title: Quantum catalysis of magnetic phase transitions in a quantum simulator.
abstract: We control quantum fluctuations to create the ground state magnetic phases of a classical Ising model with a tunable longitudinal magnetic field using a system of 6 to 10 atomic ion spins. Because of the long-range Ising interactions, the various ground state spin configurations are separated by multiple first-order phase transitions, which in our zero temperature system cannot be driven by thermal fluctuations. We instead use a transverse magnetic field as a quantum catalyst to observe the first steps of the complete fractal devil's staircase, which emerges in the thermodynamic limit and can be mapped to a large number of many-body and energy-optimization problems.
authors.affiliation: Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA.
authors.forename: P
authors.initials: P
authors.lastname: Richerme
authors.affiliation: Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA.
authors.forename: C
authors.initials: C
authors.lastname: Senko
authors.affiliation: Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA.
authors.forename: S
authors.initials: S
authors.lastname: Korenblit
authors.affiliation: Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA.
authors.forename: J
authors.initials: J
authors.lastname: Smith
authors.affiliation: Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA.
authors.forename: A
authors.initials: A
authors.lastname: Lee
authors.affiliation: Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors.forename: R
authors.initials: R
authors.lastname: Islam
authors.affiliation: Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA.
authors.forename: W C
authors.initials: WC
authors.lastname: Campbell
authors.affiliation: Joint Quantum Institute, University of Maryland Department of Physics and National Institute of Standards and Technology, College Park, Maryland 20742, USA.
authors.forename: C
authors.initials: C
authors.lastname: Monroe