Ben Lanyon

Characterizing a 20-spin quantum simulator

Institut für Quantenoptik und Quanteninformation, Innsbruck, Austria   

Quantum many-body systems are expected to display a range of fascinating phenomena, such as those related to quantum transport, thermalization and localization, and to enable various quantum-enhanced technologies. Under the influence of laser fields, strings of trapped atomic ions are well described by models of interacting quantum spins [1]. Recently, we have developed a trapped-ion system in which we can precisely initialize, manipulate and measure the quantum state of up to 20 ionic-spins.
In this talk I will first introduce our experimental system and its capabilities [2]. Next, I will present a spectroscopic method that we developed to study the low-energy physics of our system [3]. By analyzing the dynamical response of carefully prepared initial states we could determined the system dispersion relation and detect  interactions between the emergent quasi-particles in our system. Lastly, I will briefly present results from the application of matrix-product state tomography [4] to efficiently characterize the high-energy states of our system. Using measurements of only small subsets of spins we are able to put strict lower bounds on the global state fidelity.

References:
[1]    D. Porras and J. I. Cirac, PRL 92, 207901 (2004)
[2]    P. Jurcevic et al, Nature 511, 202 (2014)
[3]    P. Jurcevic et al, arXiv:1505.02066 (2015)
[4]    M. Cramer et al, Nat. Commun 1, 149 (2010)