Entanglement from Tensor Networks on a Trapped-Ion Quantum Computer

• Main Authors: Dreiling, J. (Author), Figgatt, C. (Author), Foss-Feig, M. (Author), Gaebler, J. (Author), Hall, A. (Author), Hayes, D. (Author), Moses, S. (Author), Neyenhuis, B. (Author), Pino, J. (Author), Potter, A. (Author), Ragole, S. (Author), Spaun, B. (Author)
• Format: Article
• Language: English
• Published: American Physical Society 2022
• Subjects: Infinite system; Network state; Phase transitions; Quanta computers; Quantum chemistry; Quantum circuit; Quantum entanglement; Quantum optics; Quantum simulations; Quantum system; Qubits; Resource savings; Reuse; Spatial structure; Tensors; Trapped ion; Trapped ions
• Online Access: View Fulltext in Publisher

 The ability to selectively measure, initialize, and reuse qubits during a quantum circuit enables a mapping of the spatial structure of certain tensor-network states onto the dynamics of quantum circuits, thereby achieving dramatic resource savings when simulating quantum systems with limited entanglement. We experimentally demonstrate a significant benefit of this approach to quantum simulation: the entanglement structure of an infinite system - specifically the half-chain entanglement spectrum - is conveniently encoded within a small register of "bond qubits"and can be extracted with relative ease. Using Honeywell's model H0 quantum computer equipped with selective midcircuit measurement and reset, we quantitatively determine the near-critical entanglement entropy of a correlated spin chain directly in the thermodynamic limit and show that its phase transition becomes quickly resolved upon expanding the bond-qubit register. © 2022 American Physical Society.