Entangling two levitated charged nanospheres through Coulomb interaction

Limited by the thermal environment, the entanglement of a massive object is extremely difficult to generate. Based on a coherent scattering mechanism, we propose a scheme to generate the entanglement of two optically levitated nanospheres through the Coulomb interaction. Two nanospheres are charged and coupled to each other through the Coulomb interaction.In this manner, the entanglement of two nanospheres is induced either under a weak/strong optomechanical coupling regime or under an ultra-strong optomechanical coupling regime. The charges, radius and distance of the two nanospheres are taken into consideration to enhance the Coulomb interaction, thereby achieving a higher degree of entanglement in the absence of ground-state cooling. The corresponding maximum entanglement can be attained as the dynamics of the system approaches the boundary between the steady and the unsteady regimes. This provides a useful resource for both quantum-enhanced sensing and quantum information processing, as well as a new platform for studying many-body physics.

Diffusion behavior of polyelectrolytes in dilute solution: coupling effects of hydrodynamic and Coulomb interactions

The diffusion behavior of polyelectrolytes in dilute salt-free solution is studied through a hybrid mesoscale simulation technique that combines the molecular dynamics method and the multiparticle collision dynamics approach.To elucidate the effects of hydrodynamic interactions(HI),we compare results for hydrodynamic and random solvents.When HI are taken into account,we find that the chain diffusivity decreases initially and then increases gradually with the increasing strength of the Coulomb interaction.By contrast,when HI are switched off,the electrostatic-dependent diffusivity shows three distinct regions,and a plateau of approximately constant diffusivity manifests between two decreasing regions.The findings reveal that the dynamics of polyelectrolytes in dilute solution depend on the coupling effects of hydrodynamic and Coulomb interactions,and that these dynamics can be understood by considering the conformational changes of chains,the counterion condensation,and the dynamics of counterions.

Tunable ponderomotive squeezing induced by Coulomb interaction in an optomechanical system

We investigate the properties of the ponderomotive squeezing in an optomechanical system coupled to a charged nanomecbanical oscillator （NMO） nearby via Coulomb force. We find that the introduction of Coulomb interaction allows the generation of squeezed output light from this system. Our numerical results show that the degree of squeezing can be tuned by the Coulomb coupling strength, the power of laser, and the frequencies of NMOs. Furthermore, the squeezing generated in our approach can be used to measure the Coulomb coupling strength.

The Coulomb effect on a low-energy structure in above-threshold ionization spectra induced by mid-infrared laser pulses

We investigate the low-energy structure （LES） in the above-threshold ionization spectrum at a mid-infrared laser wavelength with a semiclassical model. Using a softened Coulomb potential （CP） and changing the softening parameter, we show that though the very low-energy structure （VLES） and high low-energy structure （HLES） are both due to the interaction between the ionic CP and the electron, the two structures have different physical mechanisms： the VLES can be attributed to the electron-ion Coulomb interaction at a rather small distance and the HLES is more likely to be ascribed to the electron-ion Coulomb interaction at a large distance.

Coulombic interaction in the colloidal oriented-attachment growth of tetragonal nanorods

In this report, the analytical expression of Coulombic interaction between a spherical nanoparticle and a tetragonal nanorod is derived. To evaluate the Coulombic interaction in the oriented attachment growth of tetragonal nanorods, we analyze the correlation between the Coulombic interaction and the important growth parameters, including： nanoparticle- nanorod separation, aspect ratio of the nanorods, and surface charge density. Our work opens up the opportunity to investi-gate interparticle interactions in the oriented attachment growth of tetragonal nanorods.

Enhancing stationary entanglement between two optomechanical oscillators by Coulomb interaction with Kerr medium

We theoretically study the stationary entanglement of two charged nanomechanical oscillators coupling via Coulomb interaction in an optomechanical system with an additional Kerr medium.We show that the degree of entanglement between two nanomechanical oscillators is suppressed by Kerr interaction due to photon blockade and enhanced by Coulomb coupling strength.We also show other parameters for adjusting and obtaining entanglement,such as the driving power and the frequencies of the two oscillators,and the entanglement is robust against temperature.Our study proves a way for adjusting stationary entanglement between two optomechanical oscillators by Coulomb interaction and Kerr medium.

Stationary entanglement between two nanomechanical oscillators induced by Coulomb interaction

We propose a scheme for entangling two nanomechanical oscillators by Coulomb interaction in an optomechanical system. We find that the steady-state entanglement of two charged nanomechanical oscillators can be obtained when the coupling between them is stronger than a critical value which relies on the detuning. Remarkably, the degree of entanglement can be controlled by the Coulomb interaction and the frequencies of the two charged Oscillators.

CNDO Studies on the Intermolecular Coulomb Interaction in TCNQ-Stack

The coulomb interaction among TCNQ- molecules in different stack structures was calculated by quantum chemistry CNDO method. The results of the calculation would be used to explain the change rule of the electricity property of the TCNQ complex very well.

Coulomb Interaction in Quantum Dot with a Precessing Magnetic Field

We study electronic transport through a quantum dot （QD） with a precessing magnetic field. By using the Keldysh nonequilibrium Green function method, formulas of local density of states （LDOS） and conductance of QD are derived self-consistently. It shows that the LDOS and conductance have obvious changes with the Coulomb blockade interaction. The intensity and angle of the magnetic field or temperatures, which reflect the mesoscopic structure of the QD are derived. The superiority of this device is that the QD can be controlled easily by the magnetic field, so it is valuable to apply in generating, manipulating and probing spin state.

A DFT+U study of the structures and reactivities of polar CeO_2(100) surfaces

Density functional theory calculations corrected by on-site Coulomb interactions were carried out o study the structures of polar CeO2 （100） surfaces as well as activities during catalytic CO oxidation. The stabilities of various CeO2 （100） termination structures are discussed, and calculated energetics are presented. The most stable Ce〇2 （100） surface was obtained by removing half the outermost full layer of oxygen and the surface stability was found to decrease as the exposed oxygen concentration was increased. Assessing the reaction pathways leading to different final products during CO oxidation over the most stable CeO2 （100） surface, we determined that the formation of carbonate species competed with CO2 desorption. However, during CO oxidation on the less stable CeO2 （100） surfaces having more exposed oxygen, the CO is evidently able to react with surface oxygen, leading to CO2 formation and desorption. The calculation results and electronic analyses reported herein also indicate that the characteristic Ce 4/ orbitals are directly involved in deter-mining the surface stabilities and reactivities.

Hydrogen cold plasma for synthesizing Pd/C catalysts: the effect of support-metal ion interaction

It has been found that cold plasma is a facile and environmentally benign method for synthesizing supported metal catalysts, and great efforts have been devoted to enlarging its applications. However, little work has been done to disclose the influence mechanism, which is significant for controllable synthesis. In this work, hydrogen cold plasma was adopted to synthesize a palladium catalyst supported on activated carbon （Pd/C-P） using HzPdC14 as a Pd precursor followed by calcination in hydrogen gas to remove the chlorine ions. The Pd/C-P catalyst was found to be made of larger Pd nanoparticles showing a decreased migration to the support outer surface than that prepared by the conventional thermal hydrogen reduction method （Pd/C-C）. Meanwhile, the pore diameter of the activated carbon support is small （,-~4 nm）. Therefore, Pd/C-P exhibits lower CO oxidation activity than Pd/C-C. It was proposed that the strong interaction between the activated carbon and PdC142-, and the enhanced metal-support interaction caused by hydrogen cold plasma reduction made it difficult for Pd nanoparticles to migrate to the support outer surface. The larger-sized Pd nanoparticles for Pd/C-P may be due to the Coulomb interaction resulting in the disturbance of the metal-support interaction. This work has important guiding significance for the controllable synthesis of supported metal catalysts by hydrogen cold plasma.

Intensities and shifts of Lyman and Balmer lines of hydrogen-like ions in high density plasmas

The spectral line intensities and line shifts of Lyman and Balmer series for transitions up to n=5 of hydrogen-like ion are studied in plasmas with densities and temperatures in the ranges n_(c)~10^(18)-10^(21)cm^(-3),T_(e)=0.3e1.2 eV respectively.The screened potential used to describe the interaction between charged particles includes the electron exchange-correlation and finite-temperature gradient effects and is valid for both weakly and strongly coupled plasmas.The dependencies of alpha,beta and gamma line shifts of Lyman and Balmer series on plasma density(for fixed temperature)and temperature(for fixed density)are investigated.The results for the H_(a)line shifts are compared with the available high-density experimental data.

Variational Monte Carlo study of the nematic state in iron-pnictide superconductors with a five-orbital model

We perform a variational Monte Carlo study of the nematic state in iron-pnictide superconductors within a realistic five-orbital model. Our numerical results show that the nematic state, formed by introducing an anisotropic hopping order into the projected wave function, is not stable unless the off-site Coulomb interaction V exceeds a critical value. This demonstrates that V plays a key role in forming the nematic state in iron-pnictide superconductors. In the nematic state,the orbital order and the anisotropic spin correlations are consistent with the experimental observations. We argue that the experimentally observed anisotropic magnetic couplings and structural transition are associated with the nematic state and can be understood in a unified framework.

Influence of alkali mixed effect on the mixing enthalpy in 0.75B_2O_3-0.25[xNa_2O-(1-x)K_2O]glass system

The mixed alkali effect was investigated in the glass system 0.75B2O3-0.25[xNa2O-（1 -x）K20] through thermodynamic properties. The calorimetric measurements were performed in HF solution calorimetry at 298 K. The mixing enthalpy values show non-linear behaviour upon substitution of one alkali ion by another. This thermodynamic non-ideality is caused by the slight variations of distance between metallic cations, the macromolecular structure being unchanged. It can be explained, at least qualitatively, using electrolyte theory based on the Coulombic interactions of charged species originally developed by Debye and Hückel.

Signature of symmetry of laterally coupled quantum dots in far-infrared spectrum

We study the effect of structure asymmetry on the energy spectrum and the far-infrared spectrum （FIR） of a lateral coupled quantum dot. The calculated spectrum shows that the parity break of coupled quantum dot results in more coherent superpositions in the low-lying states and exhibits unique anti-crossing in the two-electron FIR spectrum modulated by a magnetic field. We also find that the Coulomb correlation effect can make the FIR spectrum of coupled quantum dot without strict parity deviate greatly from Kohn theorem, which is just contrary to the symmetric case. Our results therefore suggest that FIR spectrum may be used to determine the symmetry of coupled quantum dot and to evaluate the degree of Coulomb interaction.

Calculation of Neutron-Proton Mass Difference by the Monte Carlo Method

Calculation results of the Monte Carlo method of the average energy of the electrostatic interaction between the quarks are presented to the neutron and proton. The proposed model of the distribution of quarks in protons and neutrons is possible to assess the area which included a strong (gluon) interaction. Given the fact that the probability of finding a quark in the field with strong interaction is less than one, there is a good agreement between the experimental and calculated values of the mass difference between the neutron and the proton.

Coulomb expansion of a van der Waals C_(60) solid film

Scanning tunneling microscopy study revealed a van der Waals C60, solid film with 13% room-temperature lattice expansion on the GaAs(001) 2×4 surface. The mechanism involves fundamental Coulomb interaction due to charge transfer from the GaAs substrate. Theoretical calculation determines the charge transfer to be 1.76 electrons per C60 molecule. Oriented at its (110) crystallo-graphic axis this film also distinguishes itself from those formed on all other semiconductor and metal substrates where only the low-energy (111) hexagonal packing of C60 molecules was developed. It is shown that this is due to the one-dimensional confinement effect of the anisotropic substrate, which may have the prospect of controlling crystal growth.

Controllable optical multistability in hybrid optomechanical system assisted by parametric interactions

We theoretically investigate the multistable behavior of a hybrid optomechanical system, in which a charged mechanical resonator is coupled via Coulomb interaction to an optomechanical cavity containing an optical parametric amplifier （OPA）. It is shown that the multistable behavior of the mean intracavity photon number can be controlled flexibly by adjusting the nonlinear gain parameter of the OPA, the phase of the field pumping the OPA, the power and frequency of the field driving the cavity, and the Coulomb coupling strength between the two charged mechanical resonators. In particular, the increase of the nonlinear gain parameter can result in a transition from bistability to tristability. Moreover, the effect of the Coulomb coupling strength on the bistable behavior of the steady-state positions of the two mechanical resonators is discussed.

Expanding proton dripline by employing a number of muons

Through mean-field calculations,we demonstrate that,in a large Z nucleus binding multiple muons,these heavy leptons localize within a few dozen femtometers of the nucleus.The mutual Coulomb interactions between the muons and protons can lead to a substantial decrease in proton chemical potential,surpassing 1 MeV.These findings imply that,in principle,the proton-dripline can be expanded on the nuclear chart,suggesting the possible production of nuclei with Z around 120.

Functionals for Multilinear Fractional Embedding

A novel representation is developed as a measure for multilinear fractional embedding. Corresponding extensions are given for the Bourgain-Brezis-Mironescu theorem and Pitt＇s inequal- ity. New results are obtained for diagonal trace restriction on submanifolds as an application of the Hardy-Littlewood-Sobolev inequality. Smoothing estimates are used to provide new structural un- derstanding for density functional theory, the Coulomb interaction energy and quantum mechanics of phase space. Intriguing connections are drawn that illustrate interplay among classical inequalities in Fourier analysis.