Observation of dipolar spin-exchange interactions with lattice-confined polar molecules

By B. Yan, S. Moses, B. Gadway, J. Covey, K. Hazzard, Ana Maria Rey, D. Jin, Jun Ye. Nature, 2013

621 citations recorded by the source corpus.

With the production of polar molecules in the quantum regime, long-range dipolar interactions are expected to facilitate understanding of strongly interacting many-body quantum systems and to realize lattice spin models for exploring quantum magnetism. In ordinary atomic systems, where contact interactions require wavefunction overlap, effective spin interactions on a lattice can be mediated by tunnelling, through a process referred to as superexchange; however, the coupling is relatively weak and is limited to nearest-neighbour interactions. In contrast, dipolar interactions exist even in the absence of tunnelling and extend beyond nearest neighbours. This allows coherent spin dynamics to persist even for gases with relatively high entropy and low lattice filling. Measured effects of dipolar interactions in ultracold molecular gases have been limited to the modification of inelastic collisions and chemical reactions. Here we use dipolar interactions of polar molecules pinned in a three-dimensional optical lattice to realize a lattice spin model. Spin is encoded in rotational states of molecules that are prepared and probed by microwaves. Resonant exchange of rotational angular momentum between two molecules realizes a spin-exchange interaction. The dipolar interactions are apparent in the evolution of the spin coherence, which shows oscillations in addition to an overall decay of the coherence. The frequency of these oscillations, the strong dependence of the spin coherence time on the lattice filling factor and the effect of a multipulse sequence designed to reverse dynamics due to two-body exchange interactions all provide evidence of dipolar interactions. Furthermore, we demonstrate the suppression of loss in weak lattices due to a continuous quantum Zeno mechanism. Measurements of these tunnelling-induced losses allow us to determine the lattice filling factor independently. Our work constitutes an initial exploration of the behaviour of many-body spin models with direct, long-range spin interactions and lays the groundwork for future studies of many-body dynamics in spin lattices.

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

View Paper: https://www.semanticscholar.org/paper/e88aa3cb79cacbeb0a289748d406f0e361350faf

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Citations in the corpus

Quantum Chaos and Thermalization in Isolated Systems of Interacting Particles (2016, background): “They include solidstate [190, 191, 192] and liquid-state [193] NMR platforms, ultracold atoms, and molecules in optical lattices [194, 195, 196, 197, 198, 199, 200].”
Fracton hydrodynamics (2020, background): “—Atomic quantum simulators ranging from polar molecules [79] to Rydberg atoms [80] or trapped ion crystals [81] consist of degrees of freedom which exhibit long-range interactions: clusters of particles, where no two particles are separated by a distance greater than r, have interaction energies E(r”
A cold-atom Fermi–Hubbard antiferromagnet (2016, neutral): “64(6) only nearest-neighbour spin correlations remain.”
Coherent many-body spin dynamics in a long-range interacting Ising chain (2017, background): “ground state molecules [13], magnetic atoms [14], and”
Many-Body Quantum Spin Dynamics with Monte Carlo Trajectories on a Discrete Phase Space (2014, background): “The Ising limit is naturally realized in experiments with ion traps (both in 1D [10, 11] or 2D [12] geometries) and Rydberg atoms in 2D [8]; the XY limit dynamics have been realized in polar molecules in optical lattices [4, 5], magnetic atoms [26], Förster resonances in Rydberg atoms [27], and as a”
Classification of Interacting Topological Floquet Phases in One Dimension (2016, background): “[45] and ultracold lattice dipolar molecule [46,47] systems, is the bosonic SPTwithZ2 symmetry, which we describe in detail in Sec.”
Microwave-engineering of programmable XXZ Hamiltonians in arrays of Rydberg atoms (2021, methodology): “Experimental platforms that have been used for quantum simulation so far include ions [2,3], molecules [4,5], atoms [6,7], and quantum circuits [8,9].”
Robust Encoding of a Qubit in a Molecule (2019, background): “We have neglected rotational-state-dependent trapping effects, which are prominent in optical dipole traps [44, 60–62].”
Low-frequency conductivity in many-body localized systems (2015, background): “[28] B.”
Quantum trajectories and open many-body quantum systems (2014, methodology): “Quantum coherence has been observed, and decoherence studies performed in atomic systems including photon modes in cavities [11–15]; single trapped atoms [16], ions [8, 17–21], and molecules [22, 23]; and in solid state systems [9, 24] including superconducting junctions [25], and spin systems inclu”