What is Hybrid Quantum Computing?
Hybrid can mean a combination of Classical and Quantum Computing. Though some people use Hybrid Quantum Computing to signify Discrete (Qubits Based) and Continuous Variable (Photon Based) Quantum Computing.
1 – Hybrid Classical & Quantum Computing
Companies like D-wave are all gung ho about Hybrid Quantum Computing. They have solvers which can solve lets say 100-300 variable problems. And using a layer of Classical Computing on top of it they attempt to solve problems that are way larger, say 1,000 – 2000 variables.
*** Please note we said 1000 ‘variables’ not Qubits. a 1000 variable problem requires N^2 or even N^3 qubits which means a real world 1000 variable problem might require 1000,000 qubits or 1000,000,000 qubits.
2 – Hybrid Discrete & Continuous Variable Computing
Well Qubits have two basis states |0> and |1> and they exist in a super position of both these states. Thats Discrete Quantum Computing.
Qubits made from things like Photons or Magnetic Fields can have Continuous Variables.
Why would anyone use that? Its way more complex and non-intuitive.
Because CV Quantum Computing promises exponential acceleration of computation. Thats why.
“DV and CV encoding have distinct advantages and drawbacks,” says Hugues de Riedmatten of the Institute of Photonic Sciences in Barcelona. CV systems encode information in the varying intensity, or phasing, of light waves. They tend to be more efficient than DV approaches but are also more delicate, exhibiting stronger sensitivity to signal losses. Systems using DVs, which transmit information by the counting of photons, are harder to pair with conventional information technologies than CV techniques. They are also less error-prone and more fault-tolerant, however. Combining the two, de Riedmatten says, could offer “the best of both worlds.”
So proponents of Hybrid Discrete & Continuous Variable Computing say that they can build Quantum Computers using Photons which can use both Discrete Qubits and Continuous Variable Quantum Computing. And combining the benefits of both. Achieving Nirvana.
At Automatski we believe in solving the low hanging fruit first. Nobody outside Automatski has a working quantum computer (Well, crapware and vaporware aside).
So basically lets put all our money and efforts in building a Discrete Qubit based Quantum Computer before fantasizing about Type 2 Hybrid Quantum Computing. DQQC is Universal so it would be quite an achievement if done. And then we can worry about Type 2 Hybrid Quantum Computing.
As far as Type 1 Hybrid Quantum Computing is concerned. Hybrid Classical + Quantum Algorithms can be proven that they will ‘NEVER’ deliver a perfect solution. In the near term Quantum Computing it might help us solve bigger problems. But in any case it will work only to give us approximate solutions. Which are way off from the global perfect solutions. But something is better than nothing.