Experimental simulation of hybrid quantum systems and entanglement on a quantum computer

We propose the utilization of the IBM Quantum Experience quantum computing system to simulate different scenarios involving common hybrid quantum system components, the nitrogen vacancy center (NV center), and the flux qubit. We perform a series of simulation experiments and demonstrate properties of a virtual hybrid system, including its spin relaxation rate and state coherence. In correspondence with experimental investigations, we look at the scalability of such systems and show that increasing the number of coupled NV centers decreases the coherence time. We also establish the main error rate as a function of the number of control pulses in evaluating the fidelity of the four qubit virtual circuit with the simulator. Our results show that the virtual system can attain decoherence and fidelity values comparable to what has been reported for experimental investigations of similar physical hybrid systems, observing a coherence time at 0.35 s for a single NV center qubit and fidelity in the range of 0.82. This work thus establishes an effective simulation protocol to test and evaluate different technologies as a supplementary measure that complements their experimental operation.