Emergence of a control parameter for the antiferromagnetic quantum critical metal
| Autor: | Lunts, Peter, Schlief, Andres, Lee, Sung-Sik |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 95, 245109 (2017) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.95.245109 |
| Popis: | We study the antiferromagnetic quantum critical metal in $3-\epsilon$ space dimensions by extending the earlier one-loop analysis [Sur and Lee, Phys. Rev. B 91, 125136 (2015)] to higher-loop orders. We show that the $\epsilon$-expansion is not organized by the standard loop expansion, and a two-loop graph becomes as important as one-loop graphs due to an infrared singularity caused by an emergent quasilocality. This qualitatively changes the nature of the infrared (IR) fixed point, and the $\epsilon$-expansion is controlled only after the two-loop effect is taken into account. Furthermore, we show that a ratio between velocities emerges as a small parameter, which suppresses a large class of diagrams. We show that the critical exponents do not receive corrections beyond the linear order in $\epsilon$ in the limit that the ratio of velocities vanishes. The $\epsilon$-expansion gives critical exponents which are consistent with the exact solution obtained in $0 < \epsilon \leq 1$. Comment: 20 pages, 8 figures; ver2: minor corrections, comparison to ferromagnetic quantum criticality added, typos fixed, references added |
| Databáze: | arXiv |
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