Multicanonical methods, molecular dynamics, and Monte Carlo methods: Comparison for Lennard-Jones glasses

Bhattacharya, Kamal K.; Sethna, James P.

doi:10.1103/physreve.57.2553

Cited by 42 publications

(32 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Jumping ahead of ourselves, let us say that the statistics of our model at T , 0:003 is dominated by glassy states. Exactly the same behaviour of the multicanonical algorithm as that found by our study has recently been reported by Bhattacharya and Sethna [20] in the MC study of glassy Lennard -Jones liquids. It was argued that it is the entropy barriers, which trap simulations in multicanonical ensemble in contrast to the potential energy barriers trapping conventional MD simulations.…”

Section: Resultssupporting

confidence: 84%

Structural organization of a chain molecule with specific charge distribution: A molecular dynamics study

Baumketner

Shimizu

Hiwatari

2002

Molecular Simulation

View full text Add to dashboard Cite

We report the results of molecular dynamics simulations of a charged bead-monomer chain molecule with charge distribution adopted from immunoglobulin-binding domain B1 of protein-g. The beads of the model are connected by invariable bonds and interact with each other via the Coulomb potential. To study the low-temperature conformational space of the designed model we use standard canonical, microcanonical and multicanonical molecular dynamics simulations. We find that at low temperature T ¼ T c the chain undergoes a continuous freezing transition into one of many low-energy conformations. Below T c the molecule is a compact globule composed of an inner core, containing mostly charged monomers, and an outer corona, consisting of all the rest neutral units. All frozen conformations have almost equal potential energy but differ in structure. The potential energy surface of the model does not posses a pronounced ground-state minimum-an essential feature of proteinlike heteropolymers.

show abstract

Section: Resultssupporting

confidence: 84%

Structural organization of a chain molecule with specific charge distribution: A molecular dynamics study

Baumketner

Shimizu

Hiwatari

2002

Molecular Simulation

View full text Add to dashboard Cite

show abstract

“…To assess the performance of our algorithm in sampling low lying energy states quantitatively, we compare the lowest energies sampled with the results of a recent study on the optimization properties of traditional simulation algorithms applied to the Lennard-Jones glasses [13]. The authors reported on a lowest energy configuration found for N = 60 at e = −5.38 by cooling down slowly from the liquid phase using standard molecular dynamics.…”

mentioning

confidence: 99%

“…The difference in energy δe = 0.07 corresponds to a factor of 100 in computer time according to the estimate given in refs. [13,10]. For T run ≤ 0.5 around 15% of all states sampled using our method are lower in energy then e = −5.38.…”

mentioning

confidence: 99%

Energy landscape and overlap distribution of binary Lennard-Jones glasses

et al. 1999

View full text Add to dashboard Cite

Abstract. -We study the distribution of overlaps of glassy minima, taking proper care of residual symmetries of the system. Ensembles of locally stable, low lying glassy states are efficiently generated by rapid cooling from the liquid phase which has been equilibrated at a temperature Trun. Varying Trun, we observe a transition from a regime where a broad range of states are sampled to a regime where the system is almost always trapped in a metastable glassy state. We do not observe any structure in the distribution of overlaps of glassy minima, but find only very weak correlations, comparable in size to those of two liquid configurations.The phenomenology of supercooled liquids, the glass transition and the glassy phase have been related to results of analytical calculations for microscopic models of spin glasses [1,2]. The latter bear no obvious relevance to structural glasses, hence, it is particularly important to see, whether the analogy can be supported quantitatively. One of the most prominent features of those spin-glass models, which have been put forward as models of structural glasses, is one step replica symmetry breaking, resulting in a bimodal distribution of overlaps between pure states. Generally speaking, one would expect to see non-trivial correlations among glassy states, if mean field theory of spin glasses were to apply.The liquid to glass transition as it is observed e.g. in metallic glasses, is a non-equilibrium phenomenon with the crystalline state being the true ground state. Glassy states are in general metastable states, sometimes called quasi-ergodic components, which are mutually inaccessible on experimental time scales, while equilibrium within a quasi-ergodic component is reached on much shorter time scales. In contrast to mean field models of spin glasses the ensemble of metastable states depends on the preparation method and the appropriate weights for metastable states are not unique. The assumption of an idealised preparation method, which cools the liquid arbitrarily slowly and at the same time prevents crystallization, has never been verified and seems contradictory to us. We therefore prefer to use a different idealised preparation ensemble which corresponds to infinitely rapid cooling from liquid equilibrium states. This method was first introduced by Stillinger and Weber [3,4]. Typeset using EURO-T E X

show abstract

“…[38]), each update of τ -EO a variable is selected based on its rank according to the probability distribution in Eq. (8). When a rank k(≤ n)…”

Section: B Update Probabilities For Extremal Optimizationmentioning

confidence: 99%

“…Examples in the sciences are the determination of ground states for disordered magnets [2,3,4,5,6,7] or of optimal arrangements of atoms in a compound [8] or a polymer [9,10,11]. With the advent of ever faster computers, the exact study of such problems has become feasible [12,13].…”

Section: Introductionmentioning

confidence: 99%