Centre updates

CQC2T researchers (Griffith Uni) report Big Bell Test work in Nature

CQC2T researchers at Griffith University have played an important role in a major international collaboration that tested quantum nonlocality – Einsten’s “spooky action at a distance” – in a suite of experiments worldwide. Nonlocal effects such as entanglement underlie the quantum computation and communication technologies being pursued in CQC2T. The joint work of the “Big Bell Test” (BBT) consortium, published in Nature today (https://www.nature.com/articles/s41586-018-0085-3) , used random numbers sourced from people’s free will to rigorously ensure unpredictability in the measurement settings required for such tests. The project used an online game through which members of the public provided random numbers to the experiments in real time. Thus, the project is a flagship for new approaches to citizen involvement in science, and for science outreach.

The Griffith University team, led by Dr Raj Patel and Professor Geoff Pryde, performed a test of "quantum steering” as part of the BBT. Steering is a practical form of quantum non-locality testing that is resistant to real-world device imperfections, and has direct application to quantum communication tasks such as verifying that entanglement has been shared between remote parties. Pryde said, “One of the things that was exciting and really interesting for us was to be part of a big project that required a large amount of coordination. From compiling random numbers from the public to disseminating them between the experiments, and receiving and using them in a timely way, the level of collaboration was remarkable. I also particularly enjoyed the outreach and public involvement side; I enjoyed that we gave people an opportunity to do something which influenced how the experiment ran.”


CQC2T CI Prof Michael Bremner (UTS) co-authors Nature Physics paper on quantum supremacy

CQC2T CI Prof Michael Bremner (UTS)

CQC2T CI Prof Michael Bremner (UTS) links with Google, NASA, UCSB on Nature Physics paper to try to define when quantum computers will overtake classical computers. The researchers said that quantum computers would need almost 50 qubits to process information exponentially faster than a classical supercomputer.

UTS said the first research marks the first clear attempt to identify a benchmark at which quantum computing will surpass the capability of classical computers - which is known as quantum supremacy.
Chief investigator of the UTS branch of the ARC Centre for Quantum Computation and Communication Technology, Professor Michael Bremner, said the line was difficult to define because the advantages offered by quantum computers can be subtle.

“Some applications can have an exponential quantum speed-up over classical computers, while others receive no benefit at all,” he said.
“Understanding when quantum computers become useful is essential, especially when we are limited to using the noisy intermediate-scale devices that currently exist.

“We attempted to find the frontier between classical and quantum computing. We wanted to find the smallest quantum circuits that can do something that cannot be done at all on a classical computer.”