Geometric contribution to adiabatic amplification in non-Hermitian systems

Fuente: arXiv
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Autores principales: Ozawa, Tomoki, Schomerus, Henning
Formato: Preprint
Publicado: 2024
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author Ozawa, Tomoki
Schomerus, Henning
author_facet Ozawa, Tomoki
Schomerus, Henning
contents Concepts from non-Hermitian quantum mechanics have proven useful in understanding and manipulating a variety of classical systems, such as those encountered in optics, classical mechanics, and metamaterial design. Recently, the non-Hermitian analog of the Berry phase for adiabatic processes was experimentally measured. In non-Hermitian systems, the Berry phase can have an imaginary part, which contributes to the amplification or decay of the total wave intensity. When the imaginary part of the Berry curvature is zero, this geometric amplification factor is determined solely by the initial and final points of the adiabatic path in parameter space, and it does not depend on how these points are connected by the path. We list classes of non-Hermitian Hamiltonians where this path independence is guaranteed by suitable symmetries, and we find that, for some of these classes, the amplification factor can be written only in terms of the Petermann factors of the initial and final points. Our result can, in turn, be used to experimentally obtain the Petermann factor by observing how the norm of the wave function changes under adiabatic processes. We validate our theory using a couple of concrete examples of physical relevance.
format Preprint
id arxiv_https___arxiv_org_abs_2409_13595
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Geometric contribution to adiabatic amplification in non-Hermitian systems
Ozawa, Tomoki
Schomerus, Henning
Quantum Physics
Other Condensed Matter
Optics
Concepts from non-Hermitian quantum mechanics have proven useful in understanding and manipulating a variety of classical systems, such as those encountered in optics, classical mechanics, and metamaterial design. Recently, the non-Hermitian analog of the Berry phase for adiabatic processes was experimentally measured. In non-Hermitian systems, the Berry phase can have an imaginary part, which contributes to the amplification or decay of the total wave intensity. When the imaginary part of the Berry curvature is zero, this geometric amplification factor is determined solely by the initial and final points of the adiabatic path in parameter space, and it does not depend on how these points are connected by the path. We list classes of non-Hermitian Hamiltonians where this path independence is guaranteed by suitable symmetries, and we find that, for some of these classes, the amplification factor can be written only in terms of the Petermann factors of the initial and final points. Our result can, in turn, be used to experimentally obtain the Petermann factor by observing how the norm of the wave function changes under adiabatic processes. We validate our theory using a couple of concrete examples of physical relevance.
title Geometric contribution to adiabatic amplification in non-Hermitian systems
topic Quantum Physics
Other Condensed Matter
Optics
url https://arxiv.org/abs/2409.13595