Colloquia

Quantum computing promises exponential speedup for particular computational tasks, such as factoring integers[1] and quantum simulation[2]. There are two main flavors of quantum computing: the circuit model and the measurement-based model---in particular, one-way quantum computing [3], which is implemented by applying measurements on an entangled resource known as a cluster state. Complicated computation tasks require the scalable generation of cluster states, which remains a formidable challenge. Pfisterlabs at UVa has been working on generating scalable cluster states and has successfully built some interesting cluster states [4,5].

In this colloquium, I will first explain continuous variable one-way quantum computing, cluster states, and then present our new proposal of a simple, "top-down" setup to generate large-size, D-hypercubic-lattice CV cluster states of more than 6000 entangled modes using D identical optical parametric oscillators (OPOs), each with a two-frequency pump [6]. These cluster states are sufficient for universal one-way quantum computation [3], and the high dimensional lattices are useful in quantum error correction based on Kitaev's surface code [7]. Our optical construction methods eschews the limitations of a three-dimensional world, enabling simulation of measurements on these high-valence cluster graphs and also inviting theoretical and experimental investigations of their topological properties [8].

References:
1. P.W.Shor, in Proceedings, 35th Annual Symposium on Foundations of Computer Science, edited by S.Goldwasser(IEEE press, Los Alamitos, CA, Santa Fe, NM,1994) pp. 124-134.
2. R.P.Feynman, Int.J.Theor.Phys.21,467 (1982)
3. R.Raussendorf and H.J.Briegel, "A one-way quantum computer", Phys.Rev.Lett. 86,5188(2001)
4. M.Pysher et al., "Parallel generation of quadripartite cluster entanglement in the optical frequency comb", Phys.Rev.Lett. 107, 030505(2011)
5. M.Chen, N.C.Menicucci,and O.Pfister,"Experimental realization of multipartite entanglement of 60 modes of the quantum optical frequency comb", arXiv:1311.2957[quant-ph](2013)
6. P.Wang, M.Chen, N.C.Menicucci,and O.Pfister,"Weaving quantum optical frequency combs into hypercubic cluster states", arXiv:1309.4105[quant-ph] (2013)
7. R.Raussendorf, J.Harrington, and K.Goyal,"A fault-tolerant one-way quantum computer", Ann. Phys.(N.Y.) 321, 2242–2270 (2006)
8. T. F. Demarie, T. Linjordet, N. C. Menicucci, and G. K. Brennen, Detecting Topological Entanglement Entropy in a Lattice of Quantum Harmonic Oscillators, arXiv:1305.0409 [quant-ph] (2013)