Single-cycle optical pulses synchronized with molecular oscillations

Molecular modulation can produce an ultra-broad spectrum of infrared, visible, and ultraviolet light. This technique relies on the adiabatic preparation of highly coherent molecular vibrations or rotations in large ensembles of molecules. Coherent molecular motion leads to laser frequency modulation, and results in an efficient collinear generation of equidistant mutually coherent sidebands. In this paper I discuss perspectives for using this light source to synthesize sub-cycle and non-sinusoidal light pulses that are perfectly synchronized with the molecular oscillations in the given molecular system. These pulses provide a unique tool for studying ultra-fast atomic and molecular dynamics. PACS 42.50.Gy; 42.50.Hz; 42.65.Dr; 42.65.Re     

Stability of single-mode oscillations synchronized by an external signal in A multimode cyclotron-resonance maser monotron

Conclusions Premodulation of the electron beam by an external signal and appropriate choice of parameters for a synchronized CRM monotron increase the starting values of the parameters I_s proportional to the beam current and the Q's of competing modes. In maximum-efficiency regimes (for optimal beam current and externalsignal frequency), the stability of single-mode oscillations in a CRM monotron is ensured for any competing-mode Q's, regardless of the values of the parameters,, , X, or n.Scientific-Research Institute of Radio Physics. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 19, No. 3, pp. 453–459, March, 1976.     

Synchronization tomography: a method for three-dimensional localization of phase synchronized neuronal populations in the human brain using magnetoencephalography

We present a noninvasive technique which allows the anatomical localization of phase synchronized neuronal populations in the human brain with magnetoencephalography. We study phase synchronization between the reconstructed current source density (CSD) of different brain areas as well as between the CSD and muscular activity. We asked four subjects to tap their fingers in synchrony with a rhythmic tone, and to continue tapping at the same rate after the tone was switched off. The phase synchronization behavior of brain areas relevant for movement coordination, inner voice, and time estimation changes drastically when the transition to internal pacing occurs, while their averaged amplitudes remain unchanged. Information of this kind cannot be derived with standard neuroimaging techniques like functional magnetic resonance imaging or positron emission tomography.     

Regularization of synchronized chaotic bursts

The onset of regular bursts in a group of irregularly bursting neurons with different individual properties is one of the most interesting dynamical properties found in neurobiological systems. In this paper we show how synchronization among chaotically bursting cells can lead to the onset of regular bursting. In order to clearly present the mechanism behind such regularization we model the individual dynamics of each cell with a simple two-dimensional map that produces chaotic bursting behavior similar to biological neurons.     

Mesino-antimesino oscillations

The phenomenology of supersymmetric theories with low scale supersymmetry breaking and a squark as the lightest standard model superpartner are investigated. Such squarks hadronize with light quarks, forming sbaryons and mesinos before decaying. Production of these supersymmetric bound states at a high energy collider can lead to displaced jets with large negative impact parameters. Neutral mesino-antimesino oscillations are not forbidden by any symmetry and can occur at observable rates. Stop mesino-antimesino oscillations would give a sensitive probe of up-type sflavor violation, and can provide a discovery channel for supersymmetry through events with a same-sign top-top topology.     

Spatiotemporal communication with synchronized optical chaos

We propose a model system that allows communication of spatiotemporal information using an optical chaotic carrier waveform. The system is based on broad-area nonlinear optical ring cavities, which exhibit spatiotemporal chaos in a wide parameter range. Message recovery is possible through chaotic synchronization between transmitter and receiver. Numerical simulations demonstrate the feasibility of the proposed scheme, and the benefit of the parallelism of information transfer with optical wave fronts.     

Synchronization rate of synchronized coupled systems

Synchronization phenomena, an emergent property in networks of interacting dynamical elements, are widely observed in nature, and have become the subject of intense research. Here we will investigate the synchronization rate problem in coupled limit-cycle and chaotic oscillators. Based on the mode decomposition method and Gershgörin's discs theorem, some sufficient conditions for synchronization of coupled systems are obtained, and a synchronization rate is then derived. Such a synchronization rate indicates that the error functions between state variables of underlying individual systems tend to zero in the exponential form as time tends to the infinity. Several numerical examples are also given to validate the theoretical results.     

Amplifying properties of a synchronized generator

The amplifying properties of a synchronized generator are explained on the basis of an autoparametric model of the synchronization phenomenon.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 59–63, December, 1981.     

Collection of mutually synchronized chaotic systems

A general explicit coupling for mutual synchronization of two arbitrary identical continuous systems is proposed. The synchronization is proved analytically. The coupling is given for all 19 systems from Sprott's collection. For one of the systems the numerical results are shown in detail. The method could be adopted for the teaching of the topic.     

Proton-positron oscillations

The possibility that baryonic and leptonic matter in nature can oscillate into one another is considered. Consistent with electric charge conservation this leads to proton-positron (or anti-proton-electron) oscillations that conserve baryon (B) minus lepton (L) number. Other equally likely oscillations are neutron-neutrino oscillations that conserve (B+L)-number and neutron-antineutrino oscillations that conserve (B?L) number. Simple theories like the SU(5) and SO(10) predict the transition probability of such modes to be ? 10^?60.     

Sparsely sampled high-resolution 4-D experiments for efficient backbone resonance assignment of disordered proteins

Intrinsically disordered proteins (IDPs) play important roles in many critical cellular processes. Due to their limited chemical shift dispersion, IDPs often require four pairs of resonance connectivities (H(α), C(α), C(β) and CO) for establishing sequential backbone assignment. Because most conventional 4-D triple-resonance experiments share an overlapping C(α) evolution period, combining existing 4-D experiments does not offer an optimal solution for non-redundant collection of a complete set of backbone resonances. Using alternative chemical shift evolution schemes, we propose a new pair of 4-D triple-resonance experiments--HA(CA)CO(CA)NH/HA(CA)CONH--that complement the 4-D HNCACB/HN(CO)CACB experiments to provide complete backbone resonance information. Collection of high-resolution 4-D spectra with sparse sampling and FFT-CLEAN processing enables efficient acquisition and assignment of complete backbone resonances of IDPs. Importantly, because the CLEAN procedure iteratively identifies resonance signals and removes their associating aliasing artifacts, it greatly reduces the dependence of the reconstruction quality on sampling schemes and produces high-quality spectra even with less-than-optimal sampling schemes.     

Topological stabilization for synchronized dynamics on networks

A general scheme is proposed and tested to control the symmetry breaking instability of a homogeneous solution of a spatially extended multispecies model, defined on a network. The inherent discreteness of the space makes it possible to act on the topology of the inter-nodes contacts to achieve the desired degree of stabilization, without altering the dynamical parameters of the model. Both symmetric and asymmetric couplings are considered. In this latter setting the web of contacts is assumed to be balanced, for the homogeneous equilibrium to exist. The performance of the proposed method are assessed, assuming the Complex Ginzburg-Landau equation as a reference model. In this case, the implemented control allows one to stabilize the synchronous limit cycle, hence time-dependent, uniform solution. A system of coupled real Ginzburg-Landau equations is also investigated to obtain the topological stabilization of a homogeneous and constant fixed point.     

Globally coupled systems with prescribed synchronized dynamics

A system of globally coupled maps whose synchronized dynamics differs from the individual (chaotic) evolution is considered. For nonchaotic synchronized dynamics, the synchronized state becomes stable at a critical coupling intensity lower than that of the fully chaotic case. Below such critical point, synchronization is also stable in a set of finite intervals. Moreover, the system is shown to exhibit multistability, so that even when the synchronized state is stable not all the initial conditions lead to synchronization of the ensemble. Received 22 October 1999     

Time shifts and correlations in synchronized chaos

We introduce a new method for predicting characteristics of the synchronized state achieved by a wide class of unidirectional coupling schemes. Specifically, we derive a transfer function from the coupling model that provides estimates of the correlation between the drive and response waveforms, and of the time shift (i.e., lag or anticipation) of the synchronized state. To demonstrate the method, we apply it to a simulated system of coupled Rossler oscillators as well as to an experimental system of coupled chaotic electronic circuits. Finally, we show that the transfer function can be exploited to design novel coupling schemes that significantly improve the correlation and increase the maximum achievable time shift.     

Experimental investigations of three laser-induced synchronized bubbles

Herein, we investigated experimentally the dynamics of three laser-induced, same-sized, symmetrically aligned, and synchronized bubbles. Three synchronized laser beams split from the same beam using a Diffractive Optical Element splitter were focused on water, and then we obtained three bubbles. Another nanosecond laser pulse was used to probe the bubbles to obtain shadowgraphs. The exact delay of the excited and detected light was controlled using a delay generator. The results revealed that the maximum volumes of bubbles in arrays decrease as the normalized distance falls, while the lifetimes and translation increase. It was explained by the interaction between the acoustic radiation of bubbles and the surrounding bubbles. The shrinkage of linear bubble arrays exists an anomaly. The center bubbles were stretched, to ellipsoid, stick, even fractured, by the peripheral bubbles. The closer they are, the more distinct is the above phenomenon. However, when the normalized distance was sufficiently small, instead of being stretched, the center bubbles were compressed to disk shape and thus shrank with the whole array. Finally, the dependence of the distance on the energy transfer of the bubble system is also discussed.