### Abstract

Macroscopic quantum tunneling (MQT) for a single fluxon moving along a long Josephson junction is studied theoretically. To introduce a fluxon-pinning force, we consider inhomogeneities made by modifying thickness of an insulating layer locally. Two different situations are studied: one is the quantum tunneling from a metastable state caused by a single inhomogeneity, and the other is the quantum tunneling in a two-state system made by two inhomogeneities. In the quantum tunneling from a metastable state, the decay rate is estimated within the WKB approximation. Dissipation effects on a fluxon dynamics are taken into account by the Caldeira-Leggett theory. We propose a device to observe quantum tunneling of a fluxon experimentally. Required experimental resolutions to observe MQT of a fluxon seem attainable within the presently available micro-fabrication technique. For the two-state system, we study quantum resonance between two stable states, i.e., macroscopic quantum coherence (MQC). From the estimate for dissipation coefficients due to quasiparticle tunneling, the observation of MQC appears to be possible within the Caldeira-Leggett theory.

Original language | English |
---|---|

Pages (from-to) | 2963-2975 |

Number of pages | 13 |

Journal | Journal of the Physical Society of Japan |

Volume | 65 |

Issue number | 9 |

DOIs | |

Publication status | Published - 1996 Jan 1 |

Externally published | Yes |

### Fingerprint

### Keywords

- Caldeira-Leggett theory
- Dissipation
- Fluxon
- Long Josephson junction
- Macroscopic quantum coherence
- Macroscopic quantum tunneling
- Sine-Gordon equation

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*Journal of the Physical Society of Japan*,

*65*(9), 2963-2975. https://doi.org/10.1143/JPSJ.65.2963

**Macroscopic Quantum Tunneling of a Fluxon in a Long Josephson Junction.** / Kato, Takeo; Imada, Masatoshi.

Research output: Contribution to journal › Article

*Journal of the Physical Society of Japan*, vol. 65, no. 9, pp. 2963-2975. https://doi.org/10.1143/JPSJ.65.2963

}

TY - JOUR

T1 - Macroscopic Quantum Tunneling of a Fluxon in a Long Josephson Junction

AU - Kato, Takeo

AU - Imada, Masatoshi

PY - 1996/1/1

Y1 - 1996/1/1

N2 - Macroscopic quantum tunneling (MQT) for a single fluxon moving along a long Josephson junction is studied theoretically. To introduce a fluxon-pinning force, we consider inhomogeneities made by modifying thickness of an insulating layer locally. Two different situations are studied: one is the quantum tunneling from a metastable state caused by a single inhomogeneity, and the other is the quantum tunneling in a two-state system made by two inhomogeneities. In the quantum tunneling from a metastable state, the decay rate is estimated within the WKB approximation. Dissipation effects on a fluxon dynamics are taken into account by the Caldeira-Leggett theory. We propose a device to observe quantum tunneling of a fluxon experimentally. Required experimental resolutions to observe MQT of a fluxon seem attainable within the presently available micro-fabrication technique. For the two-state system, we study quantum resonance between two stable states, i.e., macroscopic quantum coherence (MQC). From the estimate for dissipation coefficients due to quasiparticle tunneling, the observation of MQC appears to be possible within the Caldeira-Leggett theory.

AB - Macroscopic quantum tunneling (MQT) for a single fluxon moving along a long Josephson junction is studied theoretically. To introduce a fluxon-pinning force, we consider inhomogeneities made by modifying thickness of an insulating layer locally. Two different situations are studied: one is the quantum tunneling from a metastable state caused by a single inhomogeneity, and the other is the quantum tunneling in a two-state system made by two inhomogeneities. In the quantum tunneling from a metastable state, the decay rate is estimated within the WKB approximation. Dissipation effects on a fluxon dynamics are taken into account by the Caldeira-Leggett theory. We propose a device to observe quantum tunneling of a fluxon experimentally. Required experimental resolutions to observe MQT of a fluxon seem attainable within the presently available micro-fabrication technique. For the two-state system, we study quantum resonance between two stable states, i.e., macroscopic quantum coherence (MQC). From the estimate for dissipation coefficients due to quasiparticle tunneling, the observation of MQC appears to be possible within the Caldeira-Leggett theory.

KW - Caldeira-Leggett theory

KW - Dissipation

KW - Fluxon

KW - Long Josephson junction

KW - Macroscopic quantum coherence

KW - Macroscopic quantum tunneling

KW - Sine-Gordon equation

UR - http://www.scopus.com/inward/record.url?scp=0030523815&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030523815&partnerID=8YFLogxK

U2 - 10.1143/JPSJ.65.2963

DO - 10.1143/JPSJ.65.2963

M3 - Article

AN - SCOPUS:0030523815

VL - 65

SP - 2963

EP - 2975

JO - Journal of the Physical Society of Japan

JF - Journal of the Physical Society of Japan

SN - 0031-9015

IS - 9

ER -