Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Apr 25;484(7395):489-92.
doi: 10.1038/nature10981.

Engineered Two-Dimensional Ising Interactions in a Trapped-Ion Quantum Simulator With Hundreds of Spins


Engineered Two-Dimensional Ising Interactions in a Trapped-Ion Quantum Simulator With Hundreds of Spins

Joseph W Britton et al. Nature. .


The presence of long-range quantum spin correlations underlies a variety of physical phenomena in condensed-matter systems, potentially including high-temperature superconductivity. However, many properties of exotic, strongly correlated spin systems, such as spin liquids, have proved difficult to study, in part because calculations involving N-body entanglement become intractable for as few as N ≈ 30 particles. Feynman predicted that a quantum simulator--a special-purpose 'analogue' processor built using quantum bits (qubits)--would be inherently suited to solving such problems. In the context of quantum magnetism, a number of experiments have demonstrated the feasibility of this approach, but simulations allowing controlled, tunable interactions between spins localized on two- or three-dimensional lattices of more than a few tens of qubits have yet to be demonstrated, in part because of the technical challenge of realizing large-scale qubit arrays. Here we demonstrate a variable-range Ising-type spin-spin interaction, J(i,j), on a naturally occurring, two-dimensional triangular crystal lattice of hundreds of spin-half particles (beryllium ions stored in a Penning trap). This is a computationally relevant scale more than an order of magnitude larger than previous experiments. We show that a spin-dependent optical dipole force can produce an antiferromagnetic interaction J(i,j) proportional variant d(-a)(i,j), where 0 ≤ a ≤ 3 and d(i,j) is the distance between spin pairs. These power laws correspond physically to infinite-range (a = 0), Coulomb-like (a = 1), monopole-dipole (a = 2) and dipole-dipole (a = 3) couplings. Experimentally, we demonstrate excellent agreement with a theory for 0.05 ≲ a ≲ 1.4. This demonstration, coupled with the high spin count, excellent quantum control and low technical complexity of the Penning trap, brings within reach the simulation of otherwise computationally intractable problems in quantum magnetism.

Comment in

Similar articles

See all similar articles

Cited by 34 articles

See all "Cited by" articles


    1. Science. 2008 Mar 28;319(5871):1808-12 - PubMed
    1. Science. 1987 Mar 6;235(4793):1196-8 - PubMed
    1. Phys Rev Lett. 2007 Mar 9;98(10):107204 - PubMed
    1. Phys Rev Lett. 2009 Jun 12;102(23):233002 - PubMed
    1. Nature. 2003 Mar 27;422(6930):412-5 - PubMed

Publication types

LinkOut - more resources