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Seminars and Colloquia

Physics

Glassy behavior associated with melting of two-dimensional Coulomb clusters 
 
Fri, Apr 06, 2018,   12:00 PM at Physics Seminar Room 31, 2nd Floor, Main Building

Dr. Amit Ghosal
IISER Kolkata

Abstract:
We present responses of a small number of Coulomb-interacting particles in two-dimensional confinements, across the crossover from their solid- to liquid-like behaviors. Here, irregular confinements emulate the role of disorder.

Focusing first on the thermal melting, where zero-point motion of the particles are frozen, we explore the signatures of a 'hexatic-glass' like behavior. While static correlations, which investigate the translational and bond orientational order [1,2], indicate a hexatic-like phase at low temperatures, dynamical correlations show considerably slow relaxations. Using density correlations we probe intriguing inhomogeneities arising from the interplay of the irregularity in the confinement and long-range interactions. The relaxation at multiple time scales show stretched-exponential decay of spatial correlations for Coulomb-particles in irregular traps [1,3]. Temperature dependence of characteristic time scales, depicting the structural relaxation of the system, show strong similarities with those observed for the glassy systems. Our results indicate that some of the key features of supercooled liquids emerge in confined systems. more so with irregular confinements. The analysis of normal modes [4] elucidates how long time behavior of the system is encoded in the quasi-localized modes.

Time permitting, we extend our discussions to include the effects of quantum fluctuations. Our results, using quantum Monte Carlo techniques for Boltzmann particles, seem to indicate complementary mechanism for the quantum and thermal crossovers in Wigner molecules [5]. We will also discuss our recent analyses upon including the effects of quantum statistics.

1. B. Ash, J. Chakrabarti and A. Ghosal, Phys. Rev. E 96, 042105(2017).
2. D. Bhattacharya and A. Ghosal, Eur. Phys. J. B 86, 499, (2013).
3. B. Ash, J. Chakrabarti and A. Ghosal, Euro. Phys. Lett., 114, 4, (2016).
4. B. Ash, C. Dasgupta and A. Ghosal (Preprint)
5. D. Bhattacharya, A. V. Filinov, A. Ghosal and M.Bonitz, Eur. Phys. J. B 89, 60, (2016)

 

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