Theory Research Of Solid-State Spin System Coupling With Photon And Application

Quantum information has attracted more and more attention due to its unique properties and powerful information processing capabilities.The scheme of solid-state spin quantum system coupling to the photon becomes popular candidates,because it combines the long coherence time and integration of spin qubit and flexibility of photon.In this paper,we consider the scheme of solid-state spin quantum system coupling to the photon,analyzing and simulating the theoretical model and specific applications.It mainly discusses two aspects:first,measurement of spin qubits by the photon,including the dispersive measurement methods,studies of measurement dynamics,and fast high-fidelity measurement.Second,the establish of quantum architecture,including the spin-photon modules for a quantum network,preparing spin qubits entanglement on a chip,and multi-functional node for quantum communication based on rare-earth ions.The main content of this paper includes:1.We briefly introduces the research background of quantum information and some quantum concepts which will be used in this article.We also list some physical implementation schemes of solid-state spin systems.In addition,we explain the network architecture in quantum architecture.2.Taking single-triple spin qubits as an example,we design a scheme for measuring spin quantum states by using photons.We simulate the evolution process by solving the master equation and equation of motion,which shows the change of spin qubit spectrum under different external magnetic fields and exchange energy.At the same time,the change of the measurement signal under the different logic gate operations is studied.3.The dynamics of spin qubit measurement are further studied.By adjusting the detuning and tunneling rate of spin qubit,the control of transverse coupling and longitudinal coupling is achieved.We analyze the decoherence effect during the system evolution and the signal-to-noise ratio during the readout.Using the equation of motion to numerically simulate the evolution of the system over time under different parameters,we found that by adjusting the operating parameters,the optimal working points of the readout signal can be obtained,which improves the efficiency and fidelity of the measurement.4.We design a new measurement scheme.By adjusting the power of the measurement microwave and the frequency of the spin qubit,the measurement process is divided into three parts:catch,disperse,and release,which not only greatly reduces the measurement time,but also achieved high fidelity of measurement.In addition,our schemes can also be used to obtain the noise spectrum of spin qubits,which is great helpful for understanding and suppressing decoherence.5.Starting from the spin-photon basic module,we realize the preparation of controllable waveform single photons through designing the drive pulses of spin qubit.Using single photons as "flying bits",the deterministic quantum state transfer and the preparation of entangled states between different node modules is achieved.We found that both the fidelity of the quantum state transfer process and the entanglement fidelity can well reach the threshold of the error correction protocol and meet the indicators and conditions for constructing a quantum network architecture.6.We analyze the coupling model of the two spin qubits and resonator,and design the microwave driving pulse in the parity measurement.By using the stochastic master equation to simulate the evolution of the system,the different parity states of the spin qubit are successfully distinguished.In addition,parity measurement can also be used to prepare the on-chip Bell states of spin qubits.By applying a feedback regulation to the final spin states,a deterministic entangled state can also be obtained7.Starting from rare earth doped ions,we design a multi-functional quantum communication node due to its unique properties.We also propose a scheme for constructing the quantum network,including four steps:electron spin entanglement,state transfer between electron spin and nuclear spin,entanglement state purification,and the network construction.At the same time,we design the proof of principle experiment of the quantum network architecture and give the experiment parameters.The main innovations of this paper are:1.Using the coupling system of spin qubit and photon,the dispersive measurement of spin qubit spectrums and logic gate operations is realized,which provides a new idea for spin qubit measurement.2.The adjustable coupling between spin qubit and photon is realized.We analyze the dynamics of the measurement process in detail,and found the optimal working points by adjusting the parameters,which improves the quality of measurement effectively.3.A new microwave pulse of measurement is designed,which eliminates the Purcell effect effectively and achieves the fast and high fidelity measurement of spin qubits.It is of great significance to the realization of quantum error correction.4.Taking the spin-photon module as the basic unit,quantum state transfer and entangled state generation between different nodes are realized.Furthermore,a scalable quantum network architecture is constructed.5.The coupling model of two spin qubit and resonator is designed,we realize the deterministic entanglement preparation and measurement between on-chip spin qubits by parity measurement.6.Taking rare-earth doped ions as multi-functional node carriers,we propose a new scheme for constructing quantum network architecture,and design a proof-of-principle experiment,which advances the research of quantum network communication.