The evolution of the chaotic dynamics of collective modes as a method for the behavioral description of living systems

Human-scaled (in complexity) systems possess a unique feature, viz., the continuous random motion of many components of the state vector x = x(t) of such living systems. Taking this property into consideration causes the rejection of any of the known types of stationary modes (e.g., dx/dt = 0) and requires revision of the concept of chaos. A new approach to the understanding of living systems (as a third paradigm of the natural sciences) and new methods for the study of living systems (as a theory of chaos and self-organization) are proposed. Common grounds of physics and theory of chaos and self-organization are revealed as a generalized uncertainty principle and a limit on the parameters of quasi-attractors.     

Size effect on the structure of Al-and Ni-based nanocrystals

The structure of nanocrystals formed upon crystallization of amorphous alloys of the Ni-Mo-B and Al-Ni-RE systems (RE = Y, Yb, Ce) was studied using x-ray diffraction and high-resolution transmission electron microscopy. It is shown that the lattice parameters and the existence of structural defects depend on the alloy composition and heat treatment conditions. At the beginning of crystallization, all nanocrystals are defectless. After the first stage of crystallization is completed, the aluminum nanocrystals remain perfect, whereas the nanocrystals of molybdenum solid solution contain numerous defects. It is revealed that the nanocrystals of the same size in different systems are either defectless (Al₈₂Ni₁₁Ce₃Si₄, Al₈₈Ni₁₀Y₂, etc.) or contain numerous defects (Ni₇₀Mo₃₀)₉₀B₁₀.     

New emission spectrum of the TeO molecule

The spectrum of Tellurium monoxide as excited in a heavy current arc run by a 2000 volt D.C. generator was studied in the visible and ultraviolet regions. Photographs of the spectrum revealed many new bands in the regionλ 6200 toλ 3300, which are clearly degraded to longer wavelengths. Some of the bands in the regionλ 3800 toλ 3300 were identified with those of the system in the regionλ 3800 toλ 3060 (here designated as system,B-X) observed and analysed byChoong Shin Piaw. The analysis of theB-X system was extended to include some of the new bands uptoλ 4500. In addition to those assigned toB-X system, a number of new bands in the regionλ 5000 toλ 3500 constitute another system designated asA-X system. The analysis of this system has led to the following quantum formula for the band heads.v=27835+408 (v′+1/2)?4·0(v′+1/2)² ?796 (v″+1/2)+3·5 (v″+1/2)². The lower state of the two systems is common and is identified as the ground state of the TeO molecule. Bands in the regionλ 6200 to 5000 were analysed as belonging to another brief system. This system appears to arise from a transition between two escited states of the TeO molecule. The nature and properties of electronic terms responsible for the observed electronic states of the TeO molecule were discussed along with those of the related molecules O₂, SO, and SeO from considerations of electron configurations.     

Synthesis,characterization and third-order nonlinear optical properties of polydiacetylene nanostructures,silver nanoparticles and polydiacetylene–silver nanocomposites

We have synthesized, characterized and studied the third-order nonlinear optical properties of two different nanostructures of polydiacetylene (PDA), PDA nanocrystals and PDA nanovesicles, along with silver nanoparticles-decorated PDA nanovesicles. The second molecular hyperpolarizability γ(?ω; ω, ?ω, ω) of the samples has been investigated by antiresonant ring interferometric nonlinear spectroscopic (ARINS) technique using femtosecond mode-locked Ti:sapphire laser in the spectral range of 720–820 nm. The observed spectral dispersion of γ has been explained in the framework of three-essential states model and a correlation between the electronic structure and optical nonlinearity of the samples has been established. The energy of two-photon state, transition dipole moments and linewidth of the transitions have been estimated. We have observed that the nonlinear optical properties of PDA nanocrystals and nanovesicles are different because of the influence of chain coupling effects facilitated by the chain packing geometry of the monomers. On the other hand, our investigation reveals that the spectral dispersion characteristic of γ for silver nanoparticles-coated PDA nanovesicles is qualitatively similar to that observed for the uncoated PDA nanovesicles but bears no resemblance to that observed in silver nanoparticles. The presence of silver nanoparticles increases the γ values of the coated nanovesicles slightly as compared to that of the uncoated nanovesicles, suggesting a definite but weak coupling between the free electrons of the metal nanoparticles and π electrons of the polymer in the composite system. Our comparative studies show that the arrangement of polymer chains in polydiacetylene nanocrystals is more favourable for higher nonlinearity.     

Focal properties of cylindrically polarized axisymmetric Bessel-modulated Gaussian beams by a high NA parabolic mirror

Focusing properties of the cylindrical vector axisymmetric Bessel-modulated Gaussian beam with quadratic radial phase dependence (QBG beam) in high numerical aperture parabolic mirror system is investigated theoretically by vector diffraction theory. Results show that intensity distribution in focal region can be altered considerably by beam parameter μ and polarization angle. The tightly focused cylindrically polarized axial symmetric Bessel-modulated Gaussian beams by a high numerical aperture parabolic mirror have possible applications in particle acceleration, optical trapping and manipulating, single molecule imaging and high resolution imaging microscopy.     

Spin-selective low temperature spectroscopy on single molecules with a triplet-triplet optical transition: Application to the NV defect center in diamond

The spin-selective photokinetics of a single matrix-isolated impurity molecule with a triplet-triplet optical transition, T ₀–T ₁, is considered and the manifestations of the photokinetics in the fluorescence excitation spectra and intensity autocorrelation functions g ⁽²⁾(τ) of the molecule undergoing narrow-band optical excitation is studied to resolve the fine structure of the transition. The rates of intersystem crossings (ISCs) T ₁→S→T ₀ to and from a nonradiating singlet state S of the molecule and the rate of population relaxation among the ground (T ₀) state sublevels can be obtained from the spectra and g ⁽²⁾(τ) using the analytical expressions obtained. New experiments on an individual NV defect center in nanocrystals of diamond, where, for the first time, the fine structure of its triplet-triplet ³ A-³ E zero-phonon optical transition (~637 nm) at 1.4 K was resolved, are interpreted. It is concluded that the rate of the ISC transition from the m _S =0 sublevel of the excited ³ E state to the singlet ¹ A state (~1 kHz) is much slower than the rates from the m _S =±1 substates, while the rates of ISC transitions to different m _S substates of the ground ³ A state are close to each other (~1 Hz). As a result, only the optical transition between m _S =0 sublevels in the ³ A-³ E manifold contributes strongly to the fluorescence. The experimentally observed double-exponential decay of the g ⁽²⁾(τ) function is explained by the two pathways available to the center for it to leave the S state: (i) the S→ T ₀(m _S )=0) transition and (ii) the S→T ⁰(m _S =±1) transitions followed by the slow spin-lattice relaxation T ₀(m _S =±1)→T ₀(m _S =0) (rate ~0.1 Hz). The work is important for studies where the NV center is used as a single photon source or for quantum information processing.     

Determination of the scattering coefficient of biological tissue considering the wavelength and absorption dependence of the anisotropy factor

The anisotropy factor g, one of the optical properties of biological tissues, has a strong influence on the calculation of the scattering coefficient μ _s in inverse Monte Carlo (iMC) simulations. It has been reported that g has the wavelength and absorption dependence; however, few attempts have been made to calculate μ _s using g values by taking the wavelength and absorption dependence into account. In this study, the angular distributions of scattered light for biological tissue phantoms containing hemoglobin as a light absorber were measured by a goniometric optical setup at strongly (405 nm) and weakly (664 nm) absorbing wavelengths to obtain g. Subsequently, the optical properties were calculated with the measured values of g by integrating sphere measurements and an iMC simulation, and compared with the results obtained with a conventional g value of 0.9. The μ _s values with measured g were overestimated at the strongly absorbing wavelength, but underestimated at the weakly absorbing wavelength if 0.9 was used in the iMC simulation.     

New superconductivity dome in LaFeAsO1−xFx far away from magnetism and accompanied by structural transition

We report on the discovery and novel physics of a new superconductivity dome in LaFeAsO_1?xF_x with high-doping rate (0.25 ≤x≤0.75) synthesized by using the high-pressure technique. The maximal critical temperature T_c = 30 K peaked at x_opt = 0.5 ～0.55, which is even higher than that at x≤ 0.2. By nuclear magnetic resonance (NMR), we find that the new superconducting dome is far away from a magnetically ordered phase without low-energy magnetic fluctuations. Instead, NMR and transmission electron microscopy measurements indicate that a C4 rotation symmetry-breaking structural transition takes place for x> 0.5 above T_c. The electrical resistivity shows a temperature-linear behavior around the doping level where the crystal transition temperature extrapolate to zero and T_c is the maximal, suggesting the importance of quantum fluctuations associated with the structural transition. Our results point to a new paradigm of high temperature superconductivity.     

The emission spectrum of the NS molecule

The investigation of the emission spectrum of NS molecule has been carried out by using a Littrow-type quartz spectrograph and a two meter normal incidence type vacuum spectrograph. Theγ-system (² σ-² π), in which only the bands havingv′=0 and 1 were known previously, has been extended tov′=4. TheδG values of the upper state do not show much regularity indicating some perturbation in this state. The vibrational constants for theΒ-system (² δ-² π) have also been modified slightly by observing more bands for this system. Four new systems, all of which have the ground state as their common lower state, have been observed in the ultraviolet and the vacuum ultraviolet regions.     

Creating Very True Quantum Algorithms for Quantum Energy Based Computing

An interpretation of quantum mechanics is discussed. It is assumed that quantum is energy. An algorithm by means of the energy interpretation is discussed. An algorithm, based on the energy interpretation, for fast determining a homogeneous linear function f(x) := s.x = s ₁ x ₁ + s ₂ x ₂ + ? + s _N x _N is proposed. Here x = (x ₁, … , x _N ), x _j ∈ R and the coefficients s = (s ₁, … , s _N ), s _j ∈ N. Given the interpolation values \((f(1), f(2),...,f(N))=\vec {y}\), the unknown coefficients \(s = (s_{1}(\vec {y}),\dots , s_{N}(\vec {y}))\) of the linear function shall be determined, simultaneously. The speed of determining the values is shown to outperform the classical case by a factor of N. Our method is based on the generalized Bernstein-Vazirani algorithm to qudit systems. Next, by using M parallel quantum systems, M homogeneous linear functions are determined, simultaneously. The speed of obtaining the set of M homogeneous linear functions is shown to outperform the classical case by a factor of N × M.     

A new crystalline HMX polymorph: ɛ-HMX

A new crystalline HMX polymorph, ?-HMX, was obtained. ?-HMX crystals were studied by X-ray structure analysis, optical microscopy, and differential scanning calorimetry. Their space group is P2₁/c. The unit cell parameters are a = 21.799(3) Å, b = 10.913(2) Å, c = 10.819(2) Å, and β = 97.43(2)°, V = 2552.15 ų, Z = 4. ?-HMX molecules are not equivalent in crystals and have chair conformations. The heat of the polymorphic transition of ?-HMX into the δ-polymorph was measured. The transition occurred with the intermediate formation of β-HMX. The dependence between the heats of polymorphic transitions and the densities of crystals of various HMX polymorphs was demonstrated. The character of this dependence was to a substantial extent determined by the type of HMX molecule conformation.     

A generalized scheme for designing multistable continuous dynamical systems

In this paper, a generalized scheme is proposed for designing multistable continuous dynamical systems. The scheme is based on the concept of partial synchronization of states and the concept of constants of motion. The most important observation is that by coupling two m-dimensional dynamical systems, multistable nature can be obtained if i number of variables of the two systems are completely synchronized and j number of variables keep a constant difference between them i.e., their differences are constants of motion, where i + j = m and 1 ≤ i, j ≤ m?1. The proposed scheme is illustrated by taking coupled Lorenz systems and coupled chaotic Lorenz-like systems. According to the scheme, two coupled systems reduce to single modified system with some initial condition-dependent parameters. Time evolution plots, phase diagrams, variation of maximum Lyapunov exponent and bifurcation diagrams of the systems are presented to show the multistable nature of the coupled systems.     

Ultraviolet bands of mercury bromide

The ultraviolet bands of mercury bromide have been excited in uncondensed discharge and photographed with a quartz Littrow spectrograph. The class II system, lying betweenλ 2900 å to 2700 å, suggested byWieland as due to the triatomic molecule, has been studied in detail and ascribed to the diatomic molecule. The bands in the regionλ 2900 å to 2770å have been analysed into two systems which may form the two components of a² II ?² σ electronic transition with a² II interval equal to 969·4 cm^?1. Another system most probably due to² σ?² σ has been observed in the regionλ 2770 to 2720.     

Strongly Incompatible Quantum Devices

The fact that there are quantum observables without a simultaneous measurement is one of the fundamental characteristics of quantum mechanics. In this work we expand the concept of joint measurability to all kinds of possible measurement devices, and we call this relation compatibility. Two devices are incompatible if they cannot be implemented as parts of a single measurement setup. We introduce also a more stringent notion of incompatibility, strong incompatibility. Both incompatibility and strong incompatibility are rigorously characterized and their difference is demonstrated by examples.     

Interaction of nitrogen dioxide molecules with the surface of silicon nanocrystals in porous silicon layers

The methods of infrared absorption spectroscopy and electron paramagnetic resonance are used for studying the effect of adsorption of NO₂ molecules, which are strong acceptors of electrons, on the electronic and optical properties of silicon nanocrystals in mesoporous silicon layers. It is found that the concentration of free charge carriers (holes) in silicon nanocrystals, which exhibits a nonmonotonic dependence on the NO₂ pressure, sharply increases in the presence of these molecules. At the same time, a monotonic increase in the concentration of dangling silicon bonds (P_b1 centers) is observed. A microscopic model proposed for explaining this effect presumes the formation of donor-acceptor pairs P ₊ ^b1 -(NO₂)^? on the surface of nanocrystals, which ensure an increase in the hole concentration in nanocrystals, as well as P_b1 centers, which are hole-trapping centers. The proposed model successfully explains a substantial increase in photoconductivity (by two or three orders of magnitude) in the layers of porous silicon in the presence of NO₂ molecules; the increment in the concentration of free charge carriers is detected within an order of magnitude of this quantity. The results can be used in designing electronic and luminescence devices based on silicon nanocrystals.     

Probing the role of metal cations on the aggregation behavior of amyloid β-peptide at a single molecule level by AFM

With the development of nanotechnology, understanding of intermolecular interactions on a single molecule level by atomic force spectroscopy (AFM) has played an important role in molecular biology and biomedical science. In recent years, some research suggested that the presence of metal cations is an important regulator in the processes of misfolding and aggregation of the amyloid β-protein (Aβ), which may be an important etiological factor of Alzheimer’s disease. However, the knowledge on the principle of interactions between Aβ and metal cations at the single molecule level is still poor understood. In this paper, the amyloid β-protein (Aβ) was fabricated on substrate of mixed thiol-modified gold nanoparticles using self-assembled monolayer method and the adhesion force in the longitudinal direction between metal cations and Aβ42 were investigated by AFM. The role of metal ions on Aβ aggregation is discussed from the perspective of single molecular force. The force results showed that the specific adhesion force F _i and the nonspecific force F ₀ between a single Aβ–Aβ pair in control experiment were calculated as 42 ± 3 and 80 pN, respectively. However, F _i between a single Aβ–Aβ pair in the presence of Cu²⁺, Zn²⁺, Ca²⁺ and Al³⁺ increased dramatically to 84 ± 6, 89 ± 3, 73 ± 5, 95 ± 5 pN successively, which indicated that unbinding between Aβ proteins is accelerated in the presence of metal cations. What is more, the imaging results showed that substoichiometric copper cations accelerate the formation of fibrils within 3 days. The combined atomic force spectroscopy and imaging analysis indicate that metal cations play a role in promoting the aggregating behavior of Aβ42.     

Microwave spectroscopy of the weakly bound CO-<Emphasis Type="Italic">ortho</Emphasis>-D<Subscript>2</Subscript> molecular complex

A van der Waals complex that consists of a deuterium molecule in the ortho state and a carbon monoxide molecule, CO-ortho-D₂, was studied in the frequency range 85–130 GHz with the help of an intracavity orotron-based spectrometer. Nine new lines, which correspond to rotational transitions and belong to the R and Q branches, were measured and identified. The positions of the rotational energy levels of CO-ortho-D₂ were refined by comparative analysis of the transition frequencies measured in this work and previously reported microwave and infrared data.     

High-order harmonic generation by atoms in a two-color laser field: Phase control of recombination radiation spectrum and duration

The feasibility of phase control over above-threshold tunnel ionization and subsequent recombination emission in two-frequency laser fields is studied. It is shown that, in such fields, we can control the instants of ionization t₀ (within optical cycle T) and recombination t _k . The conditions that minimize the characteristic times δt₀?T and δt _k ?T, within which effective ionization and recombination occur, were found. Phase control allows recombination radiation to be generated with the selection of a narrow spectral range, while additional high-frequency “background illumination” sets up high harmonic “amplification” conditions. It was shown that special two-frequency pumping with elliptically polarized radiation can generate coherent electromagnetic pulses of attosecond width. The width of the pulses decreases as the intensity of pumping increases and can reach subattosecond values. Experimental generation of such pulses may lead to a breakthrough in the development of new methods for femto-and attosecond diagnostics of fast processes.