{"product_id":"schwingers-quantum-action-principle-from-diracs-formulation-through-feynmans-path-integrals-the-schwinger-keldysh-method-quantum-field-theory-to-source-theory-von-kimball-a-milton","title":"Schwinger's Quantum Action Principle","description":"Starting from the earlier notions of stationary action principles, these tutorial notes shows how Schwinger’s Quantum Action Principle descended from Dirac’s formulation, which independently led Feynman to his path-integral formulation of quantum mechanics. Part I brings out in more detail the connection between the two formulations, and applications are discussed. Then, the Keldysh-Schwinger time-cycle method of extracting matrix elements is described. Part II will discuss the variational formulation of quantum electrodynamics and the development of source theory.\u003cdiv class=\"aw-variant-hidden-subtitle-div\" id=\"aw-variant-subtitle-9783319201276\"\u003e\u003ch3\u003eFrom Dirac’s Formulation Through Feynman’s Path Integrals, the Schwinger-Keldysh Method, Quantum Field Theory, to Source Theory\u003c\/h3\u003e\u003c\/div\u003e","brand":"Libri","offers":[{"title":"Softcover - 9783319201276","offer_id":39420375859293,"sku":"9783319201276","price":74.89,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0940\/0622\/files\/2dbc45cf-09de-4af7-843d-c98445430f68.jpg?v=1775710171","url":"https:\/\/shop.autorenwelt.de\/en\/products\/schwingers-quantum-action-principle-from-diracs-formulation-through-feynmans-path-integrals-the-schwinger-keldysh-method-quantum-field-theory-to-source-theory-von-kimball-a-milton","provider":"Autorenwelt Shop","version":"1.0","type":"link"}