Paper Can you sign a quantum state? Gorjan Alagic, Tommaso Gagliardoni, and Christian Majenz, Quantum 5, 603 (2021). Cryptography with quantum states exhibits a number of surprising and counterintuitive features. In a 2002 work, Barnum et al. argue that these features imply that digital signatures for quan…
Paper Security of quantum key distribution with intensity correlations Víctor Zapatero, Álvaro Navarrete, Kiyoshi Tamaki, and Marcos Curty, Quantum 5, 602 (2021). The decoy-state method in quantum key distribution (QKD) is a popular technique to approximately achieve the performance of ideal single-photon sources by means of simpler and practical lase…
Paper Tensor Monopoles in superconducting systems H. Weisbrich, M. Bestler, and W. Belzig, Quantum 5, 601 (2021). Topology in general but also topological objects such as monopoles are a central concept in physics. They are prime examples for the intriguing physics of gauge theories and topological stat…
Paper Physical Implementability of Linear Maps and Its Application in Error Mitigation Jiaqing Jiang, Kun Wang, and Xin Wang, Quantum 5, 600 (2021). Completely positive and trace-preserving maps characterize physically implementable quantum operations. On the other hand, general linear maps, such as positive but not completely positive m…
Paper Theory and experiment for resource-efficient joint weak-measurement Aldo C. Martinez-Becerril, Gabriel Bussières, Davor Curic, Lambert Giner, Raphael A. Abrahao, and Jeff S. Lundeen, Quantum 5, 599 (2021). Incompatible observables underlie pillars of quantum physics such as contextuality and entanglement. The Heisenberg uncertainty principle is a fundamental limitation on the measurement of th…
Paper Efficient Characterization of Quantum Evolutions via a Recommender System Priya Batra, Anukriti Singh, and T. S. Mahesh, Quantum 5, 598 (2021). We demonstrate characterizing quantum evolutions via matrix factorization algorithm, a particular type of the recommender system (RS). A system undergoing a quantum evolution can be characte…
