<p>In this paper, we study the evolution of the zero-temperature random field Ising model as the mean of the external field <i>M</i> increases from <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(-\infty \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo>-</mo> <mi>∞</mi> </mrow> </math></EquationSource> </InlineEquation> to <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\infty \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>∞</mi> </math></EquationSource> </InlineEquation>. We focus on two types of evolutions: the ground state evolution and the Glauber evolution. For the ground state evolution, we investigate the occurrence of global avalanche, a moment where a large fraction of spins flip simultaneously from minus to plus. In two dimensions, no global avalanche occurs, while in three or higher dimensions, there is a phase transition: a global avalanche happens when the noise intensity is small, but not when it is large. Additionally, we study the zero-temperature Glauber evolution, where spins are updated locally to minimize the Hamiltonian. Our results show that for small noise intensity, in dimensions <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(d =2\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>d</mi> <mo>=</mo> <mn>2</mn> </mrow> </math></EquationSource> </InlineEquation> or 3, most spins flip around a critical time <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(c_d = \frac{2 \sqrt{d}}{1 + \sqrt{d}}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>c</mi> <mi>d</mi> </msub> <mo>=</mo> <mfrac> <mrow> <mn>2</mn> <msqrt> <mi>d</mi> </msqrt> </mrow> <mrow> <mn>1</mn> <mo>+</mo> <msqrt> <mi>d</mi> </msqrt> </mrow> </mfrac> </mrow> </math></EquationSource> </InlineEquation> (but we cannot decide whether such flipping occurs simultaneously or not). We also connect this process to polluted bootstrap percolation and solve an open problem on it.</p>

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Dynamical random field Ising model at zero temperature

  • Jian Ding,
  • Peng Yang,
  • Zijie Zhuang

摘要

In this paper, we study the evolution of the zero-temperature random field Ising model as the mean of the external field M increases from \(-\infty \) - to \(\infty \) . We focus on two types of evolutions: the ground state evolution and the Glauber evolution. For the ground state evolution, we investigate the occurrence of global avalanche, a moment where a large fraction of spins flip simultaneously from minus to plus. In two dimensions, no global avalanche occurs, while in three or higher dimensions, there is a phase transition: a global avalanche happens when the noise intensity is small, but not when it is large. Additionally, we study the zero-temperature Glauber evolution, where spins are updated locally to minimize the Hamiltonian. Our results show that for small noise intensity, in dimensions \(d =2\) d = 2 or 3, most spins flip around a critical time \(c_d = \frac{2 \sqrt{d}}{1 + \sqrt{d}}\) c d = 2 d 1 + d (but we cannot decide whether such flipping occurs simultaneously or not). We also connect this process to polluted bootstrap percolation and solve an open problem on it.