Year: 2024
Type: article
Abstract: Ramsey interferometry is a widely used tool for precisely measuring transition frequencies between two energy levels of a quantum system, with applications in time keeping, precision spectroscopy, quantum optics, and quantum information. Often, the coherence time of the quantum system surpasses the one of the oscillator probing the system, thereby limiting the interrogation time and associated spectral resolution. Correlation spectroscopy overcomes this limitation by probing two quantum systems with the same noisy oscillator for a measurement of their transition frequency difference; this technique has enabled very precise comparisons of atomic clocks. Here, we extend correlation spectroscopy to the case of multiple quantum systems undergoing strong correlated dephasing. We model Ramsey correlation spectroscopy with N particles as a multiparameter phase estimation problem and demonstrate that multiparticle correlations can assist in reducing the measurement uncertainties even in the absence of entanglement. We derive precision limits and optimal sensing techniques for this problem and compare the performance of probe states and measurement with and without entanglement. Using one- and two-dimensional ion Coulomb crystals with up to 91 qubits, we experimentally demonstrate the advantage of measuring multiparticle correlations for reducing phase uncertainties and apply correlation spectroscopy to measure ion-ion distances, transition frequency shifts, laser-ion detunings, and path-length fluctuations. Our method can be straightforwardly implemented in experimental setups with globally coherent qubit control and qubit-resolved single-shot readout and is, thus, applicable to other physical systems such as neutral atoms in tweezer arrays. Published by the American Physical Society 2024
Source: Physical Review X
Language: English
Subfield: Artificial Intelligence
Field: Computer Science
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $4,200
Funders: European Commission, Austrian Science Fund, Council for Higher Education, Bundesministerium für Bildung, Wissenschaft und Forschung, Horizon 2020 Framework Programme, Institute for Quantum Information and Matter, California Institute of Technology, H2020 European Research Council, H2020 Marie Skłodowska-Curie Actions
Awards: ESQ-FP: Erwin Schrödinger Quantum Science Programme, Programmable Atomic Large-scale Quantum Simulation 2 - SGA1, ESQ-FP: Erwin Schrödinger Quantum Science Programme, G3692382436, G4016861940, G434337789, G4495373907, Simulating 2d Spin Lattices with Ion Crystals, G5334593051, G8200306319, Programmable Atomic Large-Scale Quantum Simulation, G899235810
OpenAlex ID: W4392284570