*Published Paper*

**Inserted:** 6 aug 2019

**Last Updated:** 17 sep 2023

**Journal:** Comm. Pure Appl. Math.

**Volume:** 75

**Number:** 10

**Pages:** 2279–2342

**Year:** 2022

**Notes:**

Title changed; formerly 'From the N-clock model to the XY model: emergence of concentration effects'

**Abstract:**

We investigate the relationship between the $N$-clock model (also known as planar Potts model or $Z_N$-model) and the $XY$ model (at zero temperature) through a $\Gamma$-convergence analysis of a suitable rescaling of the energy as both the number of particles and $N$ diverge. We prove the existence of rates of divergence of $N$ for which the continuum limits of the two models differ. With the aid of Cartesian currents we show that the asymptotics of the $N$-clock model in this regime features an energy which may concentrate on geometric objects of various dimensions. This energy prevails over the usual vortex-vortex interaction energy.

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