Relative-intensity squeezing of high-order harmonic "twin beams"

Relative intensity squeezing (RIS) is emerging as a promising technique for performing high-precision measurements beyond the shot-noise limit. A commonly used way to produce RIS in visible/IR range is generating correlated "twin beams" through four-wave mixing by driving atomic resonances with weak laser beams. Here, we propose an all-optical strong-field scheme to produce a series of relative-intensity squeezed high-order harmonic "twin beams". Due to the nature of high harmonics generation the frequencies of the "twin beams" can cover a broad range of photon energy. Our proposal paves the way for the development of nonclassical XUV sources and high precision spectroscopy tools in strong-field regime

3-manifolds that admit knotted solenoids as attractors

Motivated by the study in Morse theory and Smale's work in dynamics, the following questions are studied and answered: (1) When does a 3-manifold admit an automorphism having a knotted Smale solenoid as an attractor? (2) When does a 3-manifold admit an automorphism whose non-wandering set consists of Smale solenoids? The result presents some intrinsic symmetries for a class of 3-manifolds

Canonical nilpotent structure under bounded Ricci curvature and Reifenberg local covering geometry over regular limits

It is known that a closed collapsed Riemannian $n$-manifold $(M,g)$ of bounded Ricci curvature and Reifenberg local covering geometry admits a nilpotent structure in the sense of Cheeger-Fukaya-Gromov with respect to a smoothed metric $g(t)$. We prove that a canonical nilpotent structure over a regular limit space that describes the collapsing of original metric $g$ can be defined and uniquely determined up to a conjugation, and prove that the nilpotent structures arising from nearby metrics $g_\epsilon$ with respect to $g_\epsilon$'s sectional curvature bound are equivalent to the canonical one.Comment: 26 page

Quantum-trajectory analysis for charge transfer in solid materials induced by strong laser fields

We investigate the dependence of charge transfer on the intensity of driving laser field when SiO2 crystal is irradiated by an 800 nm laser. It is surprising that the direction of charge transfer undergoes a sudden reversal when the driving laser intensity exceeds critical values with different carrier envelope phases. By applying quantum-trajectory analysis, we find that the Bloch oscillation plays an important role in charge transfer in solid. Also, we study the interaction of strong laser with gallium nitride (GaN) that is widely used in optoelectronics. A pump-probe scheme is applied to control the quantum trajectories of the electrons in the conduction band. The signal of charge transfer is controlled successfully by means of theoretically proposed approach