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pro vyhledávání: '"Nielsen K"'
The properties and experimental identification of quantum spin liquids (QSL) remains an important topic with many fundamental questions. Here, we explore the dynamics of a single charge dopant (hole) in a $t$-$J_{1}$-$J_{2}$ model on a square lattice
Externí odkaz:
http://arxiv.org/abs/2407.06816
Autor:
Nielsen, K. Knakkergaard
I demonstrate a pairing mechanism of dopants in a magnetic lattice, emerging from the underlying high-temperature disorder of the spins. The effect is demonstrated in a mixed-dimensional model, where dopants travel along a two-leg ladder, while the s
Externí odkaz:
http://arxiv.org/abs/2407.01252
Autor:
Nielsen, K. Knakkergaard
Publikováno v:
SciPost Phys. Core 7, 054 (2024)
I investigate the motion of a single hole in 2D spin lattices with square and triangular geometries. While the spins have nearest neighbor Ising spin couplings $J$, the hole is allowed to move only in 1D along a single line in the 2D lattice with nea
Externí odkaz:
http://arxiv.org/abs/2404.11608
Randomness in the void distribution within a ductile metal complicates quantitative modeling of damage following the void growth to coalescence failure process. Though the sequence of micro-mechanisms leading to ductile failure is known from unit cel
Externí odkaz:
http://arxiv.org/abs/2311.07236
The physics of impurities in a bosonic quantum environment is a paradigmatic and challenging many-body problem that remains to be understood in its full complexity. Here, this problem is investigated for impurities with strong repulsive interactions
Externí odkaz:
http://arxiv.org/abs/2310.18183
Autor:
Nielsen, K. Knakkergaard
Publikováno v:
Phys. Rev. Research 6, 023325 (2024)
I unveil a novel variant of Anderson localization. This emergent phenomenon pertains to the motion of a dopant in a thermal spin lattice, rendered localized by thermal fluctuations. This is in stark contrast to the intrinsic origin of localization fo
Externí odkaz:
http://arxiv.org/abs/2310.11193
Autor:
Nielsen, K. Knakkergaard
Publikováno v:
Phys. Rev. B 108, 085125 (2023)
We study the motion of holes in a mixed-dimensional setup of an antiferromagnetic ladder, featuring nearest neighbor hopping $t$ along the ladders and Ising-type spin interactions along, $J_\parallel$, and across, $J_\perp$, the ladder. We determine
Externí odkaz:
http://arxiv.org/abs/2303.17381
Autor:
Nielsen, K. Knakkergaard
For decades, it has remained an open question, whether two dopants in the $t$--$J$ model bind in the strongly correlated regime of small spin couplings versus hopping, $J \ll t$. Here, we investigate this problem in Bethe lattice structures with Isin
Externí odkaz:
http://arxiv.org/abs/2302.07304
Autor:
Nielsen, K. Knakkergaard
Publikováno v:
Phys. Rev. B 106, 115144 (2022)
We investigate a rare instance of an exactly solvable nonequilibrium many-body problem. In particular, we derive an exact solution for the nonequilibrium dynamics of an initially localized single hole in a fully anisotropic antiferromagnetic Bethe la
Externí odkaz:
http://arxiv.org/abs/2207.01020
Publikováno v:
Phys. Rev. Lett. 129, 246601 (2022)
We develop a nonperturbative theory for hole dynamics in antiferromagnetic spin lattices, as described by the $t$-$J$ model. This is achieved by generalizing the selfconsistent Born approximation to nonequilibrium systems, making it possible to calcu
Externí odkaz:
http://arxiv.org/abs/2203.04789