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Ma Y.,East China Normal University | Wang J.,East China Normal University | Xu X.,East China Normal University | Wei Q.,East China Normal University | And 3 more authors.
Journal of the Physical Society of Japan | Year: 2014

In this work, the one-dimensional incommensurate quantum Frenkel-Kontorova model is investigated using a densitymatrix renormalization group algorithm. Special attention is given to the entanglement and ground-state energy. The energy gap between ground state and the first excited state is also calculated. From all the numerical results, we have observed clear property changes from the pinned state to the sliding state as the amount of quantum fluctuation is increased. However, no expected quantum critical point can be justified by the present data. © 2014 The Physical Society of Japan.

Fang Y.,Zhejiang University | Meng C.,National Key Laboratory of Shock Wave and Detonation Physics | Zhu W.,National Key Laboratory of Shock Wave and Detonation Physics | He D.,University of Sichuan | And 2 more authors.
Journal of Applied Physics | Year: 2013

A series of shock compression experiments on hexagonal α-Ce 3Al have been carried out using a two-stage light gas gun. No phase transition was observed in the recovered sample shock compressed at 23.5 GPa. However, as the shock pressure was increased to 27.3 GPa, a face-centered cubic Ce3Al phase was detected in the samples recovered at ambient conditions. Furthermore, a Ce2Al phase was found in the 37.1 GPa shocked sample with a space group Fd-3m and lattice parameter a 8.26(1) Å. These Ce-based alloys may have potential industrial applications due to the heavy-fermion related properties. © 2013 American Institute of Physics.

Li X.,National Key Laboratory of Shock Wave and Detonation Physics | Wang J.,East China Normal University | Zhu W.,National Key Laboratory of Shock Wave and Detonation Physics | Ye Y.,National Key Laboratory of Shock Wave and Detonation Physics | And 2 more authors.
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

The possibility of enhancing inner-shell x-ray emission, especially Kα emission, by femtosecond-laser irradiation of solid cones instead of foils was investigated theoretically. In a model for hot electron (HE) transport and Kα x-ray generation, Kα emission from laser-irradiated solid cones and foils is investigated. As a complementarity to the model, the contributions from electric and magnetic fields generated by the HE current in solid cones and foils are discussed. The results indicate that the efficiency of HE energy conversion to Kα photons is improved and the optimum HE temperature is increased. © 2011 American Physical Society.

Li A.K.,East China Normal University | Wang J.X.,East China Normal University | Ren N.,East China Normal University | Zhu W.J.,National Key Laboratory of Shock Wave and Detonation Physics | And 5 more authors.
Laser Physics | Year: 2014

In this paper a detailed numerical comparison of the high-harmonic generation (HHG) from free electrons in intense laser fields in both classical and semi-classical frameworks has been presented These two frameworks have been widely used in the literature It has been found that the HHG spectra display distinct quantitative differences for high-energy electrons In some special situations qualitative differences appear Even if the radiation reaction is included in the electron classical dynamics no consistent result can be obtained Hence it should be of critical importance to submit the present HHG theory for high-precision experimental tests which can help us not only to justify the present theories but also to check the QED predictions in the high-intensity regime © 2014 Astro Ltd.

Li A.,East China Normal University | Wang J.,East China Normal University | Ren N.,East China Normal University | Wang P.,Applied Ion Beam Physics Laboratory | And 7 more authors.
Applied Physics B: Lasers and Optics | Year: 2014

When an electron is scattered by a tightly focused laser beam in vacuum, the intensity gradient is a critical factor to influence the electron dynamics. In this paper, we have further investigated its influence upon the electron high-harmonic generation (HHG) by treating the spacial gradient of the laser intensity as a ponderomotive potential. Based upon perturbative quantum electrodynamics calculations, it has been found that the main effect of the intensity gradient is the broadening of the originally line HHG spectra. A one-to-one relationship can be built between the beam width and the corresponding line width. Hence, this finding may provide us a promising way to measure the beam width of intense lasers in experiments. In addition, for a laser pulse, we have also studied the different influences from transverse and longitudinal intensity gradients upon HHG. © 2014, Springer-Verlag Berlin Heidelberg.

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