Mainz 2017 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 55: Quantum Computing II
Q 55.4: Talk
Friday, March 10, 2017, 15:15–15:30, P 2
Continuous-Variable Instantaneous Quantum Computing is hard to sample — Tom Douce1,2, Damian Markham1, Elham Kashefi1, Eleni Diamanti1, Thomas Coudreau2, Perola Milman2, Peter van Loock3, and •Giulia Ferrini2,3 — 1Lip6, UPMC-Sorbonne Universités, 4 Place Jussieu, 75005 Paris, France — 2Laboratoire Matériaux et Phénomènes Quantiques, Sorbonne Paris Cité, Univ. Paris Diderot, CNRS UMR 7162, 75013, Paris, France — 3Institute of Physics, Johannes-Gutenberg Universität Mainz, Staudingerweg 7, 55128 Mainz, Germany
Instantaneous Quantum Computing (IQP) is a sub-universal class of quantum circuits composed of Pauli-X eigenstates, gates diagonal in the Pauli-Z basis, and Pauli-X measurements [1]. We translate this class of circuits to Continuous-Variables (CV). Using the correspondence between universal sets of gates [2], we define CV IQP circuits as composed of input momentum-squeezed states, gates diagonal in position and homodyne momentum measurements. We analyse their computational power by studying post-selected circuits [1], and we prove that CV IQP circuits are hard to sample [3]. In order to deal with post-selection we consider finite resolution homodyne detectors. Finite squeezing in the input squeezed states is treated by adding to the model ancillary GKP states and by relying on a GKP encoding of quantum information [4].
[1] M. J. Bremner, R. Josza, and D. Shepherd, Proc. R. Soc. A 459, 459 (2010). [2] M. Gu et al, PRA 79, 062318 (2009). [3] T. Douce et al, arXiv:1607.07605 (2016). [4] N. C. Menicucci, PRL 112, 120504 (2014).