TY  - JOUR
AU  - Tadić, Bosiljka
AU  - Anđelković, Miroslav
AU  - Šuvakov, Milovan
AU  - Rodgers, Geoff J.
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8930
AB  - Functional designs of nanostructured materials seek to exploit the potential of complex morphologies and disorder. In this context, the spin dynamics in disordered antiferromagnetic materials present a significant challenge due to induced geometric frustration. Here we analyse the processes of magnetisation reversal driven by an external field in generalised spin networks with higher-order connectivity and antiferromagnetic defects. Using the model in (Tadić et al. Arxiv:1912.02433), we grow nanonetworks with geometrically constrained self-assemblies of simplexes (cliques) of a given size n, and with probability p each simplex possesses a defect edge affecting its binding, leading to a tree-like pattern of defects. The Ising spins are attached to vertices and have ferromagnetic interactions, while antiferromagnetic couplings apply between pairs of spins along each defect edge. Thus, a defect edge induces n − 2 frustrated triangles per n-clique participating in a larger-scale complex. We determine several topological, entropic, and graph-theoretic measures to characterise the structures of these assemblies. Further, we show how the sizes of simplexes building the aggregates with a given pattern of defects affects the magnetisation curves, the length of the domain walls and the shape of the hysteresis loop. The hysteresis shows a sequence of plateaus of fractional magnetisation and multiscale fluctuations in the passage between them. For fully antiferromagnetic interactions, the loop splits into two parts only in mono-disperse assemblies of cliques consisting of an odd number of vertices n. At the same time, remnant magnetisation occurs when n is even, and in poly-disperse assemblies of cliques in the range n ∈ [ 2 , 10 ] . These results shed light on spin dynamics in complex nanomagnetic assemblies in which geometric frustration arises in the interplay of higher-order connectivity and antiferromagnetic interactions.
T2  - Entropy
T1  - Magnetisation Processes in Geometrically Frustrated Spin Networks with Self-Assembled Cliques
VL  - 22
IS  - 3
SP  - 336
DO  - 10.3390/e22030336
ER  - 

@article{
author = "Tadić, Bosiljka and Anđelković, Miroslav and Šuvakov, Milovan and Rodgers, Geoff J.",
year = "2020",
abstract = "Functional designs of nanostructured materials seek to exploit the potential of complex morphologies and disorder. In this context, the spin dynamics in disordered antiferromagnetic materials present a significant challenge due to induced geometric frustration. Here we analyse the processes of magnetisation reversal driven by an external field in generalised spin networks with higher-order connectivity and antiferromagnetic defects. Using the model in (Tadić et al. Arxiv:1912.02433), we grow nanonetworks with geometrically constrained self-assemblies of simplexes (cliques) of a given size n, and with probability p each simplex possesses a defect edge affecting its binding, leading to a tree-like pattern of defects. The Ising spins are attached to vertices and have ferromagnetic interactions, while antiferromagnetic couplings apply between pairs of spins along each defect edge. Thus, a defect edge induces n − 2 frustrated triangles per n-clique participating in a larger-scale complex. We determine several topological, entropic, and graph-theoretic measures to characterise the structures of these assemblies. Further, we show how the sizes of simplexes building the aggregates with a given pattern of defects affects the magnetisation curves, the length of the domain walls and the shape of the hysteresis loop. The hysteresis shows a sequence of plateaus of fractional magnetisation and multiscale fluctuations in the passage between them. For fully antiferromagnetic interactions, the loop splits into two parts only in mono-disperse assemblies of cliques consisting of an odd number of vertices n. At the same time, remnant magnetisation occurs when n is even, and in poly-disperse assemblies of cliques in the range n ∈ [ 2 , 10 ] . These results shed light on spin dynamics in complex nanomagnetic assemblies in which geometric frustration arises in the interplay of higher-order connectivity and antiferromagnetic interactions.",
journal = "Entropy",
title = "Magnetisation Processes in Geometrically Frustrated Spin Networks with Self-Assembled Cliques",
volume = "22",
number = "3",
pages = "336",
doi = "10.3390/e22030336"
}

Tadić, B., Anđelković, M., Šuvakov, M.,& Rodgers, G. J.. (2020). Magnetisation Processes in Geometrically Frustrated Spin Networks with Self-Assembled Cliques. in Entropy, 22(3), 336.
https://doi.org/10.3390/e22030336

Tadić B, Anđelković M, Šuvakov M, Rodgers GJ. Magnetisation Processes in Geometrically Frustrated Spin Networks with Self-Assembled Cliques. in Entropy. 2020;22(3):336.
doi:10.3390/e22030336 .

Tadić, Bosiljka, Anđelković, Miroslav, Šuvakov, Milovan, Rodgers, Geoff J., "Magnetisation Processes in Geometrically Frustrated Spin Networks with Self-Assembled Cliques" in Entropy, 22, no. 3 (2020):336,
https://doi.org/10.3390/e22030336 . .

TY  - JOUR
AU  - Tadić, Bosiljka
AU  - Anđelković, Miroslav
AU  - Šuvakov, Milovan
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1953
AB  - Hyperbolicity or negative curvature of complex networks is the intrinsic geometric proximity of nodes in the graph metric space, which implies an improved network function. Here, we investigate hidden combinatorial geometries in brain-to-brain coordination networks arising through social communications. The networks originate from correlations among EEG signals previously recorded during spoken communications comprising of 14 individuals with 24 speaker-listener pairs. We find that the corresponding networks are delta-hyperbolic with delta(max) = 1 and the graph diameter D = 3 in each brain. While the emergent hyperbolicity in the two-brain networks varies satisfying delta(max)/D/2 LT = 1 and can be attributed to the topology of the subgraph formed around the cross-brains linking channels. We identify these subgraphs in each studied two-brain network and decompose their structure into simple geometric descriptors ( triangles, tetrahedra and cliques of higher orders) that contribute to hyperbolicity. Considering topologies that exceed two separate brain networks as a measure of coordination synergy between the brains, we identify different neural correlation patterns ranging from weak coordination to super-brain structure. These topology features are in qualitative agreement with the listeners self-reported ratings of own experience and quality of the speaker, suggesting that studies of the cross-brain connector networks can reveal new insight into the neural mechanisms underlying human social behavior.
T2  - Frontiers in Physics
T1  - Origin of Hyperbolicity in Brain-to-Brain Coordination Networks
VL  - 6
DO  - 10.3389/fphy.2018.00007
ER  - 

@article{
author = "Tadić, Bosiljka and Anđelković, Miroslav and Šuvakov, Milovan",
year = "2018",
abstract = "Hyperbolicity or negative curvature of complex networks is the intrinsic geometric proximity of nodes in the graph metric space, which implies an improved network function. Here, we investigate hidden combinatorial geometries in brain-to-brain coordination networks arising through social communications. The networks originate from correlations among EEG signals previously recorded during spoken communications comprising of 14 individuals with 24 speaker-listener pairs. We find that the corresponding networks are delta-hyperbolic with delta(max) = 1 and the graph diameter D = 3 in each brain. While the emergent hyperbolicity in the two-brain networks varies satisfying delta(max)/D/2 LT = 1 and can be attributed to the topology of the subgraph formed around the cross-brains linking channels. We identify these subgraphs in each studied two-brain network and decompose their structure into simple geometric descriptors ( triangles, tetrahedra and cliques of higher orders) that contribute to hyperbolicity. Considering topologies that exceed two separate brain networks as a measure of coordination synergy between the brains, we identify different neural correlation patterns ranging from weak coordination to super-brain structure. These topology features are in qualitative agreement with the listeners self-reported ratings of own experience and quality of the speaker, suggesting that studies of the cross-brain connector networks can reveal new insight into the neural mechanisms underlying human social behavior.",
journal = "Frontiers in Physics",
title = "Origin of Hyperbolicity in Brain-to-Brain Coordination Networks",
volume = "6",
doi = "10.3389/fphy.2018.00007"
}

Tadić, B., Anđelković, M.,& Šuvakov, M.. (2018). Origin of Hyperbolicity in Brain-to-Brain Coordination Networks. in Frontiers in Physics, 6.
https://doi.org/10.3389/fphy.2018.00007

Tadić B, Anđelković M, Šuvakov M. Origin of Hyperbolicity in Brain-to-Brain Coordination Networks. in Frontiers in Physics. 2018;6.
doi:10.3389/fphy.2018.00007 .

Tadić, Bosiljka, Anđelković, Miroslav, Šuvakov, Milovan, "Origin of Hyperbolicity in Brain-to-Brain Coordination Networks" in Frontiers in Physics, 6 (2018),
https://doi.org/10.3389/fphy.2018.00007 . .

TY  - JOUR
AU  - Šuvakov, Milovan
AU  - Anđelković, Miroslav
AU  - Tadić, Bosiljka
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1931
AB  - Multilevel self-assembly involving small structured groups of nano-particles provides new routes to development of functional materials with a sophisticated architecture. Apart from the inter-particle forces, the geometrical shapes and compatibility of the building blocks are decisive factors. Therefore, a comprehensive understanding of these processes is essential for the design of assemblies of desired properties. Here, we introduce a computational model for cooperative self-assembly with the simultaneous attachment of structured groups of particles, which can be described by simplexes (connected pairs, triangles, tetrahedrons and higher order cliques) to a growing network. The model incorporates geometric rules that provide suitable nesting spaces for the new group and the chemical affinity of the system to accept excess particles. For varying chemical affinity, we grow different classes of assemblies by binding the cliques of distributed sizes. Furthermore, we characterize the emergent structures by metrics of graph theory and algebraic topology of graphs, and 4-point test for the intrinsic hyperbolicity of the networks. Our results show that higher Q-connectedness of the appearing simplicial complexes can arise due to only geometric factors and that it can be efficiently modulated by changing the chemical potential and the polydispersity of the binding simplexes.
T2  - Scientific Reports
T1  - Hidden geometries in networks arising from cooperative self-assembly
VL  - 8
IS  - 1
SP  - 1987
DO  - 10.1038/s41598-018-20398-x
ER  - 

@article{
author = "Šuvakov, Milovan and Anđelković, Miroslav and Tadić, Bosiljka",
year = "2018",
abstract = "Multilevel self-assembly involving small structured groups of nano-particles provides new routes to development of functional materials with a sophisticated architecture. Apart from the inter-particle forces, the geometrical shapes and compatibility of the building blocks are decisive factors. Therefore, a comprehensive understanding of these processes is essential for the design of assemblies of desired properties. Here, we introduce a computational model for cooperative self-assembly with the simultaneous attachment of structured groups of particles, which can be described by simplexes (connected pairs, triangles, tetrahedrons and higher order cliques) to a growing network. The model incorporates geometric rules that provide suitable nesting spaces for the new group and the chemical affinity of the system to accept excess particles. For varying chemical affinity, we grow different classes of assemblies by binding the cliques of distributed sizes. Furthermore, we characterize the emergent structures by metrics of graph theory and algebraic topology of graphs, and 4-point test for the intrinsic hyperbolicity of the networks. Our results show that higher Q-connectedness of the appearing simplicial complexes can arise due to only geometric factors and that it can be efficiently modulated by changing the chemical potential and the polydispersity of the binding simplexes.",
journal = "Scientific Reports",
title = "Hidden geometries in networks arising from cooperative self-assembly",
volume = "8",
number = "1",
pages = "1987",
doi = "10.1038/s41598-018-20398-x"
}

Šuvakov, M., Anđelković, M.,& Tadić, B.. (2018). Hidden geometries in networks arising from cooperative self-assembly. in Scientific Reports, 8(1), 1987.
https://doi.org/10.1038/s41598-018-20398-x

Šuvakov M, Anđelković M, Tadić B. Hidden geometries in networks arising from cooperative self-assembly. in Scientific Reports. 2018;8(1):1987.
doi:10.1038/s41598-018-20398-x .

Šuvakov, Milovan, Anđelković, Miroslav, Tadić, Bosiljka, "Hidden geometries in networks arising from cooperative self-assembly" in Scientific Reports, 8, no. 1 (2018):1987,
https://doi.org/10.1038/s41598-018-20398-x . .

TY  - JOUR
AU  - Dmitrasinovic, V.
AU  - Sato, Toru
AU  - Šuvakov, Milovan
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3797
AB  - We comment on the assertion made by Caselle et al. [M. Caselle, G. Delfino, P. Grinza, O. Jahn, and N. Magnoli, J. Stat. Mech. (2006) P008.] that the confining (string) potential for three quarks makes a smooth crossover transition from the Delta-string to the Y-string configuration at interquark distances of around 0.8 fm. We study the functional dependence of the three-quark confining potentials due to a Y-string, and the Delta string and show that they have different symmetries, which lead to different constants of the motion (i.e. they belong to different universality classes in the parlance of the theory of phase transitions). This means that there is no smooth crossover between the two, when their string tensions are identical, except at the vanishing hyper-radius. We also comment on a certain two-body potential approximation to the Y-string potential.
T2  - Physical Review D
T1  - Smooth crossover transition from the Delta-string to the Y-string three-quark potential
VL  - 80
IS  - 5
DO  - 10.1103/PhysRevD.80.054501
ER  - 

@article{
author = "Dmitrasinovic, V. and Sato, Toru and Šuvakov, Milovan",
year = "2009",
abstract = "We comment on the assertion made by Caselle et al. [M. Caselle, G. Delfino, P. Grinza, O. Jahn, and N. Magnoli, J. Stat. Mech. (2006) P008.] that the confining (string) potential for three quarks makes a smooth crossover transition from the Delta-string to the Y-string configuration at interquark distances of around 0.8 fm. We study the functional dependence of the three-quark confining potentials due to a Y-string, and the Delta string and show that they have different symmetries, which lead to different constants of the motion (i.e. they belong to different universality classes in the parlance of the theory of phase transitions). This means that there is no smooth crossover between the two, when their string tensions are identical, except at the vanishing hyper-radius. We also comment on a certain two-body potential approximation to the Y-string potential.",
journal = "Physical Review D",
title = "Smooth crossover transition from the Delta-string to the Y-string three-quark potential",
volume = "80",
number = "5",
doi = "10.1103/PhysRevD.80.054501"
}

Dmitrasinovic, V., Sato, T.,& Šuvakov, M.. (2009). Smooth crossover transition from the Delta-string to the Y-string three-quark potential. in Physical Review D, 80(5).
https://doi.org/10.1103/PhysRevD.80.054501

Dmitrasinovic V, Sato T, Šuvakov M. Smooth crossover transition from the Delta-string to the Y-string three-quark potential. in Physical Review D. 2009;80(5).
doi:10.1103/PhysRevD.80.054501 .

Dmitrasinovic, V., Sato, Toru, Šuvakov, Milovan, "Smooth crossover transition from the Delta-string to the Y-string three-quark potential" in Physical Review D, 80, no. 5 (2009),
https://doi.org/10.1103/PhysRevD.80.054501 . .

TY  - JOUR
AU  - Dmitrasinovic, V.
AU  - Sato, Toru
AU  - Šuvakov, Milovan
PY  - 2009
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/3737
AB  - We calculate the energies of three-quark states with definite permutation symmetry (i.e. of SU(6) multiplets) in the N=0, 1, 2 shells, confined by the Y-string three-quark potential. The exact Y-string potential consists of one term, the so-called three-string term, and three angle-dependent two-string terms. Due to this technical complication we treat the problem at three increasingly accurate levels of approximation: (1) the (approximate) three-string potential expanded to first order in trigonometric functions of hyper-spherical angles; (2) the (approximate) three-string potential to all orders in the power expansion in hyper-spherical harmonics, but without taking into account the transition(s) to two-string potentials; (3) the exact minimal-length string potential to all orders in a power expansion in the hyper-spherical harmonics, and taking into account the transition(s) to two-string potentials. We show the general trend of improvement of these approximations: the exact non-perturbative corrections to the total energy are of the order of one per cent, as compared with approximation (2), yet the exact energy differences between the [20,1(+)],[70,2(+)],[56,2(+)],[70,0(+)]-plets are shifted to 2:2:0.9, from the Bowler and Tynemouth separation rule 2:2:1, which is obeyed by approximation (2) at the one per cent level. The precise value of the energy separation of the first radial excitation (Roper) [56(),0(+)]-plet from the [70,1(-)]-plet depends on the approximation, but does not become negative, i.e. the Roper remains heavier than the odd-parity [70,1(-)]-plet in all of our approximations.
T2  - European Physical Journal C. Particles and Fields
T1  - Low-lying spectrum of the Y-string three-quark potential using hyper-spherical coordinates
VL  - 62
IS  - 2
SP  - 383
EP  - 397
DO  - 10.1140/epjc/s10052-009-1050-y
ER  - 

@article{
author = "Dmitrasinovic, V. and Sato, Toru and Šuvakov, Milovan",
year = "2009",
abstract = "We calculate the energies of three-quark states with definite permutation symmetry (i.e. of SU(6) multiplets) in the N=0, 1, 2 shells, confined by the Y-string three-quark potential. The exact Y-string potential consists of one term, the so-called three-string term, and three angle-dependent two-string terms. Due to this technical complication we treat the problem at three increasingly accurate levels of approximation: (1) the (approximate) three-string potential expanded to first order in trigonometric functions of hyper-spherical angles; (2) the (approximate) three-string potential to all orders in the power expansion in hyper-spherical harmonics, but without taking into account the transition(s) to two-string potentials; (3) the exact minimal-length string potential to all orders in a power expansion in the hyper-spherical harmonics, and taking into account the transition(s) to two-string potentials. We show the general trend of improvement of these approximations: the exact non-perturbative corrections to the total energy are of the order of one per cent, as compared with approximation (2), yet the exact energy differences between the [20,1(+)],[70,2(+)],[56,2(+)],[70,0(+)]-plets are shifted to 2:2:0.9, from the Bowler and Tynemouth separation rule 2:2:1, which is obeyed by approximation (2) at the one per cent level. The precise value of the energy separation of the first radial excitation (Roper) [56(),0(+)]-plet from the [70,1(-)]-plet depends on the approximation, but does not become negative, i.e. the Roper remains heavier than the odd-parity [70,1(-)]-plet in all of our approximations.",
journal = "European Physical Journal C. Particles and Fields",
title = "Low-lying spectrum of the Y-string three-quark potential using hyper-spherical coordinates",
volume = "62",
number = "2",
pages = "383-397",
doi = "10.1140/epjc/s10052-009-1050-y"
}

Dmitrasinovic, V., Sato, T.,& Šuvakov, M.. (2009). Low-lying spectrum of the Y-string three-quark potential using hyper-spherical coordinates. in European Physical Journal C. Particles and Fields, 62(2), 383-397.
https://doi.org/10.1140/epjc/s10052-009-1050-y

Dmitrasinovic V, Sato T, Šuvakov M. Low-lying spectrum of the Y-string three-quark potential using hyper-spherical coordinates. in European Physical Journal C. Particles and Fields. 2009;62(2):383-397.
doi:10.1140/epjc/s10052-009-1050-y .

Dmitrasinovic, V., Sato, Toru, Šuvakov, Milovan, "Low-lying spectrum of the Y-string three-quark potential using hyper-spherical coordinates" in European Physical Journal C. Particles and Fields, 62, no. 2 (2009):383-397,
https://doi.org/10.1140/epjc/s10052-009-1050-y . .