Compatibility of transport effects in non-Hermitian nonreciprocal systems

Ghaemi-Dizicheh, Hamed; Schomerus, Henning

doi:10.1103/physreva.104.023515

Cited by 20 publications

(20 citation statements)

References 72 publications

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“…Hence, developing a formulation for the distinct transport effects in non-Hermitian nonreciprocal systems paves the way toward investigating interesting phenomena in such platforms. Following this motivation in our previous paper, we studied (i) conditions for variant transport effects, (ii) their compatibility with each other, and (iii) their adjustment by tuning suitable parameters facilitated by symmetry or topology [26]. We then found distinct transport signatures of non-Hermitian, nonreciprocal, and topological systems.…”

Section: Introductionmentioning

confidence: 90%

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Transport effects in non-Hermitian nonreciprocal systems: General approach

Ghaemi-Dizicheh¹

2023

Preprint

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In this paper, we present a unifying analytical framework for identifying conditions for transport effects such as reflectionless and transparent transport, lasing, and coherent perfect absorption in non-Hermitian nonreciprocal systems using a generalized transfer matrix method. This provides a universal approach to studying the transport of tight-binding platforms, including higherdimensional models and those with an internal degree of freedom going beyond the previously studied case of one-dimensional chains with nearest-neighbor couplings. For a specific class of tight-binding models, the relevant transport conditions and their signatures of non-Hermitian, nonreciprocal, and topological behavior are analytically tractable from a general perspective. We investigate this class and illustrate our formalism in a paradigmatic ladder model where the system's parameters can be tuned to adjust the transport effect and topological phases.

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Section: Introductionmentioning

confidence: 90%

“…In Ref. [26], we employed the transfer matrix to define transport boundary conditions and their connection. Following the same formulation, we can extend the derivation of the transfer matrix describing transportation in a general nonreciprocal lattice.…”

Section: Introductionmentioning

confidence: 99%

Transport effects in non-Hermitian nonreciprocal systems: General approach

Ghaemi-Dizicheh¹

2023

Preprint

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“…In other symmetry classes, functionality can arise collectively from the bulk, or individually from particular states. To determine their visibility we consider a flexible one-dimensional model encompassing a wide range of paradigms [34,38,[82][83][84][85][86][87][88][89], based on an effective Hamiltonian…”

Section: Observability Of Specific Non-hermitian Effectsmentioning

confidence: 99%

Fundamental constraints on the observability of non-Hermitian effects in passive systems

Schomerus

2022

Phys. Rev. A

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Utilizing scattering theory, we quantify the consequences of physical constraints that limit the visibility of non-Hermitian effects in passive devices. The constraints arise from the fundamental requirement that the system obeys causality, and can be captured concisely in terms of an internal time-delay operator, which furthermore provides a direct quantitative measure of the visibility of specific non-Hermitian phenomena in the density of states. We illustrate the implications by contrasting two prominent non-Hermitian effects, exceptional points and the non-Hermitian skin effect, whose underlying extreme mode nonorthogonality turns out to be undetectable in the density of states.

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“…The non-Hermitian models in physics have become a vast research area in recent years, including condensed matter physics [1], photonics [2,3], biophysics [4], and acoustic [5]. Among them, the non-Hermitian generalization of topological tight-binding systems introduces new phenomena absent in Hermitian ones, such as non-Hermitian skin effect [6], distinct transport effects [7], relocation of topological edge states [8], and noise-resilient [9], to name a few. A well-known approach to making a tight-binding model non-Hermitian is introducing complex onsite potential, playing the role of gain (loss) in photonic models [10].…”

Section: Introductionmentioning

confidence: 99%

Non-Hermitian Floquet-free analytically solvable time-dependent systems [Invited]

Ghaemi-Dizicheh¹,

Ramezani²

2023

Opt. Mater. Express

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The non-Hermitian models, which are symmetric under parity (P) and time-reversal (T) operators, are the cornerstone for the fabrication of new ultra-sensitive optoelectronic devices. However, providing the gain in such systems usually demands precise control of nonlinear processes, limiting their application. In this paper, to bypass this obstacle, we introduce a class of time-dependent non-Hermitian Hamiltonians (not necessarily Floquet) that can describe a two-level system with temporally modulated on-site potential and couplings. We show that implementing an appropriate non-Unitary gauge transformation converts the original system to an effective one with a balanced gain and loss. This will allow us to derive the evolution of states analytically. Our proposed class of Hamiltonians can be employed in different platforms such as electronic circuits, acoustics, and photonics to design structures with hidden PT-symmetry potentially without imaginary onsite amplification and absorption mechanism to obtain an exceptional point.

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Compatibility of transport effects in non-Hermitian nonreciprocal systems

Cited by 20 publications

References 72 publications

Transport effects in non-Hermitian nonreciprocal systems: General approach

Transport effects in non-Hermitian nonreciprocal systems: General approach

Fundamental constraints on the observability of non-Hermitian effects in passive systems

Non-Hermitian Floquet-free analytically solvable time-dependent systems [Invited]

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