Quantum Precision Measurement And Control Based On Cavity Quantum Electrodynamics

Quantum mechanics has developed from a speculative science in physics to a technical science today.Quantum technology is the key element to the next generation of technological revolution,mainly including quantum information,quantum simulation,quantum control,and quantum precision measurement.As physics is an experimental science,quantum precision measurement,as an emerging discipline,can use quantum resources such as entanglement and compression to break through the measurement precision limit imposed by classical rules,which is crucial for further advancing physics.Quantum control predicts the motion laws of the microcosm and realizes the manipulation of quantum substance states such as photons,atoms,and spins,thus regulating and utilizing quantum phenomena,which are also indispensable for the construction of quantum devices and the development of quantum computation.In this context,this thesis will explore the influence of atoms on quantum precision measurement and quantum control.The thesis is divided into six chapters,with Chapters 3,4,and 5 being the main research contents,as follows:In chapter 1,we introduce the background and significance of this thesis.We introduce the development process from quantum mechanics to quantum optics,and furthermore to quantum science and technology,emphasizing the importance of quantum control and quantum precision measurement.In chapter 2,we introduce the basic concepts and principles required in this thesis.First,we introduce the Jaynes-Cummings model in quantum optics,and derive the dynamic process of the model.Then,by arraying optical cavities,the main equation for the atom in a cavity array environment is derived.We also introduce the SSH model,to discuss the winding number of SSH chain and the boundary-bulk relation.In quantum precision measurement,we first introduce classical Fisher information and extend it to quantum Fisher information(QFI).Then we give an approach to the parameter to via unitary parameterization.At last,we introduce error transfer formula which can be used to obtain the accuracy of the estimator and compare it with the QFI.In chapter 3,we obtain the master equation for the model in which a series of identical two-level atoms randomly pass through and interact with the cavity mode by using heat reservoir theory in quantum optics.In steady-state light field,we find that the average photon number is related to the coupling intensity of light and atom.By using of the error transfer formula,we find that measuring accuracy of the coupling intensity can achieve the Heisenberg limit.Finally,the steady state light field is analyzed by using Gaussian state method.In chapter 4,we study the coupling model between rotating Whispering-GalleryMode(WGM)optical resonators and large detuned two-level atoms.In this model,we construct SU(2)algebras via adiabatic elimination method,and obtain the optical microcavity interferometer,demonstrating that the measurement precision of rotation can reach the Heisenberg limit.We find that the effective coupling between two modes induced by the atom encodes the rotating information in both phase and amplitude during the dynamical process.On the basis of this model,by introducing Kerr nonlinearity,we got the Bose-Hubbard model.We further find that the accuracy of the parameter estimation can even break the Heisenberg limit in the large photon number case with the assistance of nonlinear interaction.This enhancement is associated with the compressibility of the state distribution.By introducing probe atoms or analyzing the dynamics of the SSH chain,we predicted the observation of the zero mode in experiments.Finally,we analyzed the robustness of the zero mode against disorder,atomic dissipation,asymmetric coupling,and next-nearest-neighbor coupling.On the other hand,we analyzed the effect of topological waveguides as the environment on giant atoms,solved the master equation of the giant atoms at nonzero temperatures,and numerically analyzed their non-Markovian dissipation dynamics in topological waveguides.In Chapter 5,we study a SSH waveguide which couples to a giant atom.On the one hand,we discuss the influence of the giant atom on the SSH chain.We analytically solved the energy spectrum and eigenstates of the system,and our analysis shows that the giant atom constitutes the effective boundary of the SSH chain.As the non-Bloch winding number is defined under the open boundary condition,we calculate the Bloch winding number of the SSH chain at this boundary.In addition,we also study nontrivial degeneracy lifted to explain the anomalies of energy spectrum.By introducing a probe atom or analyzing the SSH chain dynamic,we predict that zero mode can be observed experimentally.Finally,we analyze robustness of zero-mode to the disorder,atomic dissipation,asymmetric coupling,and next-nearest neighbor coupling.On the other hand,we analyze the influence of topological waveguides which plays as an environment on the giant atom.We derive the master equation of the giant atom at non-zero temperature and numerically analyze the non-Markov dissipation dynamics of the giant atom in the topological waveguide.In chapter 6,we make a summary and outlook.The interaction between atoms and the light of the microcavity is an important topic in quantum optics research.This thesis mainly studies the cavity quantum electrodynamics(cavity QED)system coupled with atoms-from a single-mode microcavity system to a double-mode microcavity system,and then to a coupled cavity array system.Using analytical and numerical results,we reveal the role of these systems in quantum precision measurement and quantum control.