Marginal dimensions for multicritical phase transitions
The field-theoretical model describing multicritical phenomena with two coupled order parameters with n<sub>||</sub> and n<sub>⊥</sub> components and of O(n<sub>||</sub> ⊕ O(n<sub>⊥</sub>) symmetry is considered. Conditions for realization of different...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Institute for Condensed Matter Physics
2012-12-01
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| Series: | Condensed Matter Physics |
| Subjects: | |
| Online Access: | http://dx.doi.org/10.5488/CMP.15.43001 |
| Summary: | The field-theoretical model describing multicritical phenomena with two coupled order parameters with n<sub>||</sub> and n<sub>⊥</sub> components and of O(n<sub>||</sub> ⊕ O(n<sub>⊥</sub>) symmetry is considered. Conditions for realization of different types of multicritical behaviour are studied within the field-theoretical renormalization group approach. Surfaces separating stability regions for certain types of multicritical behaviour in parametric space of order parameter dimensions and space dimension d are calculated using the two-loop renormalization group functions. Series for the order parameter marginal dimensions that control the crossover between different universality classes are extracted up to the fourth order in ϵ = 4-d and to the fifth order in a pseudo-ϵ parameter using the known high-order perturbative expansions for isotropic and cubic models. Special attention is paid to a particular case of O(1) ⊕ O(2) symmetric model relevant for description of anisotropic antiferromagnets in an external magnetic field. |
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| ISSN: | 1607-324X |