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pro vyhledávání: '"Stalhammar, Marcus"'
Autor:
Stålhammar, Marcus
It is well known that in conventional three dimensional (3D) Hermitian two band models, the intersections between the energy bands are generically given by points. The typical example are Weyl semimetals, where these singular points can be effectivel
Externí odkaz:
http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-176063
Autor:
Stålhammar, Marcus
We set out on the ambitious journey to fuse inflation and string theory. We first give a somewhat extensive, yet free from the most complicated details, review of string inflation, discussing concepts as flux compactifications, moduli stabilization,
Externí odkaz:
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-329306
Autor:
Stålhammar, Marcus
We investigate the massless and tensionless limit for the relativistic particle and string respectively. The interaction with interesting background fields, such as the electromagnetic field in the particle case and the Kalb-Ramond field in the strin
Externí odkaz:
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-255904
Despite their ubiquity, systematic characterization of multifold exceptional points, $n$-fold exceptional points (EP$n$s), remains a significant unsolved problem. In this article, we characterize Abelian topology of eigenvalues for generic EP$n$s and
Externí odkaz:
http://arxiv.org/abs/2409.09153
Autor:
Stålhammar, Marcus
Weyl semimetals are predicted to host signature magneto-optical properties sourced by their peculiar Landau level structure, including the chiral level. Analytical studies are often leaving out the Hall component of the conductivity due to its compli
Externí odkaz:
http://arxiv.org/abs/2402.08735
Autor:
Yang, Kang, Li, Zhi, König, J. Lukas K., Rødland, Lukas, Stålhammar, Marcus, Bergholtz, Emil J.
Publikováno v:
Rep. Prog. Phys. 87 078002 (2024)
Non-Hermitian matrices are ubiquitous in the description of nature ranging from classical dissipative systems, including optical, electrical, and mechanical metamaterials, to scattering of waves and open quantum many-body systems. Seminal line-gap an
Externí odkaz:
http://arxiv.org/abs/2309.14416
Publikováno v:
Phys. Rev. B 109, 064514 (2024)
Parity violating superconductors can support a low-dimension local interaction that becomes, upon condensation, a purely spatial Chern-Simons term. Solutions to the resulting generalized London equations can be obtained from solutions of the ordinary
Externí odkaz:
http://arxiv.org/abs/2309.10025
Publikováno v:
Phys. Rev. Research 5, 043043 (2023)
Non-Hermitian systems exhibit interesting band structures, where novel topological phenomena arise from the existence of exceptional points at which eigenvalues and eigenvectors coalesce. One important open question is how this would manifest at non-
Externí odkaz:
http://arxiv.org/abs/2304.09188
The biorthogonal formalism extends conventional quantum mechanics to the non-Hermitian realm. It has, however, been pointed out that the biorthogonal inner product changes with the scaling of the eigenvectors, an ambiguity whose physical significance
Externí odkaz:
http://arxiv.org/abs/2212.06004
Publikováno v:
SciPost Phys. 15, 200 (2023)
One of the unique features of non-Hermitian~(NH) systems is the appearance of non-Hermitian degeneracies known as exceptional points~(EPs). The extensively studied defective EPs occur when the Hamiltonian becomes non-diagonalizable. Aside from this d
Externí odkaz:
http://arxiv.org/abs/2204.13945