Barz, Stefanie
Date: Wednesday August 28, 2013
Time: 11:00
Place: ETH Science City, HPF G6
Host: Andreas Wallraff
Photonic quantum computing
Stefanie Barz
University of Vienna, Austria
Quantum physics has revolutionized our understanding of information processing and enables computational speed-ups that are unattainable using classical computers. In this talk I will present a series of experiments in the field of photonic quantum computing.
The first experiment is in the field of photonic state engineering and realizes the generation of heralded polarization-entangled photon pairs [1]. It overcomes the limited applicability of photon-based schemes for quantum information processing tasks, which arises from the probabilistic nature of photon generation.
The second experiment uses polarization-entangled photonic qubits to implement blind quantum computing, a new concept in quantum computing [2, 3]. Blind quantum computing enables a nearly-classical client to access the resources of a more computationally-powerful quantum server without divulging the content of the requested computation.
A third experiment shows how the concept of blind quantum computing can be applied to the field of verification. A new method is developed and experimentally demonstrated to verify the entangling capabilities of a quantum computer based on a blind Bell test [4].
Finally, I will present an experiment realizing a measured universal two-qubit photonic quantum processor by applying two consecutive CNOT gates to the same pair of polarization-encoded qubits. To demonstrate the flexibility of our system, we implement various instances of the quantum algorithm for the solving of systems of linear equations [5].
[1] S. Barz, G. Cronenberg, A. Zeilinger, and P. Walther, Nature Photonics 4, 553 (2010)
[2] A. Broadbent, J. Fitzsimons and E. Kashefi, in Proceedings of the 50th Annual Symposium on Foundations of Computer Science (2009), 517–526.
[3] S. Barz, E. Kashefi, A. Broadbent, J. Fitzsimons, A. Zeilinger, and P. Walther, Science 335, 303-308 (2012)
[4] S. Barz, J. Fitzsimons, E. Kashefi, and P. Walther, submitted
[5] S. Barz, I. Kassal, M. Ringbauer, Y. O. Lipp, B. Dakic, A. Aspuru-Guzik, P. Walther, arXiv:1302.10