Energy Spectrum of Ground State and Excitation Spectrum of Quasi-particle for Hard-Core Boson in Optical Lattices

We investigate the energy spectrum of ground state and quasi-particle excitation spectrum of hard-core bosons, which behave very much like spinless noninteracting ferrnions, in optical lattices by means of the perturbation expansion and Bogoliubov approach. The results show that the energy spectrum has a single band structure, and the energy is lower near zero momentum; the excitation spectrum gives corresponding energy gap, and the system is in Mort-insulating state at Tonks limit. The analytic result of energy spectrum is in good agreement with that calculated in terms of Green＇s function at strong correlation limit.     

Energy Spectrum of Ground State and Excitation Spectrum of Quasi-particle for Hard-Core Boson in Optical Lattices

We investigate the energy spectrum of ground state and quasi-particle excitation spectrum of hard-core bosons, which behave very much like spinless noninteracting fermions, in optical lattices by means of the perturbation expansion and Bogoliubov approach. The results show that the energy spectrum has a single band structure, and the energy is lower near zero momentum; the excitation spectrum gives corresponding energy gap, and the system is in Mott-insulating state at Tonks limit. The analytic result of energy spectrum is in good agreement with that calculated in terms of Green‘s function at strong correlation limit.     

Measurement of the neutron spectrum of a Pu-C source with a liquid scintillator

The neutron response function for a BC501A liquid scintillator （LS） has been measured using a series of monoenergetic neutrons produced by the p-T reaction. The proton energies were chosen such as to produce neutrons in the energy range of 1 to 20 MeV. The principles of the technique of unfolding a neutron energy spectrum by using the measured neutron response function and the measured Pulse Height （PH） spectrum is briefly described. The PH spectrum of neutrons from the Pu-C source, which will be used for the calibration of the reactor antineutrino detectors for the Daya Bay neutrino experiment, was measured and analyzed to get the neutron energy spectrum. Simultaneously the neutron energy spectrum of an Am-Be source was measured and compared with other measurements as a check of the result for the Pu-C source. Finally, an error analysis and a discussion of the results are given.     

CONFORMAL INVARIANCE AND THE LANCZOS METHOD STUDIES OF A SPINNING QUANTUM CHAIN

The low-lying energy spectrum of a spinning quantum chain in the critical region is calculated by using Lanczos method. According to conformal theory, the anomalous dimensions χ and the normalising factor ξ are obtained from the energy spectrum. Also a simple derivation of the field theory of the model is given.     

Cosmic ray energy spectrum from measurements of air showers

This review focuses on high-energy cosmic rays in the PeV energy range and above. Of particular interest is the knee of the spectrum around 3 PeV and the transition from cosmic rays of Galactic origin to particles from extra-galactic sources. Our goal is to establish a baseline spectrum from 1014 to 10^20 eV by combining the results of many measurements at different energies. In combination with measurements of the nuclear composition of the primaries, the shape of the energy spectrum places constraints on the number and spectra of sources that may contribute to the observed spectrum.     

Fast sinusoidal analysis algorithm based on energy of narrowband spectrum

A fast sinusoidal parameters extraction algorithm based on energy of narrowband spectrum is presented. To improve analysis accuracy and computational efficiency, the al- gorithm integrates the Fourier transforms of signal and its n-order signal derivatives. And energy of narrowband spectrum is used to approximate the energy of the whole spectrum of single sinusoidal signal, since most energy is concentrated in the main lobe of spectral windows. Experiment results show that compared with existing algorithms, the proposed algorithm improves analysis precision by 30%-60% and reduces computational complexity. Therefore it can be applied to real time signal analysis and speech communication.     

Level statistics for the even-even Yb isotopes

The level statistics of the even-even Yb isotopes are studied by using the energy levels calculated by the projected shell model. The spectrum of intrinsic states and band energies are also studied to discuss the generation of chaoticity. The energy dependence of the chaoticity is investigated, and a chaos to order transition is found.     

Level statistics for the even-even Yb isotopes

The level statistics of the even-even Yb isotopes are studied by using the energy levels calculated by the projected shell model. The spectrum of intrinsic states and band energies are also studied to discuss the generation of chaoticity. The energy dependence of the chaoticity is investigated, and a chaos to order transition is found.     

Velocity Transfer Spectroscopy of Rb 420 nm Transition

We propose and demonstrate the velocity transfer spectroscopy of a V-type energy structure with Rb atoms at 420nm transition. The weak oscillator strength of a lower excited state for V-type energy structure atoms limits the high signal-to-noise ratio of atomic laser spectroscopy, which can be usually realized by optical-optical double-resonance or double-resonance optical pumping for cascade-type energy structure atoms. For ^87Rb atoms, the weak 420 nm transition spectrum between the energy level of 5^2S1/2 and 6^2P3/2 is transferred to the spectrum on lower excited states at 780nm with strong oscillator strength, which is recorded by a 780 nm probe laser. This method, which ＆ similar to the electron-shelving detection method, at a certain degree can indirectly measure a higher excited state transition with weak oscillator strength for any V-type energy structure of atoms by transferring the transition spectrum information of the very weak oscillator strength to the strong oscillator strength in an optical-optical double-resonance configuration.     

The quantum Kirchhoff equation and quantum current and energy spectrum of a homogeneous mesoscopic dissipation transmission line

On the basis of quantization of charge, the loop equations of quantum circuits are investigated by using the Heisenberg motion equation for a mesoscopic dissipation transmission line. On the supposition that the system has a symmetry under translation in charge space, the quantum current and the quantum energy spectrum in the mesoscopic transmission line are given by solving their eigenvalue equations. Results show that the quantum current and the quantum energy spectrum are not only related to the parameters of the transmission line, but also dependent on the quantized character of the charge obviously.     

Energy spectrum of fermionized bosonic atoms in optical lattices

We investigate the energy spectrum of fermionized bosonic atoms, which behave very much like spinless noninteracting fermions, in optical lattices by means of the perturbation expansion and the retarded Green's function method. The results show that the energy spectrum splits into two energy bands with single-occupation; the fermionized bosonic atom occupies nonvanishing energy state and left hole has a vanishing energy at any given momentum, and the system is in Mott-insulating state with a energy gap. Using the characteristic of energy spectra we obtained a criterion with which one can judge whether the Tonks-Girardeau (TG) gas is achieved or not.     

Thermodynamic properties of massless Dirac–Weyl fermions under the generalized uncertainty principle

The Dirac–Weyl equation characterized quasi-particles in the T3 lattice are studied under external magnetic field using the generalized uncertainty principle(GUP). The energy spectrum of the quasi-particles is found by the Nikiforov–Uvarov method. Based on the energy spectrum obtained, the thermodynamic properties are given, and the influence of the GUP on the statistical properties of systems is discussed. The results show that the energy and thermodynamic functions of massless Dirac–Weyl fermions in the T3 lattice depend on the variation of the GUP parameter.     

Level crossing in a two-photon Jaynes—Cummings model

In this paper,the energy spectrum of the two-photon Jaynes-Cummings model(TPJCM) is calculated exactly in the non-rotating wave approximation(non-RWA),and we study the level-crossing problem by means of fidelity.A narrow peak of the fidelity is observed at the level-crossing point,which does not appear at the avoided-crossing point.Therefore fidelity is perfectly suited for detecting the level-crossing point in the energy spectrum.     

Energy spectrum of cosmic protons and helium nuclei by a hybrid measurement at 4300 m a.s.l.

The energy spectrum of cosmic Hydrogen and Helium nuclei has been measured below the so-called "knee" by using a hybrid experiment with a wide field-of-view Cherenkov telescope and the Resistive Plate Chamber(RPC) array of the ARGO-YBJ experiment at 4300 m above sea level. The Hydrogen and Helium nuclei have been well separated from other cosmic ray components by using a multi-parameter technique. A highly uniform energy resolution of about 25% is achieved throughout the whole energy range(100–700 TeV). The observed energy spectrum is compatible with a single power law with index γ =-2.63±0.06.     

Time-dependent approach to the double-channel dissociation of the NaCs molecule induced by pulsed lasers

The dynamics of the double-channel dissociation of the NaCs molecule is investigated by using the time-dependent wave packet （TDWP） method with the ＂split operator-Fourier transform＂ scheme. At a given wavelength and intensity of laser pulse, the population of each state changing with time is obtained. The photo-absorption spectra and kinetic- energy distribution of the dissociation fragments, which exhibit vibration-level structure and dispersion of the wave packet, respectively, are also obtained. The results show that by increasing the laser intensity, one can find not only the band center shift of the photo-absorption spectrum, but also the change of the fragment energy. The appearance of the diffusive band in the photo-absorption spectrum and the multiple peaks in the kinetic-energy spectrum can be attributed to the effects of the predissoeiation limit and the external field.     

Light-Induced Hofstadter＇s Butterfly Spectrum of Ultracold Atoms on the Two-Dimensional Kagomé Lattice

We investigate the energy spectrum of ultracold atoms on the two-dimensional Kagomé optical lattice under an effective magnetic field, which can be realized with laser beams. We derive the generalized Harper＇s equations from the Schr？dinger equation. The energy spectrum with a fractal band structure is obtained by numerically solving the generalized Harper＇s equations. We analyze the properties of the Hofstadter＇s butterfly spectrum and discuss its observability.     

Study of an unfolding algorithm for D-T neutron energy spectra measurement using a recoil proton method

A proton recoil method for measuring D-T neutron energy spectra using polyethylene film and a Si(Au) surface barrier detector is presented. An iteration algorithm for unfolding the recoil proton energy spectrum to the neutron energy spectrum is investigated. The response matrices R of the polyethylene film at angles of 0° and 45° were obtained by simulating the recoil proton energy spectra from mono-energetic neutrons using the MCNPX code. With an assumed D-T neutron spectrum, the recoil proton spectra from the polyethylene film at angles of 0° and 45° were also simulated using the MCNPX code. Based on the response matrices R and the simulated recoil proton spectra at 0° and 45°, the respective unfolded neutron spectra were obtained using the iteration algorithm, and compared with the assumed neutron spectrum. The results show that the iteration algorithm method can be applied to unfold the recoil proton energy spectrum to the neutron energy spectrum for D-T neutron energy spectra measurement using the recoil proton method.     

Development of the spectrum of gamma-ray burst pulses influenced by the intrinsic spectral evolution and the curvature effect

The spectral evolution of gamma-ray burst pulses assumed to arise from the emission of fireballs is explored. It is found that due to the curvature effect, the integrated flux is well related to peak energy by a power law in the decaying phase of pulses, where the index is about 3, which does not depend on intrinsic emission and the Lorentz factor. The spectra of pulses in the decaying phase are slightly different from each other when different intrinsic spectral evolution patterns are considered, indicating that it is dominated by the curvature effect. In the rising phase, the integrated flux keeps increasing whilst the peak energy remains unchanged when the intrinsic emission bears an unchanged spectrum. Within this phase, the flux decreases with the increase of the peak energy for a hard-to-soft intrinsic spectrum, and for a soft-to-hard-to-soft intrinsic spectrum, the flux generally increases with the increase of the peak energy. An intrinsic soft-to-hard-to-soft spectral evolution within a co-moving pulse would give rise to a pulse-like evolutionary curve for the peak energy.     

Monte Carlo simulation of prompt γ-ray spectra from depleted uranium under D-T neutron irradiation and electron recoil spectra in a liquid scintillator detector

To overcome the problem of inefficient computing time and unreliable results in MCNP5 calculation, a two-step method is adopted to calculate the energy deposition of prompt γ-rays in detectors for depleted uranium spherical shells under D-T neutron irradiation. In the first step, the γ-ray spectrum for energy below 7 MeV is calculated by MCNP5 code; secondly, the electron recoil spectrum in a BC501 A liquid scintillator detector is simulated based on EGSnrc Monte Carlo Code with the γ-ray spectrum from the first step as input. The comparison of calculated results with experimental ones shows that the simulations agree well with experiment in the energy region 0.4–3 MeV for the prompt γ-ray spectrum and below 4 MeVee for the electron recoil spectrum. The reliability of the two-step method in this work is validated.     

Accurate studies on the full vibrational energy spectra and molecular dissociation energies for some electronic states of halogen molecule

This paper obtains accurate vibrational spectroscopic constants and full vibrational energy spectrum by the algebraic method (AM) for some electronic states of halogen diatomic molecules.Motivated by the recent success of obtaining the dissociation energies of Li 2 molecule by using a new analytical formula,it further extends the formula to study the dissociation energies of halogen diatomic molecules.The results show that the AM spectrum and the theoretical dissociation energies agree well with RKR data and experimental data respectively.