Rigetti Computing has designed a microchip for quantum computers that would have more than six times as many qubits as Rigetti’s current 20 qubit machines. That would be more powerful than IBM’s 50-qubit computer and more powerful than Google’s 72-qubit machine. Rigetti is hoping to build a functioning computer with 128 qubits in the next 12 months. If successful, it could be the world’s most powerful quantum computer and just might have a chance of outpacing traditional supercomputers.
Simulating chemicals or organic molecules or machine learning acceleration could be the first applications.
IBM and Google due for announcement of doubling of qubits
IBM Research announced a 50 qubit quantum computer system in November, 2017. In a presentation in Sept, 2017, IBM indicated that they are doubling qubits every 8 months.
If IBM maintains an 8-month qubit doubling rate then they will announce a
100 qubit quantum computer in June, 2018 [IBM could have this in the lab and would be preparing to announce it]
a 200 qubit system in Feb, 2019 and
400 qubits in October 2019.
Similarly Google may be doubling the qubits of its 72 qubit machine.
Quantum Volume – Low error rates and high qubits are both needed
IBM Research introduced the concept of quantum volume. If we want to use quantum computers to solve real problems, the number of qubits is important, but so is the error rate. In practical devices, the effective error rate depends on the accuracy of each operation, but also on how many operations it takes to solve a particular problem as well as how the processor performs the operations.
The quantum volume measures the useful amount of quantum computing done by a device in space and time.
As we build larger quantum computing devices capable of performing more complicated algorithms, it is important to quantify their power. The origin of a quantum computer’s power is already subtle, and a quantum computer’s performance depends on many factors that can make assessing its power challenging. These factors include:
1. The number of physical qubits;
2. The number of gates that can be applied before errors make the device behave essentially classically;
3. The connectivity of the device;
4. The number of operations that can be run in parallel.
The quantum volume, to summarize performance against these factors.
D-Wave believes 5000 qubit system should provide quantum advantage
Vern Brownell, D-Wave Systems chief executive officer, believes quantum advantage, where quantum computers are faster than classical is perhaps less than 24 months away.