Engineered two-dimensional Ising interactions in a trapped-ion quantum simulator with hundreds of spins

By J. Britton, B. Sawyer, A. Keith, C.C.-Joseph Wang, J. Freericks, H. Uys, M. Biercuk, John J. Bollinger. Nature, 2012

833 citations recorded by the source corpus.

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, Ji,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 , where 0 ≤ a ≤ 3 and di,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.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/3b86aa6cc23a1aa4618d824ba29361782daf92f3

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

In Condensed Matter Physics

Citations in the corpus

A large-scale quantum simulator on a diamond surface at room temperature (2012, background): “Various architectures for quantum simulations have been constructed based on different systems, ranging from ultracold neutral atoms [13– 15], trapped ions [16, 17], and photonic systems [18] to superconducting circuits in solid-state devices [19].”
A Meet-in-the-Middle Algorithm for Fast Synthesis of Depth-Optimal Quantum Circuits (2012, background): “With recent advances in quantum information processing technologies [5], [6], [8], [24], and improvements to faulttolerant thresholds [4], [12], [13], larger quantum devices are becoming increasingly attainable; as the complexity and size of these devices grow, hand optimizations will become less fe”
Quantum metrology with nonclassical states of atomic ensembles (2016, methodology): “So far, up to 20 ions have been entangled in a Paul trap (Monz et al., 2011) and up to about 200 ions in a Penning trap (Bohnet et al., 2016; Britton et al., 2012).”
Quantum Simulators: Architectures and Opportunities (2019, background): “[93] Joseph W Britton, Brian C Sawyer, Adam C Keith, C-C Joseph Wang, James K Freericks, Hermann Uys, Michael J Biercuk, and John J Bollinger.”
Keldysh field theory for driven open quantum systems (2015, background): “Strong motivation for the exploration of non-thermal stationary states comes from a recent surge of experiments in diverse areas: in cold atomic gases [6– 8], hybrid light-matter systems of Bose-Einstein condensates placed in optical cavities are created [9, 10], or driven Rydberg ensembles are prep”
Quasiparticle engineering and entanglement propagation in a quantum many-body system (2014, methodology): “The coupling matrix Ji j ∼ 1/|i − j| has approximately a power-law dependence with distance |i − j|, with an exponent tunable [4–6] between infinite range (α = 0) and, asymptotically, short range (α = 3).”
Polynomial-Time T-Depth Optimization of Clifford+T Circuits Via Matroid Partitioning (2013, background): “However, even with recent advances in quantum information processing technologies [6, 7, 8, 26], the prospects of scalable quantum computing without some systematic way of mitigating physical errors and noise are bleak.”