Quantum Simulation of Spin Chains

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 171Yb+ 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.Spin1

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.spectroscopy-latest-01

 

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.