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 Centre (NV centre) and the Flux Qubit. We perform a series of the 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 centres 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 centre qubit and fidelity in the range of 0.82. The work thus establishes an effective simulation test protocol for different technologies to test and analyze them before experimental investigations or as a supplementary measure.Quantum computers have the potential to solve problems that scale up at polynomial time and are thus predicted to outperform classical computers in a wide range of tasks including machine learning 1 , complex simulations 2-14 and optimization problems 15 . However, to establish true quantum supremacy, there is a need to build and demonstrate universal fault tolerant and scalable computing systems that can extend beyond the capabilities of classical computational systems 16 . To accomplish this several different types of systems and architectures have been proposed and continue to be studied. More recently this has included the demonstration of hybrid systems which combine different complementary quantum device elements, often coupling a combination of a superconducting, atomic and or spin systems into a single circuit 17,18 . NV centres have been studied extensively for this purpose, this is because the spin states associated with the NV centre present a well-studied energy level splitting which can be readily accessed and addressed through both electrical and optical measurement techniques and are thus able to couple relatively easily to circuitry and other device components. It has already been shown that coupled NV centres and flux qubits 19,20 are ideal complimentary elements for such hybrid systems. As both these device elements rely on spin they can easily be coupled, and experimental investigations have demonstrated quantum information transfer between flux qubit and NV centre ensembles 19 . Additionally, NV centres present ideal quantum logic elements and have shown to be useful for a range of operations including as quantum registers and as quantum gates 21,22 . Due to their possibility of realizing fault tolerant logic operations holonomic quantum gates have been widely studied in various systems 21-27 but most notably wit...

In hybrid quantum systems a controllable coupling can be obtained by mediating the interactions with dynamically introduced photons. We propose a hybrid quantum architecture consisting of two nitrogen vacancy center ensembles coupled to a tunable flux qubit; that are contained on the transmission line of a multimode nonlinear superconducting coplanar waveguide resonator with an appended Josephson mixing device. We discuss using entangled propagating microwaves photons, which through our nonlinear wave-mixing procedure are made into macroscopically distinct quantum states. We use these states to steer the system and show that with further amplification we can create a similar photonic state, which has a more distinct reduction of its uncertainty. Furthermore, we show that all of this leads to a lengthened coherence time, a reasonable fidelity which decays to 0.94 and then later increases upward to stabilize at 0.6 as well as a strengthened entanglement.Hybrid quantum systems have emerged as a potential solution, due to the properties which the interface between the different components can provide as an open quantum system. 1,2 Nitrogen vacancy center ensembles (NVEs) have been of importance due to their ability to be coupled and their stability in an open system. [3][4][5][6][7][8] Various studies have been done involving them collectively coupled to a flux qubit (FQ). 9-11 This coupling can be extended beyond the strong coupling regime to ultrastrong domains. 12 But, with the addition of more qubits the system would not be completely robust.We use a modified superconducting coplanar waveguide resonator (CWR) as a multimode microwave photon quantum bus, [13][14][15][16] to which we apply quantum reservoir engineering, to create two-mode entangled microwave fields as the interaction medium. The microwave fields can be affected by the decoherence from the surrounding qubits, which make them less effective in transferring states within the system. One way to strengthen both the system and the microwave fields and make them less susceptible to dissipation is through transforming them into nonclassical states, 17-19 such as a coherent superposition state or Schrödinger cat state. 20 We look at the degree of squeezing applied and attempt to extend the work of Minganti et al. 21 and Hacker et al. 22 , which suggested the inherent squeezing of coherent cat states and a method of deterministically generating cat states. 23 We look at a Schrödinger cat-like state, which in our system. This state has been explored because of its ability to suppress noise, which can lead to more precise measurements, such as in quantum enhanced sensing. 24 In our study, we look at cases involving a systematic creation and distribution of coherent and squeezed coherent macroscopically distinct states by the multimode parametric waveguide 25-29 , and compare their functions and the resulting system metrics to make a comparison between them.The system under consideration as illustrated in Figure 1, contains two nitrogen-vacancy center ensemble...

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