This thesis deals with the dynamics of the classical configuration of a quantum field unstable due to pair creation. The effective action method is developed first to treat such problems for a simple two-field model. Physical quantities such as pair creation probabilities are related to a complex function called the \"effective configuration,\" which is defined to minimize the effective action. Unitarity of the S-matrix is verified at the lowest order of the weak-field approximation. At the same order, the real valued vacuum expectation value of the quantum field, named the \"real configuration,\" is constructed in terms of the effective configuration. An integro-differential equation for the real configuration is given and is used to show that the real configuration is causal, while the effective configuration is not. Two practical applications of the effective action method are discussed. The first deals with pair creation in an anisotropic universe, and the \"real geometry\" is given in terms of the \"effective geometry\" in the small anisotropy limit. The second deals with expanding vacuum bubbles. Corresponding to three possible situations, three kinds of field equations for each of the effective configuration and the real configuration are obtained. The behavior of the bubble is also studied by a semi-classical method, and one of the three situations is suggested to be plausible.
", "doi": "10.7907/d9zm-yb94", "publication_date": "1982", "thesis_type": "phd", "thesis_year": "1982" }, { "id": "thesis:400", "collection": "thesis", "collection_id": "400", "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-01292004-100142", "primary_object_url": { "basename": "Trafton_lm_1965.pdf", "content": "final", "filesize": 8570618, "license": "other", "mime_type": "application/pdf", "url": "/400/1/Trafton_lm_1965.pdf", "version": "v2.0.0" }, "type": "thesis", "title": "A Study of the Energy Balance in the Atmospheres of the Major Planets", "author": [ { "family_name": "Trafton", "given_name": "Laurence Munro", "clpid": "Trafton-Laurence-Munro" } ], "thesis_advisor": [ { "family_name": "M\u00fcnch", "given_name": "Guido", "clpid": "M\u00fcnch-G" } ], "thesis_committee": [ { "family_name": "M\u00fcnch", "given_name": "Guido", "clpid": "M\u00fcnch-G" }, { "family_name": "Christy", "given_name": "Robert F.", "clpid": "Christy-R-F" }, { "family_name": "Greenstein", "given_name": "Jesse L.", "clpid": "Greenstein-J-L" }, { "family_name": "Wildey", "given_name": "Robert", "clpid": "Wildey-R" }, { "family_name": "Oke", "given_name": "J. Beverly", "clpid": "Oke-J-B" } ], "local_group": [ { "literal": "Astronomy Department" }, { "literal": "div_pma" } ], "abstract": "The monochromatic absorption of infrared and microwave radiation due to pressure-induced rotational and translational transitions in H2 gas and gaseous mixtures of H2 and He is investigated quantitatively. Existing laboratory data are used to obtain semi-empirical absorption coefficients of the rotational transitions as a function of frequency. A quantum mechanical calculation is carried out to obtain the translational absorption coefficient as a function of frequency for a diatomic gas, mixtures of diatomic and monatomic gases and mixtures of monatomic gases. The resulting expressions are used to compute the translational absorption coefficient for H2 and the enhancement in H2-He mixtures using a 6 - 12 Lennard-Jones potential for the molecular interaction and the EXP-4 model for the expectation value of the induced dipole moment over the ground electronic and vibrational states. A numerical method is devised for the efficient computation of the translational absorption and the results of the computations are given. The infrared opacity of NH3 is also considered. With certain assumptions, existing laboratory data are used to obtain approximate, semi-empirical mean transmissions over the rotation structure of NH3 as a function of frequency.
\r\n\r\nSeveral non-gray model atmospheres are constructed for Jupiter, Saturn, Uranus and Neptune for various effective temperatures and He-H2 ratios taking the opacity due to H2 and He into account. The effect of adding the opacity due to NH3 is considered. The models are examined for self consistency and characteristic phenomena. They are then compared with the observations.
\r\n\r\nThe observations are used to restrict the range of the free parameters of the models. It is found that models of Jupiter and Neptune for which only the thermal opacity of H2 and NH3 is taken into account are incompatible with the observations. The presence of He is strongly indicated in the atmospheres of Jupiter, Uranus and Neptune. In the case of Jupiter, a rather large N(He)/N(H2) value is implied if there is no internal heat source. However, the observations indicate a preference for N(He)/N(H2) less than 2 and thus imply the existence of a small internal heat source greater than one-tenth of the incident solar flux. The effect of NH3 on the thermal equilibrium of the major planets is negligible except possibly in the case of Jupiter. However, its presence in the Jovian atmosphere does not alter the above conclusions.
", "doi": "10.7907/F2DM-WX77", "publication_date": "1965", "thesis_type": "phd", "thesis_year": "1965" } ]