



@article {2770,
	title = {Meta Hamiltonian Learning},
	year = {2021},
	month = {4/9/2021},
	abstract = {<p>Efficient characterization of quantum devices is a significant challenge critical for the development of large scale quantum computers. We consider an experimentally motivated situation, in which we have a decent estimate of the Hamiltonian, and its parameters need to be characterized and fine-tuned frequently to combat drifting experimental variables. We use a machine learning technique known as meta-learning to learn a more efficient optimizer for this task. We consider training with the nearest-neighbor Ising model and study the trained model\&$\#$39;s generalizability to other Hamiltonian models and larger system sizes. We observe that the meta-optimizer outperforms other optimization methods in average loss over test samples. This advantage follows from the meta-optimizer being less likely to get stuck in local minima, which highly skews the distribution of the final loss of the other optimizers. In general, meta-learning decreases the number of calls to the experiment and reduces the needed classical computational resources.</p>},
	url = {https://arxiv.org/abs/2104.04453},
	author = {Przemyslaw Bienias and Alireza Seif and Mohammad Hafezi}
}
@article {2595,
	title = {Minimal model for fast scrambling},
	journal = {Phys. Rev. Lett.},
	volume = {125},
	year = {2020},
	month = {9/22/2020},
	abstract = {<p>We study quantum information scrambling in spin models with both long-range all-to-all and short-range interactions. We argue that a simple global, spatially homogeneous interaction together with local chaotic dynamics is sufficient to give rise to fast scrambling, which describes the spread of quantum information over the entire system in a time that is logarithmic in the system size. This is illustrated in two exactly solvable models: (1) a random circuit with Haar random local unitaries and a global interaction and (2) a classical model of globally coupled non-linear oscillators. We use exact numerics to provide further evidence by studying the time evolution of an out-of-time-order correlator and entanglement entropy in spin chains of intermediate sizes. Our results can be verified with state-of-the-art quantum simulators.</p>},
	doi = {https://doi.org/10.1103/PhysRevLett.125.130601},
	url = {https://arxiv.org/abs/2005.05362},
	author = {Ron Belyansky and Przemyslaw Bienias and Yaroslav A. Kharkov and Alexey V. Gorshkov and Brian Swingle}
}
