dorsal/arxiv
View SchemaA magnetic model with a possible Chern-Simons phase
| Authors | Michael H. Freedman |
|---|---|
| Categories | |
| ArXiv ID | quant-ph/0110060 |
| URL | https://arxiv.org/abs/quant-ph/0110060 |
Abstract
An elementary family of local Hamiltonians $H_{\c ,\ell}, \ell = 1,2,3, ldots$, is described for a $2-$dimensional quantum mechanical system of spin $={1/2}$ particles. On the torus, the ground state space $G_{\circ,\ell}$ is $(\log)$ extensively degenerate but should collapse under $\l$perturbation" to an anyonic system with a complete mathematical description: the quantum double of the $SO(3)-$Chern-Simons modular functor at $q= e^{2 \pi i/\ell +2}$ which we call $DE \ell$. The Hamiltonian $H_{\circ,\ell}$ defines a \underline{quantum} \underline{loop}\underline{gas}. We argue that for $\ell = 1$ and 2, $G_{\circ,\ell}$ is unstable and the collapse to $G_{\epsilon, \ell} \cong DE\ell$ can occur truly by perturbation. For $\ell \geq 3$, $G_{\circ,\ell}$ is stable and in this case finding $G_{\epsilon,\ell} \cong DE \ell$ must require either $\epsilon > \epsilon_\ell > 0$, help from finite system size, surface roughening (see section 3), or some other trick, hence the initial use of quotes ${\l}\quad$". A hypothetical phase diagram is included in the introduction.
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"date_created": "2026-03-02T18:01:45.463000Z",
"date_modified": "2026-03-02T18:01:45.463000Z",
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"abstract": "An elementary family of local Hamiltonians $H_{\\c ,\\ell}, \\ell = 1,2,3,\nldots$, is described for a $2-$dimensional quantum mechanical system of spin\n$={1/2}$ particles. On the torus, the ground state space $G_{\\circ,\\ell}$ is\n$(\\log)$ extensively degenerate but should collapse under $\\l$perturbation\" to\nan anyonic system with a complete mathematical description: the quantum double\nof the $SO(3)-$Chern-Simons modular functor at $q= e^{2 \\pi i/\\ell +2}$ which\nwe call $DE \\ell$. The Hamiltonian $H_{\\circ,\\ell}$ defines a\n\\underline{quantum} \\underline{loop}\\underline{gas}. We argue that for $\\ell =\n1$ and 2, $G_{\\circ,\\ell}$ is unstable and the collapse to $G_{\\epsilon, \\ell}\n\\cong DE\\ell$ can occur truly by perturbation. For $\\ell \\geq 3$,\n$G_{\\circ,\\ell}$ is stable and in this case finding $G_{\\epsilon,\\ell} \\cong DE\n\\ell$ must require either $\\epsilon \u003e \\epsilon_\\ell \u003e 0$, help from finite\nsystem size, surface roughening (see section 3), or some other trick, hence the\ninitial use of quotes ${\\l}\\quad$\". A hypothetical phase diagram is included in\nthe introduction.",
"arxiv_id": "quant-ph/0110060",
"authors": [
"Michael H. Freedman"
],
"categories": [
"quant-ph",
"cond-mat",
"math.GT"
],
"title": "A magnetic model with a possible Chern-Simons phase",
"url": "https://arxiv.org/abs/quant-ph/0110060"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "4394c181-daee-478c-ae00-73407edc7687",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
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