Abstract

In this talk I will present a series of experiments in the field of photonic quantum information processing. In the first part of the talk, I will show how quantum physics enables us to perform secure computations in quantum networks [1]. I will present experiments realizing both quantum and classical secure delegated computations using quantum resources. In the quantum case, this means that a nearly-classical client can access the resources of a more powerful quantum server without divulging the content of the requested computation [2, 3]. Furthermore, in the classical case, a classical client with limited computing capacity can delegate a classical computation securely using non-classical resources [4]. In the second part of the talk, I will discuss multi-photon interference, both in the context of fundamental quantum optics and in quantum information processing. I will present an experiment, which studies the interference of multiple photons at multiport splitters. I will further give examples how such setups can be used for quantum information processing tasks.

[1] A. Broadbent, J. Fitzsimons and E. Kashefi, in Proceedings of the 50th Annual Symposium on Foundations of Computer Science, 517 (2009) [2] S. Barz, E. Kashefi, A. Broadbent, J. Fitzsimons, A. Zeilinger, and P. Walther, Science 335, 303 (2012) [3] S. Barz, J. Fitzsimons, E. Kashefi, and P. Walther, Nature Physics 9, 727 (2013) [4] S. Barz, V. Dunjko, F. Schlederer, M. Moore, E. Kashefi, I. A. Walmsley, arXiv:1501.06730 (2015)