超导电路凭借其可扩展性、易调节、相干性好等诸多优点，成为实现量子计算最有潜力的物理平台之一，近些年获得了飞速的发展和广泛的关注。单光子源是实现微波光量子计算的基础元件，至关重要。实现微波光子纠缠是微波量子计算的一个重要步骤。金刚石氮空位色心具有非常好的相干性，使得其在量子计算中表现优异，也是实现量子计算的非常好的平台。本博士论文主要在基于超导量子系统单光子源的构建、单光子纠缠态产生和基于NV系统的量子门构建取了一些创新型成果：
一、我们提出了基于超导系统实现可拓展的多路同步单光子源的方案。电路的结构为多个超导量子比特与一个共同的超导谐振腔耦合，腔与比特的频率大失谐。通过对腔的控制可以间接实现对所有量子比特的同步控制，完成对量子比特的同步激发，同步释放，实现同步单光子源。量子比特之间的有效关联非常的微弱，使得量子比特的行为同步的同时却又相互独立，释放的光子完美继承这一特性，保证了集成后的单光子源具有特别高的不可区分性。由于比特的有效驱动远大于光子的释放速度，比特的二次激发及单个通道中的多光子概率被有效抑制，保证了得到的单光子具有非常高的纯度。基于现有实验参数，我们实现的光子源的纯度、不可区分性、效率都高于$99\%$，且速率达到$\sim $MHz量级。当系统实现30个单光子同步发射，光子源的效率依旧高于$80\%$，速率仍旧可以达到数百kHz。 这已经比现有的用于实现波色采样的复用光子源的效率高了几个数量级。这为实现可扩展的确定性多光子源开辟了一条很有希望的道路。
二、我们提出了一种基于高品质超导谐振器实现高保真度量子纠缠的超导电路。在该电路中，两个高品质谐振腔通过穿过高频谐振腔\,(量子总线)\,两端的超导量子干涉器件\,(SQUID)\,的磁场耦合。每个高品质腔和总线之间的耦合强度可以通过穿过SQUID的外部通量独立地从零连续地调整到强耦合状态。在电路中，高品质腔与总线大失谐，保证储存在高品质腔中的量子信息不会布居到高泄漏率的总线上。总线可以同时与多高品质腔连接实现大规模量子计算。基于我们的电路，我们提出了一个可以实现两个高品质腔高保真度纠缠态产生的方案。在纠缠态产生过程中，我们不需要对耦合强度进行快速调谐或者同时打开或关闭，这使得我们的电路可以更有效地克服串扰问题，使之在大规模量子计算中具有更高的潜力。
三、我们提出了利用错误探测机制基于NV和光子系统实现鲁棒性高保真度通用量子门的方案。通过探测器对与NV相互作用后的光子输出通道进行探测，将光子与NV的不完美输入输出造成的错误规避。当系统在输出错误的通道探测到光子，那么系统的量子态将被投影到错误的量子态上。对系统做适当幺正操作便可重启系统,而不需要对系统重新初始化。原则上，即使光子与NV的在弱耦合的情况下，量子门依旧可以保持较高的保真度和不太低的效率。

Superconducting circuit has become one of the best candidates for quantum computing since its great performance in scalability, tunability, coherence. It has attracted wide attention and meet its fast growth in recent years. Single-photon source is of vital importance working as the fundamental unit in photonic quantum computing. It is a key step for microwave photonic quantum computing that entanglement construction between microwave photons. The nitrogen-vacancy colour center in diamond is also a very good candidate for quantum computing for its terrific coherence property. In this context, the present thesis proposes several innovative achievements in quantum setups, including single-photon source, entanglement generation, and quantum gates, for quantum computing with superconducting circuit or NV centers.
(1) We propose a scalable scheme to efficiently synchronize and multiplex deterministic single-photon sources. The key idea is to couple multiple emitters to an off-resonant cavity and use this common mode as the synchronizing element which triggers all sources simultaneously. Each emitter is additionally coupled to individual channels, which efficiently collect the emitted photons for later usage. Cavity-induced correlations are small for sufficiently fast sources, allowing the multiplexing error to scale only quadratically with the number of sources. Therefore, the device can emit a large number of nearly independent single-photons on-parallel and on-demand. For a state-of-the-art circuit QED implementation, we show the feasibility to generate microwave single-photons with purity, indistinguishability, and efficiency of $99\%$ at fast rates of $\sim $MHz. Due to the favorable scaling of the device, we show a 30-photon generation with efficiency above 80\% and a rate of hundreds of kHz, which is orders of magnitude more efficient than available multiplexed sources, for boson sampling, for instance. This opens a promising route towards scalable and deterministic multi-photon sources.
(2) We propose a quantum circuit implementing high-fidelity photonic entanglement between high quality resonators. Two high-quality resonators coupled to a common high-frequency resonator(quantum bus) via the flux threading through the superconducting quantum interference device (SQUID) in the two ends of the bus.  The coupling between each high-quality resonator and the bus can be tuned from zero to strong independently via the external flux. The large detuning between resonator and bus ensures the information in the resonator will not populate in the bus, which has large decay rate. The good connectivity between bus and resonators makes it possible realizing large scale quantum computing with our circuit. We propose a scheme to a generate high-fidelity entanglement state between resonators with our circuit. In the process, fast tuning on the coupling is no longer mandatory and neither the requirement that simultaneously turning on or off the coupling. This makes our circuit effectively overcome the cross-talking, and lead the route to the use in large quantum computing.
(3) we propose a scheme for robust universal quantum gates with high-fidelity working on NV and photon system using error-detect method. The error due to the imperfection of the practical input-output process is avoided via the detection of the photon from the output-channel of the NV system. The state of the system is projected to the error-state when a photon trigger a detector heralding for wrong information. The quantum gates can be restarted after several unitary operations without reinitialization. In principle, the quantum gate still work well with high-fidelity and not-so-low efficiency in weak coupling regime.