Paper Flag fault-tolerant error correction with arbitrary distance codes Christopher Chamberland and Michael E. Beverland, Quantum 2, 53 (2018). In this paper we introduce a general fault-tolerant quantum error correction protocol using flag circuits for measuring stabilizers of arbitrary distance codes. In addition to extending flag…
Paper Elementary Thermal Operations Matteo Lostaglio, Álvaro M. Alhambra, and Christopher Perry, Quantum 2, 52 (2018). To what extent do thermodynamic resource theories capture physically relevant constraints? Inspired by quantum computation, we define a set of elementary thermodynamic gates that only act on…
Paper Characterization of linear maps on $M_n$ whose multiplicity maps have maximal norm, with an application in quantum information Daniel Puzzuoli, Quantum 2, 51 (2018). Given a linear map $\Phi : M_n \rightarrow M_m$, its multiplicity maps are defined as the family of linear maps $\Phi \otimes \textrm{id}_{k} : M_n \otimes M_k \rightarrow M_m \otimes M_k$, wher…
Paper Bond dimension witnesses and the structure of homogeneous matrix product states Miguel Navascues and Tamas Vertesi, Quantum 2, 50 (2018). For the past twenty years, Matrix Product States (MPS) have been widely used in solid state physics to approximate the ground state of one-dimensional spin chains. In this paper, we study ho…
Paper ProjectQ: an open source software framework for quantum computing Damian S. Steiger, Thomas Häner, and Matthias Troyer, Quantum 2, 49 (2018). We introduce ProjectQ, an open source software effort for quantum computing. The first release features a compiler framework capable of targeting various types of hardware, a high-performanc…
Paper Machine-learning-assisted correction of correlated qubit errors in a topological code Paul Baireuther, Thomas E. O’Brien, Brian Tarasinski, and Carlo W. J. Beenakker, Quantum 2, 48 (2018). A fault-tolerant quantum computation requires an efficient means to detect and correct errors that accumulate in encoded quantum information. In the context of machine learning, neural netwo…
Paper Randomized benchmarking with gate-dependent noise Joel J. Wallman, Quantum 2, 47 (2018). We analyze randomized benchmarking for arbitrary gate-dependent noise and prove that the exact impact of gate-dependent noise can be described by a single perturbation term that decays expon…
Paper Vacuum source-field correlations and advanced waves in quantum optics Adam Stokes, Quantum 2, 46 (2018). The solution to the wave equation as a Cauchy problem with prescribed fields at an initial time $t=0$ is purely retarded. Similarly, in the quantum theory of radiation the specification of Hei…
Paper Separability of diagonal symmetric states: a quadratic conic optimization problem Jordi Tura, Albert Aloy, Ruben Quesada, Maciej Lewenstein, and Anna Sanpera, Quantum 2, 45 (2018). We study the separability problem in mixtures of Dicke states i.e., the separability of the so-called Diagonal Symmetric (DS) states. First, we show that separability in the case of DS in…
Paper BQP-completeness of scattering in scalar quantum field theory Stephen P. Jordan, Hari Krovi, Keith S. M. Lee, and John Preskill, Quantum 2, 44 (2018). Recent work has shown that quantum computers can compute scattering probabilities in massive quantum field theories, with a run time that is polynomial in the number of particles, their ener…
Paper Fault-tolerant quantum computing in the Pauli or Clifford frame with slow error diagnostics Christopher Chamberland, Pavithran Iyer, and David Poulin, Quantum 2, 43 (2018). We consider the problem of fault-tolerant quantum computation in the presence of slow error diagnostics, either caused by measurement latencies or slow decoding algorithms. Our scheme offers…
Paper Cavity assisted measurements of heat and work in optical lattices Louis Villa and Gabriele De Chiara, Quantum 2, 42 (2018). We propose a method to experimentally measure the internal energy of a system of ultracold atoms trapped in optical lattices by coupling them to the fields of two optical cavities. We show t…
Paper Zero-knowledge convincing protocol on quantum bit is impossible Pawel Horodecki, Michal Horodecki, and Ryszard Horodecki, Quantum 1, 41 (2017). Consider two parties: Alice and Bob and suppose that Bob is given a qubit system in a quantum state $\phi$, unknown to him. Alice knows $\phi$ and she is supposed to convince Bob that she knows…
Paper A nonequilibrium quantum phase transition in strongly coupled spin chains Eduardo Mascarenhas, Giacomo Giudice, and Vincenzo Savona, Quantum 1, 40 (2017). We study spin transport in a boundary driven XXZ spin chain. Driving at the chain boundaries is modeled by two additional spin chains prepared in oppositely polarized states. Emergent behavi…
Paper Genuinely multipartite noncausality Alastair A. Abbott, Julian Wechs, Fabio Costa, and Cyril Branciard, Quantum 1, 39 (2017). The study of correlations with no definite causal order has revealed a rich structure emerging when more than two parties are involved. This motivates the consideration of multipartite "nonc…
Paper Toolbox for reconstructing quantum theory from rules on information acquisition Philipp Andres Höhn, Quantum 1, 38 (2017). We develop an operational approach for reconstructing the quantum theory of qubit systems from elementary rules on information acquisition. The focus lies on an observer $O$ interrogating a sy…
