Latest Papers in Condensed Matter Physics

Statistical Mechanics

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Effects of a kinetic barrier on limited-mobility interface growth models (1902.03211v1)

Anderson J. Pereira, Sidiney G. Alves, Silvio C. Ferreira

2019-02-08

The role played by a kinetic barrier originated by out-of-plane step edge diffusion, introduced in [Leal \textit{et al.}, \href{https://doi.org/10.1088/0953-8984/23/29/292201}{J. Phys. Condens. Matter \textbf{23}, 292201 (2011)}], is investigated in the Wolf-Villain and Das Sarma-Tamborenea models with short range diffusion. Using large-scale simulations, we observed that this barrier is sufficient to produce growth instability, forming quasiregular mounds in one and two dimensions. The characteristic surface length saturates quickly indicating a uncorrelated growth of the 3d structures, which is also confirmed by a growth exponent . The out-of-plane particle current provides a large reduction of the downward flux enhancing, consequently, the net upward diffusion and formation of 3d self-arranged structures.

Many-body localization in presence of cavity mediated long-range interactions (1902.00357v2)

Piotr Sierant, Krzysztof Biedroń, Giovanna Morigi, Jakub Zakrzewski

2019-02-01

We show that a one-dimensional Hubbard model with all-to-all coupling may exhibit many-body localization in the presence of local disorder. We numerically identify the parameter space where many-body localization occurs using exact diagonalization and finite-size scaling. The time evolution from a random initial state exhibits features consistent with the localization picture. The dynamics can be observed with quantum gases in optical cavities, localization can be revealed through the time-dependent dynamics of the light emitted by the resonator.

Thermal contribution of unstable states (1902.03203v1)

Pok Man Lo, Francesco Giacosa

2019-02-08

Within the framework of the Lee model, we analyze in detail the difference between the energy derivative of the phase shift and the standard spectral function of the unstable state. The fact that the model is exactly solvable allows us to demonstrate the construction of these observables from various exact Green functions. The connection to a formula due to Krein, Friedal, and Lloyd is also examined. We also directly demonstrate how the derivative of the phase shift correctly identifies the relevant interaction contributions for consistently including an unstable state in describing the thermodynamics.

Clock Monte Carlo methods (1706.10261v3)

Manon Michel, Xiaojun Tan, Youjin Deng

2017-06-30

We propose the clock Monte Carlo technique for sampling each successive chain step in constant time. It is built on a recently proposed factorized transition filter and its core features include its O(1) computational complexity and its generality. We elaborate how it leads to the clock factorized Metropolis (clock FMet) method, and discuss its application in other update schemes. By grouping interaction terms into boxes of tunable sizes, we further formulate a variant of the clock FMet algorithm, with the limiting case of a single box reducing to the standard Metropolis method. A theoretical analysis shows that an overall acceleration of () can be achieved compared to the Metropolis method, where is the system size and the value depends on the nature of the energy extensivity. As a systematic test, we simulate long-range O spin models in a wide parameter regime: for , with disordered algebraically decaying or oscillatory Ruderman-Kittel-Kasuya-Yoshida-type interactions and with and without external fields, and in spatial dimensions from to mean-field. The O(1) computational complexity is demonstrated, and the expected acceleration is confirmed. Its flexibility and its independence from the interaction range guarantee that the clock method would find decisive applications in systems with many interaction terms.

Anomalous diffusion: A basic mechanism for the evolution of inhomogeneous systems (1902.03157v1)

Fernando A. Oliveira, Rogelma M. S. Ferreira, Luciano C. Lapas, Mendeli H. Vainstein

2019-02-08

In this article we review classical and recent results in anomalous diffusion and provide mechanisms useful for the study of the fundamentals of certain processes, mainly in condensed matter physics, chemistry and biology. Emphasis will be given to some methods applied in the analysis and characterization of diffusive regimes through the memory function, the mixing condition (or irreversibility), and ergodicity. Those methods can be used in the study of small-scale systems, ranging in size from single-molecule to particle clusters and including among others polymers, proteins, ion channels and biological cells, whose diffusive properties have received much attention lately.

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