Jeanne Colbois PRO
Physicist @ CNRS. Here you find slides for *some* of my presentations, as well as visual abstracts for recent publications.
Jeanne Colbois | TMC
Jeanne Colbois | TMC
Samuel Nyckees
Afonso Rufino
Frédéric Mila
Andrew Smerald
KIT | Germany
Frédéric Mila
EPFL | Switzerland
Frank Verstraete
Ghent University | Belgium
Laurens Vanderstraeten
Ghent University | Belgium
Bram Vanhecke
University of Vienna | Austria
COLBOIS | KASTELEYN MECHANISM | 06.2025
Acknowledgement for previous work :
COLBOIS | KASTELEYN MECHANISM | 06.2025
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COLBOIS | KASTELEYN MECHANISM | 06.2025
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COLBOIS | KASTELEYN MECHANISM | 06.2025
Constrained models
Incommensurate systems
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2nd order phase transition:
\(T\)
\(T\)
\(C_V\)
\(m\) (order parameter)
COLBOIS | KASTELEYN MECHANISM | 06.2025
2
2nd order phase transition:
\(T\)
\(T\)
\(T\)
\(T\)
\(C_V\)
\(m\) (order parameter)
"disorder" parameter
\(C_V\)
Kasteleyn / Pokrovsky-Talapov:
COLBOIS | KASTELEYN MECHANISM | 06.2025
2
2nd order phase transition:
Kasteleyn / Pokrovsky-Talapov:
\(T\)
\(T\)
\(T\)
\(T\)
\(C_V\)
\(m\) (order parameter)
"disorder" parameter
\(C_V\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
2
2nd order phase transition:
Kasteleyn / Pokrovsky-Talapov:
\(T\)
\(T\)
\(T\)
\(T\)
\(C_V\)
\(m\) (order parameter)
"disorder" parameter
\(C_V\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
2
2nd order phase transition:
Kasteleyn / Pokrovsky-Talapov:
\(T\)
\(T\)
\(T\)
\(T\)
\(C_V\)
\(m\) (order parameter)
"disorder" parameter
\(C_V\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
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COLBOIS | KASTELEYN MECHANISM | 06.2025
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1. The Kasteleyn mechanism
COLBOIS | KASTELEYN MECHANISM | 06.2025
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1. The Kasteleyn mechanism
2. Examples in frustrated magnetism
COLBOIS | KASTELEYN MECHANISM | 06.2025
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1. The Kasteleyn mechanism
2. Examples in frustrated magnetism
3. Staircases in Ising models
COLBOIS | KASTELEYN MECHANISM | 06.2025
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1. The Kasteleyn mechanism
2. Examples in frustrated magnetism
3. Staircases in Ising models
4. A Kasteleyn-driven topological staircase
COLBOIS | KASTELEYN MECHANISM | 06.2025
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Ground state of some 2D classical
constrained model
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
COLBOIS | KASTELEYN MECHANISM | 06.2025
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DEFECTS /EXCITATIONS:
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
COLBOIS | KASTELEYN MECHANISM | 06.2025
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DEFECTS /EXCITATIONS:
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
COLBOIS | KASTELEYN MECHANISM | 06.2025
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DEFECTS /EXCITATIONS:
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
COLBOIS | KASTELEYN MECHANISM | 06.2025
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J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
COLBOIS | KASTELEYN MECHANISM | 06.2025
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\(E \propto L \)
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
COLBOIS | KASTELEYN MECHANISM | 06.2025
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\(E \propto L \)
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
Entropy gain!
COLBOIS | KASTELEYN MECHANISM | 06.2025
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\(E \propto L \)
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
Entropy gain!
COLBOIS | KASTELEYN MECHANISM | 06.2025
4
\(E \propto L \)
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
Entropy gain!
COLBOIS | KASTELEYN MECHANISM | 06.2025
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\(E \propto L \)
\(F = E - TS\)
\(S \propto L \)
\(T\)
No defects
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
Entropy gain!
COLBOIS | KASTELEYN MECHANISM | 06.2025
4
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
Entropy gain!
\(E \propto L \)
\(F = E - TS\)
\(S \propto L \)
\(T\)
No defects
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
COLBOIS | KASTELEYN MECHANISM | 06.2025
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\(E \propto L \)
\(F = E - TS\)
\(S \propto L \)
\(T\)
No defects
Strings
condense
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
Entropy gain!
COLBOIS | KASTELEYN MECHANISM | 06.2025
4
\(E \propto L \)
\(F = E - TS\)
\(S \propto L \)
\(T\)
No defects
Strings
condense
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
Entropy gain!
COLBOIS | KASTELEYN MECHANISM | 06.2025
4
\(E \propto L \)
\(F = E - TS\)
\(S \propto L \)
\(T\)
No defects
Strings
condense
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
DEFECTS /EXCITATIONS:
Energy cost : linear in system size
Entropy gain!
COLBOIS | KASTELEYN MECHANISM | 06.2025
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J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Adsorption of diatomic molecules (dimers) on crystal surfaces
COLBOIS | KASTELEYN MECHANISM | 06.2025
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J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Adsorption of diatomic molecules (dimers) on crystal surfaces
1
2
3
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J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Adsorption of diatomic molecules (dimers) on crystal surfaces
Hardcore (close-packed) dimers
1
2
3
COLBOIS | KASTELEYN MECHANISM | 06.2025
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J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Adsorption of diatomic molecules (dimers) on crystal surfaces
Hardcore (close-packed) dimers
\(\varepsilon_b\) : cost of putting a dimer on \(b = 1,2,3\)
1
2
3
COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
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COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
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COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
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COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
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COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
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COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
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COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
6
COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
6
COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
6
COLBOIS | KASTELEYN MECHANISM | 06.2025
J. F. Nagle et al, Domb & Lebowitz Phase transitions and critical phenomena 13 (1989)
Constraint : hardcore
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COLBOIS | KASTELEYN MECHANISM | 06.2025
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Directed, non-crossing, non-terminating
COLBOIS | KASTELEYN MECHANISM | 06.2025
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\(T\)
"disorder" parameter
\((T-T_K)^{1/2}\)
Directed, non-crossing, non-terminating
COLBOIS | KASTELEYN MECHANISM | 06.2025
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\(T\)
"disorder" parameter
\((T-T_K)^{1/2}\)
0
in the ground state
1
at most
2/3
in the large \(T\) limit
Directed, non-crossing, non-terminating
COLBOIS | KASTELEYN MECHANISM | 06.2025
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\(T\)
"disorder" parameter
\((T-T_K)^{1/2}\)
0
in the ground state
1
at most
2/3
in the large \(T\) limit
Mapping to free fermions Hamiltonian
\(T \leftrightarrow\) chemical potential
\(n_{\mathrm{strings}} \leftrightarrow\) fermions density
Directed, non-crossing, non-terminating
Kasteleyn / Pokrovsky-Talapov transition:
entropy-driven condensation of
directed, non-crossing, non-terminating string excitations
in a constrained model.
Kasteleyn / Pokrovsky-Talapov transition:
entropy-driven condensation of
Not discussed here:
algebraic decay of correlations
fundamental anisotropy in the critical exponents
etc.
directed, non-crossing, non-terminating string excitations
in a constrained model.
COLBOIS | KASTELEYN MECHANISM | 06.2025
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Nearest-neighbor anisotropic
\(J_1-J_2-J_3-J_5\) (spontaneous anisotropy)
Smerald & Mila, Scipost (2019)
Smerald, Korshunov & Mila, PRL (2016)
Constrained limit \(J \gg T\)
Ground state
COLBOIS | KASTELEYN MECHANISM | 06.2025
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Nearest-neighbor anisotropic
\(J_1-J_2-J_3-J_5\) (spontaneous anisotropy)
Smerald & Mila, Scipost (2019)
Smerald, Korshunov & Mila, PRL (2016)
Constrained limit \(J \gg T\)
Excitations
COLBOIS | KASTELEYN MECHANISM | 06.2025
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Nearest-neighbor anisotropic
\(J_1-J_2-J_3-J_5\) (spontaneous anisotropy)
Smerald & Mila, Scipost (2019)
Smerald, Korshunov & Mila, PRL (2016)
Constrained limit \(J \gg T\)
Excitations
COLBOIS | KASTELEYN MECHANISM | 06.2025
8
Nearest-neighbor anisotropic
\(J_1-J_2-J_3-J_5\) (spontaneous anisotropy)
Smerald & Mila, Scipost (2019)
Smerald, Korshunov & Mila, PRL (2016)
Constrained limit \(J \gg T\)
Excitations
COLBOIS | KASTELEYN MECHANISM | 06.2025
8
Nearest-neighbor anisotropic
\(J_1-J_2-J_3-J_5\) (spontaneous anisotropy)
Smerald & Mila, Scipost (2019)
Smerald, Korshunov & Mila, PRL (2016)
Constrained limit \(J \gg T\)
Excitations : double domain wall
COLBOIS | KASTELEYN MECHANISM | 06.2025
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Nearest-neighbor anisotropic
\(J_1-J_2-J_3-J_5\) (spontaneous anisotropy)
Smerald & Mila, Scipost (2019)
Smerald, Korshunov & Mila, PRL (2016)
Constrained limit \(J \gg T\)
Excitations : double domain wall
NB: NN model vs anisotropic one
COLBOIS | KASTELEYN MECHANISM | 06.2025
8
Nearest-neighbor anisotropic
\(J_1-J_2-J_3-J_5\) (spontaneous anisotropy)
Smerald & Mila, Scipost (2019)
Smerald, Korshunov & Mila, PRL (2016)
Constrained limit \(J \gg T\)
Excitations : double domain wall
NB: NN model vs anisotropic one
COLBOIS | KASTELEYN MECHANISM | 06.2025
8
Nearest-neighbor anisotropic
\(J_1-J_2-J_3-J_5\) (spontaneous anisotropy)
Smerald & Mila, Scipost (2019)
Smerald, Korshunov & Mila, PRL (2016)
Constrained limit \(J \gg T\)
Excitations : double domain wall
NB: NN model vs anisotropic one
COLBOIS | KASTELEYN MECHANISM | 06.2025
L, Jaubert et. al. J.Phys.:Conf.Ser. 145, 012024 (2009)
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L, Jaubert et. al. PRL 100 (2008)
Spin ice in a [100] field
2-in 2-out ground state
COLBOIS | KASTELEYN MECHANISM | 06.2025
L, Jaubert et. al. J.Phys.:Conf.Ser. 145, 012024 (2009)
9
L, Jaubert et. al. PRL 100 (2008)
Spin ice in a [100] field
2-in 2-out ground state
Magnetization in each (100) plane is the same
COLBOIS | KASTELEYN MECHANISM | 06.2025
L, Jaubert et. al. J.Phys.:Conf.Ser. 145, 012024 (2009)
9
L, Jaubert et. al. PRL 100 (2008)
Spin ice in a [100] field
2-in 2-out ground state
Magnetization in each (100) plane is the same
1. Start from fully polarized state
2 . Lower the field
COLBOIS | KASTELEYN MECHANISM | 06.2025
L, Jaubert et. al. J.Phys.:Conf.Ser. 145, 012024 (2009)
9
L, Jaubert et. al. PRL 100 (2008)
Spin ice in a [100] field
2-in 2-out ground state
Magnetization in each (100) plane is the same
1. Start from fully polarized state
2 . Lower the field
Defects are strings
directed
non-terminating
non-crossing
COLBOIS | KASTELEYN MECHANISM | 06.2025
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Ferro \(J_1\)
AF \(J_2\) in one direction
In 3D :
Macroscopic degeneracy of arrangements for successive ferromagnetic layers
CeSb
von Boehm & Bak, PRB (1980)
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von Boehm & Bak, PRB (1980)
Fisher and Selke, PRL (1980)
COLBOIS | KASTELEYN MECHANISM | 06.2025
I. A. Chioar, N. Rougemaille, B. Canals, PRB 93, (2016)
J. Hamp, C. Castelnovo, R. Moessner, PRB 98, (2018)
L. Cugliandolo, L. Foini, M. Tarzia, PRB 101 (2020)
Z. Luo et al. Science 363, (2019)
JC et al., PRB 104 (2021)
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COLBOIS | KASTELEYN MECHANISM | 06.2025
I. A. Chioar, N. Rougemaille, B. Canals, PRB 93, (2016)
J. Hamp, C. Castelnovo, R. Moessner, PRB 98, (2018)
L. Cugliandolo, L. Foini, M. Tarzia, PRB 101 (2020)
Z. Luo et al. Science 363, (2019)
JC et al., PRB 104 (2021)
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COLBOIS | KASTELEYN MECHANISM | 06.2025
I. A. Chioar, N. Rougemaille, B. Canals, PRB 93, (2016)
J. Hamp, C. Castelnovo, R. Moessner, PRB 98, (2018)
L. Cugliandolo, L. Foini, M. Tarzia, PRB 101 (2020)
Z. Luo et al. Science 363, (2019)
JC et al., PRB 104 (2021)
Kagome lattice
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COLBOIS | KASTELEYN MECHANISM | 06.2025
I. A. Chioar, N. Rougemaille, B. Canals, PRB 93, (2016)
J. Hamp, C. Castelnovo, R. Moessner, PRB 98, (2018)
L. Cugliandolo, L. Foini, M. Tarzia, PRB 101 (2020)
Z. Luo et al. Science 363, (2019)
JC et al., PRB 104 (2021)
Kagome lattice
3 Kagome sublattices
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COLBOIS | KASTELEYN MECHANISM | 06.2025
I. A. Chioar, N. Rougemaille, B. Canals, PRB 93, (2016)
J. Hamp, C. Castelnovo, R. Moessner, PRB 98, (2018)
L. Cugliandolo, L. Foini, M. Tarzia, PRB 101 (2020)
Z. Luo et al. Science 363, (2019)
JC et al., PRB 104 (2021)
Kagome lattice
3 Kagome sublattices
3 triangular sublattices
12
COLBOIS | KASTELEYN MECHANISM | 06.2025
I. A. Chioar, N. Rougemaille, B. Canals, PRB 93, (2016)
J. Hamp, C. Castelnovo, R. Moessner, PRB 98, (2018)
L. Cugliandolo, L. Foini, M. Tarzia, PRB 101 (2020)
Z. Luo et al. Science 363, (2019)
JC et al., PRB 104 (2021)
Kagome lattice
3 Kagome sublattices
3 triangular sublattices
12
COLBOIS | KASTELEYN MECHANISM | 06.2025
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JC, B. Vanhecke et. al., PRB 106 (2022)
COLBOIS | KASTELEYN MECHANISM | 06.2025
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JC, B. Vanhecke et. al., PRB 106 (2022)
All antiferromagnetic couplings :
3 phases due to the competition (exact g.s. energy)
COLBOIS | KASTELEYN MECHANISM | 06.2025
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JC, B. Vanhecke et. al., PRB 106 (2022)
All antiferromagnetic couplings :
3 phases due to the competition (exact g.s. energy)
COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
All antiferromagnetic couplings :
3 phases due to the competition (exact g.s. energy)
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COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
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COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Zero-energy "strings"!
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COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
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COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
N.B. sub-family
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COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
Dense rows: AF order
N.B. sub-family
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COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
Sparse rows: frustrated Ising model on the triangular lattice
EXPONENTIAL NUMBER
Dense rows: AF order
N.B. sub-family
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COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
Absence of vertical dimers
Dense rows: AF order
N.B. sub-family
Sparse rows: frustrated Ising model on the triangular lattice
EXPONENTIAL NUMBER
14
COLBOIS | KASTELEYN MECHANISM | 06.2025
15
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
DDW Break the dense rows AF order
(Introduce vertical dimers)
15
COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
DDW Break the dense rows AF order
(Introduce vertical dimers)
Entropic suppression : one less row
15
COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
16
COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
Freedom inside the domain wall
Energy cost
Entropic gain
16
COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
Freedom inside the domain wall
Energy cost
Entropic gain
Replacing a green string by a DDW
Entropic cost
16
COLBOIS | KASTELEYN MECHANISM | 06.2025
JC, B. Vanhecke et. al., PRB 106 (2022)
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
\(\mathbb{Z}_2 \times \mathbb{Z}_3\) symmetry breaking
Freedom inside the domain wall
Energy cost
Entropic gain
Replacing a green string by a DDW
Entropic cost
Repulsion between domain walls
Energy cost for condensation
16
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Freedom inside the domain wall
Energy cost
Entropic gain
Replacing a green string by a DDW
Entropic cost
Repulsion between domain walls
Energy cost for condensation
17
\(T\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Freedom inside the domain wall
Energy cost
Entropic gain
Replacing a green string by a DDW
Entropic cost
Repulsion between domain walls
Energy cost for condensation
17
\(T\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Freedom inside the domain wall
Energy cost
Entropic gain
Replacing a green string by a DDW
Entropic cost
Repulsion between domain walls
Energy cost for condensation
17
\(T\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Freedom inside the domain wall
Energy cost
Entropic gain
Replacing a green string by a DDW
Entropic cost
Repulsion between domain walls
Energy cost for condensation
17
\(T\)
\(T_c^{(1)}\)
\(n_c/n_A = 1\)
\(n_c =0\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Freedom inside the domain wall
Energy cost
Entropic gain
Replacing a green string by a DDW
Entropic cost
Repulsion between domain walls
Energy cost for condensation
17
\(T\)
\(T_c^{(1)}\)
\(T_c^{(2)}\)
\(n_c/n_A = 1\)
\(n_c =0\)
\(n_c/n_A = 2\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Freedom inside the domain wall
Energy cost
Entropic gain
Replacing a green string by a DDW
Entropic cost
Repulsion between domain walls
Energy cost for condensation
17
\(T\)
\(T_c^{(1)}\)
\(n_c/n_A = 1\)
\(n_c =0\)
\(T_c^{(2)}\)
\(n_c/n_A = 2\)
\(T_c^{(3)}\)
\(n_c/n_A = 3\)
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
18
Ratio takes all integer values up to infinity
Series of 1st order transitions
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Ratio takes all integer values up to infinity
Series of 1st order transitions
18
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Ratio takes all integer values up to infinity
Density of strings is not exactly constant
Series of 1st order transitions
18
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
Ratio takes all integer values up to infinity
Density of strings is not exactly constant
Series of 1st order transitions
18
Topological
"Devil's step" ?
COLBOIS | KASTELEYN MECHANISM | 06.2025
A. Rufino, S. Nyckees, JC, F. Mila, arXiv:2505.05889 (2025)
19
Finite-\(J\) consequences ?
Other models ?
Yes!
1D quantum / 2D Strings model
A. Rufino, S. Nyckees, JC, F. Mila, in preparation
Experimental realization ?
Perhaps ?
COLBOIS | KASTELEYN MECHANISM | 06.2025
20
Kasteleyn mechanism
Topological devil's "step"
1. Two kinds of system-spanning strings
2. Internal freedom within strings.
3. Effective repulsion between strings of the same kind
COLBOIS | KASTELEYN MECHANISM | 06.2025
By Jeanne Colbois
Magnetism Meeting at Institut Néel
Physicist @ CNRS. Here you find slides for *some* of my presentations, as well as visual abstracts for recent publications.