CFT Zoo

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Table of Contents

$O(2)$ model

The $O(2)$ model is a well studied special case of the $O(N)$ model. It also goes by the name “XY model”.

Operator content

There are two relevant operators, $\phi$ (an $O(2)$ vector) and $s$ (a singlet). The scaling dimensions are \[ \Delta_\phi = 0.51926(32) \text{ and } \Delta_s = 1.5117(25) \] while the nonvanishing OPE coefficients are \[ \lambda_{sss} = 0.8286(60) \text{ and } \lambda_{\phi\phi s} = 0.68726(65 \text. \]

These data are from the bootstrap, computed here: https://arxiv.org/pdf/1603.04436.pdf.

Physical realizations

Superfluid helium (both He-3 and H-4), apparently.

Last modified: 2021/04/27 20:23
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