COMPUTATIONS ON A PROGRAMMABLE QUANTUM PROCESSOR BASED ON TRAPPED ATOMIC IONS

Realizations of small quantum computers have been achieved so far by engineering experimental systems to meet specific requirements of particular algorithms. I will present a quantum processor based on trapped atomic ions that allows a user to program any quantum algorithm in the software while staying blind to the underlying hardware [1]. The processor consists of a linear chain of trapped Ytterbium ions that can be manipulated selectively using an array of optical addressing Raman beams. I will discuss how the collective vibrations of the chain mediates long range interactions between qubits, which are engineered to realize a fully connected graph of two-qubit native gates [2]. We combine these techniques to realize a quantum computation architecture where programmed algorithm sequences are de-composed into native gate operations effected by shaped laser pulses. Using this device, we implement several algorithms that are based on the quantum Fourier transform, the Grover search, and the fault-tolerant encoding of a logical qubit. We then extend the capabilities of the processor to simulate a Hubbard like system of bosons by accessing the local vibrational (phonon) modes of individual ions in a chain [3]. We study the free hopping of phonons between sites as well as its suppression by selectively applying programmable blockades at individual sites. 

Work done at: Joint Quantum Institute, Department of Physics, University of Maryland, College Park, MD 20742, USA Currently at: Department of Physics, University of California, Berkeley, CA 94720, USA. 

[1] S. Debnath, N. M. Linke, C. Figgatt, K. A. Landsman, K. Wright, and C. Monroe Nature 536, 63 (2016).
[2] T. Choi, S. Debnath, T. A. Manning, C. Figgatt, Z.-X. Gong, L.-M. Duan,and C. Monroe Phys. Rev. Lett. 112, 19502 (2014).
[3] S. Debnath, et. al. (in preparation).