Cited by 225Quantum Mechanics and Non-Hermitian PhysicsSpectral Theory in Mathematical PhysicsQuantum Mechanics and Applications

The DOI matches its Crossref record; 42 of the 42 references it cites were found in a registry or an index; none of the 21 sources its claims cite is checked for support yet.

Optical Realization of Relativistic Non-Hermitian Quantum Mechanics

Open access
Longhi, Stefano·2010·Physical Review Letters

Abstract

Light propagation in distributed-feedback optical structures with gain or loss regions is shown to provide an accessible laboratory tool to visualize in optics the spectral properties of the one-dimensional Dirac equation with non-Hermitian interactions. Spectral singularities and PT symmetry breaking of the Dirac Hamiltonian are shown to correspond to simple observable physical quantities and are related to well-known physical phenomena such as resonance narrowing and laser oscillation.

Overview

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TL;DR

Light propagation in distributed-feedback optical structures with gain/loss regions is proposed as a classical optical simulator of the one-dimensional non-Hermitian Dirac equation. Spectral singularities and PT symmetry breaking of the Dirac Hamiltonian are mapped to observable DFB phenomena such as resonance narrowing and laser oscillation.

Key findings

  • For a PT-non-invariant uniform-gain DFB structure, the critical normalized gain is λ_c L ≈ 1.755 for m₀L = 1; at λ_c two resonances cross the real energy axis and become spectral singularities, and above λ_c bound states emerge and the spectrum ceases to be real-valued.
  • For the same structure with uniform loss, at λ_c two antiresonances cross the real axis; the spectral transmission does not diverge, and the bound states have Im(E) < 0, so perturbations are damped rather than amplified.
  • For a PT-invariant DFB structure with symmetric gain and loss regions, PT symmetry breaking occurs at λ_c ≈ 4.46/L for m₀L = 1, with two pairs of complex-conjugate eigenvalues appearing from resonances and antiresonances crossing the real axis.
  • The paper reports that spectral singularities and PT symmetry breaking of the Dirac Hamiltonian correspond to measurable DFB quantities, including resonance narrowing and the onset of lasing.

Methods

  • Theoretical mapping of the 1D Dirac equation with real mass m(x) and complex vector potential V(x) to coupled-mode equations for counterpropagating optical envelopes in a DFB grating.
  • Scattering theory and transfer-matrix analysis: the transfer matrix M(E), Green function/resolvent, and zeros of M₁₁ and M₂₂ are used to classify continuous spectrum, point spectrum, resonances, and spectral singularities.
  • Two examples are analyzed numerically for m₀L = 1: a uniform index grating with homogeneous gain (PT-non-invariant) and a uniform grating with symmetric homogeneous gain/loss regions (PT-invariant).

Limitations

  • The paper states no limitations.
  • Evident from the text: this is a theoretical proposal for a classical optical simulator, not an experimental realization; no fabricated device or measured data are reported.
  • Evident from the text: the analysis is restricted to the 1D Dirac equation and two specific DFB configurations with uniform grating and piecewise-constant gain/loss, with numerical examples given for m₀L = 1.

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Integrity signals

Registry

Crossref · 10.1103/physrevlett.105.013903

Cites

42 of 42 references verified0 citation errors · 0 not checkable

Statistics

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Verification

Claims the paper makes

0 of 21 cited sources checked · 0 supported · 0 flagged

  • It may state two separate claims as one. 16
  • Probably not a substantial claim. 4
19 of 19
  • The authors state this as an assumption.

    Both m(x) and V(x) have limited support, i.e. m = V = 0 for |x| > L/2.

    “In the following, we will assume that both m ( x ) and V ( x ) have a limited support, i.e. m = V = 0 for | x | &gt; L/ 2.”
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Metadata

Authors
Longhi, S.
Affiliations
Politecnico di Milano (IT)
Corresponding author
Longhi, Stefano
Venue
Physical Review Letters
Published
2010-06-30
Volume
105
Issue
1
Pages
013903-013903
ISSN
  • 0031-9007 (ISSN-L)
  • 1079-7114
OpenAlex
W1974418311
Cited by
225
References
41
Citations by year
2026: 8 · 2025: 13 · 2024: 10 · 2023: 9 · 2022: 17 · 2021: 17 · 2020: 18 · 2019: 10 · 2018: 6 · 2017: 10 · 2016: 20 · 2015: 15 · 2014: 18 · 2013: 13 · 2012: 20
FWCI
9.28
Type
journal article
Language
en
Open access
Locations
  • Physical Review Letters (publishedVersion)
  • PubMed (publishedVersion)
  • arXiv (Cornell University) (submittedVersion)
  • Virtual Community of Pathological Anatomy (University of Castilla La Mancha) (submittedVersion)
  • arXiv (Cornell University)
Topics
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Mechanics and Non-Hermitian Physics
  • Physical Sciences › Mathematics › Mathematical Physics › Spectral Theory in Mathematical Physics
  • Physical Sciences › Physics and Astronomy › Atomic and Molecular Physics, and Optics › Quantum Mechanics and Applications
Keywords
non-Hermitian quantum mechanics, Dirac equation, PT symmetry breaking, spectral singularities, optical gain and loss, laser oscillation

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