title: Onset of a quantum phase transition with a trapped ion quantum simulator.
abstract: A quantum simulator is a well-controlled quantum system that can follow the evolution of a prescribed model whose behaviour may be difficult to determine. A good example is the simulation of a set of interacting spins, where phase transitions between various spin orders can underlie poorly understood concepts such as spin liquids. Here we simulate the emergence of magnetism by implementing a fully connected non-uniform ferromagnetic quantum Ising model using up to 9 trapped (171)Yb(+) ions. By increasing the Ising coupling strengths compared with the transverse field, the crossover from paramagnetism to ferromagnetic order sharpens as the system is scaled up, prefacing the expected quantum phase transition in the thermodynamic limit. We measure scalable order parameters appropriate for large systems, such as various moments of the magnetization. As the results are theoretically tractable, this work provides a critical benchmark for the simulation of intractable arbitrary fully connected Ising models in larger systems.
authors: Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA.
authors: R
authors: R
authors: Islam
authors: E E
authors: EE
authors: Edwards
authors: K
authors: K
authors: Kim
authors: S
authors: S
authors: Korenblit
authors: C
authors: C
authors: Noh
authors: H
authors: H
authors: Carmichael
authors: G-D
authors: GD
authors: Lin
authors: L-M
authors: LM
authors: Duan
authors: C-C Joseph
authors: CC
authors: Wang
authors: J K
authors: JK
authors: Freericks
authors: C
authors: C
authors: Monroe
mesh_terms: D003198:Computer Simulation; D005453:Fluorescence; D007554:Isotopes / Q000737:chemistry; D008280:Magnetics; D008962:Models, Theoretical; D009010:Monte Carlo Method; D044367:Phase Transition; D011789:Quantum Theory; D013816:Thermodynamics; D015018:Ytterbium / Q000737:chemistry
chemical_list: D007554:Isotopes; D015018:Ytterbium