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January 21, 2007

Dwave roadmap has well over 1000 qubits by end of 2008

Dwave systems has a current roadmap with well over 1,000 by the end of 2008.

There are some quantum algorithms that can’t be run using the current architecture. The technical reason for this is that the devices that couple qubits i and j are of the \sigma_z^{i} \sigma_z^{j} type. There are some 16-qubit states that can’t be generated with the X + Z + ZZ Hamiltonian. Their roadmap includes the addition of an XZ coupler to their architecture, which will make their systems universal. The reason for doing this is that they plan to build processors specifically for quantum simulation, which represents a big commercial opportunity.


The current plan is to first focus on successful deployment of the X+Z+ZZ type system. Many of the hard problems in operating a X+Z+XZ type machine can be resolved in our current approach. We already have a couple good XZ coupler designs, but we probably won’t start a processor line with these until the current line’s off the ground. Our roadmap has us introducing a quantum simulation processor line in 2009.

About the scaling question: There’s no straightforward way to predict this. These systems are too complex and implementation-specific to know for sure. We will get to (and far past) the 1,000 qubit mark relatively shortly. Whether the systems will retain their current quantum behavior is unknown, but we haven’t seen anything that gives me concern about this. Part of this issue has to do with how the quantum computer is being used. The AQC approach is naturally shielded from errors in a way that the gate model isn’t, so whatever you’ve heard about error correction etc. take with a grain of salt, often these things are computational-model specific (although many people speak of them as if they were universal).


NOTE: 1000 qubits would enable 2**1000 states or about 10**300.
10**80 is the number of atoms in the observable universe
The 2009, 1000+ qubit quantum simulation processor would be a big boost for molecular nanotechnology research.

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