Paper Quantum and classical dynamics of a three-mode absorption refrigerator Stefan Nimmrichter, Jibo Dai, Alexandre Roulet, and Valerio Scarani, Quantum 1, 37 (2017). We study the quantum and classical evolution of a system of three harmonic modes interacting via a trilinear Hamiltonian. With the modes prepared in thermal states of different temperatures,…
Paper Quantum gates between distant qubits via spin-independent scattering Leonardo Banchi, Enrico Compagno, Vladimir Korepin, and Sougato Bose, Quantum 1, 36 (2017). We show how the spin independent scattering of two initially distant qubits, say, in distinct traps or in remote sites of a lattice, can be used to implement an entangling quantum gate betwe…
Paper Probing the non-classicality of temporal correlations Martin Ringbauer and Rafael Chaves, Quantum 1, 35 (2017). Correlations between spacelike separated measurements on entangled quantum systems are stronger than any classical correlations and are at the heart of numerous quantum technologies. In prac…
Paper Macroscopic superpositions require tremendous measurement devices Michalis Skotiniotis, Wolfgang Dür, and Pavel Sekatski, Quantum 1, 34 (2017). We consider fundamental limits on the detectable size of macroscopic quantum superpositions. We argue that a full quantum mechanical treatment of system plus measurement device is required,…
Paper Semi-device-independent framework based on natural physical assumptions Thomas Van Himbeeck, Erik Woodhead, Nicolas J. Cerf, Raúl García-Patrón, and Stefano Pironio, Quantum 1, 33 (2017). The semi-device-independent approach provides a framework for prepare-and-measure quantum protocols using devices whose behavior must not be characterized nor trusted, except for a single as…
Paper Quasi-probability distributions for observables in dynamic systems Patrick P. Hofer, Quantum 1, 32 (2017). We develop a general framework to investigate fluctuations of non-commuting observables. To this end, we consider the Keldysh quasi-probability distribution (KQPD). This distribution provide…
Paper Magic state distillation with low space overhead and optimal asymptotic input count Jeongwan Haah, Matthew B. Hastings, D. Poulin, and D. Wecker, Quantum 1, 31 (2017). We present an infinite family of protocols to distill magic states for $T$-gates that has a low space overhead and uses an asymptotic number of input magic states to achieve a given target err…
Paper Bose polaron as an instance of quantum Brownian motion Aniello Lampo, Soon Hoe Lim, Miguel Ángel García-March, and Maciej Lewenstein, Quantum 1, 30 (2017). We study the dynamics of a quantum impurity immersed in a Bose-Einstein condensate as an open quantum system in the framework of the quantum Brownian motion model. We derive a generalized La…
Paper Time-local unraveling of non-Markovian stochastic Schrödinger equations Antoine Tilloy, Quantum 1, 29 (2017). Non-Markovian stochastic Schrödinger equations (NMSSE) are important tools in quantum mechanics, from the theory of open systems to foundations. Yet, in general, they are but formal objects:…
Paper On the complementary quantum capacity of the depolarizing channel Debbie Leung and John Watrous, Quantum 1, 28 (2017). The qubit depolarizing channel with noise parameter $\eta$ transmits an input qubit perfectly with probability $1-\eta$, and outputs the completely mixed state with probability $\eta$. We show tha…
Paper Quantum metrology with full and fast quantum control Pavel Sekatski, Michalis Skotiniotis, Janek Kołodyński, and Wolfgang Dür, Quantum 1, 27 (2017). We establish general limits on how precise a parameter, e.g. frequency or the strength of a magnetic field, can be estimated with the aid of full and fast quantum control. We consider uncorr…
Paper Quantum algorithms for graph connectivity and formula evaluation Stacey Jeffery and Shelby Kimmel, Quantum 1, 26 (2017). We give a new upper bound on the quantum query complexity of deciding $st$-connectivity on certain classes of planar graphs, and show the bound is sometimes exponentially better than previous…
Paper The classical-quantum divergence of complexity in modelling spin chains Whei Yeap Suen, Jayne Thompson, Andrew J. P. Garner, Vlatko Vedral, and Mile Gu, Quantum 1, 25 (2017). The minimal memory required to model a given stochastic process – known as the statistical complexity – is a widely adopted quantifier of structure in complexity science. Here, we ask if qua…
Paper Tailoring spin chain dynamics for fractional revivals Alastair Kay, Quantum 1, 24 (2017). The production of quantum states required for use in quantum protocols & technologies is studied by developing the tools to re-engineer a perfect state transfer spin chain so that a separabl…
Paper Causal hierarchy of multipartite Bell nonlocality Rafael Chaves, Daniel Cavalcanti, and Leandro Aolita, Quantum 1, 23 (2017). As with entanglement, different forms of Bell nonlocality arise in the multipartite scenario. These can be defined in terms of relaxations of the causal assumptions in local hidden-variable…
Paper Quantifying high dimensional entanglement with two mutually unbiased bases Paul Erker, Mario Krenn, and Marcus Huber, Quantum 1, 22 (2017). We derive a framework for quantifying entanglement in multipartite and high dimensional systems using only correlations in two unbiased bases. We furthermore develop such bounds in cases whe…
