Entanglement Dynamics of Two Atoms in a Double Damping Jaynes-Cummings System

The entanglement between two stationary qubits is a kind of valuable quantum resources in quantum information or quantum network. This paper investigates the time evolution of the entanglement between two atoms,which are initially prepared in the Bell states and each of which interacts with its own cavity field in the identical and non-identical double damping Jaynes-Cummings(J-C) system. It mainly considers the effect of the atomic spontaneous decay Γ and the decay of cavity field κ on the two-qubit entanglement in such system. While causing the decay of entanglement, Γ and κ can also play a positive role in the entanglement evolution, which may imply a way to better control and maintain the entanglement. What is more, the rules governing the transfer of entanglement between two-qubit subsystems in strong coupling regime are finally studied by taking Γ and κ into consideration.     

Constraints on neutron skin thickness and symmetry energy of ~(208)Pb through Skyrme forces and cluster model

We used the cluster structure properties of the 212Po to estimate the neutron skin thickness of 208Pb.For this purpose,we considered two important components:(a)alpha decay is a low energy phenomenon;therefore,one can expect that the mean-field,which can explain the ground state properties of 212Po,does not change during the alpha decay process.(b)212Po has a high alpha cluster-like structure,two protons and two neutrons outside its core nucleus with a double magic closed-shell,and the cluster model is a powerful formalism for the estimation of alpha decay preformation factor of such nuclei.The slope of the symmetry energy of 208Pb is estimated to be 75±25 MeV within the selected same mean-fields and Skyrme forces,which can simultaneously satisfy the ground-state properties of parent and daughter nuclei,as their neutron skin thicknesses are consistent with experimental data.     

Theoretical Prediction of Differential Cross Sections for Reaction pp → pK^＋A in a Resonance Model

The reaction of pp → pK^＋A is a very good channel to study N^＊ resonances through their KA decay mode, because there is no mixing of isospin I = 1/2 and I = 3/2 due to isospin conservation. In this work, we extend a resonance model, which can reproduce the total cross section very well, to offer differential cross section information about this reaction. It can serve as a reference to build the scheduled hadron detector at Lanzhou Cooler Storage Ring （CSR）. Experiment measurement of these differential cross sections in the future will supply us more constraints on the model and help us understanding the strangeness production dynamics better.     

A simple scheme for implementing four-atom quantum dense coding in cavity QED

An experimentally feasible scheme for implementing four-atom quantum dense coding of an atom--cavity system is proposed. The cavity is only virtually excited and no quantum information will be transferred from the atoms to the cavity. Thus the scheme is insensitive to cavity decay and the thermal field. In the scheme, Alice can send faithfully 4 bits of classical information to Bob by sending two qubits. Generalized Bell states can be exactly distinguished by detecting the atomic state, and quantum dense coding can be realized in a simple way.     

Theoretical Prediction of Differential Cross Sections for Reaction pp → pK Λ in a Resonance Model

The reaction of pp → pK Λ is a very good channel to study N* resonances through their KΛ decay mode, because there is no mixing of isospin Ⅰ = 1/2 and Ⅰ = 3/2 due to isospin conservation. In this work, we extend a resonance model, which can reproduce the total cross section very well, to offer differential cross section information about this reaction. It can serve as a reference to build the scheduled hadron detector at Lanzhou Cooler Storage Ring (CSR). Experiment measurement of these differential cross sections in the future will supply us more constraints on the model and help us understanding the strangeness production dynamics better.     

A scheme for transferring an unknown atomic entangledstate via cavity quantum electrodynamics

In this paper, we propose a scheme for transferring an unknown atomic entangled state via cavity quantum electrodynamics (QED). This scheme, which has a successful probability of 100 percent, does not require Bell-state measurement and performing any operations to reconstruct an initial state. Meanwhile, the scheme only involves atom--field interaction with a large detuning and does not require the transfer of quantum information between the atoms and cavity. Thus the scheme is insensitive to the cavity field states and cavity decay. This scheme can also be extended to transfer ring an entangled state of $n$-atom.     

New physics search in the doubly weak decay ■→K~+π~(-*)

The doubly weak transition b-dd■ is highly suppressed in the Standard Model,which makes it a potential channel for exploring new physics signals.We present a study of the exclusive two-body wrong sign weak decay ■→K+π-,which belongs to this class,in the perturbative QCD framework.We perform a model independent analysis for various effective dimension-6 operators for which large effects are possible.We further analyze the considered process in the Randall-Sundrum model,including the custodially protected and the bulk-Higgs Randall-Sundrum models.Exploring the experimentally favored parameter space of these models leads to a large and significant enhancement of the decay rate compared to the Standard Model,which might be accessible in future experiments.We propose to search for the wrong sign decay ■→K+π-via flavor-tagged time-dependent analyses,which can be performed at LHCb and Belle-Ⅱ.     

Dynamic properties of atomic collective decay in cavity quantum electrodynamics

We theoretically study the collective decay of two atoms trapped in a single mode cavity and we describe the evolution of the population of Dicke states. We show that the collective decay property is strongly dependent on the phase of atomic radiation and the speeding up of collective decay can only be observed in a bad cavity regime. For in-or out-phase case,this occurs due to the quantum interference enhancement, no matter which atom is excited initially. For π/2 phase, the speeding up of collective decay takes place if the first atom is excited at the beginning. However, it disappears due to the quantum interference cancellation if the second atom is excited. Compared with the in-phase and out-phase cases,we also show that the speeding up of collective decay can be significantly enhanced in strong coupling regime for π/2 phase, although one atom is decoupled to the cavity in this condition. The study presented here is helpful to understand the physical mechanism of collective decay in cavity quantum electrodynamics and it provides a useful method to control the collective decay phenomenon via quantum interference effect.     

Scheme for Generalized Quantum State Sharing of a Single-Qubit State in Cavity QED

An experimentally feasible scheme for generalized quantum state sharing of an arbitrary unknown single- qubit state in cavity QED is presented. Using a generalized Greenberger-Horne-Zeilinger （GHZ） state as the quantum channel among the three parties, the quantum information （i.e. the single-qubit state） from the sender can be split in such a way that the information can be recovered if and only if both receivers collaborate. Moreover, the scheme is insensitive to both the effects of thermal field and cavity decay.     

Quantum dynamics on a lossy non-Hermitian lattice

We investigate quantum dynamics of a quantum walker on a finite bipartite non-Hermitian lattice,in which the particle can leak out with certain rate whenever it visits one of the two sublattices.Quantum walker initially located on one of the non-leaky sites will finally totally disappear after a length of evolution time and the distribution of decay probability on each unit cell is obtained.In one regime,the resultant distribution shows an expected decreasing behavior as the distance from the initial site increases.However,in the other regime,we find that the resultant distribution of local decay probability is very counterintuitive,in which a relatively high population of decay probability appears on the edge unit cell which is the farthest from the starting point of the quantum walker.We then analyze the energy spectrum of the non-Hermitian lattice with pure loss,and find that the intriguing behavior of the resultant decay probability distribution is intimately related to the existence and specific property of the edge states,which are topologically protected and can be well predicted by the non-Bloch winding number.The exotic dynamics may be observed experimentally with arrays of coupled resonator optical waveguides.     

Engineering steady-state entanglement for two atoms held in separate cavities through laser cooling

We propose a scheme to prepare the steady-state entanglement for two atoms, which are held in separate cavities that are coupled through a short optical fiber or optical resonator. The entangled steady-state with a high fidelity can be achieved even with a low cooperativity parameter, by making use of the driving laser fields. Such a cooling mechanism is based on a resonant laser pump of the unwanted ground states to the excited states, which finally decay to the desired steady-state.     

Incomplete Erasure of Which-Way Information Encoded in Atomic Hyperfine States

We propose an experimental scheme to investigate incomplete erasure of which-way information encoded in atomichy perfine states. Due to the incomplete erasure of the which-way information, it is shown that the interference patterns of the atomic wave packets initially confined in a spin-dependent optical lattice are destroyed to a certain extent, which provides a new straight way to test further the validity of the theoretical model developed in our recent work. The remarkable merit of the proposal is that it is simple and can be implemented easily.     

Remote atomic information concentration without Bell-state measurement

This paper proposes a scheme for information concentration of two remote two-level atoms in cavity QED. This scheme does not involve the Bell-state measurement. During the interaction between atom and cavity, the cavity frequency is large-detuned from the atomic transition frequency, thus the scheme is insensitive to both the cavity decay and the thermal field. This idea can directly be generalized in the case of multi-atom information concentration.     

On-shell mediator dark matter models and the Xenon1T excess

We present a dark matter model to explain the excess events in the electron recoil data recently reported by the Xenon1 T experiment. In our model, dark matter χ annihilates into a pair of on-shell particles Φ, which subsequently decay into the ψψ final state;ψ interacts with electrons to generate the observed excess events. Because of the mass hierarchy, the velocity of ψ can be rather large and can have an extended distribution, providing a good fit to the electron recoil energy spectrum. We estimate the flux of ψ from dark matter annihilations in the galaxy and further determine the interaction cross section, which is sizable but sufficiently small to allow ψ to penetrate the rocks to reach the underground labs.     

Multiqubit Nonlocal Operation and Physical Implementation

We propose a scheme of preparing four-atom cluster states in thermal cavity. Four two-level atoms, three thermal cavities and classical field are used in the scheme. Compared with previous schemes, the scheme can be generalized to n-atom cluster states and the successful probability can be 100%, which the system of the photon can never reach. In addition, the system is insensitive to cavity decay and the thermal field. Using the four-atom cluster state, we also propose a simpler scheme for remote controlled not gate （CNOT）, in which we detect the separate states instead of the joint-Bell states measurement.     

Can VMD improve the estimate of the muon g－2?

We show that a VMD based theoretical input allows for a significantly improved accuracy for the hadronic vacuum polarization of the photon which contributes to the theoretical estimate of the muon g-2.We also show that the only experimental piece of information in the τ decay which cannot be accounted for within this VMD framework is the accepted value for Br(τ→ππντ),while the τ spectum lineshape is in agreement with expectations from e+e-annihilations.     

Image registration by maximization of mutual information based on edge width matching using particle swarm optimization

Registration of multimodal medical images is the firstimportant step in successful fusion of multimodal med-ical images, which produces different information. Themutual information (MI) between two images can be re-garded as a statistical tool to measure the degree to whichan image can be predicted from the other. It has beenfound to be an appropriate similarity measure for manymultimodal images's registration problems[1,2]. However,the local maxima of MI make it difficult to register im-age…     

An Implantation and Detection System for Spectroscopy of 22,24Si

A new decay detection system with high detection efficiency and low detection threshold has been developed for charged-particle decay studies, including -delayed proton, decay or direct proton emission from proton-rich nuclei. The detection system was tested by using the -delayed proton emitter 24Si and was commissioned in the decay study of 22Si produced by projectile fragmentation at the First Radioactive Ion Beam Line in Lanzhou. Under a continuous-beam mode, the isotopes of interest were implanted into two double-sided silicon strip detectors, where the subsequent decays were measured and correlated to the preceding implantations by using position and time information. The system allows to measure protons with energies down to about 200 keV without obvious background in the proton spectrum. Further application of the detection system can be extended to the measurements of -delayed proton decay and the direct proton emission of other exotic proton-rich nuclei.     

Control of sudden transition between classical and quantum correlations of two strongly driven atoms in dissipative cavities

We investigate analytically the dynamics of classical and quantum correlations between two strongly driven atoms, each of which is trapped inside a dissipative cavity. It is found that there exists a finite time interval during which the quantum discord initially prepared in the X-type states is not destroyed by the decay of the cavities. The sudden transition between classical correlation and quantum discord is sensitive to the initial-state parameter, the cavity decay rate, and the cavity mode-driving field detuning. Interestingly, we show that the transition time can be prolonged significantly by increasing the degree of the detuning.     

Study of ■ decay parameter in J/ψ→Λ■ decay

The helicity amplitudes for J/ψ→Λ■ and the relevant background decays are presented for measuring the ■ decay parameter α (■→π ) in J/ψ→Λ■. The Monte Carlo (MC) simulations based on the helicity amplitudes information are carried out. The likelihood fit method to determine the ■ decay parameter is presented. Based on the MC generated sample, the sensitivity of the measurement for α has been estimated, which shows that the J/ψ→Λ■ channel can be used to measure the ■ decay parameter α (■→π ) well.