Quantum simulation of a spin chain with superconducting circuits

An Ising chain is one of the simplest many-body systems to exhibit a quantum phase transition. In the presence of a transverse field and disorder, this model produces a rich variety of non integrable ground states giving rise to exotic phase transitions including many body localization and Anderson localization.
Initial experimental efforts to simulate this model have focused on cold atoms [1] and trapped ion systems [2,3] with limited coupling strength imposed by the laws of nature. Our experiment uses an artificial spin chain made of highly anharmonic fluxonium qubits [4] arranged on a lattice and coupled to one another by mutual inductance. While the transverse magnetic field and on-site energy can be tuned in situ, disorder and coupling strength can be adjusted at will by microfabrication enabling us to reach unprecedented parameter regimes.
A deeper understanding of the competition and resulting transitions between phases of matter could provide insights into the properties of complex materials and more generally into the many-body physics of quantum systems.

[1] Jo, G. et al. Science 325, 1521–1524 (2009).
[2] Friedenauer, A., et al. Nature Phys. 4, 757–761 (2008)
[3] Kim, K. et al. Nature 465, 590–593 (2010).
[4] V. E. Manucharyan, et al. Science 326, 113 (2009).