Flach, Sergej

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  • Flach, Sergej (8)

Author's Bibliography

Probing Band Topology Using Modulational Instability

Leykam, Daniel; Smolina, Ekaterina; Maluckov, Aleksandra; Flach, Sergej; Smirnova, Daria A

(2021)

TY  - JOUR
AU  - Leykam, Daniel
AU  - Smolina, Ekaterina
AU  - Maluckov, Aleksandra
AU  - Flach, Sergej
AU  - Smirnova, Daria A
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9153
AB  - We analyze the modulational instability of nonlinear Bloch waves in topological photonic lattices. In the initial phase of the instability development captured by the linear stability analysis, long wavelength instabilities and bifurcations of the nonlinear Bloch waves are sensitive to topological band inversions. At longer timescales, nonlinear wave mixing induces spreading of energy through the entire band and spontaneous creation of wave polarization singularities determined by the band Chern number. Our analytical and numerical results establish modulational instability as a tool to probe bulk topological invariants and create topologically nontrivial wave fields. © 2021 American Physical Society.
T2  - Physical Review Letters
T1  - Probing Band Topology Using Modulational Instability
VL  - 126
IS  - 7
SP  - 073901
DO  - 10.1103/PhysRevLett.126.073901
ER  - 
@article{
author = "Leykam, Daniel and Smolina, Ekaterina and Maluckov, Aleksandra and Flach, Sergej and Smirnova, Daria A",
year = "2021",
abstract = "We analyze the modulational instability of nonlinear Bloch waves in topological photonic lattices. In the initial phase of the instability development captured by the linear stability analysis, long wavelength instabilities and bifurcations of the nonlinear Bloch waves are sensitive to topological band inversions. At longer timescales, nonlinear wave mixing induces spreading of energy through the entire band and spontaneous creation of wave polarization singularities determined by the band Chern number. Our analytical and numerical results establish modulational instability as a tool to probe bulk topological invariants and create topologically nontrivial wave fields. © 2021 American Physical Society.",
journal = "Physical Review Letters",
title = "Probing Band Topology Using Modulational Instability",
volume = "126",
number = "7",
pages = "073901",
doi = "10.1103/PhysRevLett.126.073901"
}
Leykam, D., Smolina, E., Maluckov, A., Flach, S.,& Smirnova, D. A.. (2021). Probing Band Topology Using Modulational Instability. in Physical Review Letters, 126(7), 073901.
https://doi.org/10.1103/PhysRevLett.126.073901
Leykam D, Smolina E, Maluckov A, Flach S, Smirnova DA. Probing Band Topology Using Modulational Instability. in Physical Review Letters. 2021;126(7):073901.
doi:10.1103/PhysRevLett.126.073901 .
Leykam, Daniel, Smolina, Ekaterina, Maluckov, Aleksandra, Flach, Sergej, Smirnova, Daria A, "Probing Band Topology Using Modulational Instability" in Physical Review Letters, 126, no. 7 (2021):073901,
https://doi.org/10.1103/PhysRevLett.126.073901 . .
52
1

Nonlinear Bloch wave dynamics in photonic Aharonov–Bohm cages

Chang, Nana; Gundogdu, Sinan; Leykam, Daniel; Angelakis, Dimitris G.; Kou, SuPeng; Flach, Sergej; Maluckov, Aleksandra

(2021)

TY  - JOUR
AU  - Chang, Nana
AU  - Gundogdu, Sinan
AU  - Leykam, Daniel
AU  - Angelakis, Dimitris G.
AU  - Kou, SuPeng
AU  - Flach, Sergej
AU  - Maluckov, Aleksandra
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9141
AB  - We study the properties of nonlinear Bloch waves in a diamond chain waveguide lattice in the presence of a synthetic magnetic flux. In the linear limit, the lattice exhibits a completely flat (wavevector k-independent) band structure, resulting in perfect wave localization, known as Aharonov-Bohm caging. We find that in the presence of nonlinearity, the Bloch waves become sensitive to k, exhibiting bifurcations and instabilities. Performing numerical beam propagation simulations using the tight-binding model, we show how the instabilities can result in either the spontaneous or controlled formation of localized modes, which are immobile and remain pinned in place due to the synthetic magnetic flux. © 2021 Author(s.
T2  - APL Photonics
T1  - Nonlinear Bloch wave dynamics in photonic Aharonov–Bohm cages
VL  - 6
IS  - 3
SP  - 030801
DO  - 10.1063/5.0037767
ER  - 
@article{
author = "Chang, Nana and Gundogdu, Sinan and Leykam, Daniel and Angelakis, Dimitris G. and Kou, SuPeng and Flach, Sergej and Maluckov, Aleksandra",
year = "2021",
abstract = "We study the properties of nonlinear Bloch waves in a diamond chain waveguide lattice in the presence of a synthetic magnetic flux. In the linear limit, the lattice exhibits a completely flat (wavevector k-independent) band structure, resulting in perfect wave localization, known as Aharonov-Bohm caging. We find that in the presence of nonlinearity, the Bloch waves become sensitive to k, exhibiting bifurcations and instabilities. Performing numerical beam propagation simulations using the tight-binding model, we show how the instabilities can result in either the spontaneous or controlled formation of localized modes, which are immobile and remain pinned in place due to the synthetic magnetic flux. © 2021 Author(s.",
journal = "APL Photonics",
title = "Nonlinear Bloch wave dynamics in photonic Aharonov–Bohm cages",
volume = "6",
number = "3",
pages = "030801",
doi = "10.1063/5.0037767"
}
Chang, N., Gundogdu, S., Leykam, D., Angelakis, D. G., Kou, S., Flach, S.,& Maluckov, A.. (2021). Nonlinear Bloch wave dynamics in photonic Aharonov–Bohm cages. in APL Photonics, 6(3), 030801.
https://doi.org/10.1063/5.0037767
Chang N, Gundogdu S, Leykam D, Angelakis DG, Kou S, Flach S, Maluckov A. Nonlinear Bloch wave dynamics in photonic Aharonov–Bohm cages. in APL Photonics. 2021;6(3):030801.
doi:10.1063/5.0037767 .
Chang, Nana, Gundogdu, Sinan, Leykam, Daniel, Angelakis, Dimitris G., Kou, SuPeng, Flach, Sergej, Maluckov, Aleksandra, "Nonlinear Bloch wave dynamics in photonic Aharonov–Bohm cages" in APL Photonics, 6, no. 3 (2021):030801,
https://doi.org/10.1063/5.0037767 . .
1
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Compact discrete breathers on flat-band networks

Danieli, Carlo; Maluckov, Aleksandra; Flach, Sergej

(2018)

TY  - JOUR
AU  - Danieli, Carlo
AU  - Maluckov, Aleksandra
AU  - Flach, Sergej
PY  - 2018
UR  - http://aip.scitation.org/doi/10.1063/1.5041434
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/7914
AB  - Linear wave equations on flat-band networks host compact localized eigenstates (CLS). Nonlinear wave equations on translationally invariant flat-band networks can host compact discrete breathers-time-periodic and spatially compact localized solutions. Such solutions can appear as one-parameter families of continued linear compact eigenstates, or as discrete sets on families of non-compact discrete breathers, or even on purely dispersive networks with fine-tuned nonlinear dispersion. In all cases, their existence relies on destructive interference. We use CLS amplitude distribution properties and orthogonality conditions to derive existence criteria and stability properties for compact discrete breathers as continued CLS. Published by AIP Publishing.
T2  - Low Temperature Physics
T1  - Compact discrete breathers on flat-band networks
VL  - 44
IS  - 7
SP  - 865
EP  - 876
DO  - 10.1063/1.5041434
ER  - 
@article{
author = "Danieli, Carlo and Maluckov, Aleksandra and Flach, Sergej",
year = "2018",
abstract = "Linear wave equations on flat-band networks host compact localized eigenstates (CLS). Nonlinear wave equations on translationally invariant flat-band networks can host compact discrete breathers-time-periodic and spatially compact localized solutions. Such solutions can appear as one-parameter families of continued linear compact eigenstates, or as discrete sets on families of non-compact discrete breathers, or even on purely dispersive networks with fine-tuned nonlinear dispersion. In all cases, their existence relies on destructive interference. We use CLS amplitude distribution properties and orthogonality conditions to derive existence criteria and stability properties for compact discrete breathers as continued CLS. Published by AIP Publishing.",
journal = "Low Temperature Physics",
title = "Compact discrete breathers on flat-band networks",
volume = "44",
number = "7",
pages = "865-876",
doi = "10.1063/1.5041434"
}
Danieli, C., Maluckov, A.,& Flach, S.. (2018). Compact discrete breathers on flat-band networks. in Low Temperature Physics, 44(7), 865-876.
https://doi.org/10.1063/1.5041434
Danieli C, Maluckov A, Flach S. Compact discrete breathers on flat-band networks. in Low Temperature Physics. 2018;44(7):865-876.
doi:10.1063/1.5041434 .
Danieli, Carlo, Maluckov, Aleksandra, Flach, Sergej, "Compact discrete breathers on flat-band networks" in Low Temperature Physics, 44, no. 7 (2018):865-876,
https://doi.org/10.1063/1.5041434 . .
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Compact discrete breathers on flat-band networks

Danieli, Carlo; Maluckov, Aleksandra; Flach, Sergej

(2018)

TY  - JOUR
AU  - Danieli, Carlo
AU  - Maluckov, Aleksandra
AU  - Flach, Sergej
PY  - 2018
UR  - http://aip.scitation.org/doi/10.1063/1.5041434
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/7918
AB  - Linear wave equations on flat-band networks host compact localized eigenstates (CLS). Nonlinear wave equations on translationally invariant flat-band networks can host compact discrete breathers-time-periodic and spatially compact localized solutions. Such solutions can appear as one-parameter families of continued linear compact eigenstates, or as discrete sets on families of non-compact discrete breathers, or even on purely dispersive networks with fine-tuned nonlinear dispersion. In all cases, their existence relies on destructive interference. We use CLS amplitude distribution properties and orthogonality conditions to derive existence criteria and stability properties for compact discrete breathers as continued CLS. Published by AIP Publishing.
T2  - Low Temperature Physics
T1  - Compact discrete breathers on flat-band networks
VL  - 44
IS  - 7
SP  - 678
EP  - 687
DO  - 10.1063/1.5041434
ER  - 
@article{
author = "Danieli, Carlo and Maluckov, Aleksandra and Flach, Sergej",
year = "2018",
abstract = "Linear wave equations on flat-band networks host compact localized eigenstates (CLS). Nonlinear wave equations on translationally invariant flat-band networks can host compact discrete breathers-time-periodic and spatially compact localized solutions. Such solutions can appear as one-parameter families of continued linear compact eigenstates, or as discrete sets on families of non-compact discrete breathers, or even on purely dispersive networks with fine-tuned nonlinear dispersion. In all cases, their existence relies on destructive interference. We use CLS amplitude distribution properties and orthogonality conditions to derive existence criteria and stability properties for compact discrete breathers as continued CLS. Published by AIP Publishing.",
journal = "Low Temperature Physics",
title = "Compact discrete breathers on flat-band networks",
volume = "44",
number = "7",
pages = "678-687",
doi = "10.1063/1.5041434"
}
Danieli, C., Maluckov, A.,& Flach, S.. (2018). Compact discrete breathers on flat-band networks. in Low Temperature Physics, 44(7), 678-687.
https://doi.org/10.1063/1.5041434
Danieli C, Maluckov A, Flach S. Compact discrete breathers on flat-band networks. in Low Temperature Physics. 2018;44(7):678-687.
doi:10.1063/1.5041434 .
Danieli, Carlo, Maluckov, Aleksandra, Flach, Sergej, "Compact discrete breathers on flat-band networks" in Low Temperature Physics, 44, no. 7 (2018):678-687,
https://doi.org/10.1063/1.5041434 . .
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13

Nonlinear localized flat-band modes with spin-orbit coupling

Gligorić, Goran; Maluckov, Aleksandra; Hadžievski, Ljupčo; Flach, Sergej; Malomed, Boris A.

(2016)

TY  - JOUR
AU  - Gligorić, Goran
AU  - Maluckov, Aleksandra
AU  - Hadžievski, Ljupčo
AU  - Flach, Sergej
AU  - Malomed, Boris A.
PY  - 2016
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/1287
AB  - We report the coexistence and properties of stable compact localized states (CLSs) and discrete solitons (DSs) for nonlinear spinor waves on a flat-band network with spin-orbit coupling (SOC). The system can be implemented by means of a binary Bose-Einstein condensate loaded in the corresponding optical lattice. In the linear limit, the SOC opens a minigap between flat and dispersive bands in the systems band-gap structure, and preserves the existence of CLSs at the flat-band frequency, simultaneously lowering their symmetry. Adding on-site cubic nonlinearity, the CLSs persist and remain available in an exact analytical form, with frequencies that are smoothly tuned into the minigap. Inside of the minigap, the CLS and DS families are stable in narrow areas adjacent to the FB. Deep inside the semi-infinite gap, both the CLSs and DSs are stable too.
T2  - Physical Review B: Condensed Matter and Materials Physics
T1  - Nonlinear localized flat-band modes with spin-orbit coupling
VL  - 94
IS  - 14
SP  - 144302
DO  - 10.1103/PhysRevB.94.144302
ER  - 
@article{
author = "Gligorić, Goran and Maluckov, Aleksandra and Hadžievski, Ljupčo and Flach, Sergej and Malomed, Boris A.",
year = "2016",
abstract = "We report the coexistence and properties of stable compact localized states (CLSs) and discrete solitons (DSs) for nonlinear spinor waves on a flat-band network with spin-orbit coupling (SOC). The system can be implemented by means of a binary Bose-Einstein condensate loaded in the corresponding optical lattice. In the linear limit, the SOC opens a minigap between flat and dispersive bands in the systems band-gap structure, and preserves the existence of CLSs at the flat-band frequency, simultaneously lowering their symmetry. Adding on-site cubic nonlinearity, the CLSs persist and remain available in an exact analytical form, with frequencies that are smoothly tuned into the minigap. Inside of the minigap, the CLS and DS families are stable in narrow areas adjacent to the FB. Deep inside the semi-infinite gap, both the CLSs and DSs are stable too.",
journal = "Physical Review B: Condensed Matter and Materials Physics",
title = "Nonlinear localized flat-band modes with spin-orbit coupling",
volume = "94",
number = "14",
pages = "144302",
doi = "10.1103/PhysRevB.94.144302"
}
Gligorić, G., Maluckov, A., Hadžievski, L., Flach, S.,& Malomed, B. A.. (2016). Nonlinear localized flat-band modes with spin-orbit coupling. in Physical Review B: Condensed Matter and Materials Physics, 94(14), 144302.
https://doi.org/10.1103/PhysRevB.94.144302
Gligorić G, Maluckov A, Hadžievski L, Flach S, Malomed BA. Nonlinear localized flat-band modes with spin-orbit coupling. in Physical Review B: Condensed Matter and Materials Physics. 2016;94(14):144302.
doi:10.1103/PhysRevB.94.144302 .
Gligorić, Goran, Maluckov, Aleksandra, Hadžievski, Ljupčo, Flach, Sergej, Malomed, Boris A., "Nonlinear localized flat-band modes with spin-orbit coupling" in Physical Review B: Condensed Matter and Materials Physics, 94, no. 14 (2016):144302,
https://doi.org/10.1103/PhysRevB.94.144302 . .
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Nonlinear localized flat-band modes with spin-orbit coupling

Gligorić, Goran; Maluckov, Aleksandra; Hadžievski, Ljupčo; Flach, Sergej; Malomed, Boris A.

(2016)

TY  - JOUR
AU  - Gligorić, Goran
AU  - Maluckov, Aleksandra
AU  - Hadžievski, Ljupčo
AU  - Flach, Sergej
AU  - Malomed, Boris A.
PY  - 2016
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8840
AB  - We report the coexistence and properties of stable compact localized states (CLSs) and discrete solitons (DSs) for nonlinear spinor waves on a flat-band network with spin-orbit coupling (SOC). The system can be implemented by means of a binary Bose-Einstein condensate loaded in the corresponding optical lattice. In the linear limit, the SOC opens a minigap between flat and dispersive bands in the systems band-gap structure, and preserves the existence of CLSs at the flat-band frequency, simultaneously lowering their symmetry. Adding on-site cubic nonlinearity, the CLSs persist and remain available in an exact analytical form, with frequencies that are smoothly tuned into the minigap. Inside of the minigap, the CLS and DS families are stable in narrow areas adjacent to the FB. Deep inside the semi-infinite gap, both the CLSs and DSs are stable too.
T2  - Physical Review B: Condensed Matter and Materials Physics
T1  - Nonlinear localized flat-band modes with spin-orbit coupling
VL  - 94
IS  - 14
SP  - 144302
DO  - 10.1103/PhysRevB.94.144302
ER  - 
@article{
author = "Gligorić, Goran and Maluckov, Aleksandra and Hadžievski, Ljupčo and Flach, Sergej and Malomed, Boris A.",
year = "2016",
abstract = "We report the coexistence and properties of stable compact localized states (CLSs) and discrete solitons (DSs) for nonlinear spinor waves on a flat-band network with spin-orbit coupling (SOC). The system can be implemented by means of a binary Bose-Einstein condensate loaded in the corresponding optical lattice. In the linear limit, the SOC opens a minigap between flat and dispersive bands in the systems band-gap structure, and preserves the existence of CLSs at the flat-band frequency, simultaneously lowering their symmetry. Adding on-site cubic nonlinearity, the CLSs persist and remain available in an exact analytical form, with frequencies that are smoothly tuned into the minigap. Inside of the minigap, the CLS and DS families are stable in narrow areas adjacent to the FB. Deep inside the semi-infinite gap, both the CLSs and DSs are stable too.",
journal = "Physical Review B: Condensed Matter and Materials Physics",
title = "Nonlinear localized flat-band modes with spin-orbit coupling",
volume = "94",
number = "14",
pages = "144302",
doi = "10.1103/PhysRevB.94.144302"
}
Gligorić, G., Maluckov, A., Hadžievski, L., Flach, S.,& Malomed, B. A.. (2016). Nonlinear localized flat-band modes with spin-orbit coupling. in Physical Review B: Condensed Matter and Materials Physics, 94(14), 144302.
https://doi.org/10.1103/PhysRevB.94.144302
Gligorić G, Maluckov A, Hadžievski L, Flach S, Malomed BA. Nonlinear localized flat-band modes with spin-orbit coupling. in Physical Review B: Condensed Matter and Materials Physics. 2016;94(14):144302.
doi:10.1103/PhysRevB.94.144302 .
Gligorić, Goran, Maluckov, Aleksandra, Hadžievski, Ljupčo, Flach, Sergej, Malomed, Boris A., "Nonlinear localized flat-band modes with spin-orbit coupling" in Physical Review B: Condensed Matter and Materials Physics, 94, no. 14 (2016):144302,
https://doi.org/10.1103/PhysRevB.94.144302 . .
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Make slow fast -How to speed up interacting disordered matter

Gligorić, Goran; Rayanov, Kristian; Flach, Sergej

(2013)

TY  - JOUR
AU  - Gligorić, Goran
AU  - Rayanov, Kristian
AU  - Flach, Sergej
PY  - 2013
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/5282
AB  - Anderson and dynamical localization have been experimentally observed with ultra-cold atomic matter. Feshbach resonances are used to efficiently control the strength of interactions between atoms. This allows to study the delocalization effect of interactions for localized wave packets. The delocalization processes are subdiffusive and slow, thereby limiting the quantitative experimental and numerical analysis. We propose an elegant solution of the problem by proper ramping the interaction strength in time. We demonstrate that subdiffusion is speeded up to normal diffusion for interacting disordered and kicked atomic systems. The door is open to test these theoretical results experimentally, and to attack similar computational quests in higher space dimensions Copyright (C) EPLA, 2013
T2  - Europhysics Letters / EPL
T1  - Make slow fast -How to speed up interacting disordered matter
VL  - 101
IS  - 1
DO  - 10.1209/0295-5075/101/10011
ER  - 
@article{
author = "Gligorić, Goran and Rayanov, Kristian and Flach, Sergej",
year = "2013",
abstract = "Anderson and dynamical localization have been experimentally observed with ultra-cold atomic matter. Feshbach resonances are used to efficiently control the strength of interactions between atoms. This allows to study the delocalization effect of interactions for localized wave packets. The delocalization processes are subdiffusive and slow, thereby limiting the quantitative experimental and numerical analysis. We propose an elegant solution of the problem by proper ramping the interaction strength in time. We demonstrate that subdiffusion is speeded up to normal diffusion for interacting disordered and kicked atomic systems. The door is open to test these theoretical results experimentally, and to attack similar computational quests in higher space dimensions Copyright (C) EPLA, 2013",
journal = "Europhysics Letters / EPL",
title = "Make slow fast -How to speed up interacting disordered matter",
volume = "101",
number = "1",
doi = "10.1209/0295-5075/101/10011"
}
Gligorić, G., Rayanov, K.,& Flach, S.. (2013). Make slow fast -How to speed up interacting disordered matter. in Europhysics Letters / EPL, 101(1).
https://doi.org/10.1209/0295-5075/101/10011
Gligorić G, Rayanov K, Flach S. Make slow fast -How to speed up interacting disordered matter. in Europhysics Letters / EPL. 2013;101(1).
doi:10.1209/0295-5075/101/10011 .
Gligorić, Goran, Rayanov, Kristian, Flach, Sergej, "Make slow fast -How to speed up interacting disordered matter" in Europhysics Letters / EPL, 101, no. 1 (2013),
https://doi.org/10.1209/0295-5075/101/10011 . .
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Interactions destroy dynamical localization with strong and weak chaos

Gligorić, Goran; Bodyfelt, J. D.; Flach, Sergej

(2011)

TY  - JOUR
AU  - Gligorić, Goran
AU  - Bodyfelt, J. D.
AU  - Flach, Sergej
PY  - 2011
UR  - http://vinar.vin.bg.ac.rs/handle/123456789/4548
AB  - Bose-Einstein condensates loaded into kicked optical lattices can be treated as quantum kicked-rotor systems. Noninteracting rotors show dynamical localization in momentum space. The experimentally tunable condensate interaction is included in a qualitative Gross-Pitaevskii-type model based on two-body interactions. We observe strong- and weak-chaos regimes of wave packet spreading in momentum space. In the intermediate strong-chaos regime the condensate energy grows as t(1/2). In the asymptotic weak-chaos case the growth crosses over into a t(1/3) law. The results do not depend on the details of the kicking. Copyright (C) EPLA, 2011
T2  - Europhysics Letters / EPL
T1  - Interactions destroy dynamical localization with strong and weak chaos
VL  - 96
IS  - 3
DO  - 10.1209/0295-5075/96/30004
ER  - 
@article{
author = "Gligorić, Goran and Bodyfelt, J. D. and Flach, Sergej",
year = "2011",
abstract = "Bose-Einstein condensates loaded into kicked optical lattices can be treated as quantum kicked-rotor systems. Noninteracting rotors show dynamical localization in momentum space. The experimentally tunable condensate interaction is included in a qualitative Gross-Pitaevskii-type model based on two-body interactions. We observe strong- and weak-chaos regimes of wave packet spreading in momentum space. In the intermediate strong-chaos regime the condensate energy grows as t(1/2). In the asymptotic weak-chaos case the growth crosses over into a t(1/3) law. The results do not depend on the details of the kicking. Copyright (C) EPLA, 2011",
journal = "Europhysics Letters / EPL",
title = "Interactions destroy dynamical localization with strong and weak chaos",
volume = "96",
number = "3",
doi = "10.1209/0295-5075/96/30004"
}
Gligorić, G., Bodyfelt, J. D.,& Flach, S.. (2011). Interactions destroy dynamical localization with strong and weak chaos. in Europhysics Letters / EPL, 96(3).
https://doi.org/10.1209/0295-5075/96/30004
Gligorić G, Bodyfelt JD, Flach S. Interactions destroy dynamical localization with strong and weak chaos. in Europhysics Letters / EPL. 2011;96(3).
doi:10.1209/0295-5075/96/30004 .
Gligorić, Goran, Bodyfelt, J. D., Flach, Sergej, "Interactions destroy dynamical localization with strong and weak chaos" in Europhysics Letters / EPL, 96, no. 3 (2011),
https://doi.org/10.1209/0295-5075/96/30004 . .
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