Quantum

Paper

Playing Pool with $|ψ\rangle$: from Bouncing Billiards to Quantum Search

Adam R. Brown,

Quantum 4, 357 (2020).

In “Playing Pool with $\pi$'' [1], Galperin invented an extraordinary method to learn the digits of $\pi$ by counting the collisions of billiard balls. Here I demonstrate an exact isomorphism b…

Paper

Quantum linear network coding for entanglement distribution in restricted architectures

Niel de Beaudrap and Steven Herbert,

Quantum 4, 356 (2020).

In this paper we propose a technique for distributing entanglement in architectures in which interactions between pairs of qubits are constrained to a fixed network $G$. This allows for two-qu…

Paper

General Quantum Resource Theories: Distillation, Formation and Consistent Resource Measures

Kohdai Kuroiwa and Hayata Yamasaki,

Quantum 4, 355 (2020).

Quantum resource theories (QRTs) provide a unified theoretical framework for understanding inherent quantum-mechanical properties that serve as resources in quantum information processing, b…

Paper

Time Observables in a Timeless Universe

Tommaso Favalli and Augusto Smerzi,

Quantum 4, 354 (2020).

Time in quantum mechanics is peculiar: it is an observable that cannot be associated to an Hermitian operator. As a consequence it is impossible to explain dynamics in an isolated system wit…

Paper

Bell nonlocality with a single shot

Mateus Araújo, Flavien Hirsch, and Marco Túlio Quintino,

Quantum 4, 353 (2020).

In order to reject the local hidden variables hypothesis, the usefulness of a Bell inequality can be quantified by how small a $p$-value it will give for a physical experiment. Here we show th…

Paper

Optimization of the surface code design for Majorana-based qubits

Rui Chao, Michael E. Beverland, Nicolas Delfosse, and Jeongwan Haah,

Quantum 4, 352 (2020).

The surface code is a prominent topological error-correcting code exhibiting high fault-tolerance accuracy thresholds. Conventional schemes for error correction with the surface code place q…

Paper

Classical Simulations of Quantum Field Theory in Curved Spacetime I: Fermionic Hawking-Hartle Vacua from a Staggered Lattice Scheme

Adam G. M. Lewis and Guifré Vidal,

Quantum 4, 351 (2020).

We numerically compute renormalized expectation values of quadratic operators in a quantum field theory (QFT) of free Dirac fermions in curved two-dimensional (Lorentzian) spacetime. First,…

Paper

Emergence of the Born rule in quantum optics

Brian R. La Cour and Morgan C. Williamson,

Quantum 4, 350 (2020).

The Born rule provides a fundamental connection between theory and observation in quantum mechanics, yet its origin remains a mystery. We consider this problem within the context of quantum…

Paper

A three-player coherent state embezzlement game

Zhengfeng Ji, Debbie Leung, and Thomas Vidick,

Quantum 4, 349 (2020).

We introduce a three-player nonlocal game, with a finite number of classical questions and answers, such that the optimal success probability of $1$ in the game can only be achieved in the lim…

Paper

Transforming graph states to Bell-pairs is NP-Complete

Axel Dahlberg, Jonas Helsen, and Stephanie Wehner,

Quantum 4, 348 (2020).

Critical to the construction of large scale quantum networks, i.e. a quantum internet, is the development of fast algorithms for managing entanglement present in the network. One fundamental…

Paper

Environmentally Induced Entanglement – Anomalous Behavior in the Adiabatic Regime

Richard Hartmann and Walter T. Strunz,

Quantum 4, 347 (2020).

Considering two non-interacting qubits in the context of open quantum systems, it is well known that their common environment may act as an entangling agent. In a perturbative regime the inf…

Paper

A generalization of CHSH and the algebraic structure of optimal strategies

David Cui, Arthur Mehta, Hamoon Mousavi, and Seyed Sajjad Nezhadi,

Quantum 4, 346 (2020).

$\textit{Self-testing}$ has been a rich area of study in quantum information theory. It allows an experimenter to interact classically with a black box quantum system and to test that a specif…

Paper

Quantum prescriptions are more ontologically distinct than they are operationally distinguishable

Anubhav Chaturvedi and Debashis Saha,

Quantum 4, 345 (2020).

Based on an intuitive generalization of the Leibniz principle of `the identity of indiscernibles', we introduce a novel ontological notion of classicality, called bounded ontological distinc…

Paper

Bounding sets of sequential quantum correlations and device-independent randomness certification

Joseph Bowles, Flavio Baccari, and Alexia Salavrakos,

Quantum 4, 344 (2020).

An important problem in quantum information theory is that of bounding sets of correlations that arise from making local measurements on entangled states of arbitrary dimension. Currently, t…

Paper

Probing nonclassicality with matrices of phase-space distributions

Martin Bohmann, Elizabeth Agudelo, and Jan Sperling,

Quantum 4, 343 (2020).

We devise a method to certify nonclassical features via correlations of phase-space distributions by unifying the notions of quasiprobabilities and matrices of correlation functions. Our app…

Paper

A quantum extension of SVM-perf for training nonlinear SVMs in almost linear time

Jonathan Allcock and Chang-Yu Hsieh,

Quantum 4, 342 (2020).

We propose a quantum algorithm for training nonlinear support vector machines (SVM) for feature space learning where classical input data is encoded in the amplitudes of quantum states. Base…

Category: Paper