We propose a method to measure the carrier-envelop phase （CEP） and the intensity of a few-cycle pulse by controlling the non-sequentiai double ionization （NSDI） process. By using an additional static electric fiel...
详细信息
We propose a method to measure the carrier-envelop phase （CEP） and the intensity of a few-cycle pulse by controlling the non-sequentiai double ionization （NSDI） process. By using an additional static electric field, we can change the momentum distribution of the double-charged ions parallel to the laser polarization from an asymmetrical double-hump structure to a nearly symmetrical one. It is found that the ratio between the strength of the static electric field and that of the laser field is sensitive to the CEP but robust against the intensity fluctuation. Therefore we can determine the OEP of a few-cycle pulse precisely by measuring the static electric field. Fhrthermore, if the CEP of the few-cycle pulse is fixed at a certain value, we can also calibrate the intensity of the laser pulse by the static electric field.
Using R-matrix method, the collision cross sections of sodium from ground state to the first a few excited states at incident energy range 0-5.4 eV are calculated. The influence of the Rydberg states to the collision ...
详细信息
In this article, the authors show the existence of global solution of two-dimensional viscous Camassa-Holm (Navier-Stokes-alpha) (NS-α) equations. The authors also prove that the solution of the NS-α equations conve...
In this article, the authors show the existence of global solution of two-dimensional viscous Camassa-Holm (Navier-Stokes-alpha) (NS-α) equations. The authors also prove that the solution of the NS-α equations converges to the solution of the 2D NS equations in the inviscid limit and give the convergence rate of the difference of the solution.
Fusion frames are an emerging topic of frame theory, with applications to communications and distributed processing. However, until recently, little was known about the existence of tight fusion frames, much less how ...
详细信息
We investigate the width of the resonance zone in a degenerate Hamiltonian system with two degrees of freedom, in which the Hamiltonian lacks the quadratic term in the Taylor expansion. This leads to larger excursions...
详细信息
We investigate the width of the resonance zone in a degenerate Hamiltonian system with two degrees of freedom, in which the Hamiltonian lacks the quadratic term in the Taylor expansion. This leads to larger excursions of action in the phase space than the nondegenerate one, and corresponding resonance frequency widths would become narrower. However, in contrast to the nonautonomous Hamiltonian system with one and half degree of freedom, we find that the above case is not generic and only occurs at particular resonances. An example relevant to the interaction of resonances is considered. Analytic results are verified in numerical simulations.
A semiclassical model is developed to investigate the atomic nonsequential double-ionization process in elliptically polarized intense laser field. First, the ellipticity dependence of the ion yield of Ne2+ is calcula...
详细信息
A semiclassical model is developed to investigate the atomic nonsequential double-ionization process in elliptically polarized intense laser field. First, the ellipticity dependence of the ion yield of Ne2+ is calculated and a good agreement with the experiment observation is found. Second, the frequency dependence of the ratio of Ne2+:Ne+ is investigated for fields with different ellipticities. In the high-frequency regime, the ratio increases rapidly with increasing wavelength and is not dependent on the ellipticity. However, the ratio reaches maximum which decreases with increasing ellipticity and decreases with wavelength in the long-wavelength regime.
The alignment-dependent nonsequential double ionization (NSDI) of diatomic molecule N2 in intense fields is studied using the S-matrix theory. Our results show that the valence orbitals play an important role in align...
详细信息
The alignment-dependent nonsequential double ionization (NSDI) of diatomic molecule N2 in intense fields is studied using the S-matrix theory. Our results show that the valence orbitals play an important role in alignment-dependent NSDI process: in addition to the contribution from the outmost 1πu orbital of N2+ in all the alignment angles, the suboutmost 3σg orbital plays an important role at small alignment angles, which is more pronounced at high intensity. Taking into account the experimental alignment condition, the ratio of N22+:N+2 for the parallel alignment to that for perpendicular alignment obtained, including the 3σg orbital, is closer to the experimental result than that without considering this orbital.
We investigate theoretically the electronic transport properties in narrow graphene ribbons with an adatom-induced defect. It is found that the lowest conductance step of a metallic graphene nanoribbon may develop a d...
详细信息
We investigate theoretically the electronic transport properties in narrow graphene ribbons with an adatom-induced defect. It is found that the lowest conductance step of a metallic graphene nanoribbon may develop a dip even down to zero at certain values of the Fermi energy due to the defect. Accompanying the occurrence of the conductance dip, a loop current develops around the defect. We show how the properties of the conductance dip depend on the parameters of the defect such as the relative position and severity of the defect as well as the width and edges of the graphene ribbons. In particular, for metallic armchair-edges graphene nanoribbons, whether the conductance dip appears or not, they can be controlled by choosing the position of the single defect.
Random Stealing (RS) is a well-known dynamic load-balancing algorithm, used both in shared-memory and distributed-memory systems. However, for a large-scale cluster, the simple RS policy is no longer efficient because...
详细信息
We consider the control problem of generating unitary transformations, which is especially relevant to current research in quantum information processing and computing, in contrast to the usual state-to-state or the m...
详细信息
We consider the control problem of generating unitary transformations, which is especially relevant to current research in quantum information processing and computing, in contrast to the usual state-to-state or the more general observable expectation value control problems. A previous analysis of optimal control landscapes for unitary transformations from a kinematic perspective in the finite-dimensional unitary matrices is extended to a dynamical one in the infinite-dimensional function space of the time-dependent external field. The underlying dynamical landscape is defined as the Frobenius square norm of the difference between the control unitary matrix and the target matrix. A nonsingular adaptation matrix is introduced to provide additional freedom for exploring and manipulating key features, specifically the slope and curvature, of the control landscapes. The dynamical analysis reveals many essential geometric features of optimal control landscapes for unitary transformations, including bounds on the local landscape slope and curvature. Close examination of the curvatures at the critical points shows that the unitary transformation control landscapes are free of local traps and proper choices of the adaptation matrix may facilitate the search for optimal control fields producing desired unitary transformations, in particular, in the neighborhood of the global extrema.
暂无评论