



01527nas a2200181   4500008004100000245006900041210006900110260001500179300001100194490000700205520098100212100002001193700002401213700002301237700002201260700002501282856003801307       2015                        eng d00aBilayer fractional quantum Hall states with ultracold dysprosium0 aBilayer fractional quantum Hall states with ultracold dysprosium  c2015/09/10  a0336090 v923 a  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.
1 aYao, Norman, Y.1 aBennett, Steven, D.1 aLaumann, Chris, R.1 aLev, Benjamin, L.1 aGorshkov, Alexey, V.  uhttp://arxiv.org/abs/1505.03099v101995nas a2200205   4500008004100000245005100041210005100092260001300143490000700156520142000163100002001583700001901603700002301622700002401645700001801669700002301687700001701710700002501727856003701752       2013                        eng d00aQuantum Logic between Remote Quantum Registers0 aQuantum Logic between Remote Quantum Registers  c2013/2/60 v873 a  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.
1 aYao, Norman, Y.1 aGong, Zhe-Xuan1 aLaumann, Chris, R.1 aBennett, Steven, D.1 aDuan, L., -M.1 aLukin, Mikhail, D.1 aJiang, Liang1 aGorshkov, Alexey, V.  uhttp://arxiv.org/abs/1206.0014v101351nas a2200181   4500008004100000245006100041210006100102260001400163490000800177520081800185100002001003700002501023700002301048700002601071700001201097700002301109856003701132       2013                        eng d00aRealizing Fractional Chern Insulators with Dipolar Spins0 aRealizing Fractional Chern Insulators with Dipolar Spins  c2013/4/290 v1103 a  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.
1 aYao, Norman, Y.1 aGorshkov, Alexey, V.1 aLaumann, Chris, R.1 aLäuchli, Andreas, M.1 aYe, Jun1 aLukin, Mikhail, D.  uhttp://arxiv.org/abs/1212.4839v101443nas a2200217   4500008004100000245007500041210006900116260001400185300000900199490000600208520080900214100002001023700002301043700002501066700002001091700001701111700001901128700001801147700002301165856003701188       2013                        eng d00aTopologically Protected Quantum State Transfer in a Chiral Spin Liquid0 aTopologically Protected Quantum State Transfer in a Chiral Spin   c2013/3/12  a15850 v43 a  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.
1 aYao, Norman, Y.1 aLaumann, Chris, R.1 aGorshkov, Alexey, V.1 aWeimer, Hendrik1 aJiang, Liang1 aCirac, Ignacio1 aZoller, Peter1 aLukin, Mikhail, D.  uhttp://arxiv.org/abs/1110.3788v101339nas a2200193   4500008004100000245005300041210005300094260001500147490000800162520078600170100002000956700002300976700002500999700002401024700001901048700001801067700002301085856003701108       2012                        eng d00aTopological Flat Bands from Dipolar Spin Systems0 aTopological Flat Bands from Dipolar Spin Systems  c2012/12/260 v1093 a  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.
1 aYao, Norman, Y.1 aLaumann, Chris, R.1 aGorshkov, Alexey, V.1 aBennett, Steven, D.1 aDemler, Eugene1 aZoller, Peter1 aLukin, Mikhail, D.  uhttp://arxiv.org/abs/1207.4479v3