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| 2. |
- Baek, Seung Ki, 1979-, et al.
(författare)
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Bounds of percolation thresholds in the enhanced binary tree
- 2011
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Ingår i: Physica A. - : Elsevier. - 0378-4371 .- 1873-2119. ; 390:8, s. 1447-1452
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Tidskriftsartikel (refereegranskat)abstract
- It is argued that the lower critical percolation threshold of the enhanced binary tree is bounded as $p_{c1} < 0.355~059$ by studying its subgraphs while the upper threshold is bounded both from above and below by $1/2$ according to renormalization-group arguments. We also review a correlation analysis in an earlier work, which claimed a significantly higher estimate of $p_{c2}$ than $1/2$, to show that this analysis in fact gives a consistent result with this bound. It confirms that the duality relation between critical thresholds does not hold exactly for the EBT and its dual, possibly due to the lack of transitivity.
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| 3. |
- Baek, Seung Ki
(författare)
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Cluster Monte Carlo study of magnetic dipoles
- 2011
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Ingår i: Journal of the Korean Physical Society. - : Korean Physical Society. - 0374-4884 .- 1976-8524. ; 59:3, s. 2381-2386
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Tidskriftsartikel (refereegranskat)abstract
- We implement a cluster-update Monte Carlo algorithm to simulate magnetic dipoles of the XY-spin type, confined in the two-dimensional plane. The long-range character and anisotropy in the dipole interaction are handled by the Luijten-Bl\"ote algorithm and the Dotsenko-Selke-Talapov algorithm, respectively. We have checked performance of this algorithm in comparison to the Metropolis algorithm and found that it equilibrates the system faster in terms of the number of flipped spins, although the overall computational complexity of the problem remains the same.
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| 5. |
- Baek, Seung Ki, 1979-, et al.
(författare)
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Comment on `Six-state clock model on the square lattice: Fisher zeroapproach with Wang-Landau sampling'
- 2010
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - 1063-651X .- 1095-3787. ; 81:6, s. 3101-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Hwang in [Phys. Rev. E {\bf{80}}, 042103 (2009)] suggested that the two transitions of the six-state clock model on the square lattice are\emph{not} of the Kosterlitz-Thouless type. Here we show from simulations thatat the upper transition, the helicity modulus does make a discontinuous jumpto zero. This gives strong evidence for a Kosterlitz-Thoulesstransition.
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| 6. |
- Baek, Seung Ki, et al.
(författare)
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Critical condition of the water-retention model
- 2012
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - : American Physical Society. - 1539-3755 .- 1550-2376. ; 85:3, s. 032103-
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Tidskriftsartikel (refereegranskat)abstract
- We study how much water can be retained without leaking through boundarieswhen each unit square of a two-dimensional lattice is randomly assigned a blockof unit bottom area but with different heights from zero to $n-1$.As more blocks are put into the system,there exists a phase transition beyond whichthe system retains a macroscopic volume of water.We locate the critical points and verify that the criticalitybelongs to the two-dimensional percolation universality class.If the height distribution can be approximated as continuous for large $n$,the system is always close to a critical point and the fraction of the areabelow the resulting water level is given by the percolation threshold.This provides a universal upper bound ofareas that can be covered by water in a random landscape.
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| 7. |
- Baek, Seung Ki, et al.
(författare)
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Critical temperatures of the three- and four-state Potts models on the kagome lattice
- 2011
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Ingår i: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics. - : American Physical Society. - 1063-651X .- 1095-3787. ; 83:6, s. 061104-
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Tidskriftsartikel (refereegranskat)abstract
- The value of the internal energy per spin is independent of the strip widthfor a certain class of spin systems on two dimensional infinite strips. Itis verified that the Ising model on the kagome lattice belongs to this classthrough an exact transfer-matrix calculation of the internal energy for thetwo smallest widths. More generally, one can suggest an upper bound forthe critical coupling strength $K_c(q)$ for the $q$-state Potts model fromexact calculations of the internal energy for the two smallest stripwidths. Combining this with the corresponding calculation for the duallattice and using an exact duality relation enables us to conjecture thecritical coupling strengths for the three- and four-state Pottsmodels on the kagome lattice. The values are $K_c(q=3)=1.056~509~426~929~0$and $K_c(q=4) = 1.149~360~587~229~2$,and the values can, in principle, be obtained to an arbitrary precision. Wediscuss the fact that these values are in the middle of earlierapproximate results and furthermore differ from earlier conjecturesfor the exact values.
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| 8. |
- Baek, Seung Ki, 1979-, et al.
(författare)
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Curvature-induced frustration in the XY model on hyperbolic surfaces
- 2009
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Ingår i: Physical Review E - Statistical, Nonlinear, and Soft Matter Physics. - 1539-3755. ; 79:6, s. 060106(R)-
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Tidskriftsartikel (refereegranskat)abstract
- We study low-temperature properties of the XY spin model on a negatively curved surface. Geometric curvature of the surface gives rise to frustration in local spin configuration, which results in the formation of high-energy spin clusters scattered over the system. Asymptotic behavior of the spin-glass susceptibility suggests a zero-temperature glass transition, which is attributed to multiple optimal configurations of spin clusters due to nonzero surface curvature of the system. It implies that a constant ferromagnetic spin interaction on a regular lattice can exhibit glasslike behavior without possessing any disorder if the lattice is put on top of a negatively curved space such as a hyperbolic surface.
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| 9. |
- Baek, Seung Ki, et al.
(författare)
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Dworkin's Paradox
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:6, s. e38529-
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Tidskriftsartikel (refereegranskat)abstract
- How to distribute welfare in a society is a key issue in the subject of distributional justice, which is deeply involved with notions of fairness. Following a thought experiment by Dworkin, this work considers a society of individuals with different preferences on the welfare distribution and an official to mediate the coordination among them. Based on a simple assumption that an individual's welfare is proportional to how her preference is fulfilled by the actual distribution, we show that an egalitarian preference is a strict Nash equilibrium and can be favorable even in certain inhomogeneous situations. These suggest how communication can encourage and secure a notion of fairness.
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| 10. |
- Baek, Seung Ki, 1979-, et al.
(författare)
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Equilibrium solution to the lowest unique positive integer game
- 2010
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Ingår i: Fluctuation and Noise Letters. - : World Scientific Publishing. - 0219-4775 .- 1793-6780. ; 9:1, s. 61-68
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Tidskriftsartikel (refereegranskat)abstract
- We address the equilibrium concept of a reverse auction game so that no one can enhance the individual payoff by a unilateral change when all the others follow a certain strategy. In this approach the combinatorial possibilities to consider become very much involved even for a small number of players, which has hindered a precise analysis in previous works. We here present a systematic way to reach the solution for a general number of players, and show that this game is an example of conflict between the group and the individual interests.
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