@article{wenzel_fermi-liquid_2025,

title = {Fermi-liquid behavior of nonaltermagnetic RuO_{2}},

author = {M. Wenzel and E. Uykur and S. Rößler and M. Schmidt and O. Janson and A. Tiwari and M. Dressel and A. A. Tsirlin},

url = {https://link.aps.org/doi/10.1103/PhysRevB.111.L041115},

doi = {10.1103/PhysRevB.111.L041115},

year  = {2025},

date = {2025-01-28},

urldate = {2025-01-28},

journal = {Phys. Rev. B},

volume = {111},

number = {4},

pages = {L041115},

abstract = {The presence of magnetism in potentially altermagnetic RuO2 has been a subject of intense debate. Using broadband infrared spectroscopy combined with density-functional band-structure calculations, we show that the optical conductivity of RuO2, the bulk probe of its electronic structure, is best described by a nonmagnetic model. The sharp Pauli edge demonstrates the presence of a Dirac nodal line lying 45 meV below the Fermi level. An excellent match between the experimental and ab initio plasma frequencies underpins the weakness of electronic correlations. The intraband part of the optical conductivity indicates Fermi-liquid behavior with two distinct scattering rates below 150 K. Fermi-liquid theory also accounts for the temperature-dependent magnetic susceptibility of RuO2 and allows a consistent description of this material as a paramagnetic metal.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{shen_pressure-dependent_2025,

title = {Pressure-dependent magnetism of the Kitaev candidate Li_{2}RhO_{3}},

author = {B. Shen and Insuasti Pazmino, E. and R. Dhakal and F. Freund and P. Gegenwart and S. M. Winter and A. A. Tsirlin},

url = {https://doi.org/10.1038/s41535-025-00730-1},

doi = {10.1038/s41535-025-00730-1},

year  = {2025},

date = {2025-01-22},

urldate = {2025-01-22},

journal = {npj Quantum Mater.},

volume = {10},

number = {1},

pages = {9},

abstract = {We use magnetization measurements under pressure along with ab initio and cluster many-body calculations to investigate magnetism of the Kitaev candidate Li2RhO3. Hydrostatic compression leads to a decrease in the magnitude of the nearest-neighbor ferromagnetic Kitaev coupling K1 and the corresponding increase in the off-diagonal anisotropy Γ1, whereas the experimental Curie-Weiss temperature changes from negative to positive with the slope of +40 K/GPa. On the other hand, spin freezing persists up to at least 3.46 GPa with the almost constant freezing temperature of 5 K that does not follow the large changes in the exchange couplings and indicates the likely extrinsic origin of spin freezing. Magnetic frustration in Li2RhO3 is mainly related to the interplay between ferromagnetic K1 and antiferromagnetic Γ1, along with the weakness of the third-neighbor coupling J3 that would otherwise stabilize zigzag order. The small J3 distinguishes Li2RhO3 from other Kitaev candidates.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{xu_entanglement_2025,

title = {Entanglement Properties of Gauge Theories from Higher-Form Symmetries},

author = {W. -T. Xu and T. Rakovszky and M. Knap and F. Pollmann},

doi = {10.1103/PhysRevX.15.011001},

year  = {2025},

date = {2025-01-02},

urldate = {2025-01-01},

journal = {Phys. Rev. X},

volume = {15},

number = {1},

pages = {011001},

abstract = {We explore the relationship between higher-form symmetries and entanglement properties in lattice gauge theories with discrete gauge groups, which can exhibit both topologically ordered phases and higher-form symmetry-protected topological (SPT) phases. Our study centers on a generalization of the Fradkin-Shenker model describing ℤ2 lattice gauge theory with matter, where the Gauss law constraint can be either emergent or exact. The phase diagram includes a topologically ordered deconfined phase and a nontrivial SPT phase protected by a 1-form and a 0-form symmetry, among others. We obtain the following key findings: First, the entanglement properties of the model depend on whether the 1-form symmetries and the Gauss law constraint are exact or emergent. For the emergent Gauss law, the entanglement spectrum (ES) of the nontrivial SPT phase exhibits degeneracies, which are robust at low energies against weak perturbations that explicitly break the exact 1-form symmetry. When the Gauss law and the 1-form symmetry are both exact, the ES degeneracy is extensive. This extensive degeneracy turns out to be fragile and can be removed completely by infinitesimal perturbations that explicitly break the exact 1-form symmetry while keeping the Gauss law exact. Second, we consider the ES in the topologically ordered phase where 1-form symmetries are spontaneously broken. In contrast to the ES of the nontrivial SPT phase, we find that spontaneous higher-form symmetry breaking removes “half” of the ES levels, leading to a nondegenerate ES in the topologically ordered phase, in general. Third, we derive a connection between spontaneous higher-form symmetry breaking and the topological entanglement entropy (TEE). Using this relation, we investigate the entanglement entropy that can be distilled in the deconfined phase of the original Fradkin-Shenker model using gauge-invariant measurements. We show that the TEE is robust against the measurement when the 1-form symmetry is emergent but it is fragile when the 1-form symmetry is exact. Our results demonstrate the advantage of higher-form symmetries for understanding entanglement properties of gauge theories.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}