119173827
Inverse scattering approach for massive Thirring models with integrable type-II defects
We discuss the integrability of the bosonic and Grassmannian massive Thirring models in the presence of defects through the inverse scattering approach. We present a general method to compute the generating functions of modified conserved quantities for any integrable field equation associated with the m × m spectral linear problem. We apply the method to derive in particular the defect contributions for the number of occupation, energy and momentum of the massive Thirring models.
53655762
Type-II defects in the super-Liouville theory
The introduction of type-II defects is discussed under the Lagrangian formalism and Lax representation for the N = 1 super-Liouville model. We derive a new kind of super-Backlund transformation for the model and show explicitly the conservation of the modified energy and momentum, as well as supercharge.
119172404
N=1 super sinh-Gordon model with defects revisited
A bstractThe Lax pair formalism is considered to discuss the integrability of the N = 1 supersymmetric sinh-Gordon model with a defect. We derive associated defect matrix for the model and construct the generating functions of the modified conserved quantities. The corresponding defect contributions for the modified energy and momentum of the model are explicitly computed.
119104294
Surviving the crash: Assessing the aftermath of cosmic bubble collisions
This paper is the third in a series investigating the possibility that if we reside in an inflationary “bubble universe,” we might observe the effects of collisions with other such bubbles. Here, we study the interior structure of a bubble collision spacetime, focusing on the issue of where observers can reside. Numerical simulations indicate that if the interbubble domain wall accelerates away, infinite spacelike surfaces of homogeneity develop to the future of the collision; this strongly suggests that observers can have collisions to their past, and previous results then imply that this is very likely. However, for observers at nearly all locations, the restoration of homogeneity relegates any observable effects to a vanishingly small region on the sky. We find that bubble collisions may also play an important role in defining measures in inflation: a potentially infinite relative volume factor arises between two bubble types depending on the sign of the acceleration of the domain wall between them; this may in turn correlate with observables such as the scale or type of inflation.
119605713
Towards observable signatures of other bubble universes
We evaluate the possibility of observable effects arising from collisions between vacuum bubbles in a universe undergoing false-vacuum eternal inflation. Contrary to conventional wisdom, we find that under certain assumptions most positions inside a bubble should have access to a large number of collision events. We calculate the expected number and angular size distribution of such collisions on an observer's "sky," finding that for typical observers the distribution is anisotropic and includes many bubbles, each of which will affect the majority of the observer's sky. After a qualitative discussion of the physics involved in collisions between arbitrary bubbles, we evaluate the implications of our results, and outline possible detectable effects. In an optimistic sense, then, the present paper constitutes a first step in an assessment of the possible effects of other bubble universes on the cosmic microwave background and other observables.
119228685
How the diffuse Universe cools
In this work we investigate the cooling channels of diffuse gas (i.e. n_H<0.1 cm^-3) in cosmology. We aim to identify the wavelengths where most of the energy is radiated in the form of emission lines or continuum radiation, and the main elements and ions responsible for the emission. We use a subset of cosmological, hydrodynamical runs from the OWLS project to calculate the emission of diffuse gas and its evolution with time. We find that at z=0 (z=2) about 70 (80) per cent of the energy emitted by diffuse gas is carried by emission lines, with the continuum radiation contributing the remainder. Hydrogen lines in the Lyman series are the primary contributors to the line emission, with a share of 16 (20) per cent. Oxygen lines are the main metal contributors at high redshift, while silicon, carbon and iron lines are strongest at low redshift, when the contributions of AGB stars and supernova Ia explosions to the metal budget become important and when there is more hot gas. The ionic species carrying the most energy are OIII, CII, CIII, SiII, SiIII, FeII and SIII. The great majority of energy is emitted in the UV band (lambda=100-4000 A), both as continuum radiation and line emission. With almost no exception, all the strongest lines fall in this band. At high energies, continuum radiation is dominant (e.g., 80 per cent in the X-ray band), while lines contribute progressively more at lower energies. While the results do depend on the details of the numerical implementation of the physical processes modelled in the simulations, the comparison of results from different simulations demonstrates that the variations are overall small, and that the conclusions are fairly robust. Given the overwhelming importance of UV emission for the cooling of diffuse gas, it is desirable to build instruments dedicated to the detection and characterisation of diffuse UV emission.