Schedule

 

13:30-14.20     Prof. Dr. Xiao HU

14:20-15:10     Prof. Dr. Yu-qiang Ma

15:10-16:00     Prof. Dr. Pei-qing Tong

16:00-16:10     break

16:10-17:10     Prof. Dr. Lei-han Tang   (Colloquium)

17:10-17:40     Prof. Dr. Qing-hu CHEN

 

 

Titles and abstract

 

 

1.    Prof. Dr. Xiao HU

      Computational Materials Science Center

      National Institute for Materials Science

      Tsukuba 305-0047, Japan

              

Equilibrium Vortex States and Phase Transitions in High-Tc Superconductors

 

1)      Introductions: flux quantum and type II superconductors

2)      1st order melting of pancake vortex lattice

3)      Continuous melting of interlayer Josephson vortex lattice

4)      Glassy properties of vortex matters with defects

 

2.  Distinguished Prof. Yu-qiang Ma

   National Laboratory of Solid State Microstructures, Nanjing University, Nanjing
 

 

 Self organization in soft matter



In this talk,  I first present a review of a wide variety of self-organizing behaviors in soft materials,
and then discuss how to  design and control self-assembled ordering structures from our recent works.
In particular, we will examine in detail the formation of self-organizing ordering structures in phase-separating
 systems due to competing interactions, externally fluctuating forces, and entropy effects,   and find
that a moderate amount of `` noise"  may assist the formation of highly ordered structures by removing
topological defects or reorganizing structures.
The results clearly indicate a possibility for the production of highly ordered and defect-free multi-scale materials
  by introducing ``disordering" factors, and provide an interesting and universal picture to account for 
``noise-induced ordering" phenomena in soft materials.

 

3.  Prof. Dr. Pei-qing Tong

    Department of Physics, Nanjing Normal Univeirsty, Nanjing
 

quantum phase transition and entanglement of anisotropic XY chain in transverse filed



The quantum phase transitions of periodic and
quasiperiodic anisotropic XY chains in a transverse
magnetic field are studied by analytical and numerical
method. It is found that the number of phase transition
points is depended on the ratio of strengths of exchange
interactions and parameter of anisotropy. The reason of
the phase transitions is discussed. Finally, we discuss
the entanglements of two spin in the chain at phase
transition points.
 

4.  Prof. Dr. Lei-han Tang

    Department of Physics, Hong Kong Baptist University, Hong Kong

 

Multicanonical Monte Carlo Sampling Applied to Quantum Phase Transitions



Through a path integral formalism, it is well-known that a two-dimensional
quantum system of bosons can be mapped to a three-dimensional classical
system whose thermodynamic properties can be studied using Monte Carlo
methods. In connection with recent experiments on superconducting thin
films and the bose condensate of alkali gases, there have been renewed
interest in the phase diagram of an interacting bose system at zero
temperature. The multicanonical Monte Carlo scheme, which has been
demonstrated to be very efficient for sampling the phase space of systems
with a rugged energy landscape (at least when the size is small), is
well-suited for such studies. We have recently implemented a variant of
Berg's iterative procedure to determine the multicanonical weights that
extends the original scheme in two ways: (i) a variable bin size to handle
continuous degrees of freedom and (ii) a polynomial extrapolation
step that speeds up convergence to the final entropy function.
The algorithm is applied to a two-dimensional quantum rotor model
with quenched phase disorder. Measurement of the helicity and twist
modulus shows that, in addition to the superfluid (or superconducting)
and the Mott insulator, there is a gapless phase known as phase glass,
with unusual transport properties at zero temperature.
 

5.  Prof. Dr. Qing-hu CHEN

1. Computational Materials Science Center, National Institute for Materials Science, Tsukuba 305-0047, Japan
2. Department of Physics, Zhejiang University, Hangzhou

 

Dynamics of Vortex Matter in Three-Dimensional Layered Superconductors



In this talk, we will report our recent progress in the numerical study on dynamics of
vortex matter in weak random pinning potential in 3D layered superconductors.  The  
first-order phase transition from the moving Bragg glass to the moving smectic is clarified,
based on thermodynamic quantities. A washboard noise is observed in the moving Bragg glass
in 3D systems at finite temperature for the first time. It is found that  activation of 
vortex loops play the dominant role in the dynamical melting at high drive. A brief
introduction will also be given.