The semistrong limit of multipulse interaction in a thermally driven optical system (original) (raw)

Renormalization group reduction of pulse dynamics in thermally loaded optical parametric oscillators

Physica D: Nonlinear Phenomena, 2005

We derive a perturbed parametrically forced nonlinear Schrödinger equation to model pulse evolution in an optical parametric oscillator with absorption-induced heating. We apply both a rigorous renormalization group (RG) technique and the formal Wilsonian renormalization group to obtain a low-dimensional system of equations which captures the mutual interaction of pulses as well as their response to the thermally induced potential.

Nonlinear Asymptotic Stability of the Semistrong Pulse Dynamics in a Regularized Gierer–Meinhardt Model

SIAM Journal on Mathematical Analysis, 2007

We use renormalization group (RG) techniques to prove the nonlinear asymptotic stability for the semistrong regime of two-pulse interactions in a regularized Gierer-Meinhardt system. In the semistrong limit the localized activator pulses interact strongly through the slowly varying inhibitor. The interaction is not tail-tail as in the weak interaction limit, and the pulse amplitudes and speeds change as the pulse separation evolves on algebraically slow time scales. In addition the point spectrum of the associated linearized operator evolves with the pulse dynamics. The RG approach employed here validates the interaction laws of quasi-steady two-pulse patterns obtained formally in the literature, and establishes that the pulse dynamics reduce to a closed system of ordinary differential equations for the activator pulse locations. Moreover, we fully justify the reduction to the nonlocal eigenvalue problem (NLEP) showing that the large difference between the quasi-steady NLEP operator and the operator arising from linearization about the pulse is controlled by the resolvent.

Modelling, Analysis and Simulation Nonlinear asymptotic stability of the semi-strong pulse dynamics in a regularized Gierer-Meinhardt model

2005

We use renormalization group (RG) techniques to prove the nonlinear asymptotic stability for the semi-strong regime of two-pulse interactions in a regularized Gierer-Meinhardt system. In the semi-strong limit the strongly localized activator pulses interact through the weakly localized inhibitor, the interaction is not tail-tail as in the weak interaction limit, and the pulses change amplitude and even stability as their separation distance evolves on algebraically slow time scales. The RG approach employed here validates the interaction laws of quasi-steady pulse patterns obtained formally in the literature, and establishes that the pulse dynamics reduce to a closed system of ordinary differential equations for the activator pulse locations. Moreover, we fully justify the reduction to the nonlocal eigenvalue problem (NLEP) showing the large difference between the quasi-steady NLEP operator and the operator arising from linearization about the pulse is controlled by the resolvent. 2...

Interactions of quantum systems with pulses of quantized radiation: From a cascaded master equation to a traveling mode perspective

Physical Review A

The interaction of a propagating pulse of quantum radiation with a localized quantum system can be described by a cascaded master equation with a distinct initially populated input and a finally populated output field mode [Kiilerich and Mølmer, Phys. Rev. Lett. 123, 123604 (2019)]. By transformation to an appropriate interaction picture, we break the cascaded nature of the master equation and recover an effective time-dependent interaction with a lossless single mode and a supplementary lossy mode. The former closely represents the traveling pulse, while the latter constitutes a non-Markovian component in the exchange of quanta between the scatterer and the quantized field. The transformed master equation offers important insights into the system dynamics, and it permits numerically efficient solutions.

Interaction of pulses in the nonlinear Schrödinger model

Physical Review E, 2003

The interaction of two rectangular pulses in the nonlinear Schrödinger model is studied by solving the appropriate Zakharov-Shabat system. It is shown that two real pulses may result in an appearance of moving solitons. Different limiting cases, such as a single pulse with a phase jump, a single chirped pulse, in-phase and out-of-phase pulses, and pulses with frequency separation, are analyzed. The thresholds of creation of new solitons and multisoliton states are found.

Pulse-driven quantum dynamics beyond the impulsive regime

Physical Review A, 2004

We review various unitary time-dependent perturbation theories and compare them formally and numerically. We show that the Kolmogorov-Arnold-Moser technique performs better owing to both the superexponential character of correction terms and the possibility to optimize the accuracy of a given level of approximation which is explored in details here. As an illustration, we consider a two-level system driven by short pulses beyond the sudden limit.

Adiabatic stability under semi-strong interactions: The weakly damped regime

Indiana University Mathematics Journal, 2013

We rigorously derive multi-pulse interaction laws for the semi-strong interactions in a family of singularly-perturbed and weakly-damped reaction-diffusion systems in one space dimension. Most significantly, we show the existence of a manifold of quasi-steady N -pulse solutions and identify a "normal-hyperbolicity" condition which balances the asymptotic weakness of the linear damping against the algebraic evolution rate of the multi-pulses. Our main result is the adiabatic stability of the manifolds subject to this normal hyperbolicity condition. More specifically, the spectrum of the linearization about a fixed N -pulse configuration contains essential spectrum that is asymptotically close to the origin as well as semi-strong eigenvalues which move at leading order as the pulse positions evolve. We characterize the semi-strong eigenvalues in terms of the spectrum of an explicit N × N matrix, and rigorously bound the error between the N -pulse manifold and the evolution of the full system, in a polynomially weighted space, so long as the semi-strong spectrum remains strictly in the left-half complex plane, and the essential spectrum is not too close to the origin.

On semi-classical limit of nonlinear quantum scattering

Annales scientifiques de l'École normale supérieure, 2016

We consider the nonlinear Schrödinger equation with a short-range external potential, in a semi-classical scaling. We show that for fixed Planck constant, a complete scattering theory is available, showing that both the potential and the nonlinearity are asymptotically negligible for large time. Then, for data under the form of coherent state, we show that a scattering theory is also available for the approximate envelope of the propagated coherent state, which is given by a nonlinear equation. In the semi-classical limit, these two scattering operators can be compared in terms of classical scattering theory, thanks to a uniform in time error estimate. Finally, we infer a large time decoupling phenomenon in the case of finitely many initial coherent states.

A Review of Dispersive Limits of (Non)Linear Schr¨odinger-Type Equations

Taiwanese Journal of Mathematics, 2000

In this review paper we present the most important mathematical properties of dispersive limits of (non)linear Schrödinger type equations. Different formulations are used to study these singular limits, e.g., the kinetic formulation of the linear Schrödinger equation based on the Wigner transform is well suited for global-in-time analysis without using WKB-(expansion) techniques, while the modified Madelung transformation reformulating Schrödinger equations in terms of a dispersive perturbation of a quasilinear symmetric hyperbolic system usually only gives local-in-time results due to the hyperbolic nature of the limit equations. Deterministic analogues of turbulence are also discussed. There, turbulent diffusion appears naturally in the zero dispersion limit.

Long and short time quantum dynamics: III. Transients

Physica E-low-dimensional Systems & Nanostructures, 2005

The quantum transport equations for fast transients have the structure of a Generalized Master Equations for the single-particle distribution, with causal memory terms. Nonequilibrium Green's functions are reduced to GME if the Generalized Kadanoff-Baym Ansatz is applied. This Ansatz has been used with success both to non-linear transport and to optical transients in semiconductors ; further progress is linked with its extension to a family of the Causal Ansatzes, differing primarily in renormalization of the propagators. For the switch-on non-equilibrium states, generated by a perturbation from equilibrium, the renormalization to the dark dressed Green's function followed by calculation of the induced self-energies is a productive direction. It also circumvents the problem of correlated initial conditions, far from a general solution otherwise. Such initial conditions appear as incompatible with a Causal Ansatz in general. The presently available formalism permits to study a transient process in the whole time range using the complete NGF, but making a flexible Ansatz-based reduction appropriate to the stage of dynamic evolution.