@article {1268, title = {Experimental Performance of a Quantum Simulator: Optimizing Adiabatic Evolution and Identifying Many-Body Ground States }, journal = {Physical Review A}, volume = {88}, year = {2013}, month = {2013/7/31}, abstract = { We use local adiabatic evolution to experimentally create and determine the ground state spin ordering of a fully-connected Ising model with up to 14 spins. Local adiabatic evolution -- in which the system evolution rate is a function of the instantaneous energy gap -- is found to maximize the ground state probability compared with other adiabatic methods while only requiring knowledge of the lowest $\sim N$ of the $2^N$ Hamiltonian eigenvalues. We also demonstrate that the ground state ordering can be experimentally identified as the most probable of all possible spin configurations, even when the evolution is highly non-adiabatic. }, doi = {10.1103/PhysRevA.88.012334}, url = {http://arxiv.org/abs/1305.2253v1}, author = {Philip Richerme and Crystal Senko and Jacob Smith and Aaron Lee and Simcha Korenblit and Christopher Monroe} } @article {1270, title = {Quantum Catalysis of Magnetic Phase Transitions in a Quantum Simulator}, journal = {Physical Review Letters}, volume = {111}, year = {2013}, month = {2013/9/5}, 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. Due to 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{\textquoteright}s staircase, which emerges in the thermodynamic limit and can be mapped to a large number of many-body and energy-optimization problems. }, doi = {10.1103/PhysRevLett.111.100506}, url = {http://arxiv.org/abs/1303.6983v2}, author = {Philip Richerme and Crystal Senko and Simcha Korenblit and Jacob Smith and Aaron Lee and Rajibul Islam and Wesley C. Campbell and Christopher Monroe} } @article {1492, title = {Quantum Simulation of Spin Models on an Arbitrary Lattice with Trapped Ions }, journal = {New Journal of Physics}, volume = {14}, year = {2012}, month = {2012/09/27}, pages = {095024}, abstract = { A collection of trapped atomic ions represents one of the most attractive platforms for the quantum simulation of interacting spin networks and quantum magnetism. Spin-dependent optical dipole forces applied to an ion crystal create long-range effective spin-spin interactions and allow the simulation of spin Hamiltonians that possess nontrivial phases and dynamics. Here we show how appropriate design of laser fields can provide for arbitrary multidimensional spin-spin interaction graphs even for the case of a linear spatial array of ions. This scheme uses currently existing trap technology and is scalable to levels where classical methods of simulation are intractable. }, doi = {10.1088/1367-2630/14/9/095024}, url = {http://arxiv.org/abs/1201.0776v1}, author = {Simcha Korenblit and Dvir Kafri and Wess C. Campbell and Rajibul Islam and Emily E. Edwards and Zhe-Xuan Gong and Guin-Dar Lin and Luming Duan and Jungsang Kim and Kihwan Kim and Christopher Monroe} }