Influence of Impurity Scattering on Surface Plasmons in Graphene in the Lindhard Approximation

We study the influence of impurity scattering on transverse magnetic (TM) and transverse electric (TE) surface plasmons (SPs) in graphene using the Lindhard approximation. We show how the behaviour and domains of TM SPs are affected by the impurity strength γ and determine the critical value γc below which no SPs exist. The quality factor of TM SPs, for single-band and two-band transitions, is proportional to the square of αλSP/γ, with α being the fine-structure constant and λSP being the plasmon wavelength. In addition, we show that impurity scattering suppresses TE SPs.

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PHOTON PAIRING AND THE STRONG COUPLING PHASE OF MASSIVE QUANTUM ELECTRODYNAMICS COOPER EQUATION

Modern Physics Letters A ◽

10.1142/s0217732390000445 ◽

1990 ◽

Vol 05 (06) ◽

pp. 381-390 ◽

Cited By ~ 2

Author(s):

T. INAGAKI ◽

M. KOMACHIYA ◽

R. FUKUDA

Keyword(s):

Fine Structure ◽

External Field ◽

Strong Coupling ◽

Quantum Electrodynamics ◽

Structure Constant ◽

Critical Value ◽

Low Energy ◽

Fine Structure Constant ◽

Coupling Phase ◽

Effective Lagrangian

Through the Cooper equation of the photon pairing, the instability of the normal vacuum of the Quantum Electrodynamics with the massive electron is studied. Using the low energy effective Lagrangian, the normal vacuum is shown to be unstable against the condensation of the photon pairs above the critical value of the fine structure constant. These agree with the previous results obtained by the Bethe-Salpeter equation. The presence of the weak electric external field enhances the instability thus lowering the critical value. This can be a basis for the explanation of the anomalous GSI e+e− events.

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New Limit on Space-Time Variations in the Proton-to-Electron Mass Ratio from Analysis of Quasar J110325-264515 Spectra

Symmetry ◽

10.3390/sym12030344 ◽

2020 ◽

Vol 12 (3) ◽

pp. 344

Author(s):

T. D. Le

Keyword(s):

Fine Structure ◽

Structure Constant ◽

Space Time ◽

Fine Structure Constant ◽

Electron Mass ◽

Mass Ratio ◽

Quasar Spectra ◽

Time Variations ◽

Using Data ◽

The Universe

Astrophysical tests of current values for dimensionless constants known on Earth, such as the fine-structure constant, α , and proton-to-electron mass ratio, μ = m p / m e , are communicated using data from high-resolution quasar spectra in different regions or epochs of the universe. The symmetry wavelengths of [Fe II] lines from redshifted quasar spectra of J110325-264515 and their corresponding values in the laboratory were combined to find a new limit on space-time variations in the proton-to-electron mass ratio, ∆ μ / μ = ( 0.096 ± 0.182 ) × 10 − 7 . The results show how the indicated astrophysical observations can further improve the accuracy and space-time variations of physics constants.

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Magnetic plasmons induced in a dielectric-metal heterostructure by optical magnetism

Nanophotonics ◽

10.1515/nanoph-2021-0146 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Shulei Li ◽

Lidan Zhou ◽

Mingcheng Panmai ◽

Jin Xiang ◽

Sheng Lan

Keyword(s):

Transverse Electric ◽

Incidence Angle ◽

High Sensitivity ◽

Critical Value ◽

Transverse Magnetic ◽

Quality Factors ◽

Light Spectrum ◽

Optical Resonances ◽

Scattering Spectra ◽

Plasmon Polaritons

Abstract We investigate numerically and experimentally the optical properties of the transverse electric (TE) waves supported by a dielectric-metal heterostructure. They are considered as the counterparts of the surface plasmon polaritons (i.e., the transverse magnetic (TM) waves) which have been extensively studied in the last several decades. We show that TE waves with resonant wavelengths in the visible light spectrum can be excited in a dielectric-metal heterostructure when the optical thickness of the dielectric layer exceeds a critical value. We reveal that the electric and magnetic field distributions for the TE waves are spatially separated, leading to higher quality factors or narrow linewidths as compared with the TM waves. We calculate the thickness, refractive index and incidence angle dispersion relations for the TE waves supported by a dielectric-metal heterostructure. In experiments, we observe optical resonances with linewidths as narrow as ∼10 nm in the reflection or scattering spectra of the TE waves excited in a Si3N4/Ag heterostructure. Finally, we demonstrate the applications of the lowest-order TE wave excited in a Si3N4/Ag heterostructure in optical display with good chromaticity and optical sensing with high sensitivity.

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Measurement of the running of the fine structure constant below 1 GeV with the KLOE detector

EPJ Web of Conferences ◽

10.1051/epjconf/201921802012 ◽

2019 ◽

Vol 218 ◽

pp. 02012

Author(s):

Graziano Venanzoni

Keyword(s):

Fine Structure ◽

Energy Region ◽

Direct Evidence ◽

Branching Ratio ◽

Structure Constant ◽

Fine Structure Constant ◽

Recent Measurement ◽

Single Measurement ◽

Lepton Universality ◽

Hadronic Contribution

I will report on the recent measurement of the fine structure constant below 1 GeV with the KLOE detector. It represents the first measurement of the running of α(s) in this energy region. Our results show a more than 5σ significance of the hadronic contribution to the running of α(s), which is the strongest direct evidence both in time-and space-like regions achieved in a single measurement. From a fit of the real part of Δα(s) and assuming the lepton universality the branching ratio BR(ω → µ+µ−) = (6.6 ± 1.4stat ± 1.7syst) · 10−5 has been determined

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