ALBERT

Description: Systematic numerical study of near-infrared radiation formed during filamentation in air revealed the formation of robust light bullet first registered in the experiment (Chen et al. in Appl Phys B 91:219, 2008 ). The near-infrared light bullet propagates along the filament axis with the divergence 〈1 mrad and the quasi-constant duration of ~30 fs. The central wavelength of the bullet gradually increases from 860 to 900 nm during the propagation. The results of our numerical simulation are in agreement with the experiments (Chen et al. in Appl Phys B 91:219,  2008 ; Uryupina et al. in Appl Phys B 110:123, 2013 ).

Description: Flame flatness is one of the most critical factors in evaluating the performance of a flat-flame burner. In this paper, the flame flatness of a flat-flame burner is validated using a resolution-doubled one-dimensional wavelength modulation spectroscopy tomography (1D-WMST) technique that only uses one view of multiple parallel laser beams. When the interval of two neighboring parallel laser beams is Δ r , a designed novel geometry of the parallel laser beams realizes a doubled tomographic resolution of Δ r /2. Using the proposed technique, the distributions of temperature and H 2 O mole fraction in an axisymmetric premixed flame are simultaneously reconstructed and hence the flame flatness of a flat-flame burner can be validated. The flatness factor is quantitatively described by the similarity between the reconstructed and expected distributions of H 2 O mole fraction. For flat and non-flat flames, the experimental results agree well with the CFD simulation results, denoting that the resolution-doubled 1D-WMST technique provides a noninvasive, reliable and low cost way to validate the flame flatness of the flat-flame burner.

Description: We report on the optical performances of laccaic acid dye in solution at different concentrations and dye–poly(methyl methacrylate) composite thin films. The linear spectral characteristics including optical constants, i.e. refractive index ( n ) and extinction coefficient ( k ), were carried out in a comprehensive way through absorbance, fluorescence and ellipsometric studies. The nonlinear optical parameters such as nonlinear absorption coefficient β eff (or β 2 ), the imaginary third-order susceptibility (Im[ χ (3) ]) and the imaginary part of second-order hyperpolarizability ( γ ) of the samples were evaluated using the open-aperture Z-scan technique with a laser pulse duration of 10 ns at 532 nm wavelength. The corresponding numerical values of these parameters were of 10 −10 , 10 −11 and 10 −32 order, respectively. Two-photon absorption was revealed to be the main driving physical mechanism in the nonlinear response. This suggests that laccaic acid dye can be a potential candidate for NLO materials application.

Description: We demonstrate a sensor based on tunable diode laser absorption spectroscopy for the detection of hydrogen fluoride (HF) gas at ambient pressure. Absorption from the HF R(1) ro-vibrational peak at ν̃  = 4038.962 cm −1 (2.476 µm) in the fundamental (Δ ν  = 1) band is measured. A quantitative spectral fit based on HITRAN data is used to account for overlapping spectral peaks of HF and water vapor, with an rms residual noise of 5 × 10 −4 absorbance units. The sensor is optimized for the detection of transient variations in HF concentration. We measure noise-equivalent concentrations for HF of 38 parts-per-trillion by volume (ppt) for 1-s integration times and 2.3 ppt for 10-min integration times.

Description: We report on the absorption profile of the monoclinic holmium-doped \(\hbox {KY}(\hbox {WO}_4)_2\) crystal near the optic axis for the maximal absorption wavelength at 1960 nm. The full angular distribution of the absorption coefficient at the vicinity of such optical singularity has been experimentally and numerically investigated. Furthermore, laser experiments along the optic axis have been carried out. So-called conical refraction laser and classical Gaussian laser operation are compared near the optic axis, taking into account the complex absorption profile.

Description: We demonstrate a novel and compact fiber-probe pressure sensor based on a micro-Fabry–Perot interferometer (FPI). The device is fabricated by splicing both ends of a short-section simplified hollow-core photonic crystal fiber (SHC-PCF) with single-mode fibers. Then, a microchannel is drilled by a femtosecond laser micromachining in the SHC-PCF to allow air to diffuse in. The pressure sensing mechanism is based on the dependence of the air refractive index on pressure. We use both theory and experiment to investigate the sensing characteristics. A micro-FPI with a length of 272 μm demonstrates a pressure sensitivity of 4.071 nm/MPa at 1580 nm and a low-temperature sensitivity of 1.1 pm/°C at atmospheric pressure. We further study the temperature cross sensitivity of the sensor under different pressures. The sensor also shows strong stability and good reversibility, and may be potentially used in pressure sensing applications.

Description: We study the thermo-optic Goos–Hänchen (TOGH) effect in a prism–waveguide coupling structure with silicon-on-insulator waveguide. Stationary-phase method is utilized to calculate the TOGH shift. When the waveguide is regarded as a two-dimensional planar waveguide, a nonlinear relation between GH shift and temperature is obtained. Based on the noticeable TOGH effect, a sensitive temperature modulator or sensor can be realized. As the waveguide width is limited, the proposed structure can be regarded as a three-dimensional rectangular waveguide. We explore the GH shift and TOGH effect for different modes propagating in rectangular waveguide which show different linear relations between GH shift and temperature, which can be used to design mode-selective device based on TO effect.

Description: Transportation and communication networks are ubiquitous in nature and society. Uncovering the underlying topology as well as link weights, is fundamental to understanding traffic dynamics and designing effective control strategies to facilitate transmission efficiency. We develop a general method for reconstructing transportation networks from detectable traffic flux data using the aid of a compressed sensing algorithm. Our approach enables full reconstruction of network topology and link weights for both directed and undirected networks from relatively small amounts of data compared to the network size. The limited data requirement and certain resistance to noise allows our method to achieve real-time network reconstruction. We substantiate the effectiveness of our method through systematic numerical tests with respect to several different network structures and transmission strategies. We expect our approach to be widely applicable in a variety of transportation and communication systems.

Description: The dynamic shot noise in a molecular quantum dot connected to two non-collinear ferromagnetic terminals under the perturbation of ac fields has been investigated by the nonequilibrium Green’s function approach. The formulas of current, current correlation, and shot noise have been presented in the weak electron-phonon (el-ph) interaction regime to address the cooperated behaviors generated by the photon and phonon perturbation. The photon and phonon perturbations induce quite different current correlations, and the noise suppression occurs unambiguously by increasing the phonon energy in the valley regime. The suppression of shot noise comes from drawing the unbalanced current correlation towards the balanced one, where coherent current correlation takes major role. The suppression of photon-assisted shot noise can be completed mainly by rotating polarization angle of the terminals, and increasing the phonon energy ħ ω 0 . The Fano factor is enhanced considerably by the el-ph interaction, and it is also enhanced by increasing the polarization angle from θ = 0 to θ = π .

Description: We report on an experimental study of vacuum-induced suppression and enhancement of four-wave mixing (FWM) signal in a composite atom–cavity system. By scanning the additional dressing field, the suppression ratio of the FWM signal can reach 90 % compared with 40 % without cavity. We attribute the enhanced suppression and enhancement to the atom–cavity coupling arising from a vacuum-induced Raman process, which amplifies the dressing effect from the additional field. Also, the dressing asymmetry of the atom–cavity coupling is discussed and used to estimate the nonlinearity of atomic medium in the cavity. The suppression and enhancement can be interpreted by a dressed-state picture and agree with theoretical calculations. The investigation may find applications in optical switch and quantum memory controlled by cavity.

Description: By simultaneously using a multi-walled carbon nanotube (MWCNT) and a monolayer graphene saturable absorber (SA) in the cavity, a laser-diode-pumped dual-loss-modulated passively Q-switched Tm:LuAG laser at 2 μm is demonstrated for the first time. In comparison with the singly passively Q-switched laser with MWCNT or monolayer graphene SA, the doubly passively Q-switched laser with both MWCNT and monolayer graphene SA can generate shorter pulse width and higher peak power. A maximum pulse width compression ratio of 2.8 and a highest peak power enhancement factor of 4 were obtained at the incident pump power of 5.8 W, respectively. The experimental results show that the dual-loss modulation is an efficient method to compress the pulse widths and improve the peak powers of the Q-switched lasers at 2 μm.

Description: Photoexcitation dynamics in a three-step photoionization of atomic uranium has been investigated using time-resolved two-color three-photon and delayed three-color three-photon photoionization signals. Investigations are carried out in an atomic beam of uranium coupled to a high-resolution time-of-flight mass spectrometer using three tunable pulsed dye lasers. Dependence of both the signals on the second-step laser photon fluence is studied. Excited-level-to-excited-level photoexcitation cross section and photoionization cross section from the second excited level are simultaneously determined by analyzing the two-color three-photon and three-color three-photon photoionization signals using population rate equation model. Using this methodology, photoexcitation and photoionization cross sections at seven values of the second-step laser wavelength have been measured. From the measured values of the photoexcitation cross sections, we have obtained excited-level-to-excited-level transition probabilities and compared these with the values reported in the literature.

Description: A theoretical analysis of the photorefractive sensitivity of Ti:PPLN ridge waveguides in comparison with conventional Ti:PPLN channel waveguides is presented. In particular, intensity-dependent photorefraction, effective indices, waveguide modes and power-dependent SHG in Ti:PPLN ridge and channel waveguides are modeled for a wide range of parameters. Results predict a much better damage resistance of Ti:PPLN waveguides with ridge geometry in comparison with conventional indiffused channels. This superiority of ridge waveguides is attributed to their higher effective refractive index contrast and more tightly confined guided modes. The theoretical predictions are supported by experimental results for second harmonic generation (SHG) at room temperature and for light-induced detuning characteristics of the phase-matching wavelength.

Description: In this paper, we develop a new method for the multifractal characterization of two-dimensional nonstationary signal, which is based on the detrended fluctuation analysis (DFA). By applying to two artificially generated signals of two-component ARFIMA process and binomial multifractal model, we show that the new method can reliably determine the multifractal scaling behavior of two-dimensional signal. We also illustrate the applications of this method in finance and physiology. The analyzing results exhibit that the two-dimensional signals under investigation are power-law correlations, and the electricity market consists of electricity price and trading volume is multifractal, while the two-dimensional EEG signal in sleep recorded for a single patient is weak multifractal. The new method based on the detrended fluctuation analysis may add diagnostic power to existing statistical methods.

Description: We investigate the universality aspects of the four-dimensional random-field Ising model (RFIM) using numerical simulations at zero temperature. We consider two different, in terms of the field distribution, versions of the model, namely a Gaussian RFIM and an equal-weight trimodal RFIM. By implementing a computational approach that maps the ground-state of the system to the maximum-flow optimization problem of a network, we employ the most up-to-date version of the push-relabel algorithm and simulate large ensembles of disorder realizations of both models for a broad range of random-field values and system sizes. Using as finite-size measures the sample-to-sample fluctuations of the order parameter of the system, we propose, for both types of distributions, estimates of the critical field h c and the critical exponent ν of the correlation length, the latter suggesting that the two models in four dimensions share the same universality class.

Description: Some temporal networks, most notably citation networks, are naturally represented as directed acyclic graphs (DAGs). To detect communities in DAGs, we propose a modularity for DAGs by defining an appropriate null model (i.e., randomized network) respecting the order of nodes. We implement a spectral method to approximately maximize the proposed modularity measure and test the method on citation networks and other DAGs. We find that the attained values of the modularity for DAGs are similar for partitions that we obtain by maximizing the proposed modularity (designed for DAGs), the modularity for undirected networks and that for general directed networks. In other words, if we neglect the order imposed on nodes (and the direction of links) in a given DAG and maximize the conventional modularity measure, the obtained partition is close to the optimal one in the sense of the modularity for DAGs.

Description: Diffusion of information via networks has been extensively studied for decades. We study the general threshold model that embraces most of the existing models for information diffusion. In this paper, we first analyze diffusion processes under the linear threshold model, then generalize it into the general threshold model. We give a closed formula for estimating the final cascade size for those models and prove that the actual final cascade size is concentrated around the estimated value, for any network structure with node degrees ω (log  n ), where n is the number of nodes. Our analysis analytically explains the tipping point phenomenon that is commonly observed in information diffusion processes. Based on the formula, we devise an efficient algorithm for estimating the cascade size for general threshold models on any network with any given initial adopter set. Our algorithm can be employed as a subroutine for numerous algorithms for diffusion analysis such as influence maximization problem. Through experiments on real-world and synthetic networks, we confirm that the actual cascade size is very close to the value computed by our formula and by our algorithm, even when the degrees of the nodes are not so large.

Description: Building upon the findings of Muto et al. [Phys. Lett. A 136 , 33 (1989)] and Marchesoni and Lucheroni [Phys. Rev. E 44 , 5303 (1991)] about the growth of the number of (anharmonic) lattice solitons with increasing temperature and using a recent transport theory developed by the present authors [A.P. Chetverikov, W. Ebeling, G. Röpke, M.G. Velarde, Eur. Phys. J. B 87 , 153 (2014)] here we provide the fractional power law of the temperature dependence of resistivity in a rather general model for one-dimensional crystal lattices as, e.g., conducting polymers. We also show that the determining factor for the transport is the possibility of forming electron-soliton bound states (in short solectrons) with a most significant contribution arising from the (bosonic) bound state of two electrons to a soliton (in short bisolectrons).

Description: The electronic structure of isolated finite graphene nanoribbons is investigated by solving, at the Hartree-Fock (HF) level, the Pariser, Parr and Pople (PPP) many-body Hamiltonian. The study is mainly focused on 7-AGNR and 13-AGNR (Armchair Graphene Nano-Ribbons), whose electronic structures have been recently experimentally investigated. Only paramagnetic solutions are considered. The characteristics of the forbidden gap are studied as a function of the ribbon length. For a 7-AGNR, the gap monotonically decreases from a maximum value of ~6.5 eV for short nanoribbons to a very small value of ~0.12 eV for the longer calculated systems. Gap edges are defined by molecular orbitals that are spatially localized near the nanoribbon extremes, that is, near both zig-zag edges. On the other hand, two delocalized orbitals define a much larger gap of about 5 eV. Conductance measurements report a somewhat smaller gap of ~3 eV. The small real gap lies in the middle of the one given by extended states and has been observed by STM and reproduced by DFT calculations. On the other hand, the length dependence of the gap is not monotonous for a 13-AGNR. It decreases initially but sharply increases for lengths beyond 30 Å remaining almost constant thereafter at a value of ~2.1 eV. Two additional states localized at the nanoribbon extremes show up at energies 0.31 eV below the HOMO (Highest Occupied Molecular Orbital) and above the LUMO (Lowest Unoccupied Molecular Orbital). These numbers compare favorably with those recently obtained by means of STS for a 13-AGNR sustained by a gold surface, namely 1.4 eV for the energy gap and 0.4 eV for the position of localized band edges. We show that the important differences between 7- and 13-AGNR should be ascribed to the charge rearrangement near the zig-zag edges obtained in our calculations for ribbons longer than 30 Å, a feature that does not show up for a 7-AGNR no matter its length.

Description: We study the effect of interfacial phenomena in two-dimensional perfect and random (or disordered) q -state Potts models with continuous phase transitions, using, mainly, Monte Carlo techniques. In particular, for the total interfacial adsorption, the critical behavior, including corrections to scaling, are analyzed. The role of randomness is scrutinized. Results are discussed applying scaling arguments and invoking findings for bulk critical properties. In all studied cases, i.e., q = 3, 4, and q = 8, the spread of the interfacial adsorption profiles is observed to increase linearly with the lattice size at the bulk transition point.

Description: Two-color laser-induced incandescence (LII) measurements are carried out in diffusion flames and at the exhaust of a homemade soot generator, both fueled with ethylene and methane. Two-color prompt LII signals, their ratio and the corresponding temperature have been analyzed as a function of laser fluence. In particular, the effect of fuel, soot load and gas/particle initial temperature on LII measurements have been investigated. LII spectral measurements have also been performed in all conditions for validation. The results suggest that the incandescence is sensitive to both optical and non-optical physical properties of the particles. Moreover, soot volume fraction measurements are dependent on the laser fluence used, indicating that the soot temperature influences the refractive index absorption function. Such issues can be overcome by working at high laser fluences, where the saturation curves are independent from the experimental conditions if the soot absorption function near soot sublimation threshold is known.

Description: Inclusion of spin-dependent interactions in graphene in the vicinity of the Dirac points can be posed in terms of non-Abelian gauge potentials. Such gauge potentials being surrogates of physical electric fields and material parameters, only enjoy a limited gauge freedom. A general gauge transformation thus changes the physical model. We argue that this property can be useful in connecting reference physical situations, such as free particle or Rashba interactions to non-trivial physical Hamiltonians with a new set of spin-orbit interactions, albeit constrained to being isoenergetic. We analyse different combinations of spin-orbit interactions in the case of monolayer graphene and show how they are related by means of selected non-Abelian gauge transformations.

Description: The Hubbard model of bosons on two dimensional lattices with a lowest flat band is discussed. In these systems there is a critical density, where the ground state is known exactly and can be represented as a charge density wave. Above this critical filling, depending on the lattice structure and the interaction strength, the additional particles are either delocalised and condensate in the ground state, or they form pairs. Pairs occur at strong interactions, e.g., on the chequerboard lattice. The general mechanism behind this phenomenon is discussed.

Description: Investigations of the electronic properties and transport properties of Mg 2 Si under uniaxial [110] strain have been performed by using first-principle density-functional and Boltzmann’s transport theories. The effect of compressive and tensile uniaxial strains has been studied by changing the γ angle of the conventional cell from ± 1° to ± 4°. We show that, the Seebeck property of the constrained bulk lattice at high temperature, when plotted with respect to the charge carrier concentrations, is similar to that of the (110) thin film at low temperature. This behaviour is evidenced when superimposing the Seebeck coefficient curves of both materials by shifting down the S curve of the constrained structure by about 150 K with respect to the temperature.

Description: In this study, In 2 O 3 /Ag/MoO 3 (IAM) nano-multilayer films are designed, and optimum thickness of each layer is calculated. These films were deposited by thermal evaporation technique and then annealed in air atmosphere at different temperatures for 1 h. The effects of annealing temperature on electrical, optical, and structural properties of the IAM system were investigated. The UV–visible–near-IR transmittance and reflectance spectra confirmed that the annealing temperature has significant influence on the electro‐optical characteristics of IAM films. High-quality IAM films with a low sheet resistance of 8.2 (Ω/□) and the maximum optical transmittance of 85 % at 120 °C annealing temperature were obtained. The effect of heat treatment on surface roughness of the layers was also investigated. Figure-of-merit quantity showed that the IAM films annealed at 120 °C have the best performance. X-ray diffraction patterns showed that the crystallinity of the structures enhanced with increase in annealing temperature. Organic light-emitting diodes (OLEDs) were fabricated on IAM anodes. The current density–voltage–luminance (J–V–L) characteristic measurements show that the electroluminescence performances of OLED with IAM anode are improved compared with the conventional ITO-based device. The results indicate that the designed system is suitable for use as transparent conductive anode in optoelectronic devices.

Description: We demonstrate the effectiveness of silicon phase masks to implement spatially resolved, multispectral imaging capabilities in the range of terahertz frequencies, using a standard setup of basic interest for time-domain spectrometry with a single-cell source and a single-cell detector. Our principle primarily aims at the development of robust and inexpensive systems. It consists of appropriate space-to-time encoding, in order to ensure single-scan triggering and then take advantage of rapid and self-consistent measurements in the two-dimensional space. The process enables very efficient discrimination giving access to a relevant spatial resolution in the analysis of small size, planar assemblies made of inhomogeneous materials. Benchmark results are provided to validate the concept, thanks to prototyping phase masks with 2 × 2 pixels, prior evidencing actual performance limitations in the case of 3 × 3 pixels. Due to the frequency bandwidth of 0.1–1.5 THz in our setup and to the available operating conditions, currently acceptable pixel resolutions lie in the range of 3–4 mm. Numerical modeling by means of finite elements helps to discuss these numbers and to investigate the relevant theoretical issues, figuring the main propagation issues in connection with a sub-picosecond seed pulse throughout various masks. This involves diffraction and trailing edge effects when crossing the mask together with residual, parasitic reflections. Finally, we give a consistent prospective for improved performance, via realistic updates regarding the architecture of the setup and complementary post-processing. Further values for the attainable spatial resolution then range from 5 × 5 to 6 × 6 pixels.

Description: The probability density functions (PDFs) of earthquake energy fluctuations at different times have fat tails with a q -Gaussian form. We analyze the PDFs of energy fluctuations for different faulting styles and the relationship between the deviation from the Gaussian distribution and the faulting style. There are common features between the b -value and q -parameter dependence on the faulting styles. We suggest that the deviation from Gaussian distribution for the PDFs of earthquake energy fluctuation may be a useful indicator in earthquake-hazard research.

Description: This paper analyzes several interest rates time series from the United Kingdom during the period 1999 to 2014. The analysis is carried out using a pioneering statistical tool in the financial literature: the complexity-entropy causality plane. This representation is able to classify different stochastic and chaotic regimes in time series. We use sliding temporal windows to assess changes in the intrinsic stochastic dynamics of the time series. Anomalous behavior in the Libor is detected, especially around the time of the last financial crisis, that could be consistent with data manipulation.

Description: A combination of optical emission spectroscopy (OES) and cavity ring-down spectroscopy (CRDS) has enabled to determinate the number densities of CH(A 2 Δ) and CH(X 2 Π) radicals simultaneously in a cascaded arc plasma reactor operating with a CH 4 /Ar mixture. It is found that the number density of CH(A 2 Δ) radical increases with discharge current at first and then decreases. However, the number density of CH(X 2 Π) radical decreases with discharge current when the rate of CH 4 flow to total flow is lower than 1 %, while it increases slightly with discharge current when the rate is 1.5 %. The results reveal that CH radicals are deviation from excitation equilibrium. Although OES is the simplest and most straightforward means to investigate the CH radical behavior, it is not enough to provide the information of the CH(X 2 Π) number density, and additional methods, such as CRDS, are needed in the cascaded arc plasma jet.

Description: In this paper, we present a numerical study based on 3D FDTD (finite-difference time-domain) simulations that demonstrate the high sensitivity of the optical response of a bowtie nano-aperture antenna (BNA), engraved at the apex of a metal-coated tip, to the distance variation between it and a given substrate. This study mainly discussed the case of the collection mode regime of the BNA and considered the case of two different substrates (high and low refractive index). The coupling between the substrate and the BNA may greatly affect the properties of the optical resonance of the nano-antenna. A blueshift of the resonance wavelength, as large as \(\frac{\varDelta \lambda }{\lambda }=0.3\) , is obtained when the tip moves away over only 10 nm from the substrate (InP) interface. These results open the way to the design of stand-alone optical near-field probes that allow faithful interaction control with a given sample as a function of the distance between them.

Description: This paper demonstrates the effect of sintering parameters on the electrocaloric effect (ECE) in BaTiO 3 ferroelectric ceramics, especially the sintering temperature and atmosphere. The samples were prepared by solid-state reaction method. With the rise of sintering temperature from 1200 °C to 1350 °C, the grain size increases remarkably and the densification is improved. The 1350 °C sintered sample has better ferroelectricity and higher latent heat for ferroelectric-paraelectric phase transition than those of the 1200 °C sintered sample. Correspondingly, it exhibits much better ECE. If the sample is sintered in pure oxygen, instead of in air, all ferroelectricity, dielectric strength and ECE are further enhanced. The sample sintered at 1350 °C in oxygen exhibits an excellent ECE performance with ΔT max = 1.37 K and ΔS max = 1.75 J/kg K.

Description: The low energy continuum limit of graphene is effectively known to be modeled using the Dirac equation in (2 + 1) dimensions. We consider the possibility of using a modulated high frequency periodic driving of a two-dimensional system (optical lattice) to simulate properties of rippled graphene. We suggest that the Dirac Hamiltonian in a curved background space can also be effectively simulated by a suitable driving scheme in an optical lattice. The time dependent system yields, in the approximate limit of high frequency pulsing, an effective time independent Hamiltonian that governs the time evolution, except for an initial and a final kick. We use a specific form of 4-phase pulsed forcing with suitably tuned choice of modulating operators to mimic the effects of curvature. The extent of curvature is found to be directly related to ω −1 the time period of the driving field at the leading order. We apply the method to engineer the effects of curved background space. We find that the imprint of curvilinear geometry modifies the electronic properties, such as LDOS, significantly. We suggest that this method shall be useful in studying the response of various properties of such systems to non-trivial geometry without requiring any actual physical deformations.

Description: The structural, electronic, and optical properties of NpO 2 and PuO 2 have been investigated by means of the hybrid density functional theory (HDFT) using the full-potential linearized augmented plane (FP-LAPW) wave plus local orbitals (lo) method. The weight of exact Hartree-Fock (HF) exchange, α = 0.25, 0.35 and 0.40, are chosen for the hybrid density functional calculation. The obtained energy band gaps of NpO 2 and PuO 2 are 2.75 eV and 2.80 eV within α = 0.35 scheme, respectively, which are in excellent agreement with the recent experimental data. The calculated charge density and charge density differences in the (110) plane suggest the chemical bonds for the two actinide dioxides have main ionic character. Furthermore, the dielectric function and related optical parameters of the two compounds are firstly calculated using the HDFT method. In particular, the obtained refractive index n for PuO 2 is consistent well with the experimental value in the wavelength range of 400 to 900 nm. We also predicted the effective number of electrons ( n eff ) contributing in the inter-band transitions reach a saturation value above 32 eV per unit cell for NpO 2 and PuO 2 .

Description: We present a theory for Raman scattering on 2D quantum antiferromagnets. The microscopic Fleury-Loudon Hamiltonian is expressed in terms of an effective O (3)-model. Well within the Néel ordered phase, the Raman spectrum contains a two-magnon and a two-Higgs contribution, which are calculated diagramatically. The vertex functions for both the Higgs and magnon contributions are determined from a numerical solution of the corresponding Bethe-Salpeter equation. Due to the momentum dependence of the Raman vertex in the relevant B 1 g + E 2 g symmetry, the contribution from the Higgs mode is strongly suppressed. Except for intermediate values of the Higgs mass, it does not show up as separate peak in the spectrum but gives rise to a broad continuum above the dominant contribution from two-magnon excitations. The latter give rise to a broad, asymmetric peak at ω ≃ 2.44 J, which is a result of magnon-magnon interactions mediated by the Higgs mode. The full Raman spectrum is determined completely by the antiferromagnetic exchange coupling J and a dimensionless Higgs mass. Experimental Raman spectra of undoped cuprates turn out to be in very good agreement with the theory only with inclusion of the Higgs contribution. They thus provide a clear signature of the presence of a Higgs mode in spin one-half 2D quantum antiferromagnets.

Description: The present paper describes the research of the optical device for two-dimensional straightness measurement of technological machines. Mathematical study of an optical device, operating on the phase principle and measuring transversal displacements of machine parts in two directions ( X and Y ) during their linear longitudinal motion in a machine (alongside the Z axis), is presented. How to estimate the range of travel along the Z axis is analytically shown. At this range, the measurer gives correct measurements of transverse displacement. The necessary distance from the objective focus to the image plane was defined mathematically. The sample results of measuring the displacement of the table of a technological machine by using the optical device are presented in the paper. This optical device for non-contact straightness measurement can be used for measurement straightness in turning, milling, drilling, grinding machines and other technological machines, also in geodesy and cartography, and for moving accuracy testing of mechatronic devices, robotics and others.

Description: Non-resonant laser-induced thermal acoustics (LITA), a four-wave mixing technique, was applied to post-shock flows within a shock tube. Simultaneous single-shot determination of temperature, speed of sound and flow velocity behind incident and reflected shock waves at different pressure and temperature levels are presented. Measurements were performed non-intrusively and without any seeding. The paper describes the technique and outlines its advantages compared to more established laser-based methods with respect to the challenges of shock tube experiments. The experiments include argon and nitrogen as test gas at temperatures of up to 1000 K and pressures of up to 43 bar. The experimental data are compared to calculated values based on inviscid one-dimensional shock wave theory. The single-shot uncertainty of the technique is investigated for worst-case test conditions resulting in relative standard deviations of 1, 1.7 and 3.4 % for Mach number, speed of sound and temperature, respectively. For all further experimental conditions, calculated values stay well within the 95 % confidence intervals of the LITA measurement.

Description: Airflow induced by femtosecond laser (800 nm/1 kHz/25 fs) filamentation with different lengths was investigated in a laboratory cloud chamber. Various filament lengths were generated by adjusting laser energy and lens focal length. It was found that airflow patterns are closely related to filament intensity and length. Intense and long filaments are beneficial in updraft generation with large vortices above the filament, while intense and short filaments tend to promote the formation of well-contacted vortices below the filament. Differently patterned airflows induced elliptical snow piles with different masses. We simulated airflow in a cloud chamber numerically taking laser filaments as heat sources. The mechanisms of differently patterned airflow and snow formation induced by filaments were discussed.

Description: Tissue simulators, the so-called tissue phantoms, have been used to mimic human tissue for spectroscopic applications. Phantoms’ design depends on patterning the optical properties, namely absorption and scattering coefficients which characterize light propagation mechanisms inside the tissues. In this work, two calibration models based on measurements adopting integrating sphere systems have been used to determine the optical properties of the studied solid phantoms. Integrating sphere measurement results were fed into the calibration models using the multiple polynomial regression method and Newton–Raphson algorithm. The third-order polynomials have been used for optical properties predictions. Good agreement between the two models has been obtained. Role of solid phantoms’ components, namely titanium dioxide as a scatterer and black carbon as an absorber, has been discussed. Both of the two components showed observable effects on the absorption and scattering of light inside the solid tissue phantoms.

Description: We report a novel time-resolved photoacoustic-based technique for studying the thermal decomposition mechanisms of some secondary explosives such as RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine), picric acid, 4,6-dinitro-5-(4-nitro-1 H -imidazol-1-yl)-1 H -benzo[ d ] [ 1 – 3 ] triazole, and 5-chloro-1-(4-nitrophenyl)-1 H -tetrazole. A comparison of the thermal decomposition mechanisms of these secondary explosives was made by detecting NO 2 molecules released under controlled pyrolysis between 25 and 350 °C. The results show excellent agreement with the thermogravimetric and differential thermal analysis (TGA–DTA) results. A specially designed PA cell made of stainless steel was filled with explosive vapor and pumped using second harmonic, i.e., λ  = 532 nm, pulses of duration 7 ns at a 10 Hz repetition rate, obtained using a Q-switched Nd:YAG laser. The use of a combination of PA and TGA–DTA techniques enables the study of NO 2 generation, and this method can be used to scale the performance of these explosives as rocket fuels. The minimum detection limits of the four explosives were 38 ppmv to 69 ppbv, depending on their respective vapor pressures.

Description: For the first time, spatial distribution of major and trace elements has been studied in cholesterol gallstones using time-of-flight secondary mass ion mass spectrometry (TOF-SIMS). The TOF-SIMS has been used to study the elemental constituents of the center and surface parts of the gallstone sample. We have classified the gallstone sample using Fourier transform spectroscopy. The detected elements in cholesterol gallstone sample were carbon (C), hydrogen (H), calcium (Ca), sodium (Na), potassium (K), strontium (Sr), copper (Cu), iron (Fe), chromium (Cr), mercury (Hg) and lead (Pb). The detected molecules in the cholesterol gallstone were CH 3 + , CO 3 + , CaCO 3 + and C 3 H + . Our results revealed that the contents of these elements in cholesterol gallstone were higher in the center part than that in the surface part. In the present paper, we have also presented the UV–Vis spectroscopic studies of the center and surface parts of the gallstone sample which indicated the presence of a higher content of cholesterol in the surface part and bilirubin in the center part.

Description: Numerical experiments are carried out to calculate continuum emissivity and opacity of plasmas produced from laser-irradiated Au and Pb targets as hohlraum wall materials. Targets are considered to be solid or porous with different initial densities. Simulation results show a good agreement compared with the measured data. The results show that under identical conditions, X-ray emission is higher for Au plasma; however, by decreasing initial densities, X-ray yield enhancement is greater for Pb plasma. By using a Pb target with initial density of about 1.14 g cm −3 instead of solid Au target, the same X-ray yield even more can be obtained. Calculations also show that in the conditions of solid density targets, Pb plasma offers a little lower opacity in soft X-ray region. Decreasing initial density of Pb causes its opacity to increase and get closer to the opacity of solid Au which in turn reduces energy losses in hohlraum wall.

Description: In the present work, the atomic and the electronic structures of Au 3 N, AuN and AuN 2 are investigated using first-principles density-functional theory (DFT). We studied cohesive energy vs. volume data for a wide range of possible structures of these nitrides. Obtained data were fitted to a Birch-Murnaghan third-order equation of state (EOS) so as to identify the most likely candidates for the true crystal structure in this subset of the infinite parameter space, and to determine their equilibrium structural parameters. The analysis of the electronic properties was achieved by the calculations of the band structure and the total and partial density of states (DOS). Some possible pressure-induced structural phase transitions have been pointed out. Further, we carried out GW 0 calculations within the random-phase approximation (RPA) to the dielectric tensor to investigate the optical spectra of the experimentally suggested modification: Au 3 N(D0 9 ). Obtained results are compared with experiment and with some available previous calculations.

Description: In this work, materials used in the field of accessories for electrical cables have been characterised from a thermomechanical and electrical point of view, so to offer a realistic picture of material behaviour under a service involving the combined application of electrical charges and thermo-mechanical stresses. In particular, both materials are based on ethylene-vinylacetate (EVA) blend with the introduction in one case of aluminium trihydrate, whereas in the other case, carbon black was added, the two materials being referred as insulating and semi-conductive, respectively. The two materials had different rheological and thermal characteristics, which had an effect on electrical behaviour: however, the application of levels of radiation up to 60 kGy did not prove to widely change the profile of either polymer blends.

Description: A formula to obtain the cyclotron transition line-widths for a system of electrons interacting with confined-acoustic phonons through the deformation potential in a quantum well is derived using the projection-reduction method. The result contains the distribution functions for the electrons and phonons properly. Therefore, the phonon absorption and emission processes can be explained in an organized manner and the result can be represented diagrammatically, through which insight into the quantum dynamics of electrons in a solid can be obtained. The formula is used to calculate the cyclotron transition line-widths in silicon. It is shown that the line-width increases with increasing temperature but the well width and magnetic field dependence of the line-width are complicated. It is also shown that only a few low-energy confined modes contribute significantly to the line-widths.

Description: This paper investigates multi-crossing dynamics of multi-particle Landau-Zener (LZ) systems applying Dynamic matrix approach (DMA) that is found to generalize probability amplitudes. It is also observed that for exceedingly low frequencies, the system exhibits one crossing while for high frequencies, the multi-crossing. It is shown that for particular phenomenological parameters of the system, there is total population transfer that achieves the values one or zero useful for implementing quantum logic gates.

Description: We study the thermodynamic properties of a single particle occupying one of three available energy levels in a non-equilibrium regime. The particle is thermally coupled to a classical Maxwell-Boltzmann thermal reservoir and can jump among the available levels by exchanging energy with the heat bath. The bottom and middle energy levels are simultaneously raised at a given rate regardless of particle occupation, but keeping the energy gaps among the three levels fixed. We explicitly calculate the work, heat and entropy production rates, and the classical efficiency. We also consider the case of a Bose-Einstein thermal reservoir and provide explicit expressions for the non-equilibrium, steady-state probabilities.

Description: We report the two-photon interference properties of a photon pair generated in a type-II collinear periodically poled KTiOPO 4 (PPKTP) crystal pumped by a 406-nm diode laser capable of producing a single or dual longitudinal mode (LM). When the Hong–Ou–Mandel (HOM) interference signals in the PPKTP crystal pumped by a dual-mode diode laser were investigated at various crystal temperatures, it was found that the maximum visibility of the HOM interference signal depends on the relative strength of the dual LMs of the pump laser. The HOM interference pattern was numerically calculated considering the dual LM components of the pump laser diode and the crystal temperature, and was found to be in good agreement with the experimental results.

Description: One- and two-ring aromatics such as toluene and naphthalene are frequently used molecular tracer species in laser-induced fluorescence (LIF) imaging diagnostics. Quantifying LIF signal intensities requires knowledge of the photo-physical processes that determine the fluorescence quantum yield. Collision-induced and intramolecular energy transfer processes in the excited electronic state closely interact under practical conditions. They can be separated through experiments at variable low pressures. Effective fluorescence lifetimes of gaseous toluene, 1,2,4-trimethylbenzene, anisole, naphthalene, and 1-methylnaphthalene diluted in CO 2 were measured after picosecond laser excitation at 266 nm and time-resolved detection of fluorescence intensities. Measurements in an optically accessible externally heated cell between 296 and 475 K and 0.010–1 bar showed that effective fluorescence lifetimes generally decrease with temperature, while the influence of the bath-gas pressure depends on the respective target species and temperature. The results provide non-radiative and fluorescence rate constants and experimentally validate the effect of photo-induced cooling.

Description: We present a mid-infrared pulsed cavity ring-down spectroscopy (CRDS) setup based on difference frequency mixing of a tunable dye laser pumped by a Nd:YAG laser and the residual 1064 nm pulse in a temperature-stabilized lithium niobate (LiNbO 3 ) crystal. The performances of such a spectrometer have been investigated by studying the absorption spectrum of methane around 3 µm at room temperature. Our results show a minimum detectable absorption coefficient of 5 × 10 −8  cm −1 . Our approach combines the excellent sensitivity of CRDS with the wide tunable range of difference frequency generation (DFG) with a dye laser. However, the relatively low resolution of this spectrometer prevents the quantification of methane in a wide pressure range. To our knowledge, we report here the first realization and application of a pulsed DFG-based CRDS experiment used for sensitive trace gas detection.

Description: A telescope-grating-deformable scheme is proposed to compensate the angular dispersion of ultrabroadband spectrum. A simple design consideration is formulated based on the large angular dispersion of the idler from noncollinear optical parametric amplification. A proof of principle experiment is demonstrated. A 3-μJ ultrabroadband near-infrared pulse with spectrum range from 700 to 1400 nm has been generated. The technique has great potential to provide an ultrabroadband seed with negligible angular dispersion for high-power amplification of few-cycle pulses.

Description: We study the Shannon entropy of the cluster size distribution in classical as well as explosive percolation, in order to estimate the uncertainty in the sizes of randomly chosen clusters. At the critical point the cluster size distribution is a power-law, i.e. there are clusters of all sizes, so one expects the information entropy to attain a maximum. As expected, our results show that the entropy attains a maximum at this point for classical percolation. Surprisingly, for explosive percolation the maximum entropy does not match the critical point. Moreover, we show that it is possible to determine the critical point without using the conventional order parameter, just analysing the entropy’s derivatives.

Description: In this work we investigate time varying networks with complex dynamics at the nodes. We consider two scenarios of network change in an interval of time: first, we have the case where each link can change with probability p t , i.e. the network changes occur locally and independently at each node. Secondly we consider the case where the entire connectivity matrix changes with probability p t , i.e. the change is global. We show that network changes, occuring both locally and globally, yield an enhanced range of synchronization. When the connections are changed slowly (i.e. p t is low) the nodes display nearly synchronized intervals interrupted by intermittent unsynchronized chaotic bursts. However when the connections are switched quickly (i.e. p t is large), the intermittent behavior quickly settles down to a steady synchronized state. Furthermore we find that the mean time taken to reach synchronization from generic random initial states is significantly reduced when the underlying links change more rapidly. We also analyse the probabilistic dynamics of the system with changing connectivity and the stable synchronized range thus obtained is in broad agreement with those observed numerically.

Description: A procedure based on stochastic Langevin equations is presented and shows how a stochastic model of driver behavior can be estimated directly from given data. The Langevin analysis allows the separation of a given data-set into a stochastic diffusion- and a deterministic drift field. Form the drift field a potential can be derived. In particular the method is here applied on driving data from a simulator. We overcome typical problems like varying sampling rates, low noise levels, low data amounts, inefficient coordinate systems, and non-stationary situations. From the estimation of the drift- and diffusion vector-fields derived from the data, we show different ways how to set up Monte-Carlo simulations for the driver behavior.

Description: Up-conversion can be the main mechanism of energy losses in laser glasses with high concentration of erbium ions. This investigation is devoted to the evaluation of up-conversion parameters in several phosphate and silicate Er-doped glasses. Analysis of the luminescent lifetime shortening at high excitation level has shown that the up-conversion parameters in different glasses can differ by an order of magnitude. The smallest up-conversion was observed in Ba crown silicate glass and Li–Ln-phosphate glass.

Description: The evolution of cooperation is still an enigma. Resolution of cooperative dilemma is a hot topic as a perplexing interdisciplinary project, and has captured wide attention of researchers from many disciplines as a multidisciplinary field. Our main concern is the design of a networked evolutionary game model in which players show difference in memory capability. The idea of different memory capacities has its origin on the pervasive individual heterogeneity of real agents in nature. It is concluded that this proposed multiple memory capacity stimulates cooperation in lattice-structured populations. The networking effect is also investigated via a scale free network which is associated with the heterogeneous populations structure. Interestingly, results suggest that the effectiveness of a heterogeneous network at fostering cooperation is reduced in the presence of individual memory here. A thorough inquiry in the coevolutionary dynamics of individual memory and spatial structure in evolutionary games is planned for the immediate future.

Description: The quantum dynamics of a few bosons in a double well potential is studied using a Bose Hubbard model. We consider both signs for the on-site interparticle interaction and also investigated the situations where they are large and small. Interesting distinctive features are noted for the tunneling oscillations of these bosons corresponding to the above scenarios. Further, the sensitivity of the particle dynamics to the initial conditions has been studied. It is found that corresponding to an odd number of particles, such as three (or five), an initial condition of having unequal number of particles in the wells has interesting consequences, which is most discernible when the population difference between the wells is unity.

Description: We present a proposal for a single-parametric electron pump composed of a quantum dot between two unbiased leads with energy-gapped electron density of states (DOS). The model tight-binding Hamiltonian and the evolution operator technique are used in the calculations. The quantum dot is driven by the external harmonic field which leads to the pumping current flowing from the left or right electrode depending on the system parameters. We show that the net pumping current appears in the system if (i) there are at least two sideband states: one of them lying below and the second lying above the Fermi energy; (ii) the left and right lead DOS in the vicinity of these sideband states are different. Moreover, the energy-gapped structure of DOS is visible on the average quantum dot charge and the pumped current curves as well as on the transconductance characteristics. Thus mono-parametric pumping provides useful information about the system parameters, in particular about the lead DOS structure.

Description: We show that, contrary to previous belief, the transition to the antiferromagnetic state of Sr 2 IrO 4 in zero magnetic field does show up in the transverse resistivity. We attribute this to a change in transverse integrals associated to the magnetic ordering, which is evaluated considering hopping of the localized charge. The evolution of the resistivity anomaly associated to the magnetic transition under applied magnetic field is studied. It tracks the magnetic phase diagram, allowing to identify three different lines, notably the spin-flip line, associated with the reordering of the ferromagnetic component of the magnetization, and an intriguing line for field induced magnetism, also corroborated by magnetization measurements.

Description: Wavefront aberrations are one of the largest uncertainty factors in present atom interferometers. We present a detailed numerical and experimental analysis of this effect based on measured aberrations from optical windows. By placing windows into the Raman beam path of our atomic gravimeter, we verify for the first time the induced bias in very good agreement with theory. Our method can be used to reduce the uncertainty in atomic gravimeters by one order of magnitude, resulting in an error of 〈3 × 10 −10 g, and it is suitable in a wide variety of atom interferometers with thermal or ultracold atoms. We discuss the limitations of our method, potential improvements, and its role in future generation experiments.

Description: In this review, we have discussed the potential application of the emerging imaging modality, i.e., optical coherence tomography (OCT) for glucose monitoring in biological tissues. OCT provides monitoring of glucose diffusion in different fibrous tissues like in sclera by determining the permeability rate with acceptable accuracy both in type 1 and in type 2 diabetes. The maximum precision of glucose measurement in Intralipid suspensions, for example, with the OCT technique yields the accuracy up to 4.4 mM for 10 % Intralipid and 2.2 mM for 3 % Intralipid.

Description: Optical-feedback cavity-enhanced absorption spectroscopy is a highly sensitive trace gas sensing technique that relies on feedback from a resonant intracavity field to successively lock the laser to the cavity as the wavelength is scanned across a molecular absorption with a comb of resonant frequencies. V-shaped optical cavities have been favoured in the past in order to avoid additional feedback fields from non-resonant reflections that potentially suppress the locking to the resonant cavity frequency. A model of the laser–cavity coupling demonstrates, however, that the laser can stably lock to a resonant linear cavity, within certain constraints on the relative intensity of the two feedback sources. By mode mismatching the field into the linear cavity, we have shown that it is theoretically and practically possible to spatially filter out the unwanted non-resonant component in order for the resonant field to dominate the feedback competition at the laser. A 5.3  \(\upmu \hbox {m}\)  cw quantum cascade laser scanning across a \(\hbox {CO}_2\) absorption feature demonstrated stable locking to achieve a minimum detectable absorption coefficient of \(2.7\,\times \,10^{-9}\,\hbox {cm}^{-1}\) for 1-s averaging. Detailed investigations of feedback effects on the laser output verified the validity of our theoretical models.

Description: The article deals with the mathematical model for media with hierarchical structure. Using the Hamiltonian formalism, the dynamical system describing the state of hierarchically connected structural elements was derived. According to the analysis of the Poincaré sections, we found the localized quasi-periodic and chaotic trajectories in the three-level hierarchical model. Moreover, studies of correlation functions showed that the power spectrum for three-level model possesses local maxima characterizing temporal scales with strong correlation. Using the Fourier analysis of the solution’s components, we have studied the distribution of energy injected in the system over hierarchical levels. Dynamical phenomena in the multi-level system were studied as well.

Description: Lottery is the most famous branch among all the games of chance. By analysing data from Mega-Sena, the major lottery in Brazil, we investigated the presence of persistent behaviour in the time series of the number of winners. We found that the demand for tickets grew collectively as an exponential driven by the size of the accumulated jackpot. Finally, we identified that a stochastic model grounded on the rolling-over feature of lotteries can generate correlations qualitatively similar to those observed empirically. The model is consistent with the idea that the growth in the number of bets, motivated by the size of the expected jackpot, is a mechanism generator of correlations in an apparently random scenario.

Description: We obtain a special Fano-like resonance in a semi-closed T-shaped waveguide with nanodisk resonator, in which only two bright plasmon modes work. It is found that the transmission spectrum occurs a red-shift by increasing either length of the nanoslot or radius of the nanodisk. Moreover, when the length of the nanoslot and radius of the nanodisk reach to some particular values at the same time, the transmission spectrum will show an inverse line shape or the Fano-like resonance will disappear. Meanwhile, the classical figure of merit obtained by calculation is as high as 199 with a sizable classical sensitivity value reaches to 1114 nm/RIU. The generalized figure of merit also comes to an impressive value of 7961 nm/RIU. Besides, it is worth noting that the maximums of these two kinds of FOM lie in the dips of different linewidth, which can be utilized in diverse types of sensors. Our studies further provide a guidance for fabricating planar devices in near-infrared region.

Description: We present a numerical study of ferromagnetic Josephson junctions with one intermediate layer and spin active interfaces in the ballistic regime, comparing the behaviour of one, two and three dimensional junctions. We find that in two and three dimensional junctions the geometries which lack spin flip scattering at one of the interfaces have a critical current that decays to zero, as we increase the magnetization of the intermediate layer towards the half metal limit. As known, magnetization direction inhomogeneity produces a long range supercurrent with width variation, even when spin flip scattering exists in one of the interfaces only, although of lower characteristic decay length, compared to junctions with spin flip scattering at both interfaces. In the case of a single spin-flip interface and large thickness of the junction, we find a dominant second harmonic in the current-phase relation, in agreement with earlier work. We apply a diagrammatic approach, which explains the strong second harmonic and the long range property of the supercurrent. We find that in the three dimensional junction case the main contribution to both the long range supercurrent and the second harmonic in thick Josephson junctions with one spin flip interface comes from diagrammatic terms that correspond to scattering loops inside the junction which are subject to anomalous Andreev reflections on the spin flip interface and normal Andreev reflections at the non spin flip interface, thus exhibiting the triplet nature of the phenomenon. We also find the emergence of the strong first harmonic for small variation of the magnetization geometry and comment on the effect of normal interface scattering and temperature on the second harmonic.

Description: We derive the distribution function of work performed by a harmonic force acting on a uniformly dragged Brownian particle subjected to a rotational torque. Following the Onsager and Machlup’s functional integral approach, we obtain the transition probability of finding the Brownian particle at a particular position at time t given that it started the journey from a specific location at an earlier time. The difference between the forward and the time-reversed form of the generalized Onsager-Machlup’s Lagrangian is identified as the rate of medium entropy production which further helps us develop the stochastic thermodynamics formalism for our model. The probability distribution for the work done by the harmonic trap is evaluated for an equilibrium initial condition. Although this distribution has a Gaussian form, it is found that the distribution does not satisfy the conventional work fluctuation theorem.

Description: We investigate, using Monte Carlo simulations, the phase diagram of a system of hard rectangles of size m × mk on a square lattice when the aspect ratio k is a non-integer. The existence of a disordered isotropic phase, a nematic with only orientational order, a columnar phase with orientational and partial translational order, and a high density phase with no orientational order is shown. The high density phase is a solid-like sublattice phase only if the length and width of the rectangles are not mutually prime, else, it is an isotropic phase. The minimum value of k beyond which the nematic and columnar phases exist are determined for m = 2 and 3. The nature of the transitions between different phases is determined, and the critical exponents are numerically obtained for the continuous transitions.

Description: We consider the quasi-static thermodynamic processes with constraints, but with additional uncertainty about the control parameters. Motivated by inductive reasoning, we assign prior distribution that provides a rational guess about likely values of the uncertain parameters. The priors are derived explicitly for both the entropy-conserving and the energy-conserving processes. The proposed form is useful when the constraint equation cannot be treated analytically. The inference is performed using spin-1/2 systems as models for heat reservoirs. Analytical results are derived in the high-temperatures limit. An agreement beyond linear response is found between the estimates of thermal quantities and their optimal values obtained from extremum principles. We also seek an intuitive interpretation for the prior and the estimated value of temperature obtained therefrom. We find that the prior over temperature becomes uniform over the quantity kept conserved in the process.

Description: An inertial Brownian motor under the influence of a biased biharmonic signal is investigated numerically. For a finite positive bias force, the maximized negative current occurs at a relatively large noise intensity ( D = 0.01), while the magnitude of the anomalous velocity is also very large (greater than 1.5). This result means one can observe remarkably abnormal transport behaviors at relatively high temperature by means of a biharmonic drive.

Description: The stability of supersolid (SS) state in lattice boson model is highly dependent on lattice topology and particle-particle interaction. We investigate hard-core bosons on dice lattice where the bosons interact via nearest-neighbor (NN) repulsion either on whole lattice or on sublattices, by using large-scale quantum Monte Carlo simulations which are based on a continuous-time worm algorithm. In the case with NN repulsion on the whole lattice, we confirm the particle density modulation which arises from the asymmetry between sublattices — honeycomb and triangular sublattices — of dice lattice. We then place emphasis on the case with NN repulsion on the sublattices, and demonstrate spontaneously broken translational symmetries on different sublattices which lead to various crystalline orders. By evaluating the coexistence of crystalline order and superfluidity, we identify a variety of SS phases and establish a rich phase diagram. The microscopic pictures of these SS phases are figured out. Further, we demonstrate paradigmatic examples of first-order solid-to-SS and SS-to-SS quantum phase transitions.

Description: Analytical techniques developed in the field of materials science are now widely applied to objects of art and archaeology to gain information about the material composition and structure and hence to understand the way of manufacturing artefacts. Reciprocally, ancient artefacts studies show potential important contribution in the materials science field. This topical review will cover all these input and output aspects between materials science and ancient artefacts through the study of the first ceramics made by men e.g. potteries. To study these heterogeneous and complex materials, an approach based on the decomposition into sub systems of materials and the applications of traditional and novel analytical methods to scan the different scales of the material is not only mandatory but also innovative.

Description: A new method of pump-coupling in diode-pumped alkali vapor amplifier is reported, which uses ring-LD to tightly surround the alkali vapor cell for directly coupled side-pumping. The kinetic and fluid dynamic modeling, numerical approaches of the ring-LD side-pumped configuration are proposed and applied to the static and the flowing-gas Cs vapor amplifiers. Pump intensity and temperature distribution in the cell are simulated. Influences of some important factors on laser power are calculated and analyzed. Comparisons of different pumped configurations are made, demonstrating the highest utilizing efficiency of pump power of the ring-LD side-pumped configuration. Thus the model is very helpful for designing high-power side-pumped alkali vapor amplifiers.