Quantum Collapse-revival Effect And Path-Level Entanglement In A Multiphoton Jaynes-Cummings Model

The interaction between photons and matter plays a key role in modern physics.One of the most interesting and important models that described the interaction between electromagnetic waves and atoms is the Jaynes-Cummings model(JCM),which describes the interaction of two level atoms with a single mode of quantized electromagnetic fields.JCM is exactly solvable in rotating wave approximation and can be applied to investigation of many quantum optical effects such as quantum Rabi oscillations,atomic population-inversion quantum collapses and revivals,atom-photon polariton entanglement,photon antibunching,cavity quantum electrodynamical effects,radiation field squeezing,and so on.One of the crucial features of JCM is quantum collapses and revivals,which directly reflects the quantum nature of the light fields involved in the interaction.In the JCM,only one photon can be emitted or absorbed by the atom when the atomic level transition occurs.But under certain conditions relevant to quantum nonlinearity,multiphoton transition would also take place in atomic level evolution.In this sense,the single-photon JCM is generalized to a multiphoton-transition model,which exhibit a supersymmetric Lie algebra structure in its Hamiltonian.Supersymmetry is a symmetry relates fermions and bosons,such symmetry proposes that to each fermion there exists a corresponding boson and vice versa.Thus we define a fermion type and a boson type of photon-atom quantum states.If the frequency detuning is zero,the fermionic state and the bosonic state have exactly the same energy eigenvalue and the system is invariant under supersymmetry.We address the quantum collapses and revivals in atomic population inversion driven by different quantum light fields.The collapse-revival pattern can persist for extremely long times under certain circumstances.We expect that the characteristics of quantum collapses and revivals in such a quantum optical system could be of certain significance in design of quantum computing devices,e.g.qubits and quantum logic gates.We show that for a moving atom,because of Doppler effect and the relativistic electromagnetic induction for the incident optical field,there appears equivalent gauge vector potentials induced by the multiphoton transition.In addition,we shall consider the interaction among atom paths,atomic internal levels and the photon field.Such a coupling leads to an atomic path-level-photon entangled state,and the traditional atomic-level quantum Rabi oscillation and quantum collapse-revival effect that occurred in time domain would be exhibited in the atom spatial wavefunctions(or in atomic paths).In addition,by using the law of conservation of electromagnetic angular momentum,the spin current density tensor of a general electromagnetic field is derived.Thus we obtain the spin current density tensor of surface plasmon polaritons.The plasmonic spin on a metal ring and a straight thin metal belt is calculated,and based on this,a nanomechanical effect caused by plasmonic spin current transfer is suggested.It is expected that such a nontrivial nanomechanical effect will be useful in the design of new nanophotonic devices aiming at sensitive,accurate measurement techniques.