Speaker
Karan Tiwana
(Ecoles des Mines, Paris)
Description
We study a generalisation of $\phi_2^4$ with self coupling constant $g$ to two species coupled via the cross term $2\lambda\phi_1^2\phi_2^2$. The $\mathbb{Z}_2$ symmetry group of $\phi_2^4$ is now generalised to the diherdral group $D_4$, apart from $g=\lambda$ line where the symmetry is enhanced to $O(2)$. In $1 + 1\, d$, spontaneous breaking of continuous symmetries is forbidden. Nonetheless, such systems can still undergo phase transitions of topological nature of BKT type as exemplified by compactified boson. Away from the $O(2)$ line, the model has a potentially rich phase diagram akin to the Ashkin-Teller model. We use the RCMPS ansatz to variationally optimise for the ground state and study the physics of this model.
Author
Karan Tiwana
(Ecoles des Mines, Paris)
Co-author
Mr
Antoine Tilloy
(Ecoles des Mines, Paris)
