Fine Structure of the Hydrogen Atom by a Microwave Method

Lamb, Willis E.; Retherford, Robert C.

doi:10.1103/physrev.72.241

Cited by 1,130 publications

(790 citation statements)

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“…Although such infinities became visible only at extremely short distances, where modifications to the theory could be expected, the divergences could not simply be ignored; for example, Oppenheimer (1930) predicted an infinite shift of the spectral lines of the hydrogen atom due to interaction of the electron with the radiation field. Of course, the measurable experimental value of that shift (Lamb and Retherford, 1947) is finite and very small.…”

Section: Mass and Charge Renormalizationmentioning

confidence: 99%

Fundamental statistical descriptions of plasma turbulence in magnetic fields

Krommes¹

2002

Physics Reports

267

397

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A pedagogical review of the historical development and current status (as of early 2000) of systematic statistical theories of plasma turbulence is undertaken. Emphasis is on conceptual foundations and methodology, not practical applications. Particular attention is paid to equations and formalism appropriate to strongly magnetized, fully ionized plasmas. Extensive reference to the literature on neutral-fluid turbulence is made, but the unique properties and problems of plasmas are emphasized throughout. Discussions are given of quasilinear theory, weak-turbulence theory, resonance-broadening theory, and the clump algorithm. Those are developed independently, then shown to be special cases of the direct-interaction approximation (DIA), which provides a central focus for the article. Various methods of renormalized perturbation theory are described, then unified with the aid of the generating-functional formalism of Martin, Siggia, and Rose. A general expression for the renormalized dielectric function is deduced and discussed in detail. Modern approaches such as decimation and PDF methods are described. Derivations of DIA-based Markovian closures are discussed. The eddy-damped quasinormal Markovian closure is shown to be nonrealizable in the presence of waves, and a new realizable Markovian closure is presented. The test-field model and a realizable modification thereof are also summarized. Numerical solutions of various closures for some plasmaphysics paradigms are reviewed. The variational approach to bounds on transport is developed. Miscellaneous topics include Onsager symmetries for turbulence, the interpretation of entropy balances for both kinetic and fluid descriptions, self-organized criticality, statistical interactions between disparate scales, and the roles of both mean and random shear. Appendices are provided on Fourier transform conventions, dimensional and scaling analysis, the derivations of nonlinear gyrokinetic and gyrofluid equations, stochasticity criteria for quasilinear theory, formal aspects of resonance-broadening theory, Novikov's theorem, the treatment of weak inhomogeneity, the derivation of the Vlasov weak-turbulence wave kinetic equation from a fully renormalized description, some features of a code for solving the direct-interaction approximation and related Markovian closures, the details of the solution of the EDQNM closure for a solvable three-wave model, and the notation used in the article.

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Section: Mass and Charge Renormalizationmentioning

confidence: 99%

Fundamental statistical descriptions of plasma turbulence in magnetic fields

Krommes¹

2002

Physics Reports

267

397

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“…Ela teve como pontos principais a discussão de dois experimentos. O primeiro mediu uma pequena discrepância, no nível n = 2, na estrutura fina do átomo de Hidrogênio [16], e o outro a estrutura hiperfina do Hidrogênio e do Deutério, série H α (transições dos níveis superiores para o nível n = 2) e D α , respectivamente [17]. [18][19][20].…”

Section: A Conferência De Shelter Islandunclassified

“…De fato, a observação da estrutura fina foi a primeira indicação da existência do spin do elétron [25]. 4 De fato, depois da guerra Willis Lamb e Robert Retherford, usando espectroscopia de micro-ondas, técnicas desenvolvidas durante a segunda guerra, mediram ∆E(2s 1/2 -− 2p 1/2 ) = 1000 MHz, ou 0, 033 cm −1 [16]. Se na teoria de Dirac para o átomo de Hidrogênio, o paradigma da época, previa que esses níveis seriam degenerados, então estaria a teoria rejeitada?…”

Section: A Conferência De Shelter Islandunclassified

“…16 Vemos que aparecem a contribuição ao momento magnético anômalo do elétron e a [49] são similares entre si, estão baseadas na tradição do formalismo Hamiltoniano e no uso de transformações canônicas e a teoria de muitos tempos de Dirac [50]. Já o de Feynman é mais original ainda que inspirado em trabalhos anteriores dele, e permite fazer cálculos de maneira muito mais simples que no caso dos outros formalismos.…”

Section: Figura 4: Diagrama Correspondente à Eq (29)unclassified

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Richard Feynman e a QED

Pleitez

2018

Rev. Bras. Ensino Fís.

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Neste artigo comentamos e contextualizamos os dois principais artigos de Richard Feynman nos quais reformula a eletrodinâmica quântica incluindo o algoritmo da renormalização. Palavras-chave: Eletrodinâmica Quântica, QED, renormalização, Richard Feynman In this article, we comment and contextualize the main works of Richard Feynman, which reformulate the quantum electrodynamics including the renormalization algorithm. Keywords: Quantum Electrodynamics, QED, renormalization, Richard Feynman. Introdução it. The decision to give the Nobel prize to the authors of QED was made only after Bohr's death. When it was published ...R. Oppenheimer was in Israel ... He sent Feynman a telegram from Tel Aviv with only one word: enfin (at last, in French)Parece que Bohr nunca aceitou o conceito de "fóton" [3].De fato, muitos dos fundadores da mecânica quântica achavam que uma proposta revolucionária deveria ser feita para evitar os infinitos na QED. Dirac aos 75 anos disse [4] I really spent my life trying to find better equations for quantum electrodynamics, and so far without success, but I continue to work on it.A solução no entanto foi bem conservadora: redefina os pârametros livres da teoria mantendo a covariância de Lorentz e a invariância de gauge. Não se precisava de física nova.A estrutura deste artigo é a seguinte. Na Sec. 2 consideramos a QED antes dos trabalhos de Feynman, Schwinger, e Tomonaga (FST). Na Sec. 3 discutimos os resultados principais da Conferência de Shelter Island que motivou os autores americanos a formular sua respectiva versão da QED renormalizável. A Sec. 4 é a principal, dado que o objetivo deste artigo é discutir os artigos de Feynman nos quais ele formula seu método de fazer cálculos finitos na QED. Na Sec. 5 comentamos as contribuições de dois físicos que também tiveram um papel importante na formulação da QED renormalizável, Dyson e Stückelberg. As concluções aparecem na Sec. 7.

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“…In 1948, when physicists were developing new ideas in quantum field theory, Lamb made a seminal measurement showing a shift in the energy levels of the hydrogen atom that was interpreted as due to the interaction of the atom with the quantum fluctuations of the vacuum state of the quantized electromagnetic field [4]. Theory showed this field produced a complex radiative shift that shifted both the energy level and its lifetime [5].…”

Section: Introductionmentioning

confidence: 99%

A Gedanken Spacecraft that Operates Using the Quantum Vacuum (Dynamic Casimir Effect)

Maclay

Forward²

2004

Foundations of Physics

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Conventional rockets are not a suitable technology for deep space missions. Chemical rockets require a very large weight of propellant, travel very slowly compared to light speed, and require significant energy to maintain operation over periods of years. For example, the 722 kg Voyager spacecraft required 13,600 kg of propellant to launch and would take about 80,000 years to reach the nearest star, Proxima Centauri, about 4.3 light years away. There have been various attempts at developing ideas on which one might base a spacecraft that would permit deep space travel, such as spacewarps. In this paper we consider another suggestion from science fiction and explore how the quantum vacuum might be utilized in the creation of a novel spacecraft. The spacecraft is based on the dynamic Casimir effect, in which electromagnetic radiation is emitted when an uncharged mirror is properly accelerated in the vacuum. The radiative reaction produces a dissipative force on the mirror that tends to resist the acceleration of the mirror. This force can be used to accelerate a spacecraft attached to the mirror. We also show that, in principal, one could obtain the power to operate the accelerated mirror in such a spacecraft using energy extracted from the quantum vacuum using the standard Casimir effect with a parallel plate geometry. Unfortunately the method as currently conceived generates a miniscule thrust, and is no more practical than a spacewarp, yet it does provide an interesting demonstration of our current understanding of the physics of the quantized electromagnetic field in vacuum. * Electronic address: jordanmaclay@quantumfields.com

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Fine Structure of the Hydrogen Atom by a Microwave Method

Cited by 1,130 publications

References 5 publications

Fundamental statistical descriptions of plasma turbulence in magnetic fields

Fundamental statistical descriptions of plasma turbulence in magnetic fields

Richard Feynman e a QED

A Gedanken Spacecraft that Operates Using the Quantum Vacuum (Dynamic Casimir Effect)

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