SearcharxivSearch

arXiv subjects

Andrea B. Rava

Publications and source records attributed to Andrea B. Rava.

2 recordsLinked to original sources

Benchmarking neutral atom-based quantum processors at scale

In recent years, neutral atom-based quantum computation has been established as a competing alternative for the realization of fault-tolerant quantum computation. However, as with other quantum technologies, various sources of noise limit their performance. With processors continuing to scale up, new techniques are needed to characterize and compare them in order to track their progress. In this work, we present two systematic benchmarks that evaluate these quantum processors at scale. We use the quantum adiabatic algorithm (QAA) and the quantum approximate optimization algorithm (QAOA) to solve maximal independent set (MIS) instances of random unit-disk graphs. These benchmarks are scalable, relying not on prior knowledge of the system's evolution but on the quality of the MIS solutions obtained. Rather than isolating individual sources of noise, they provide an application-level figure of merit: improvements in a QPU and its implementation of the protocols should be reflected in higher-quality MIS solutions. We benchmark quera_aquila and pasqal_fresnel on problem sizes up to 102 and 85 qubits, respectively. Overall, quera_aquila performs better on QAOA and QAA instances. Finally, we generate MIS instances of up to 1000 qubits, providing scalable benchmarks for evaluating future, larger processors as they become available. The proposed protocols can therefore serve as a common reference for comparisons, allowing future work to assess whether advances in hardware translate into measurable improvements in MIS solution quality.

quant-ph

Interplay of Confinement and Localization in a Programmable Rydberg Atom Chain

Analog quantum simulators promise access to complex many-body dynamics, yet their performance is ultimately set by how device imperfections compete with intrinsic physical mechanisms. Here we present an end-to-end study of correlation spreading in a programmable Rydberg-atom chain realizing a longitudinal-field transverse-field Ising model, focusing on the joint impact of confinement and effective disorder. Experiments performed on QuEra's Aquila quantum processor are benchmarked against large-scale coherent emulations using the Juelich Quantum Annealing Simulator (JUQAS), enabling the controlled inclusion of realistic hardware imperfections. In the ideal coherent limit, a tunable longitudinal field induces confinement of domain-wall excitations into mesonic bound states, leading to a progressive truncation of the correlation light cone. When experimentally relevant inhomogeneities and fluctuations are included, correlations instead saturate at finite distance even in the nominally deconfined regime, revealing localization driven by emergent disorder. The close quantitative agreement between noisy emulations and experimental data allows us to attribute the observed saturation to specific hardware error channels and to identify the dominant contribution. Our results establish a practical framework for diagnosing and modeling error-induced localization in Rydberg quantum processors, while demonstrating that confinement remains a robust and programmable mechanism for engineering non-ergodic dynamics on near-term quantum hardware.

quant-ph