Measuring out-of-time-order correlations and multiple quantum spectra in a trapped-ion quantum magnet
By Martin Gärttner, J. Bohnet, Arghavan Safavi-Naini, Michael L. Wall, John J. Bollinger, Ana Maria Rey. Nature Physics, 2016
625 citations recorded by the source corpus.
Controllable arrays of ions and ultracold atoms can simulate complex many-body phenomena and may provide insights into unsolved problems in modern science. To this end, experimentally feasible protocols for quantifying the buildup of quantum correlations and coherence are needed, as performing full state tomography does not scale favourably with the number of particles. Here we develop and experimentally demonstrate such a protocol, which uses time reversal of the many-body dynamics to measure out-of-time-order correlation functions (OTOCs) in a long-range Ising spin quantum simulator with more than 100 ions in a Penning trap. By measuring a family of OTOCs as a function of a tunable parameter we obtain fine-grained information about the state of the system encoded in the multiple quantum coherence spectrum, extract the quantum state purity, and demonstrate the buildup of up to 8-body correlations. Future applications of this protocol could enable studies of many-body localization, quantum phase transitions, and tests of the holographic duality between quantum and gravitational systems. Characterizing the correlations of quantum many-body systems is known to be hard, but there are ways around: for example, a new method for measuring out-of-time correlations demonstrated in a Penning trap quantum simulator with over 100 ions.
Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics
View Paper: https://www.semanticscholar.org/paper/0df2bb08f87a378a070e46a7f8ba28227baf55f2
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Citations in the corpus
- Disentangling Scrambling and Decoherence via Quantum Teleportation (2018, methodology): “Despite this challenge, a tremendous amount of interest has been devoted to the development of protocols [33–35] and platforms [36,37] for the direct measurement of OTOCs.”
- Random Quantum Circuits (2022, background): “OTOCs have been addressed in a range of experiments (181, 182, 183, 184, 105).”
- Emergent statistical mechanics of entanglement in random unitary circuits (2018, background): “[40] Martin Gärttner, Justin G Bohnet, Arghavan SafaviNaini, Michael L Wall, John J Bollinger, and Ana Maria Rey.”
- Quantum metrology with nonclassical states of atomic ensembles (2016, background): “For instance, Ûnl can be the inverse of the nonlinear transformation that generates the entangled probe state, thus realizing an echo sequence (Garttner et al., 2017; Macr̀ı et al., 2016).”
- Open quantum systems with local and collective incoherent processes: Efficient numerical simulations using permutational invariance (2018, background): “[80], permutation-symmetric simulation of Eq.”
- Onset of many-body chaos in the $O(N)$ model (2017, background): “Several experimental proposals have also appeared recently [28] [29] [30] that enable one to measure OTO correlators and scrambling and three preliminary experiments have already been carried out [31] [32] [33].”