Paper On the energy landscape of symmetric quantum signal processing Jiasu Wang, Yulong Dong, and Lin Lin, Quantum 6, 850 (2022). Symmetric quantum signal processing provides a parameterized representation of a real polynomial, which can be translated into an efficient quantum circuit for performing a wide range of com…
Paper Spectral resolutions in effect algebras Anna Jenčová and Sylvia Pulmannová, Quantum 6, 849 (2022). Effect algebras were introduced as an abstract algebraic model for Hilbert space effects representing quantum mechanical measurements. We study additional structures on an effect algebra $E$ t…
Paper Coherent feedback in optomechanical systems in the sideband-unresolved regime Jingkun Guo and Simon Gröblacher, Quantum 6, 848 (2022). Preparing macroscopic mechanical resonators close to their motional quantum groundstate and generating entanglement with light offers great opportunities in studying fundamental physics and…
Paper Using the Environment to Understand non-Markovian Open Quantum Systems Dominic Gribben, Aidan Strathearn, Gerald E. Fux, Peter Kirton, and Brendon W. Lovett, Quantum 6, 847 (2022). Tracing out the environmental degrees of freedom is a necessary procedure when simulating open quantum systems. While being an essential step in deriving a tractable master equation it repre…
Paper Transformations of Stabilizer States in Quantum Networks Matthias Englbrecht, Tristan Kraft, and Barbara Kraus, Quantum 6, 846 (2022). Stabilizer states and graph states find application in quantum error correction, measurement-based quantum computation and various other concepts in quantum information theory. In this work,…
Paper Classically Replaceable Operations Guoding Liu, Xingjian Zhang, and Xiongfeng Ma, Quantum 6, 845 (2022). Quantum information science provides powerful technologies beyond the scope of classical physics. In practice, accurate control of quantum operations is a challenging task with current quant…
Paper Projected Least-Squares Quantum Process Tomography Trystan Surawy-Stepney, Jonas Kahn, Richard Kueng, and Madalin Guta, Quantum 6, 844 (2022). We propose and investigate a new method of quantum process tomography (QPT) which we call projected least squares (PLS). In short, PLS consists of first computing the least-squares estimator…
Paper Simple and practical DIQKD security analysis via BB84-type uncertainty relations and Pauli correlation constraints Michele Masini, Stefano Pironio, and Erik Woodhead, Quantum 6, 843 (2022). According to the entropy accumulation theorem, proving the unconditional security of a device-independent quantum key distribution protocol reduces to deriving tradeoff functions, i.e., boun…
Paper Stable factorization for phase factors of quantum signal processing Lexing Ying, Quantum 6, 842 (2022). This paper proposes a new factorization algorithm for computing the phase factors of quantum signal processing. The proposed algorithm avoids root finding of high degree polynomials by using…
Paper Extraction of ergotropy: free energy bound and application to open cycle engines Tanmoy Biswas, Marcin Łobejko, Paweł Mazurek, Konrad Jałowiecki, and Michał Horodecki, Quantum 6, 841 (2022). The second law of thermodynamics uses change in free energy of macroscopic systems to set a bound on performed work. Ergotropy plays a similar role in microscopic scenarios, and is defined a…
Paper Quantifying fermionic interactions from the violation of Wick’s theorem Jiannis K. Pachos and Chrysoula Vlachou, Quantum 6, 840 (2022). In contrast to interacting systems, the ground state of free systems has a highly ordered pattern of quantum correlations, as witnessed by Wick's decomposition. Here, we quantify the effect…
Paper Contextuality in entanglement-assisted one-shot classical communication Shiv Akshar Yadavalli and Ravi Kunjwal, Quantum 6, 839 (2022). We consider the problem of entanglement-assisted one-shot classical communication. In the zero-error regime, entanglement can increase the one-shot zero-error capacity of a family of classic…
Paper Faster Born probability estimation via gate merging and frame optimisation Nikolaos Koukoulekidis, Hyukjoon Kwon, Hyejung H. Jee, David Jennings, and M. S. Kim, Quantum 6, 838 (2022). Outcome probability estimation via classical methods is an important task for validating quantum computing devices. Outcome probabilities of any quantum circuit can be estimated using Monte…
Paper Model predictive control for robust quantum state preparation Andy J. Goldschmidt, Jonathan L. DuBois, Steven L. Brunton, and J. Nathan Kutz, Quantum 6, 837 (2022). A critical engineering challenge in quantum technology is the accurate control of quantum dynamics. Model-based methods for optimal control have been shown to be highly effective when theory…
Paper Design of quantum optical experiments with logic artificial intelligence Alba Cervera-Lierta, Mario Krenn, and Alán Aspuru-Guzik, Quantum 6, 836 (2022). Logic Artificial Intelligence (AI) is a subfield of AI where variables can take two defined arguments, True or False, and are arranged in clauses that follow the rules of formal logic. Sever…
Paper How to design quantum-jump trajectories via distinct master equation representations Dariusz Chruściński, Kimmo Luoma, Jyrki Piilo, and Andrea Smirne, Quantum 6, 835 (2022). Every open-system dynamics can be associated to infinitely many stochastic pictures, called unravelings, which have proved to be extremely useful in several contexts, both from the conceptua…
