On the theory of chirped optical solitons in fiber lines with varying dispersion

We study a soliton solution of a path-averaged (in the spectral domain) propagation equation governing the transmission of a chirped breather pulse in the fiber lines with dispersion compensation. We demonstrate that the averaged Hamiltonian model correctly describes features of the chirped soliton observed in numerical simulations and experiments. We show that the Hamiltonian is bounded from below if the average dispersion is anomalous 〈 d〉>0); that, together with the condition H _sol<0, indicates stability of dispersion-managed solitons in this region. Pis’ma Zh. éksp. Teor. Fiz. 68, No. 11, 791–795 (10 December 1998) Published in English in the original Russian journal. Edited by Steve Torstveit.     

Thermal entanglement and teleportation in a two-qubit Heisenberg XXZ chain with different Dzyaloshinskii-Moriya interactions

We study the thermal output entanglement and teleportation in a two qubit Heisenberg XXZ chain with different Dzyaloshinskii-Moriya (DM) interactions. The analytical expressions of the output entanglement and the average fidelity are obtained for this model. We find the entanglement of replica states will be induced by some large value of D_z and the output entanglement exists for the case of J_z < − 1. The influences of the different DM interactions on the fidelity of teleportation are studied. We show that by introducing the x-component DM interaction, the average fidelity F_A can reach its maximum value 1.     

Phenomenology of colored radiative neutrino mass model and its implications on cosmic-ray observations

We extend the colored Zee–Babu model with a gauged U(1)B-L symmetry, and a scalar singlet dark matter(DM) candidate S. The spontaneous breaking of U(1)B-L leaves a residual Z_2 symmetry that stabilizes the DM, and generates a tiny neutrino mass at the two-loop level with the color seesaw mechanism. After investigating the DM and flavor phenomenology of this model systematically, we further focus on its imprint on two cosmic-ray anomalies: The Fermi-LAT gamma-ray excess at the Galactic Center(GCE), and the Pe V ultra-high energy(UHE)neutrino events at the IceCube. We found that the Fermi-LAT GCE spectrum can be well-fitted by DM annihilation into a pair of on-shell singlet Higgs mediators while being compatible with the constraints from the relic density,direct detections, and dwarf spheroidal galaxies, in the Milky Way. Although the UHE neutrino events at the IceCube could be accounted for by the resonance production of a Te V-scale leptoquark, the relevant Yukawa couplings have been severely limited by the current low-energy flavor experiments. We subsequently derive the IceCube limits on the Yukawa couplings by employing its latest six-year data.     

Entanglement in Mixed-Spin (1/2, 3/2) Heisenberg XXZ Model with Dzyaloshinskii-Moriya Interaction

In this paper, the entanglement in a mixed-spin (1/2, 3/2) Heisenberg XXZ model with Dzyaloshinskii-Moriya (DM) interaction in an inhomogeneous external magnetic field is studied. We not only calculate the ground-state entanglement but also investigate the behaviors of quantum phase transition following the changes of DM interaction and nonuniform magnetic field. More importantly, we note that the DM interaction improves the critical magnetic field B _c , the critical temperature T _c and broadens the region of entanglement.     

Heavy decaying dark matter and large-scale anisotropy of high-energy cosmic rays

We examine the role of the large-scale anisotropy of the high-energy cosmic ray distribution in a search for the heavy decaying dark matter (DM) signal. Using recent anisotropy measurements from the extensive air shower (EAS) observatories, we constrain the lifetime of the DM particles with masses 10⁷ ≤ M _X ≤ 10¹⁶ GeV. These constraints appear to be weaker than that obtained with the high-energy gamma-ray limits. We also estimate the desired precision level for the anisotropy measurements to discern the decaying DM signal marginally allowed by the gamma-ray limits and discuss the prospects of the DM search with the modern EAS facilities.     

The supersymmetric Standard Models with decaying and stable dark matters

We propose two supersymmetric Standard Models (SMs) with decaying and stable dark matter (DM) particles. To explain the SM fermion masses and mixings and have a heavy decay DM particle S, we consider the Froggatt–Nielsen mechanism by introducing an anomalous U(1) _X gauge symmetry. Around the string scale, the U(1) _X gauge symmetry is broken down to a Z ₂ symmetry under which S is odd while all the SM particles are even. S obtains a vacuum expectation value around the TeV scale, and then it can three-body decay dominantly to the second/third family of the SM leptons in Model I and to the first family of the SM leptons in Model II. Choosing a benchmark point in the constrained minimal supersymmetric SM with exact R parity, we show that the lightest neutralino DM is consistent with the CDMS II experiment. Considering S three-body decay and choosing suitable parameters, we show that the PAMELA and Fermi-LAT experiments and the PAMELA and ATIC experiments can be explained in Model I and Model II, respectively.     

Self-similar core and oscillatory tails of a path-averaged chirped dispersion-managed optical pulse

We describe the breathing dynamics of the self-similar core and the oscillating tails of a dispersion-managed (DM) soliton. The path-averaged propagation equation governing the shape of the DM soliton in an arbitrary dispersion map is derived. The developed theory correctly predicts the locations of the dips in the tails of the DM soliton. A general solution of the propagation equation is presented in terms of chirped Gauss-Hermite orthogonal functions.     

Dispersion-managed soliton in a strong dispersion map limit

A dispersion-managed optical system with stepwise periodic variation of dispersion is studied in a strong dispersion map limit in the framework of the path-averaged Gabitov-Turitsyn equation. The soliton solution is obtained by analytical and numerical iteration of the path-averaged equation. An efficient numerical algorithm for finding a DM soliton shape is developed. The envelope of soliton oscillating tails is found to decay exponentially in time, and the oscillations are described by a quadratic law.     

Quantum Coherence and Correlation in Spin Models with Dzyaloshinskii-Moriya Interaction

We study quantum coherence and quantum correlation for detecting quantum phase transition (QPT) by means of quantum renormalization group (QRG) in various spin chain models with Dzyaloshinskii-Moriya (DM) interaction, including XXZ model with DM interaction, Ising model with DM interaction and XY model with DM interaction. It is found that through enough QRG iterations, l ₁ norm quantum coherence and one-norm geometric quantum discord can effectively characterize QPT. We also discuss the effect of DM interaction and anisotropy on quantum coherence and quantum correlation.     

Dark Matter annihilation in small-scale clumps in the Galactic halo

The enhancement of the annihilation signal due to Dark Matter (DM) clumpiness in the Galactic halo, valid for arbitrary DM particles, is described. The mass spectrum of small-scale DM clumps with M≤10³ M _⊙ is calculated with tidal destruction of the clumps taken into account within the hierarchical model of clump structure. The mass distribution of the clumps has a cutoff at M _min due to diffusion of DM particles out of a fluctuation and free streaming. In the case of neutralino (considered as a pure bino) being a DM particle, M _min～10⁸ M _⊙. The evolution of the density profile in a DM clump does not result in singularity, because of formation of the core under the influence of tidal interaction. The number density of clumps as a function of their mass, radius, and distance to the Galactic center is presented.     

Real gauge singlet scalar extension of the Standard Model: A possible candidate for cold dark matter

The simplest extension of Standard Model (SM) is considered in which a real SM gauge singlet scalar with an additional discrete symmetry Z ₂ is introduced to SM. This additional scalar can be a viable candidate of cold dark matter (CDM) since the stability of S is achieved by the application of Z ₂ symmetry on S. Considering S as a possible candidate of CDM, Boltzmann’s equation is solved to find the freeze-out temperature and relic density of S for Higgs mass 120 GeV in the scalar mass range 5 GeV to 1 TeV. As HHSS coupling δ ₂ appearing in Lagrangian depends upon the value of scalar mass m _S and Higgs mass m _h, the m _S???δ ₂ parameter space has been constrained by using the Wilkinson microwave anisotropy probe (WMAP) limit on the relic density of DM in the Universe and the results of recent ongoing DM direct search experiments, namely CDMS-II, CoGeNT, DAMA, EDELWEISS-II, XENON-10 and XENON-100. From such analyses, two distinct mass regions are found (a lower and higher mass domain) for such a DM candidate that satisfy both the WMAP limit and the experimental results considered here. The possible differential direct detection rates and annual variation of total detection rates have been estimated for this scalar DM candidate S for two detector materials, namely Ge and Xe. Finally, the γ-ray flux has been calculated from the galactic centre due to annihilation of two 130 GeV scalar DM into two monoenergetic γ-rays.     

Critical behavior of XY spin chain with Dzyaloshinsky-Moriya interaction studied in terms of Loschmidt echo

In this paper, the critical behavior of the general XY spin chain with the Dzyaloshinsky-Moriya (DM) interaction is studied by means of a Loschmidt Echo (LE) calculation. LE presents a Gauss decay in the region of magnetic field intensity |λ|<1 and an exponential decay in the region of |λ|>1. There exists a critical spin chain size N_C. When spin chain size is larger than N_C, the value of λ corresponding to the minimum value of LE (λ_m) is independent of the spin chain size and keeps a stable value. In the region of λ<0, the stable value is same for different DM interactions. In the region of λ>0, the stable value varies with changing DM interaction.     

Exploring the singlet scalar dark matter from direct detections and neutrino signals via its annihilation in the Sun

We explore the singlet scalar dark matter (DM) from direct detections and high energy neutrino signals generated by the solar DM annihilation. Two singlet scalar DM models are discussed, one is the real singlet scalar DM model as the simple extension of the standard model (SSDM-SM) with a discrete _Z2$Z_2$ symmetry, and another is the complex singlet scalar DM model as the simple extension of the left–right symmetric two Higgs bidoublet model (SSDM-2HBDM) with P and CP   symmetries. To derive the Sun capture rate, we consider the uncertainties in the hadronic matrix elements and calculate the spin-independent DM-nucleon elastic scattering cross section. We find that the predicted neutrino induced upgoing muon fluxes in the region 3.7 GeV?_mD?4.2 GeV$3.7\text{GeV}?m_D?4.2\text{GeV}$ slightly exceed the Super-Kamiokande limit in the SSDM-SM. However, this exceeded region can be excluded by the current DM direct detection experiments. For the SSDM-2HBDM, one may adjust the Yukawa couplings to avoid the direct detection limits and enhance the predicted muon fluxes. For the allowed parameter space of the SSDM-SM and SSDM-2HBDM, the produced muon fluxes in the Super-Kamiokande and muon event rates in the IceCube are less than the experiment upper bound and atmosphere background, respectively.     

Optoacoustic laser Stark spectroscopy in the ν2 band of 14NH3

Laser Stark spectroscopy of the R(5, K) transitions in the ν₂ band of ammonia was carried out using coincidences with the 9-μm band CO₂ laser lines. We observed 22 Doppler-free resonances by using an optoacoustic detector and a Lamb-dip stabilized CO₂ laser. A simultaneous analysis of sa, aa, and ss lines yields zero-field transition frequencies with an absolute accuracy of 1 ～ 2 MHz.     

Enhancing the Trace Norm and Bures Norm Measurement-Induced Nonlocality in the Heisenberg XYZ Model

Nonlocality is one unique characteristic of quantum mechanics and an essential resource for quantum communication and computation. We investigate two measures of the well-defined geometric measurement-induced nonlocality (MIN) in the Heisenberg XYZ model, and found that considerable enhancement of the MINs can be achieved by tuning strength of the anisotropic parameter, the J_z coupling, and the Dzyaloshinsky-Moriya (DM) interaction of the model. Particularly, the maxima of the two MINs can be obtained when the strength of the J_z coupling or the DM interaction approaches infinity. We have also demonstrated the singular behaviors of the two MINs such as the nonunique states ordering and the sudden change behaviors.     

Path-averaged differential meter of atmospheric turbulence parameters

A path-averaged differential meter of the structure constant of the atmospheric refractive index, C _n ², has been developed and tested. The results of a model numerical experiment on measuring C _n ² and the horizontal component of average wind velocity transverse to the path are reported.     

Interpretation of the DAMPE 1.4 TeV peak according to the decaying dark matter model

Highly accurate measurements of cosmic ray electron flux by the dark matter particle explorer(DAMPE) ranging between 25 Ge V and 4.6 Te V have recently been published. A sharp peak structure was found at ～ 1.4 Te V. This unexpected peak structure can be reproduced by the annihilation/decay of a nearby dark matter(DM) halo. In this study, we adopt the decaying-DM model to interpret the ～ 1.4 Te V peak. We found that the decay products of the local DM subhalo could contribute to the DMAPE peak with mDM= 3 Te V and τ～ 10~(28) s. We also obtain constraints on DM lifetime and the distance of the local DM subhalo by comparison with DAMPE data.     

Long-wave IR emission in CH3I pumped by a continuously tunable,narrowed-line,CO2 laser

About 150 FIR lines are produced in CH₃I by pumping with a narrowed-line continuously tunable CO₂ laser the 2ν₃ P, Q bands at 9.6 μm. We have obtained in the 330–1560 μm wavelength range, up to 2 μJ pulsed energies by pumping some of the K-sublevels of the P (16≤J≤46) and R (16≤J≤60) absorption lines.     

Water in planetary and cometary atmospheres: H2O/HDO transmittance and fluorescence models

We developed a modern methodology to retrieve water (H₂O) and deuterated water (HDO) in planetary and cometary atmospheres, and constructed an accurate spectral database that combines theoretical and empirical results. On the basis of a greatly expanded set of spectroscopic parameters, we built a full non-resonance cascade fluorescence model and computed fluorescence efficiencies for H₂O (500 million lines) and HDO (700 million lines). The new line list was also integrated into an advanced terrestrial radiative transfer code (LBLRTM) and adapted to the CO₂ rich atmosphere of Mars, for which we adopted the complex Robert–Bonamy formalism for line shapes. We retrieved water and D/H in the atmospheres of Mars, comet C/2007 W1 (Boattini), and Earth by applying the new formalism to spectra obtained with the high-resolution spectrograph NIRSPEC/Keck II atop Mauna Kea (Hawaii). The new model accurately describes the complex morphology of the water bands and greatly increases the accuracy of the retrieved abundances (and the D/H ratio in water) with respect to previously available models. The new model provides improved agreement of predicted and measured intensities for many H₂O lines already identified in comets, and it identifies several unassigned cometary emission lines as new emission lines of H₂O. The improved spectral accuracy permits retrieval of more accurate rotational temperatures and production rates for cometary water.     

Kinetic and mass mixing with three abelian groups

We present the possible mixing effects associated with the low-energy limit of a Standard-Model extension by two abelian gauge groups U₁(1)×U₂(1). We derive general formulae and approximate expressions that connect the gauge eigenstates to the mass eigenstates. Applications using the well-studied groups UB(1), U(1)_B−L, U(1)_Lα−Lβ (Lα being lepton flavor numbers), and UDM(1) (a symmetry acting only on the dark matter sector) are discussed briefly.