Energy Levels of Strong Coupling Magnetopolaron in Quantum Dot

By using variational method of Pekar type, we have studied the energy levels of strong coupling magnetopolaron in disk shape quantum dot(QD) and quantum well(QW). Our results show that, with the increasing magnetic field and confinement strength, the magnetopolaron binding energy of QD and QW in the ground state and in the excited state is enhanced. The limiting results of bulk type and strict two dimensional type are obtained.

Size and Magnetic Field Dependence of Strong Coupling Magnetopolaron in Quantum Dot

By using the variational method of Pekar type, the ground state and the first excited state of the strong coupling magnetopolaron in cylinder shape quantum dot are considered. The results show that, with the increasing cyclotron frequency and the confinement strength, the magnetopolaron binding energies in both the ground state and the excited state, and the resonance frequency of magnetopolaron are enhanced. The limiting case of the bulk and strict one dimensional type is also discussed.

Cavity optomechanics： Manipulating photons and phonons towards the single-photon strong coupling

Cavity optomechanical systems provide powerful platforms to manipulate photons and phonons, open potential ap- plications for modern optical communications and precise measurements. With the refrigeration and ground-state cooling technologies, studies of cavity optomechanics are making significant progress towards the quantum regime including non- classical state preparation, quantum state tomography, quantum information processing, and future quantum internet. With further research, it is found that abundant physical phenomena and important applications in both classical and quan- tum regimes appeal as they have a strong optomechanical nonlinearity, which essentially depends on the single-photon optomechanical coupling strength. Thus, engineering the optomechanical interactions and improving the single-photon optomechanical coupling strength become very important subjects. In this article, we first review several mechanisms, theoretically proposed for enhancing optomechanical coupling. Then, we review the experimental progresses on enhancing optomechanical coupling by optimizing its structure and fabrication process. Finally, we review how to use novel structures and materials to enhance the optomechanical coupling strength. The manipulations of the photons and phonons at the level of strong optomechanical coupling are also summarized.

Optical strong coupling in hybrid metal-graphene metamaterial for terahertz sensing

We propose a terahertz hybrid metamaterial composed of subwavelength metallic slits and graphene plasmonic ribbons for sensing application.This special design can cause the interaction between the plasmon resonances of the metallic slits and graphene ribbons,giving rise to a strong coupling effect and Rabi splitting.Intricate balancing in the strong coupling region can be perturbed by the carrier concentration of graphene,which is subject to the analyte on its surface.Thereby,the detection of analyte can be reflected as a frequency shift of resonance in terahertz transmission spectra.The result shows that this sensor can achieve a theoretical detection limit of 325 electrons or holes per square micrometer.Meanwhile,it also works well as a refractive index sensor with the frequency sensitivity of 485 GHz/RIU.Our results may contribute to design of ultra-micro terahertz sensors.

Enhanced circular dichroism of plasmonic system in the strong coupling regime

The circular dichroism(CD) signal of a molecule is usually weak,however,a strong CD signal in optical spectrum is desirable because of its wide range of applications in biosensing,chiral photo detection,and chiral catalysis.In this work,we show that a strong chiral response can be obtained in a hybridized system consisting of an artificial chiral molecule and a nanorod in the strong coupling regime.The artificial chiral molecule is composed of six quantum dots in a helix assembly,and its CD signal arises from internal Coulomb interactions between quantum dots.The CD signal of the hybridized system is highly dependent on the Coulomb interactions and the strong coupling progress through the electromagnetic interactions.We use the coupled oscillator model to analyze strong coupling phenomenon and address that the strong coupling progress can amplify the CD signal.This work provides a scenario for designing new plasmonic nanostructures with a strong chiral optical response.

Multiple ionization of atoms and molecules impacted by very high-q fast projectiles in the strong coupling regime(q/v > 1)

In this paper, we present a simple theoretical approach to calculate the multiple ionization of big atoms and molecules induced by very high-q fast projectiles in a strong coupling regime （q/v 〉 1）. The results obtained from this approach are in excellent agreement with the available experimental data. A probable scenario of molecular multiple ionization by fast and very high-q projectiles is discussed. The very small computational time required here and the good agreement with the existing experimental data make it a good candidate for studying the multiple ionization of complex molecules under high linear energy transfers.

Strong coupling in silver-molecular J-aggregates-silver structure sandwiched between two dielectric media

We theoretically investigate the strong coupling in silver-molecular J-aggregates-silver structure sandwiched between two dielectric media by using classical methods. Fresnel equations are employed to solve our proposed structure. The results show that both the reflection and transmission spectra show a Rabi splitting-like line shape, revealing the strong coupling phenomenon. Furthermore, the radiative angle versus incident wavelength exhibits a Fano line shape. The strong coupling phenomenon can be well tuned by controlling the surface plasmon excitation, such as the incident angle and the thickness of the silver films. Our structure has potential applications in quantum networks, optical switches, and so on.

Fluctuation theorem for entropy production at strong coupling

Fluctuation theorems have been applied successfully to any system away from thermal equilibrium,which are helpful for understanding the thermodynamic state evolution.We investigate fluctuation theorems for strong coupling between a system and its reservoir,by path-dependent definition of work and heat satisfying the first law of thermodynamics.We present the fluctuation theorems for two kinds of entropy productions.One is the informational entropy production,which is always non-negative and can be employed in either strong or weak coupling systems.The other is the thermodynamic entropy production,which differs from the informational entropy production at strong coupling by the effects regarding the reservoir.We find that,it is the negative work on the reservoir,rather than the nonequilibrium of the thermal reservoir,which invalidates the thermodynamic entropy production at strong coupling.Our results indicate that the effects from the reservoir are essential to understanding thermodynamic processes at strong coupling.

Galactic Route to the Strong Coupling Constant αs(mz) and Its Implication on the Mass Constituents of the Universe

Some fundamental physical quantities need an alternative description. We derive the word average value of interaction coupling constant αs(mz) from the observed maximum galactic rotation velocity by the simple relation , where is the velocity, at which the difference between galactic rotation velocity and Thomas precession is equal, and α is Sommerfeld’s constant. The result is in excellent agreement with the value of αs = 0.1170 ± 0.0019, recently measured and verified via QCE analysis by CERN researchers. One can formulate a reciprocity relation, connecting αs with the circle constant: . It is the merit of Preston Guynn to derive the Milky Way maximum value of the galactic rotation velocity βg, pointing to its “extremely important role in all physics”. The mass (energy) constituents of the Universe follow a golden mean hierarchy and can simply be related to the maximum of Guynn’s difference velocity respectively to αs(mz), therewith excellently confirming Bouchet’s WMAP data analysis. We conclude once more that the golden mean concept is the leading one of nature.

Strong coupling between a plasmon mode and multiple different exciton states

Strong coupling between plasmons and multiple different exciton states(MESs)enables the creation of multiple hybrid polariton states under ambient conditions.These hybrid states possess unique optical properties different from those of their separate identities,making them ideal candidates for exploiting room-temperature multimode hybridization and multiqubit operation.In this study,we revealed the static spectral response properties of plasmon-MES strong coupling via a fully quantum mechanics approach.These theoretical predictions were experimentally demonstrated in plasmonic nanocavities containing two and three different exciton species.Additionally,the dynamical absorption processes of such strong coupling systems were investigated,and results indicated that the damping of the hybrid polariton states induced by the strong coupling could be markedly modulated by the acoustic oscillations from the plasmonic nanocavities.Our findings contribute a theoretical approach for accurately describing the plasmon-MES interactions and a platform for developing the high-speed active plasmonic devices based on multiqubit strong coupling.

Experimental realization of strong coupling between a cold atomic ensemble and an optical fiber microcavity

The cavity quantum electrodynamics (QED) system is a promising platform for quantum optics and quantum information experiments.Its core is the strong coupling between atoms and optical cavity,which causes difficulty in the overlap between the atoms and the antinode of optical cavity mode.Here,we use a programmable movable optical dipole trap to load a cold atomic ensemble into an optical fiber microcavity and realize the strong coupling between the atoms and the optical cavity in which the coupling strength can be improved by polarization gradient cooling and adiabatic loading.By the measurement of vacuum Rabi splitting,the coupling strength can be as high as g_(N)=2π×400 MHz,which means the effective atom number is N_(eff)=16 and the collective cooperativity is C_(N)=1466.These results show that this experimental system can be used for cold atomic ensemble and cold molecule based cavity QED research.

Teleportation of unknown states of a qubit and a single-mode field in strong coupling regime without Bell-state measurement

In this paper,we develop the teleportation scheme in[Zheng in Phys Rev A 69,064302,2004],in the sense that,we work in the strong atom-field coupling regime wherein the rotating wave approximation(RWA)is no longer valid.To achieve the purpose,a scheme consisting of a qubit interacting with a single-mode quantized field is described via the Rabi model(counter rotation terms are taken into account).Our first aim is to teleport an unknown atomic state of a qubit(which interacts with the quantized field in a cavity)to a second qubit(exists in another distant cavity field),beyond the RWA and without the Bell-state measurement method.In the continuation,in a similar way,we teleport an unknown state of a single-mode field too.In fact,it is shown that,in this regime,after applying some particular conditions,containing the interaction time of atom-field in the cavities,adjusting the involved frequencies,as well as the atom-field coupling in the model,if a proper measurement is performed on the state of the first qubit(the related field in the cavity),the unknown states of the qubit(field)can be teleported from the first qubit(cavity field)to the second qubit(cavity field),appropriately.We show that in both considered cases,the teleportation protocol is successfully performed with the maximum possible fidelity,1,and the acceptable success probability,0.25.

Algorithm Selection Method Based on Coupling Strength for Partitioned Analysis of Structure-Piezoelectric-Circuit Coupling

In this study, we propose an algorithm selection method based on coupling strength for the partitioned analysis ofstructure-piezoelectric-circuit coupling, which includes two types of coupling or inverse and direct piezoelectriccoupling and direct piezoelectric and circuit coupling. In the proposed method, implicit and explicit formulationsare used for strong and weak coupling, respectively. Three feasible partitioned algorithms are generated, namely(1) a strongly coupled algorithm that uses a fully implicit formulation for both types of coupling, (2) a weaklycoupled algorithm that uses a fully explicit formulation for both types of coupling, and (3) a partially stronglycoupled and partially weakly coupled algorithm that uses an implicit formulation and an explicit formulation forthe two types of coupling, respectively.Numerical examples using a piezoelectric energy harvester,which is a typicalstructure-piezoelectric-circuit coupling problem, demonstrate that the proposed method selects the most costeffectivealgorithm.

Empowering magnetic strong coupling and its application for nonlinear refractive index sensing

In the context of quantum strong coupling,the magnetic dipole(MD)emitters are largely overlooked due to the rarity of MD source and the non-magnetic nature of matters at high frequencies.Based on a semi-classic model,we theoretically demonstrate magnetic strong coupling between an MD cluster(Er^(3+):4 I13/2→4 I15/2 transition at 1,550 nm)and an antenna-in-cavity structure.It is found that placing the plasmonic diabolo/s-diabolo nanoantenna,which supports strong electric/magnetic dipole mode,inside a dielectric cavity could largely improve the strong coupling coefficient while suppressing the cavity loss rate compared to the bare nanoantenna counterparts,empowering the magnetic quantum strong coupling at a level of 104 emitters,which is remarkable considering the weak MD dipole momentum and small hotspot region at high frequency.Furthermore,the two Rabi resonance branches undergo highly asymmetrical changes upon a small variation on the environmental refractive index,which leads to an exotic exponential sensitivity profile by tracing the ratio between the two resonances widths.The proposed magnetic strong coupling for nonlinear refractive index sensing may add a new category to quantum plasmonic sensors.

Study of spin sum rules (and the strong coupling constant at large distances)

We present recent results from Jefferson Lab on sum rules related to the spin structure of the nucleon. We then discuss how the Bjorken sum rule with its connection to the Gerasimov-Drell-Hearn sum, allows us to conveniently define an effective coupling for the strong force at all distances.

Boron nitride nanoresonators for phonon-enhanced molecular vibrational spectroscopy at the strong coupling limit

Enhanced light-matter interactions are the basis of surface-enhanced infrared absorption(SEIRA)spectroscopy,and conventionally rely on plasmonic materials and their capability to focus light to nanoscale spot sizes.Phonon polariton nanoresonators made of polar crystals could represent an interesting alternative,since they exhibit large quality factors,which go far beyond those of their plasmonic counterparts.The recent emergence of van der Waals crystals enables the fabrication of highquality nanophotonic resonators based on phonon polaritons,as reported for the prototypical infrared-phononic material hexagonal boron nitride(h-BN).In this work we use,for the first time,phonon-polariton-resonant h-BN ribbons for SEIRA spectroscopy of small amounts of organic molecules in Fourier transform infrared spectroscopy.Strikingly,the interaction between phonon polaritons and molecular vibrations reaches experimentally the onset of the strong coupling regime,while numerical simulations predict that vibrational strong coupling can be fully achieved.Phonon polariton nanoresonators thus could become a viable platform for sensing,local control of chemical reactivity and infrared quantum cavity optics experiments.

Determination of the strong coupling constant using available experimental data

We determine the strong coupling constant α s up to 4-loop in perturbative QCD.Testing QCD requires the measurement of α s over ranges of energy scales.In this analysis,the value of α s is determined from the unpolarized structure functions data points by minimizing the χ ^2 function between the theory result and experimental data.Using perturbative QCD calculations from threshold corrections,we obtain α s （M 2 Z ） = 0.1139±0.0020 at N ^3 LO which is in good agreement with the very recently results from the inclusive jet cross section in pp collisions at√ s=1.96 TeV.

Strong Coupling Constants of the Doubly Heavy Spin-1/2 Baryons with Light Pseudoscalar Mesons

The strong coupling constants of hadronic multiplets are fundamental parameters which carry information about the strong interactions among participating particles.These parameters can help us construct the hadron-hadron strong potential and gain information about the structure of the involved hadrons.Motivated by the recent observation of the doubly charmed cc state by LHCb,we determine the strong coupling constants among the doubly heavy spin-1/2 baryons, Ξ_(QQ′)/(′),Ω_(QQ′)/(′) and light pseudoscalar mesons,π,κ,η and η′within the framework of the light cone QCD sum rules.The obtained results may help experimental groups in analysis of the related data at hadron colliders.

D^*Dρ and B^*Bρ strong couplings in light-cone sum rules

We present an improved calculation of the strong coupling constants gD*Dp and gB*Bp in light-cone sum rules,including one-loop QCD corrections of leading power with meson distribution amplitudes.We further compute subleading-power corrections from two-particle and three-particle higher-twist contributions at leading order up to twist-4 accuracy.The next-to-leading order corrections to the leading power contribution numerically offset the subleading-power corrections to a certain extent,and our numerical results are consistent with those of previous studies on sum rules.A comparison between our results and existing model-dependent estimations is also made.

Strong coupling,charm- and bottom-quark masses from electron-positron annihilation

The cross section for electron-positron annihilation into hadrons allows for a precise determination of the strong coupling constant and the charm- and bottom-quark masses. Recent theoretical and experimental results are presented with emphasis on the energy region accessible by B-meson factories and below.