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Baek, Seung Ki
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Bokma, F., Baek, S. K. & Minnhagen, P. (2014). 50 years of inordinate fondness. Systematic Biology, 63(2), 251-256
Open this publication in new window or tab >>50 years of inordinate fondness
2014 (English)In: Systematic Biology, ISSN 1063-5157, E-ISSN 1076-836X, Vol. 63, no 2, p. 251-256Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Oxford University Press, 2014
Keywords
Taxa, species, distributions, maximum entropy, random group formation
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:umu:diva-81886 (URN)10.1093/sysbio/syt067 (DOI)000332044900010 ()
Available from: 2013-10-22 Created: 2013-10-22 Last updated: 2018-06-08Bibliographically approved
Baek, S. K. & Kim, B. J. (2012). Critical condition of the water-retention model. Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, 85(3), 032103
Open this publication in new window or tab >>Critical condition of the water-retention model
2012 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1539-3755, E-ISSN 1550-2376, Vol. 85, no 3, p. 032103-Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
American Physical Society, 2012
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-54259 (URN)10.1103/PhysRevE.85.032103 (DOI)000302117900008 ()
Funder
Swedish Research Council, 621-2008-4449 Available from: 2012-04-23 Created: 2012-04-23 Last updated: 2018-06-08Bibliographically approved
Baek, S. K., Choi, J.-K. & Kim, B. J. (2012). Dworkin's Paradox. PLoS ONE, 7(6), e38529
Open this publication in new window or tab >>Dworkin's Paradox
2012 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 6, p. e38529-Article in journal (Refereed) Published
Abstract [en]

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.

National Category
Probability Theory and Statistics
Identifiers
urn:nbn:se:umu:diva-57437 (URN)10.1371/journal.pone.0038529 (DOI)000305808700004 ()
Available from: 2012-07-23 Created: 2012-07-23 Last updated: 2018-06-08Bibliographically approved
Bernhardsson, S., Baek, S. K. & Minnhagen, P. (2011). A Paradoxical Property of the Monkey Book. Journal of Statistical Mechanics: Theory and Experiment, P07013
Open this publication in new window or tab >>A Paradoxical Property of the Monkey Book
2011 (English)In: Journal of Statistical Mechanics: Theory and Experiment, ISSN 1742-5468, E-ISSN 1742-5468, p. P07013-Article in journal (Refereed) Published
Abstract [en]

A 'monkey book' is a book consisting of a random sequence of letters and blanks, where a group of letters surrounded by two blanks is defined as a word. We compare the statistics of the word distribution for a monkey book to real books. It is shown that the word distribution statistics for the monkey book is different and quite distinct from a typical real book. In particular, the monkey book obeys Heaps' power law to an extraordinarily good approximation, in contrast to the word distributions for real books, which deviate from Heaps' law in a characteristic way. This discrepancy is traced to the different properties of a 'spiked' distribution and its smooth envelope. The somewhat counter-intuitive conclusion is that a 'monkey book' obeys Heaps' power law precisely because its word-frequency distribution is not a smooth power law, contrary to the expectation based on simple mathematical arguments that if one is a power law, so is the other.

Place, publisher, year, edition, pages
Institute of Physics, 2011
Keywords
analysis of algorithms, growth processes
Natural Sciences
Identifiers
urn:nbn:se:umu:diva-47758 (URN)10.1088/1742-5468/2011/07/P07013 (DOI)
Available from: 2011-09-29 Created: 2011-09-28 Last updated: 2018-06-08Bibliographically approved
Baek, S. K. & Minnhagen, P. (2011). Bounds of percolation thresholds in the enhanced binary tree. Physica A: Statistical Mechanics and its Applications, 390(8), 1447-1452
Open this publication in new window or tab >>Bounds of percolation thresholds in the enhanced binary tree
2011 (English)In: Physica A: Statistical Mechanics and its Applications, ISSN 0378-4371, E-ISSN 1873-2119, Vol. 390, no 8, p. 1447-1452Article in journal (Refereed) Published
Abstract [en]

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.

Elsevier, 2011
Keywords
percolation threshold, enhanced binary tree, hyperbolic lattice
National Category
Condensed Matter Physics
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:umu:diva-39227 (URN)10.1016/j.physa.2010.12.030 (DOI)
Funder
Swedish Research Council, 621-2002-4135 Available from: 2011-01-18 Created: 2011-01-18 Last updated: 2018-06-08Bibliographically approved
Baek, S. K. (2011). Cluster Monte Carlo study of magnetic dipoles. Journal of the Korean Physical Society, 59(3), 2381-2386
Open this publication in new window or tab >>Cluster Monte Carlo study of magnetic dipoles
2011 (English)In: Journal of the Korean Physical Society, ISSN 0374-4884, E-ISSN 1976-8524, Vol. 59, no 3, p. 2381-2386Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
Korean Physical Society, 2011
Keywords
Magnetic dipole, Long-range Monte Carlo, Cluster update algorithm
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-47761 (URN)10.3938/jkps.59.2381 (DOI)
Funder
Swedish Research Council, 621-2008-4449 Available from: 2011-09-29 Created: 2011-09-28 Last updated: 2018-06-08Bibliographically approved
Baek, S. K., Mäkelä, H., Minnhagen, P. & Kim, B. J. (2011). Critical temperatures of the three- and four-state Potts models on the kagome lattice. Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, 83(6), 061104
Open this publication in new window or tab >>Critical temperatures of the three- and four-state Potts models on the kagome lattice
2011 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics: Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, ISSN 1063-651X, E-ISSN 1095-3787, Vol. 83, no 6, p. 061104-Article in journal (Refereed) Published
Abstract [en]

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.

Place, publisher, year, edition, pages
American Physical Society, 2011
National Category
Condensed Matter Physics
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:umu:diva-44393 (URN)10.1103/PhysRevE.83.061104 (DOI)
Funder
Swedish Research Council, 621-2008-4449 Available from: 2011-06-09 Created: 2011-06-07 Last updated: 2018-06-08Bibliographically approved
Baek, S. K. & Minnhagen, P. (2011). Hierarchical renormalization-group study on the planar bond-percolation problem. Physica Scripta, 83(5), 055601
Open this publication in new window or tab >>Hierarchical renormalization-group study on the planar bond-percolation problem
2011 (English)In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 83, no 5, p. 055601-Article in journal (Refereed) Published
Abstract [en]

For certain hierarchical structures, one can study the percolation problemusing the renormalization-group method in a very precise way.We show that the idea can be alsoapplied to two-dimensional planar lattices by regarding them as hierarchicalstructures. Either a lower bound or an exact critical probability can beobtained with this method and the correlation-length critical exponent isapproximately estimated as $\nu \approx 1$.

Place, publisher, year, edition, pages
IOP Publishing, 2011
Keywords
Percolation, Critical point phenomena, Renormalization-group theory
National Category
Condensed Matter Physics
Research subject
Theoretical Physics
Identifiers
urn:nbn:se:umu:diva-43641 (URN)10.1088/0031-8949/83/05/055601 (DOI)
Funder
Swedish Research Council, 621-2008-4449 Available from: 2011-05-10 Created: 2011-05-05 Last updated: 2018-06-08Bibliographically approved
Baek, S. K., Mäkelä, H., Minnhagen, P. & Kim, B. J. (2011). Ising model on a hyperbolic plane with a boundary. Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, 84, 032103
Open this publication in new window or tab >>Ising model on a hyperbolic plane with a boundary
2011 (English)In: Physical Review E. Statistical, Nonlinear, and Soft Matter Physics, ISSN 1539-3755, E-ISSN 1550-2376, Vol. 84, p. 032103-Article in journal (Refereed) Published
Abstract [en]

A hyperbolic plane can be modeled by a structure called the enhanced binarytree. We study the ferromagnetic Ising model on top of the enhanced binarytree using the renormalization-group analysis in combination withtransfer-matrix calculations. We find a reasonable agreement with MonteCarlo calculations on the transition point, and the resulting criticalexponents suggest the mean-field surface critical behavior.

Place, publisher, year, edition, pages
American Physical Society, 2011
National Category
Condensed Matter Physics
Identifiers
urn:nbn:se:umu:diva-47877 (URN)10.1103/PhysRevE.84.032103 (DOI)
Funder
Swedish Research Council, 621-2008-4449 Available from: 2011-10-03 Created: 2011-10-02 Last updated: 2018-06-08Bibliographically approved
Baek, S. K., Minnhagen, P. & Kim, B. J. (2011). Kosterlitz-Thouless transition of magnetic dipoles on thetwo-dimensional plane. Physical Review B. Condensed Matter and Materials Physics, 83(18), 184409-5 p
Open this publication in new window or tab >>Kosterlitz-Thouless transition of magnetic dipoles on thetwo-dimensional plane
2011 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 83, no 18, p. 184409-5 pArticle in journal (Refereed) Published
Abstract [en]

The universality class of a phase transition is often determined by factorslike dimensionality and inherent symmetry. We study the magneticdipole system in which the ground-state symmetry and the underlying latticestructure are coupled to each other in an intricate way. A two-dimensional(2D)square-lattice system of magnetic dipoles undergoes an order-disorder phasetransition belonging to the 2D Ising universality class.According to Prakash and Henley [Phys. Rev. B {\bf 42}, 6572 (1990)], this can berelated to the fourfold-symmetric ground states which suggests a similarityto the four-state clock model. Provided that this type ofsymmetry connection holds true, the magnetic dipoles on a honeycomb lattice,which possess sixfold-symmetric ground states, should exhibit aKosterlitz-Thouless transition in accordance with the six-state clock model.This is verified through numerical simulations in the present investigation.However, it is pointed out that this symmetry argument does not alwaysapply, which suggests that factors other than symmetry can be decisive forthe universality class of the magnetic dipole system.

APS, 2011
National Category
Condensed Matter Physics Condensed Matter Physics
Research subject
Theoretical Physics; Solid State Physics
Identifiers
urn:nbn:se:umu:diva-44071 (URN)10.1103/PhysRevB.83.184409 (DOI)
Funder
Swedish Research Council, 621-2008-4449 Available from: 2011-05-18 Created: 2011-05-18 Last updated: 2018-06-08Bibliographically approved

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