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Microphysical Approach To Nonequilibrium Dynamics Of Quantum Fields, Marcelo Gleiser, Rudnei O. Ramos
Microphysical Approach To Nonequilibrium Dynamics Of Quantum Fields, Marcelo Gleiser, Rudnei O. Ramos
Dartmouth Scholarship
We examine the nonequilibrium dynamics of a self-interacting λφ4 scalar field theory. Using a real time formulation of finite temperature field theory we derive, up to two loops and O(λ2), the effective equation of motion describing the approach to equilibrium. We present a detailed analysis of the approxi- mations used in order to obtain a Langevin-like equation of motion, in which the noise and dissipation terms associated with quantum fluctuations obey a fluctuation-dissipation relation. We show that, in general, the noise is colored (time-dependent) and multiplicative (couples nonlinearly to the field), even though it is still Gaussian distributed. The noise …
Pseudostable Bubbles, Marcelo Gleiser
Pseudostable Bubbles, Marcelo Gleiser
Dartmouth Scholarship
The evolution of spherically symmetric unstable scalar field configura- tions (“bubbles”) is examined for both symmetric (SDWP) and asymmet- ric (ADWP) double-well potentials. Bubbles with initial static energiesE0 ∼< Ecrit, where Ecrit is some critical value, shrink in a time scale deter- mined by their linear dimension, or “radius”. Bubbles with E0 ∼> Ecrit evolve into time-dependent, localized configurations which are very long-lived com- pared to characteristic time-scales in the models examined. The stability of these configurations is investigated and possible applications are briefly discussed.