NEWS
June 17 2011
Prof. Xu's work on the calculation of the volume of basins of attraction was published in Physical Review Letters
Prof. Xu's work on the calculation of the volume of basins of attraction was published in Physical Review Letters
In collaboration with Prof. Daan Frenkel from Department of Chemistry at University of Cambridge and Prof. Andrea Liu from Department of Physics and Astronomy at
University of Pennsylvania, Prof. Xu has achieved some important progress on the statistical study of the potential energy landscape (PEL). The work has been published in
Physical Review Letters on June 17, 2011 (Phys. Rev. Lett. 106, 245502 (2011)).
In many body systems, if the potential energy is plotted as a function of particle coordinates, the PEL is constructed, as a complicated multi-dimensional surface. The PEL consists of an astronomically large number of basins of attraction whose bottoms are local potential energy minima, i.e. meta-stable configurations accessible at zero temperature. In excitations, the system walks randomly in the PEL. The PEL is very important in the understanding of many physical phenomena such as crystallization, melting, glass transition, jamming transition, plasticity, and protein folding. Prof. Xu and his collaborators developed a novel method based on the free-energy calculation to directly measure the size of a single basin of attraction in the PEL, which makes it possible to statistically measure the number of distinct basins of attraction and the configurational entropy from sampling. Unlike all the previous methods which were based on specific assumptions, this new method does not rely on any assumptions, which is in itself a very important and useful result in the development of theories. Moreover, the ideas applied in this work are stimulating to some related studies.
This work was partly supported by the National Natural Science Foundation of China No. 11074228.
In many body systems, if the potential energy is plotted as a function of particle coordinates, the PEL is constructed, as a complicated multi-dimensional surface. The PEL consists of an astronomically large number of basins of attraction whose bottoms are local potential energy minima, i.e. meta-stable configurations accessible at zero temperature. In excitations, the system walks randomly in the PEL. The PEL is very important in the understanding of many physical phenomena such as crystallization, melting, glass transition, jamming transition, plasticity, and protein folding. Prof. Xu and his collaborators developed a novel method based on the free-energy calculation to directly measure the size of a single basin of attraction in the PEL, which makes it possible to statistically measure the number of distinct basins of attraction and the configurational entropy from sampling. Unlike all the previous methods which were based on specific assumptions, this new method does not rely on any assumptions, which is in itself a very important and useful result in the development of theories. Moreover, the ideas applied in this work are stimulating to some related studies.
This work was partly supported by the National Natural Science Foundation of China No. 11074228.
March 25 2011
Our work on deep jamming was published in Physical Review Letters
Our work on deep jamming was published in Physical Review Letters
Our paper by Cang Zhao, Kaiwen Tian, and Ning Xu, "New Jamming Scenario: From Marginal Jamming to Deep Jamming", was published in Physical Review Letters (PRL 106, 125503, 2011) on March 25, 2011.
This work was supported by the National Natural Science Foundation of China (No. 91027001) and startup grant from USTC.
In this paper, we studied properties of jammed packings of frictionless spheres over a wide range of volume fractions. We observed a crossover volume fraction which separates marginally jammed solids and a new type of amorphous solids that we refer to as deeply jammed solids. Deeply jammed solids exhibit surprisingly different behaviors from marginally jammed ones in the critical scalings, structures, and vibrations. This work opens a route to explore the new jamming phase deeply inside the jamming phase diagram and seek experimental realizations and applications of this novel type of amorphous systems.
In this paper, we studied properties of jammed packings of frictionless spheres over a wide range of volume fractions. We observed a crossover volume fraction which separates marginally jammed solids and a new type of amorphous solids that we refer to as deeply jammed solids. Deeply jammed solids exhibit surprisingly different behaviors from marginally jammed ones in the critical scalings, structures, and vibrations. This work opens a route to explore the new jamming phase deeply inside the jamming phase diagram and seek experimental realizations and applications of this novel type of amorphous systems.