Quantum

Paper

The Platonic solids and fundamental tests of quantum mechanics

Armin Tavakoli and Nicolas Gisin,

Quantum 4, 293 (2020).

The Platonic solids is the name traditionally given to the five regular convex polyhedra, namely the tetrahedron, the octahedron, the cube, the icosahedron and the dodecahedron. Perhaps stro…

Paper

Squeezing metrology: a unified framework

Lorenzo Maccone and Alberto Riccardi,

Quantum 4, 292 (2020).

Quantum metrology theory has up to now focused on the resolution gains obtainable thanks to the entanglement among $N$ probes. Typically, a quadratic gain in resolution is achievable, going fr…

Paper

Option Pricing using Quantum Computers

Nikitas Stamatopoulos, Daniel J. Egger, Yue Sun, Christa Zoufal, Raban Iten, Ning Shen, and Stefan Woerner,

Quantum 4, 291 (2020).

We present a methodology to price options and portfolios of options on a gate-based quantum computer using amplitude estimation, an algorithm which provides a quadratic speedup compared to c…

Paper

Variational quantum state preparation via quantum data buses

Viacheslav V. Kuzmin and Pietro Silvi,

Quantum 4, 290 (2020).

We propose a variational quantum algorithm to prepare ground states of 1D lattice quantum Hamiltonians specifically tailored for programmable quantum devices where interactions among qubits…

Paper

Quantum Zeno Dynamics from General Quantum Operations

Daniel Burgarth, Paolo Facchi, Hiromichi Nakazato, Saverio Pascazio, and Kazuya Yuasa,

Quantum 4, 289 (2020).

We consider the evolution of an arbitrary quantum dynamical semigroup of a finite-dimensional quantum system under frequent kicks, where each kick is a generic quantum operation. We develop…

Paper

Optimal probes and error-correction schemes in multi-parameter quantum metrology

Wojciech Górecki, Sisi Zhou, Liang Jiang, and Rafał Demkowicz-Dobrzański,

Quantum 4, 288 (2020).

We derive a necessary and sufficient condition for the possibility of achieving the Heisenberg scaling in general adaptive multi-parameter estimation schemes in presence of Markovian noise.…

Paper

Efficient Quantum Walk Circuits for Metropolis-Hastings Algorithm

Jessica Lemieux, Bettina Heim, David Poulin, Krysta Svore, and Matthias Troyer,

Quantum 4, 287 (2020).

We present a detailed circuit implementation of Szegedy's quantization of the Metropolis-Hastings walk. This quantum walk is usually defined with respect to an oracle. We find that a direct…

Paper

On the Entanglement Cost of One-Shot Compression

Shima Bab Hadiashar and Ashwin Nayak,

Quantum 4, 286 (2020).

We revisit the task of visible compression of an ensemble of quantum states with entanglement assistance in the one-shot setting. The protocols achieving the best compression use many more q…

Paper

Optimal Detection of Rotations about Unknown Axes by Coherent and Anticoherent States

John Martin, Stefan Weigert, and Olivier Giraud,

Quantum 4, 285 (2020).

Coherent and anticoherent states of spin systems up to spin $j=2$ are known to be optimal in order to detect rotations by a known angle but unknown rotation axis. These optimal quantum rotosen…

Paper

Quantum Codes of Maximal Distance and Highly Entangled Subspaces

Felix Huber and Markus Grassl,

Quantum 4, 284 (2020).

We present new bounds on the existence of general quantum maximum distance separable codes (QMDS): the length $n$ of all QMDS codes with local dimension $D$ and distance $d \geq 3$ is bounded by…

Paper

Switching Quantum Reference Frames for Quantum Measurement

Jianhao M. Yang,

Quantum 4, 283 (2020).

Physical observation is made relative to a reference frame. A reference frame is essentially a quantum system given the universal validity of quantum mechanics. Thus, a quantum system must b…

Paper

A two-player dimension witness based on embezzlement, and an elementary proof of the non-closure of the set of quantum correlations

Andrea Coladangelo,

Quantum 4, 282 (2020).

We describe a two-player non-local game, with a fixed small number of questions and answers, such that an $\epsilon$-close to optimal strategy requires an entangled state of dimension…

Paper

Real Time Dynamics and Confinement in the $\mathbb{Z}_{n}$ Schwinger-Weyl lattice model for 1+1 QED

Giuseppe Magnifico, Marcello Dalmonte, Paolo Facchi, Saverio Pascazio, Francesco V. Pepe, and Elisa Ercolessi,

Quantum 4, 281 (2020).

We study the out-of-equilibrium properties of $1+1$ dimensional quantum electrodynamics (QED), discretized via the staggered-fermion Schwinger model with an Abelian $\mathbb{Z}_{n}$ gauge group.…

Paper

Quantifying Bell: the Resource Theory of Nonclassicality of Common-Cause Boxes

Elie Wolfe, David Schmid, Ana Belén Sainz, Ravi Kunjwal, and Robert W. Spekkens,

Quantum 4, 280 (2020).

We take a resource-theoretic approach to the problem of quantifying nonclassicality in Bell scenarios. The resources are conceptualized as probabilistic processes from the setting variables…

Paper

Graph-theoretic Simplification of Quantum Circuits with the ZX-calculus

Ross Duncan, Aleks Kissinger, Simon Perdrix, and John van de Wetering,

Quantum 4, 279 (2020).

We present a completely new approach to quantum circuit optimisation, based on the ZX-calculus. We first interpret quantum circuits as ZX-diagrams, which provide a flexible, lower-level lang…

Paper

Characterization of solvable spin models via graph invariants

Adrian Chapman and Steven T. Flammia,

Quantum 4, 278 (2020).

Exactly solvable models are essential in physics. For many-body spin-$\mathbf{\sf{1}/{2}}$ systems, an important class of such models consists of those that can be mapped to free fermions hopp…

Category: Paper