Chaitin Phase Transition

Fuente: arXiv
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Auteurs principaux: Purcell, James, Li, Zhi, Cubitt, Toby
Format: Preprint
Publié: 2024
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author Purcell, James
Li, Zhi
Cubitt, Toby
author_facet Purcell, James
Li, Zhi
Cubitt, Toby
contents We construct a family of Hamiltonians whose phase diagram is guaranteed to have a single phase transition, yet the location of this phase transition is uncomputable. The Hamiltonians $H(ϕ)$ describe qudits on a two-dimensional square lattice with translationally invariant, nearest-neighbour interactions tuned by a continuous parameter $ϕ\in(0,1]$. For all $ϕ\in(0,1]$, $H(ϕ)$ is in one of two phases, one a gapless phase, the other a gapped phase. The phase transition occurs when $ϕ$ equals the Chaitin's constant $Ω$, a well-defined real number that encodes the Halting problem, and hence is uncomputable for Turing machines and undecidable for any consistent recursive axiomatization of mathematics. Our result implies that no general algorithm exists to determine the phase diagrams even under the promise that the phase diagram is exceedingly simple, and illustrates how uncomputable numbers may manifest in physical systems.
format Preprint
id arxiv_https___arxiv_org_abs_2410_02600
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Chaitin Phase Transition
Purcell, James
Li, Zhi
Cubitt, Toby
Quantum Physics
Other Condensed Matter
Mathematical Physics
We construct a family of Hamiltonians whose phase diagram is guaranteed to have a single phase transition, yet the location of this phase transition is uncomputable. The Hamiltonians $H(ϕ)$ describe qudits on a two-dimensional square lattice with translationally invariant, nearest-neighbour interactions tuned by a continuous parameter $ϕ\in(0,1]$. For all $ϕ\in(0,1]$, $H(ϕ)$ is in one of two phases, one a gapless phase, the other a gapped phase. The phase transition occurs when $ϕ$ equals the Chaitin's constant $Ω$, a well-defined real number that encodes the Halting problem, and hence is uncomputable for Turing machines and undecidable for any consistent recursive axiomatization of mathematics. Our result implies that no general algorithm exists to determine the phase diagrams even under the promise that the phase diagram is exceedingly simple, and illustrates how uncomputable numbers may manifest in physical systems.
title Chaitin Phase Transition
topic Quantum Physics
Other Condensed Matter
Mathematical Physics
url https://arxiv.org/abs/2410.02600