Paper Continuous groups of transversal gates for quantum error correcting codes from finite clock reference frames Mischa P. Woods and Álvaro M. Alhambra, Quantum 4, 245 (2020). Following the introduction of the task of $\textit{reference frame error}$ $\textit{correction}$ [1], we show how, by using reference frame alignment with clocks, one can add a continuous Abelia…
Paper Resource Preservability Chung-Yun Hsieh, Quantum 4, 244 (2020). Resource theory is a general, model-independent approach aiming to understand the qualitative notion of resource quantitatively. In a given resource theory, free operations are physical proc…
Paper Device-independent characterization of quantum instruments Sebastian Wagner, Jean-Daniel Bancal, Nicolas Sangouard, and Pavel Sekatski, Quantum 4, 243 (2020). Among certification techniques, those based on the violation of Bell inequalities are appealing because they do not require assumptions on the underlying Hilbert space dimension and on the a…
Paper $ψ$-epistemic interpretations of quantum theory have a measurement problem Joshua B. Ruebeck, Piers Lillystone, and Joseph Emerson, Quantum 4, 242 (2020). $\psi$-epistemic interpretations of quantum theory maintain that quantum states only represent incomplete information about the physical states of the world. A major motivation for this view i…
Paper Quantum Speedup Based on Classical Decision Trees Salman Beigi and Leila Taghavi, Quantum 4, 241 (2020). Lin and Lin [16] have recently shown how starting with a classical query algorithm (decision tree) for a function, we may find upper bounds on its quantum query complexity. More precisely, t…
Paper Thermodynamics of Quantum Causal Models: An Inclusive, Hamiltonian Approach Philipp Strasberg, Quantum 4, 240 (2020). Operational quantum stochastic thermodynamics is a recently proposed theory to study the thermodynamics of open systems based on the rigorous notion of a quantum stochastic process or quantu…
Paper Engineering Schrödinger cat states with a photonic even-parity detector G. S. Thekkadath, B. A. Bell, I. A. Walmsley, and A. I. Lvovsky, Quantum 4, 239 (2020). When two equal photon-number states are combined on a balanced beam splitter, both output ports of the beam splitter contain only even numbers of photons. Consider the time-reversal of this…
Paper How post-selection affects device-independent claims under the fair sampling assumption Davide Orsucci, Jean-Daniel Bancal, Nicolas Sangouard, and Pavel Sekatski, Quantum 4, 238 (2020). Device-independent certifications employ Bell tests to guarantee the proper functioning of an apparatus from the sole knowledge of observed measurement statistics, i.e. without assumptions o…
Paper Classical and Quantum Algorithms for Tensor Principal Component Analysis Matthew B. Hastings, Quantum 4, 237 (2020). We present classical and quantum algorithms based on spectral methods for a problem in tensor principal component analysis. The quantum algorithm achieves a $quartic$ speedup while using expon…
Paper Analysing causal structures in generalised probabilistic theories Mirjam Weilenmann and Roger Colbeck, Quantum 4, 236 (2020). Causal structures give us a way to understand the origin of observed correlations. These were developed for classical scenarios, but quantum mechanical experiments necessitate their generali…
Paper Compilation by stochastic Hamiltonian sparsification Yingkai Ouyang, David R. White, and Earl T. Campbell, Quantum 4, 235 (2020). Simulation of quantum chemistry is expected to be a principal application of quantum computing. In quantum simulation, a complicated Hamiltonian describing the dynamics of a quantum system i…
Paper Approximating Hamiltonian dynamics with the Nyström method Alessandro Rudi, Leonard Wossnig, Carlo Ciliberto, Andrea Rocchetto, Massimiliano Pontil, and Simone Severini, Quantum 4, 234 (2020). Simulating the time-evolution of quantum mechanical systems is BQP-hard and expected to be one of the foremost applications of quantum computers. We consider classical algorithms for the app…
Paper Extension of the Alberti-Uhlmann criterion beyond qubit dichotomies Michele Dall’Arno, Francesco Buscemi, and Valerio Scarani, Quantum 4, 233 (2020). The Alberti-Uhlmann criterion states that any given qubit dichotomy can be transformed into any other given qubit dichotomy by a quantum channel if and only if the testing region of the form…
Paper Control of anomalous diffusion of a Bose polaron Christos Charalambous, Miguel Ángel García-March, Gorka Muñoz-Gil, Przemysław Ryszard Grzybowski, and Maciej Lewenstein, Quantum 4, 232 (2020). We study the diffusive behavior of a Bose polaron immersed in a coherently coupled two-component Bose-Einstein Condensate (BEC). We assume a uniform, one-dimensional BEC. Polaron superdiffus…
Paper By-passing fluctuation theorems Paul Boes, Rodrigo Gallego, Nelly H. Y. Ng, Jens Eisert, and Henrik Wilming, Quantum 4, 231 (2020). Fluctuation theorems impose constraints on possible work extraction probabilities in thermodynamical processes. These constraints are stronger than the usual second law, which is concerned o…
Paper Quantum SDP-Solvers: Better upper and lower bounds Joran van Apeldoorn, András Gilyén, Sander Gribling, and Ronald de Wolf, Quantum 4, 230 (2020). Brandão and Svore [14] recently gave quantum algorithms for approximately solving semidefinite programs, which in some regimes are faster than the best-possible classical algorithms in terms…
