%0 Journal Article
%J Physical Review A
%D 2015
%T Bilayer fractional quantum Hall states with ultracold dysprosium
%A Norman Y. Yao
%A Steven D. Bennett
%A Chris R. Laumann
%A Benjamin L. Lev
%A Alexey V. Gorshkov
%X We show how dipolar interactions between dysprosium atoms in an optical lattice can be used to obtain fractional quantum Hall states. In our approach, dysprosium atoms are trapped one atom per site in a deep optical lattice with negligible tunneling. Microwave and spatially dependent optical dressing fields are used to define an effective spin-1/2 or spin-1 degree of freedom in each atom. Thinking of spin-1/2 particles as hardcore bosons, dipole-dipole interactions give rise to boson hopping, topological flat bands with Chern number 1, and the \nu = 1/2 Laughlin state. Thinking of spin-1 particles as two-component hardcore bosons, dipole-dipole interactions again give rise to boson hopping, topological flat bands with Chern number 2, and the bilayer Halperin (2,2,1) state. By adjusting the optical fields, we find a phase diagram, in which the (2,2,1) state competes with superfluidity. Generalizations to solid-state magnetic dipoles are discussed.
%B Physical Review A
%V 92
%P 033609
%8 2015/09/10
%G eng
%U http://arxiv.org/abs/1505.03099v1
%N 3
%! Phys. Rev. A
%R 10.1103/PhysRevA.92.033609
%0 Journal Article
%J Physical Review A
%D 2013
%T Quantum Logic between Remote Quantum Registers
%A Norman Y. Yao
%A Zhe-Xuan Gong
%A Chris R. Laumann
%A Steven D. Bennett
%A L. -M. Duan
%A Mikhail D. Lukin
%A Liang Jiang
%A Alexey V. Gorshkov
%X We analyze two approaches to quantum state transfer in solid-state spin systems. First, we consider unpolarized spin-chains and extend previous analysis to various experimentally relevant imperfections, including quenched disorder, dynamical decoherence, and uncompensated long range coupling. In finite-length chains, the interplay between disorder-induced localization and decoherence yields a natural optimal channel fidelity, which we calculate. Long-range dipolar couplings induce a finite intrinsic lifetime for the mediating eigenmode; extensive numerical simulations of dipolar chains of lengths up to L=12 show remarkably high fidelity despite these decay processes. We further consider the extension of the protocol to bosonic systems of coupled oscillators. Second, we introduce a quantum mirror based architecture for universal quantum computing which exploits all of the spins in the system as potential qubits. While this dramatically increases the number of qubits available, the composite operations required to manipulate "dark" spin qubits significantly raise the error threshold for robust operation. Finally, as an example, we demonstrate that eigenmode-mediated state transfer can enable robust long-range logic between spatially separated Nitrogen-Vacancy registers in diamond; numerical simulations confirm that high fidelity gates are achievable even in the presence of moderate disorder.
%B Physical Review A
%V 87
%8 2013/2/6
%G eng
%U http://arxiv.org/abs/1206.0014v1
%N 2
%! Phys. Rev. A
%R 10.1103/PhysRevA.87.022306
%0 Journal Article
%J Physical Review Letters
%D 2013
%T Realizing Fractional Chern Insulators with Dipolar Spins
%A Norman Y. Yao
%A Alexey V. Gorshkov
%A Chris R. Laumann
%A Andreas M. LĂ¤uchli
%A Jun Ye
%A Mikhail D. Lukin
%X Strongly correlated quantum systems can exhibit exotic behavior controlled by topology. We predict that the \nu=1/2 fractional Chern insulator arises naturally in a two-dimensional array of driven, dipolar-interacting spins. As a specific implementation, we analyze how to prepare and detect synthetic gauge potentials for the rotational excitations of ultra-cold polar molecules trapped in a deep optical lattice. While the orbital motion of the molecules is pinned, at finite densities, the rotational excitations form a fractional Chern insulator. We present a detailed experimental blueprint for KRb, and demonstrate that the energetics are consistent with near-term capabilities. Prospects for the realization of such phases in solid-state dipolar systems are discussed as are their possible applications.
%B Physical Review Letters
%V 110
%8 2013/4/29
%G eng
%U http://arxiv.org/abs/1212.4839v1
%N 18
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.110.185302
%0 Journal Article
%J Nature Communications
%D 2013
%T Topologically Protected Quantum State Transfer in a Chiral Spin Liquid
%A Norman Y. Yao
%A Chris R. Laumann
%A Alexey V. Gorshkov
%A Hendrik Weimer
%A Liang Jiang
%A J. Ignacio Cirac
%A Peter Zoller
%A Mikhail D. Lukin
%X Topology plays a central role in ensuring the robustness of a wide variety of physical phenomena. Notable examples range from the robust current carrying edge states associated with the quantum Hall and the quantum spin Hall effects to proposals involving topologically protected quantum memory and quantum logic operations. Here, we propose and analyze a topologically protected channel for the transfer of quantum states between remote quantum nodes. In our approach, state transfer is mediated by the edge mode of a chiral spin liquid. We demonstrate that the proposed method is intrinsically robust to realistic imperfections associated with disorder and decoherence. Possible experimental implementations and applications to the detection and characterization of spin liquid phases are discussed.
%B Nature Communications
%V 4
%P 1585
%8 2013/3/12
%G eng
%U http://arxiv.org/abs/1110.3788v1
%! Nat Comms
%R 10.1038/ncomms2531
%0 Journal Article
%J Physical Review Letters
%D 2012
%T Topological Flat Bands from Dipolar Spin Systems
%A Norman Y. Yao
%A Chris R. Laumann
%A Alexey V. Gorshkov
%A Steven D. Bennett
%A Eugene Demler
%A Peter Zoller
%A Mikhail D. Lukin
%X We propose and analyze a physical system that naturally admits two-dimensional topological nearly flat bands. Our approach utilizes an array of three-level dipoles (effective S = 1 spins) driven by inhomogeneous electromagnetic fields. The dipolar interactions produce arbitrary uniform background gauge fields for an effective collection of conserved hardcore bosons, namely, the dressed spin-flips. These gauge fields result in topological band structures, whose bandgap can be larger than the corresponding bandwidth. Exact diagonalization of the full interacting Hamiltonian at half-filling reveals the existence of superfluid, crystalline, and supersolid phases. An experimental realization using either ultra-cold polar molecules or spins in the solid state is considered.
%B Physical Review Letters
%V 109
%8 2012/12/26
%G eng
%U http://arxiv.org/abs/1207.4479v3
%N 26
%! Phys. Rev. Lett.
%R 10.1103/PhysRevLett.109.266804