Pegasus is the first fundamental change in D-Wave’s architecture since the D-Wave One.
The D-Wave Two, 2X, and 2000Q all used the Chimera architecture, which had unit cells of K4,4 graphs. D-Wave machines added more qubits but the cells and architecture were mostly the same.
The Pegasus graph allows each qubit to couple to 15 other qubits instead of 6 qubits.
In mid-2018, D-Wave revealed that they had built 680 Pegasus qubit chip. The D-Wave 2000Q has 2048 Chimera qubits.
Where was D-Wave in 2018?
* annealing options
* reverse annealing
* quantum materials simulation
Where are they going?
* next generation processor – improved connectivity
* lower noise
* new Hamiltonian
D-Wave is lowering the noise by 5 to 10 times compared to their first machines. The D-Wave 2000Q is materials that are three times less noisy than their first machine. They are researching materials that are again another three times less noisy.
They have a P16 prototype with 5,640 qubits.
If you have a problem that needs a fully connected quantum system then you might only get the square root of the power of the total D-Wave qubits. This means in the worst case you would only get the power of about 45 qubits out of 2048 and only get 75 qubits out of 5,640. However, this worst case does not exist in most cases and the higher connectivity of the Pegasus architecture prevents or mitigates more of these and other limitations.
D-Wave could release the 680 Pegasus qubit chip as a product.
It would make sense for D-Wave Systems to try to make the 5,640 Pegasus qubit chip as a product.
Four to Nine Years Away From Interesting Level of Quantum Factoring Levels
Unless there are surprise breakthroughs we are about four to nine years away from an interesting level of quantum factoring levels. This would be when current financial encryption would be at serious risk of being broken by new quantum computing.
D-Wave Systems cannot implement Shor’s algorithm. However, they have implemented inverse multiplication in order to factor numbers. They had a 1000 times speed up in inverse multiplication by going from 512 qubits to 2048 qubits.