I've heard that you run up against the very large constant factors when comparing run times of quantum and classical computers -- things simply take much longer in a carefully controlled quantum setup than in a GHz CPU. So even though a quantum algorithm may have exponential speed-up, we will start with a big constant-factor disadvantage and only realize an actual speed-up once the problem is large enough that the scaling advantage overcomes the constant factor. But what are these constant factors? So this question is actually two:
- Are there already hypothetical durations of how long a continuous-variable gate would take on a continuous-variable quantum computer?
- What are these constant factors that makes the speed up for quantum algorithms on qc more difficult?