Seminar on Quantum Computing


   Testing Quantum Devices and Quantum Mechanics


   Prof Umesh Vazirani, EECS, UC Berkeley


   Room 501, Bharti Building


   Aug 26th 2016 4:00PM


The tremendous recent progress in the physical realization of devices based on the principles of quantum mechanics also throws up a fundamental challenge: how to test quantum devices, which are by nature imperfect and susceptible to uncontrollable faults. The classical verifier of such a device is necessarily at a disadvantage due to the exponential power of quantum systems, but nevertheless, an exciting sequence of results show that uniquely quantum features such as entanglement (Einstein's "spooky action at a distance") can be leveraged to make such testing possible. I will describe how such testing can thwart a malicious adversary in quantum cryptographic settings such as quantum key distribution and certifying quantum random numbers. More sophisticated such schemes can be used to verify that a quantum computer is truly quantum. At a conceptual level, such tests of quantum devices are really tests of quantum mechanics, that go well beyond the famous Bell tests that disproved Einstein's objections to quantum mechanics.

I will also describe a more pragmatic but principled approach to the testing of large scale quantum annealers - by performing a quantum Turing test comparing the quantum annealer to a suitable classical benchmark. I will discuss the results of applying such a test to the D-Wave 108 qubit quantum annealer, as well as the ~1000 qubit D-Wave 2X quantum annealer.

The talk will be accessible to broad audience of computer scientists,physicists and mathematicians.

Speaker Bio:

Umesh Vazirani is the Rogrer A. Strauch Professor of Electrical Engineering and Computer Science at the University of California, Berkeley, and director of the Berkeley Quantum Computation Center. He is one of the founders of the field of quantum computation, a recipient of the Fulkerson Prize in discrete math awarded by the American Mathematical Association, and author of the books “An Introduction to Computational Learning Theory'' with Michael Kearns, and "Algorithms" with Sanjoy Dasgupta and Christos Papadimitriou.