Seminar after Easter break

[Cond.Matt. & Stat.Mech.Section]

SEMINAR on  Disorder and strong electron correlations


Thursday, 4 April -  11:30 a.m.


Luigi Stasi Seminar Room,  Leonardo Building - first floor

 

Werner KRAUTH   (Ecole Normale Supérieure, Paris)

 

"Melting transition of hard disks: New algorithms, new insights "


Abstract


The hard-disk model has exerted outstanding influence on computational physics and statistical mechanics.  Decades ago, hard disks were the first system to be studied by Markov-chain Monte Carlo methods and by molecular dynamics.  It was in hard disks, through numerical simulations, that a two-dimensional melting transition was first seen to occur even though such systems cannot develop long-range crystalline order.  Analysis of the system was made difficult by the absence of adequate simulation methods.

In recent years, we  have developed a number of powerful Monte Carlo algorithms for hard disks and related systems. I will in particular show how  the powerful event-chain Monte Carlo algorithm has allowed us to

show that hard disks melt  with a first-order transition from the liquid to the hexatic and a continuous transition from the hexatic to the solid. I will finish with discussions on the general theory of two-dimensional melting and on the generalizations of the event-chain algorithm.