Quantum

Paper

Error-corrected Hadamard gate simulated at the circuit level

György P. Gehér, Campbell McLauchlan, Earl T. Campbell, Alexandra E. Moylett, and Ophelia Crawford,

Quantum 8, 1394 (2024).

We simulate the logical Hadamard gate in the surface code under a circuit-level noise model, compiling it to a physical circuit on square-grid connectivity hardware. Our paper is the first t…

Paper

Wigner Analysis of Particle Dynamics and Decoherence in Wide Nonharmonic Potentials

Andreu Riera-Campeny, Marc Roda-Llordes, Piotr T. Grochowski, and Oriol Romero-Isart,

Quantum 8, 1393 (2024).

We derive an analytical expression of a Wigner function that approximately describes the time evolution of the one-dimensional motion of a particle in a nonharmonic potential. Our method inv…

Paper

Protecting coherence from the environment via Stark many-body localization in a Quantum-Dot Simulator

Subhajit Sarkar and Berislav Buča,

Quantum 8, 1392 (2024).

Semiconductor platforms are emerging as a promising architecture for storing and processing quantum information, e.g., in quantum dot spin qubits. However, charge noise coming from interacti…

Paper

Polynomial Equivalence of Complexity Geometries

Adam R. Brown,

Quantum 8, 1391 (2024).

This paper proves the polynomial equivalence of a broad class of definitions of quantum computational complexity. We study right-invariant metrics on the unitary group—often called `complexi…

Paper

Objectivity of classical quantum stochastic processes

Piotr Szańkowski and Łukasz Cywiński,

Quantum 8, 1390 (2024).

We investigate what can be concluded about a quantum system when sequential quantum measurements of its observable – a prominent example of the so-called quantum stochastic process – fulfill…

Paper

Efficient Quantum Algorithm for Filtering Product States

Reinis Irmejs, Mari Carmen Bañuls, and J. Ignacio Cirac,

Quantum 8, 1389 (2024).

We introduce a quantum algorithm to efficiently prepare states with a small energy variance at the target energy. We achieve it by filtering a product state at the given energy with a Lorent…

Paper

Bayesian Optimization for Robust State Preparation in Quantum Many-Body Systems

Tizian Blatz, Joyce Kwan, Julian Léonard, and Annabelle Bohrdt,

Quantum 8, 1388 (2024).

New generations of ultracold-atom experiments are continually raising the demand for efficient solutions to optimal control problems. Here, we apply Bayesian optimization to improve a state-…

Paper

Relating non-local quantum computation to information theoretic cryptography

Rene Allerstorfer, Harry Buhrman, Alex May, Florian Speelman, and Philip Verduyn Lunel,

Quantum 8, 1387 (2024).

Non-local quantum computation (NLQC) is a cheating strategy for position-verification schemes, and has appeared in the context of the AdS/CFT correspondence. Here, we connect NLQC to the wid…

Paper

Synthesizing and multiplexing autonomous quantum coherences

Artur Slobodeniuk, Tomáš Novotný, and Radim Filip,

Quantum 8, 1386 (2024).

Quantum coherence is a crucial prerequisite for quantum technologies. Therefore, the robust generation, as autonomous as possible, of quantum coherence remains the essential problem for deve…

Paper

Reduction of finite sampling noise in quantum neural networks

David A. Kreplin and Marco Roth,

Quantum 8, 1385 (2024).

Quantum neural networks (QNNs) use parameterized quantum circuits with data-dependent inputs and generate outputs through the evaluation of expectation values. Calculating these expectation…

Paper

Which entropy for general physical theories?

Paolo Perinotti, Alessandro Tosini, and Leonardo Vaglini,

Quantum 8, 1384 (2024).

We address the problem of quantifying the information content of a source for an arbitrary information theory, where the information content is defined in terms of the asymptotic achievable…

Paper

Quantum Computed Green’s Functions using a Cumulant Expansion of the Lanczos Method

Gabriel Greene-Diniz, David Zsolt Manrique, Kentaro Yamamoto, Evgeny Plekhanov, Nathan Fitzpatrick, Michal Krompiec, Rei Sakuma, and David Muñoz Ramo,

Quantum 8, 1383 (2024).

In this paper, we present a quantum computational method to calculate the many-body Green's function matrix in a spin orbital basis. We apply our approach to finite-sized fermionic Hubbard m…

Paper

Comparison of Discrete Variable and Continuous Variable Quantum Key Distribution Protocols with Phase Noise in the Thermal-Loss Channel

Sebastian P. Kish, Patrick J. Gleeson, Angus Walsh, Ping Koy Lam, and Syed M. Assad,

Quantum 8, 1382 (2024).

Discrete-variable (DV) quantum key distribution (QKD) based on single-photon detectors and sources have been successfully deployed for long-range secure key distribution. On the other hand,…

Paper

Quantum chi-squared tomography and mutual information testing

Steven T. Flammia and Ryan O’Donnell,

Quantum 8, 1381 (2024).

For quantum state tomography on rank-$r$ dimension-$d$ states, we show that $\widetilde{O}(r^{.5}d^{1.5}/\epsilon) \leq \widetilde{O}(d^2/\epsilon)$ copies suffice for accuracy $\epsilon$ with respe…

Paper

Quantum Merkle Trees

Lijie Chen and Ramis Movassagh,

Quantum 8, 1380 (2024).

Committing to information is a central task in cryptography, where a party (typically called a prover) stores a piece of information (e.g., a bit string) with the promise of not changing it.…

Paper

Unifying flavors of fault tolerance with the ZX calculus

Hector Bombin, Daniel Litinski, Naomi Nickerson, Fernando Pastawski, and Sam Roberts,

Quantum 8, 1379 (2024).

There are several models of quantum computation which exhibit shared fundamental fault-tolerance properties. This article makes commonalities explicit by presenting these different models in…

Category: Paper