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Title | : Optimal tuning of a confined Brownian information engine |
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Author | : Noh, Jae Dong,Lee, Jae Sung |
Journal | : PHYSICAL REVIEW E, 2016 |
NUMBER | Q17029 |
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AUTHOR | Noh, Jae Dong,Lee, Jae Sung |
TITLE | Optimal tuning of a confined Brownian information engine |
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JOURNAL | PHYSICAL REVIEW E, 2016 |
ABSTRACT | A Brownian information engine is a device extracting mechanical work from a single heat bath by exploiting the information on the state of a Brownian particle immersed in the bath. As for engines, it is important to find the optimal operating condition that yields the maximum extracted work or power. The optimal condition for a Brownian information engine with a finite cycle time tau has been rarely studied because of the difficulty in finding the nonequilibrium steady state. In this study, we introduce a model for the Brownian information engine and develop an analytic formalism for its steady-state distribution for any tau. We find that the extracted work per engine cycle is maximum when t approaches infinity, while the power is maximum when t approaches zero. |
Title | : Scaling of cluster heterogeneity in percolation transitions |
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Author | : Noh, Jae Dong,Park, Hyunggyu |
Journal | : PHYSICAL REVIEW E, 2011 |
NUMBER | P11029 |
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AUTHOR | Noh, Jae Dong,Park, Hyunggyu |
TITLE | Scaling of cluster heterogeneity in percolation transitions |
ARCHIVE | arXiv:1106.0354 |
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JOURNAL | PHYSICAL REVIEW E, 2011 |
ABSTRACT | We investigate a critical scaling law for the cluster heterogeneity H in site and bond percolations in d-dimensional lattices with d = 2,...,6. The cluster heterogeneity is defined as the number of distinct cluster sizes. As an occupation probability p increases, the cluster size distribution evolves from a monodisperse distribution to a polydisperse one in the subcritical phase, and back to a monodisperse one in the supercritical phase. We show analytically that H diverges algebraically, approaching the percolation critical point p(c) as H similar to vertical bar p - p(c)vertical bar(-1/sigma) with the critical exponent sigma associated with the characteristic cluster size. Interestingly, its finite-size-scaling behavior is governed by a new exponent v(H) = (1 + d(f)/d)v, where d(f) is the fractal dimension of the critical percolating cluster and v is the correlation length exponent. The corresponding scaling variable defines a singular path to the critical point. All results are confirmed by numerical simulations. |
Title | : Nonequilibrium fluctuations for linear diffusion dynamics |
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Author | : Noh, Jae Dong,Park, Hyunggyu |
Journal | : PHYSICAL REVIEW E, 2011 |
NUMBER | P11018 |
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AUTHOR | Noh, Jae Dong,Park, Hyunggyu |
TITLE | Nonequilibrium fluctuations for linear diffusion dynamics |
ARCHIVE | 1102.2973 |
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JOURNAL | PHYSICAL REVIEW E, 2011 |
ABSTRACT | We present the theoretical study on nonequilibrium (NEQ) fluctuations for diffusion dynamics in high dimensions driven by a linear drift force. We consider a general situation in which NEQ is caused by two conditions: (i) drift force not derivable from a potential function, and (ii) diffusion matrix not proportional to the unit matrix, implying nonidentical and correlated multidimensional noise. The former is a well-known NEQ source and the latter can be realized in the presence of multiple heat reservoirs or multiple noise sources. We develop a statistical mechanical theory based on generalized thermodynamic quantities such as energy, work, and heat. The NEQ fluctuation theorems are reproduced successfully. We also find the time-dependent probability distribution function exactly as well as the NEQ work production distribution P(W) in terms of solutions of nonlinear differential equations. In addition, we compute low-order cumulants of the NEQ work production explicitly. In two dimensions, we carry out numerical simulations to check out our analytic results and also to get P(W). We find an interesting dynamic phase transition in the exponential tail shape of P(W), associated with a singularity found in solutions of the nonlinear differential equation. Finally, we discuss possible realizations in experiments. |