Momentum interferences of a freely expanding Bose-Einstein condensate due to interatomic interaction change

A Bose-Einstein condensate may be prepared in a harmonic trap with negligible interatomic interactions using a Feshbach resonance. If a strong repulsive interatomic interaction is switched on and the trap is removed to let the condensate evolve freely, a time dependent quantum interference pattern takes place in the short time (Thomas-Fermi) regime, in which the number of peaks of the momentum distribution increases one by one, whereas the spatial density barely changes. The effect is stable for initial states with interactions and realistic time-dependence of the scattering length.     

The B(3) Field from Curved Spacetime Embedded in the Irreducible Representation of the Einstein Group

The details of this paper build on the previous work of M. Sachs and M. Evans that describe an enhanced form of general relativity which contains an inherently non-abelian field tensor. We focus on a particular field arising from the non-abelian form of electrodynamics. In particular, the form of this field will be demonstrated in a first-order perturbation approach within the context of a simple manifold, and also the leading order contribution to this field due to the presence of matter. The enhanced form of general relativity, as detailed in [1], is that of antisymmetrized general relativity which relies on the irreducible representation of the Einstein translation group. We also discuss the possibility of an inherent energy induced by curvature.     

Event-by-event study of DCC-like fluctuation in ultra-relativistic nuclear collisions

A method based on sliding window scheme is developed to search for patches in the pseudorapidity-azimuth plane, on an event-by-event basis, having unusual fluctuation in the neutral pion fraction which may arise due to the formation of Disoriented Chiral Condensates (DCC) in high energy nuclear collisions. The efficiency of the method to extract the patches and the purity of the extracted sample are studied for possible experimental situations.     

利用爱因斯坦转盘推求中心引力场中的光频红移--在普通物理教学中讲解等效原理的一种尝试

通过球对称引力场与爱因斯坦转盘上的惯性离心力场的对比，利用强等效原理导出光频的引力红移。     

Topological defect formation in rotating binary dipolar Bose–Einstein condensate

We investigate the topological defects and spin structures of a rotating binary Bose–Einstein condensate, which consists of both dipolar and scalar bosonic atoms confined in spin-dependent optical lattices, for an arbitrary orientation of the dipoles with respect to their plane of motion. Our results show that the tunable dipolar interaction, especially the orientation of the dipoles, can be used to control the direction of stripe phase and its related half-vortex sheets. In addition, it can also be used to obtain a regular arrangement of various topological spin textures, such as meron, circular and cross disgyration spin structures. We point out that such topological defects and regular arrangement of spin structures arise primarily from the long-range and anisotropic nature of dipolar interaction and its competition with the spin-dependent optical lattices and rotation.     

在$L^p$条件下完备Ricci孤立子流形的刚性定理

我们证明了在一定曲率和$L^p$条件下完备Ricci孤立子流形的一些刚性结果.     

On Einstein Matsumoto metrics

We study a special class of Finsler metrics,namely,Matsumoto metrics F=α2α-β,whereαis a Riemannian metric andβis a 1-form on a manifold M.We prove that F is a(weak)Einstein metric if and only ifαis Ricci flat andβis a parallel 1-form with respect toα.In this case,F is Ricci flat and Berwaldian.As an application,we determine the local structure and prove the 3-dimensional rigidity theorem for a(weak)Einstein Matsumoto metric.