## Abstract

Strong-coupling expansion is performed for the lattice φ^{4} model in 1 + 1 dimensions. Because the strong-coupling limit itself is not solvable, we employed numerical calculations so as to set up unperturbed eigensystems. Restricting the number of Hilbert-space bases, we performed linked-cluster expansion up to 11th order. We carried out an alternative simulation by means of the density-matrix renormalization group. Thereby, we confirmed that our series-expansion data with a convergence-acceleration trick are in good agreement with the simulation result. Through the analytic continuation to the domain of negative biquadratic interaction, we obtain the false-vacuum decay rate. Contrary to common belief that the tunnelling phenomenon lies out of perturbative treatments, our series expansion reproduces the instanton-theory behaviour for a high potential barrier. For a shallow barrier, in contrast, our result tells us that the relaxation is no longer described by an instanton, but the decay rate acquires notable enhancement.

Original language | English |
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Pages (from-to) | 11215-11223 |

Number of pages | 9 |

Journal | Journal of Physics A: Mathematical and General |

Volume | 34 |

Issue number | 50 |

DOIs | |

Publication status | Published - Dec 21 2001 |

## ASJC Scopus subject areas

- Statistical and Nonlinear Physics
- Mathematical Physics
- Physics and Astronomy(all)

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