** SPIN-1** Three-level systems are useful as “qutrits” in quantum information processing with more storage capacity than qubits, but they can also represent effective “spin-1” particles that have interesting magnetic properties. We have encoded qutrits in three levels of

^{171}Yb

^{+}ions, and engineered Ising and XY magnetic interactions between several ions to entangle and prepare complex ground states of this system. Future work will study certain topological phases that emerge from this many body spin-1 system.

- “Realization of a Quantum Integer-Spin Chain with Controllable Interactions,” Phys. Rev. X 5, 021026 (2015)
- “Simulating the Haldane Phase in Trapped Ion Spins Using Optical Fields,” Phys. Rev. A 92, 012334 (2015).
- JQI News release

** MANY BODY SPECTROSCOPY** It is computationally intractable to calculate the spectrum of energy levels in a lattice of spins fully-connected through Ising or XY magnetic interactions. We have developed a new technique akin to MRI that images particular energy levels of a spin chain encoded in an array of trapped ions, by modulating a transverse magnetic field and directly observing the resulting spin configuration.

- “Coherent Imaging Spectroscopy of a Quantum Many-Body Spin System,” Science
**345**, 430 (2014). - Supplementary Information
- JQI News Release

* QUANTUM “LIGHT CONES” OF ENTANGLEMENT PROPAGATION* We have measured dynamics of the propagation of quantum information through a many body spin chain connected by long-range Ising or XY magnetic interactions, and observe that the “speed limit” of this propagation can break bounds associated with conventional local interactions, first described by Lieb and Robinson in 1972.