A10 Designing spin-spin interactions in cold ion crystals Rene Gerritsma, Ferdinand Schmidt-Kaler (Universität Mainz) Planar Ion Trap Probing atom-ion interactions Techniques Asymptotic states: |nCOM, nstretch, natom |001 |000 |100 |002 |101 |010 collision laser atoms Glass chip with 50µm deep trenches to minimize stray fields from the substrate. Trenches on the back side decrease the distance between the trap center and the source of the magnetic field. Simulations predict a gradient up to 50T/m. ion 2 ion 1 Analysis of atom-ion collisions via the Coulomb interaction between the two ions followed by fluorescence state detection. [1] Hempel, Lanyon, Jurcevic, Gerritsma, Blatt and Roos, Nature Phot. 7, 630 (2013). [2] Kotler, Akerman, Navon, Glickman and Ozeri, Nature 510, 376 (2014). [3] Schmidt-Kaler and Gerritsma, EPL 99, 53001 (2012). A3 A5 A12 Stable high current pulse Ion controlled Josephson-Junction We consider a setup in which atoms are trapped in an double-well potential with a trapped ion in between. By tuning the internal or motional state of the ion, the atomic tunnelling rate between the wells can be controlled [4,5]. Stable current pulses of 20A for a few milliseconds with a transistor circuit. Heat from wires dissiplated into AlN substrate coupled to water cooling. Integrated argon gun for in-situ cleaning of the surface, reported to reduce surface-induced ion heating rate [1]. 1) 1) force Future Goals 2) 2) Short term goals: Measurement of magnetic gradient with single-ion probe Measurement of heating rate and surface cleaning Observing mediated spin-spin coupling with a linear ion crystal Mid term goals: Scale up spin-spin interactions to two-dimensional ion crystals Characterizing frustration effects in spin-spin interactions Experimentally realizing spin-spin models such as the J1-J2 in ladder systems Study spin-boson coupling along the Jahn-Teller dynamics[7] Magnetic gradient B (left) Spectrum of a double-well system for an inter-well separation of d = 2.5R* = 765 nm for 87Rb and 171Yb+ with ωa = 2π 1.8 kHz and ωi = 2π 9.9 kHz. In the lower panel, the tunnelling rate is plotted. (right) Corresponding probability distributions of the ion-atom states. Paramagnetic linear ion crystal Phase transition, observed in radial phonons when increasing the coupling 20 equidistant spins Jahn-Teller transition B (left) The effect of micromotion: Spectrum for the groundstates of 7Li and 171Yb+ with ωa = 2π 1.8 kHz, Ω = 2π 70.5 kHz for q = 0.4 and a = 0 such that ω i ≈ 2π 10 kHz. Energy crossings appear but avoided crossings remain very small. (right) Fidelity F(Ƭ) of the tunnelling dynamics for the atom-ion pair 87Rb / 171Yb+ at finite temperatures Ƭ. anti-ferromag. ordering Inhomogenious case: ion crystal [4] Joger, Negretti and Gerritsma, PRA 89, 063621 (2014). [5] Gerritsma, Negretti, Doerk, Idziaszek, Calarco and Schmidt-Kaler PRL 109, 080402 (2012). A3 A5 A9 A12 B1 B3 coupling strength g Critical point Long term goals: Drive structural phase transitions and observe spin-driven quench dynamics New trap with current wires included in a multi layer chip to minimize the distance to the trap center and further optimizing of the magnetic gradient Observe the effect of impurities: - local modes pinned to impurities - modification of Kibble Zurek defect generation at impurity sites Workplan technology A8 B1 optimize trap control volt. spin-spin Surface cleaning atom-ion measure magn. gradient trapping impurities theory Zigzag ion crystals Theory for magnetic simulation S>1/2 [8]: magnetic field gradient in z-direction Effective Hamiltonian after adiabatic ellimination , m = projection of 50Mn+ – spin. two ion spin-spin coupl. Jahn Teller transition Planar ion crystal spin-spin coupl. Spin-induced struct. Phase transition Field of activity for PhD I: Operate planar ion trap with high magnetic gradient for spin-spin interaction Hybrid trap characterization BEC Spin-motion coupling atomic double well Determine scattering rate Raman laser enhanced sensor entangled ions Field of activity for PhD II: Operate hybrid trap for atom-ion interaction heating/cooling rate Polaron theory of ions in BEC Quantum gate theory in ultra-cold bath Year 1 Year 2 Year 3 Year 4 [6] N. Daniilidis et al., arXiv 1307.7194 (2013) [7] P. A. Ivanov et al., J. Phys. B 46, 104008 (2013) [8] P. A. Ivanov et al., NJP 13, 125008 (2011) A3 A5 A12 Transregional Collaborative Research Centre SFB/TR 49 Frankfurt / Kaiserslautern / Mainz