124354849
Dynamics of nuclear fluid. III. General considerations on the kinetic theory of quantum fluids
From the quantum kinetic equation of Bogoliubov, Gurov, Born, and Green, the equations of motion for macroscopic variables are examined in many different ways. First, in the configuration space a hierarchy of generalized fluid-dynamical equations can be obtained by taking the appropriate limits of the quantum kinetic equation. The resultant equations of continuity, of momentum, and of energy are similar in form to those one encounters in classical fluid dynamics with the exception of additional terms proportional to h/sup 2/. Secondly, the quantum kinetic equation is examined in phase space. The same set of equations of continuity, of momentum, and of energy can be derived by taking the first three moments of the quantum kinetic equation. The exact results we obtained are utilized to form the starting point for many simplifying approximations for the investigation of the dynamics of quantum many-body systems such as the elastic response limit, the hydrodynamical limit, Landau's Fermi-liquid theory, and finally the time-dependent Hartree-Fock and the multideterminant time-dependent Hartree-Fock approximations. The fact that all these different dynamical descriptions can be traced to a common origin provides a unifying viewpoint to the present approach with the quantum kinetic equation.
62325539
Computing Environments for Data Analysis. Part 2. Hardware
This is the second in a series of papers on aspects of modern computing environments that are relevant to statistical data analysis. We argue that a network of graphics workstations is far superior to conventional batch or time-sharing computers as an environment for interactive data analysis. The second paper in the series discusses the hardware of graphics workstations in detail.
15812806
Unparticles: Interpretation and Cosmology.
We discuss the physical interpretation of unparticles and review the constraints from cosmology. Unparticles may be understood in terms of confined states of a strongly-coupled scale-invariant theory, where scale-invariance implies that the confined states have continuous masses. This picture is consistent with the observation that unparticle operators can be represented in terms of continuous mass fields. Finite results in scattering processes are obtained by compensating the infinite number of unparticle final states with an infinitesimal coupling per unparticle. As a result, unparticles are stable with respect to decay or annihilation to Standard Model particles, implying a one-way flow of energy from the Standard Model sector to the unparticle sector. The qualitative properties of unparticles, which result from their continuous mass nature, are unchanged in the case where scale-invariance is broken by a mass gap. Unparticles with a mass gap can evade constraints from astrophysical and 5th force considerations, in which case cosmology provides the strongest constraints.
1977978
Flat direction condensate instabilities in the MSSM
Coherently oscillating scalar condensates formed along flat directions of the MSSM scalar potential are unstable with respect to spatial perturbations if the potential is flatter than φ2, resulting in the formation of non-topological solitons such as Q-balls. Using the renormalization group we calculate the corrections to the φ2 potential for a range of flat directions and show that unstable condensates are a generic feature of the MSSM. Exceptions arise for an experimentally testable range of stop and gluino masses when there are large admixtures of stops in the flat direction scalar.
119508847
The dynamics of Affleck-Dine condensate collapse
In the MSSM, cosmological scalar field condensates formed along flat directions of the scalar potential (Affleck-Dine condensates) are typically unstable with respect to formation of Q-balls, a type of non-topological soliton. We consider the dynamical evolution of the Affleck-Dine condensate in the MSSM. We discuss the creation and linear growth, in F- and D-term inflation models, of the quantum seed perturbations which in the non-linear regime catalyse the collapse of the condensate to non-topological soliton lumps. We study numerically the evolution of the collapsing condensate lumps and show that the solitons initially formed are not in general Q-balls, but Q-axitons, a pseudo-breather which can have very different properties from Q-balls of the same charge. We calculate the energy and charge radiated from st spherically symmetric condensate lump as it evolves into a Q-axiton. We also discuss the implications for baryogenesis and dark matter. (C) 2000 Elsevier Science B,V. All rights reserved.
13167169
Spontaneous discrete symmetry breaking during inflation and the NMSSM domain wall problem
The Next to Minimal Supersymmetric Standard Model (NMSSM), proposed as a solution of the mu problem of the Minimal Supersymmetric Standard Model, has a discrete Z(3) symmetry which is spontaneously broken at the electroweak phase transition, resulting in a cosmological domain wall problem. In most cases this domain wall problem cannot be solved by explicit Z(3) breaking without introducing supergravity tadpole corrections which destabilize the weak scale hierarchy. Here we consider the possibility of solving the domain wall problem of the NMSSM via spontaneous discrete symmetry breaking occurring during inflation. For the case where the discrete symmetry breaking field has renormalizable couplings to the NMSSM fields, we find that the couplings must be less than 10(-5) if the reheating temperature is larger than 10(7) GeV, but can be up to 10(-3) for reheating temperatures of the order of the electroweak phase transition temperature, For the case of non-renormalizable couplings, we present a model which can solve the domain wall problem for large reheating temperatures without requiring any very small coupling constants. In this model the domain walls are eliminated by a pressure coming from their interaction with a coherently oscillating scalar field whose phase is fixed during inflation. This oscillating scalar field typically decays after the electroweak phase transition but before nucleosynthesis, leaving no additional Z(3) symmetry breaking in the zero-temperature theory. (C) 1998 Elsevier Science B.V.
16971604
Two-field Q-ball solutions of supersymmetric hybrid inflation.
We demonstrate the existence of two-field Q-ball solutions of the scalar field equations of supersymmetric D- and F-term hybrid inflation. The solutions consist of a complex inflaton field together with a real symmetry breaking field. Such inflatonic Q-balls may play a fundamental role in reheating and the post-inflation era of supersymmetric hybrid inflation models.