Question 1

What is a quantum computer?

Accepted Answer

A quantum computer is a machine that performs its calculations byharnessing unique features of quantum physics. The most often quoted among suchfeatures are superposition and entanglement, but they are not sufficient togive a computational advantage over classical computers. Quantum computers needan extra feature called "magic", which prevents the computations frombeing efficiently simulated on a classical computers. Unfortunately, there isno layman-accessible way to explain such feature, and we prefer not to attemptusing metaphors that would likely provide a distorted description of the truth.

Question 2

What is a quantum computer good for?

Accepted Answer

A quantum computer is a machine that performs its calculations byharnessing unique features of quantum physics. The most often quoted among suchfeatures are superposition and entanglement, but they are not sufficient togive a computational advantage over classical computers. Quantum computers needan extra feature called "magic", which prevents the computations frombeing efficiently simulated on a classical computers. Unfortunately, there isno layman-accessible way to explain such feature, and we prefer not to attemptusing metaphors that would likely provide a distorted description of the truth.

Question 3

When will we have one?

Accepted Answer

We already have small-scale, noisy prototypes. They are extremelyuseful to flesh out the challenges to be overcome before building full-scale,error-corrected versions, and for learning how to compile algorithms and errorcorrection routines. Utility-scale quantum computers - defined as computerscapable of solving problems whose economic value exceeds the cost of buildingand operating the computer itself - are still some years away. A key objectiveof QPI is to deliver the breakthrough research that will accelerate the pathtowards utility-scale quantum computers.

Question 4

How can academic research compete with industry for the development of quantum computers?

Accepted Answer

It's not a competition. Academia and industry have different, complementary roles in the quantum computing ecosystem. Academic research, even with limited funding, has free range for exploration of novel ideas, fast prototyping of new devices, and openness of communication and collaboration. It can tackle challenges that are not of immediate concern, but might be show-stoppers a decade from now. Industry has the budget, the focus, and the infrastructure to turn such ideas into a technological revolution. The construction of utility-scale quantum computers requires deep synergy between academia and industry; our Centre of Excellence is a vehicle to cement and grow such synergy.

Question 5

What are the major scientific challenges that prevent us from having useful quantum computers?

Accepted Answer

The key scientific challenges that need to be addressed in thenext decade can be divide in three groups. 1) Better quantum hardware. We needto reduce the physical error rate of the quantum hardware by a few orders ofmagnitude compared to the current state of the art, in order to allow thecomputer to perform useful calculation from beginning to end, without crashing.2) Better quantum codes. Much of the effort in running a quantum computer liesin applying quantum error correction codes that clean up the errors occurringduring the operations. Existing codes demand exorbitant hardware overheads,which are not sustainable or economical in the long term. 3) Betterconnectivity. Deeply intertwined with the previous challenges, strongconnectivity between physical qubits can enable more efficient quantum codes,as well as provide a multiplicative effect on the computational power of themachine.

Addressing these three challenges with breakthrough research isthe key mission of QPI.

Question 6

Would it be better to focus all research efforts on a single hardware platform, or diversify?

Accepted Answer

We are far from the stage where there exists a clear"winner" in quantum computer hardware. In fact, in the past year wehave observed big industry players, who spent a decade focussing a singleplatform, starting to diversify their technology. Academic research continuesto produce breakthrough ideas that offer new avenues for hardware development.It is a very exciting time for creative research in quantum computing.

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