Many Body Theory for Quartets, Trions, and Pairs in Low Density Multi-Component Fermi-Systems

A selfconsistent many body approach for the description of gases with quartets, trions, and pairs is presented. Applications to 3D Fermi systems at low density are discussed

Atomic Bose-Fermi mixed condensates with Boson-Fermion quasi-bound cluster states

The boson-fermion atomic bound states (composite fermion) and their roles for the phase structures are studied in a bose-fermi mixed condensate of atomic gas in finite temperature and density. The two-body scattering equation is formulated for a boson-fermion pair in the mixed condensate with the Yamaguchi-type potential. By solving the equation, we evaluate the binding energy of a composite fermion, and show that it has small T-dependence in the physical region, because of the cancellation of the boson- and fermion- statistical factors in the equation. We also calculate the phase structure of the BF mixed condensate under the equilibrium B+F -> BF, and discuss the role of the composite fermions: the competitions between the degenerate state of the composite fermions and the Bose-Einstein condensate (BEC) of isolated bosons. The criterion for the BEC realization is obtained from the algebraically-derived phase diagrams at T=0.Comment: 5 pages, 3 figure

Alpha-particle condensation in nuclei

A round up of the present status of the conjecture that n alpha nuclei form an alpha-particle condensate in excited states close to the n alpha threshold is given. Experiments which could demonstrate the condensate character are proposed. Possible lines of further theoretical developments are discussed.Comment: 6 page

What is the relationship between photospheric flow fields and solar flares?

We estimated photospheric velocities by separately applying the Fourier Local Correlation Tracking (FLCT) and Differential Affine Velocity Estimator (DAVE) methods to 2708 co-registered pairs of SOHO/MDI magnetograms, with nominal 96-minute cadence and ~2" pixels, from 46 active regions (ARs) from 1996-1998 over the time interval t45 when each AR was within 45^o of disk center. For each magnetogram pair, we computed the average estimated radial magnetic field, B; and each tracking method produced an independently estimated flow field, u. We then quantitatively characterized these magnetic and flow fields by computing several extensive and intensive properties of each; extensive properties scale with AR size, while intensive properties do not depend directly on AR size. Intensive flow properties included moments of speeds, horizontal divergences, and radial curls; extensive flow properties included sums of these properties over each AR, and a crude proxy for the ideal Poynting flux, the total |u| B^2. Several magnetic quantities were also computed, including: total unsigned flux; a measure of the amount of unsigned flux near strong-field polarity inversion lines, R; and the total B^2. Next, using correlation and discriminant analysis, we investigated the associations between these properties and flares from the GOES flare catalog, when averaged over both t45 and shorter time windows, of 6 and 24 hours. We found R and total |u| B^2 to be most strongly associated with flares; no intensive flow properties were strongly associated with flares.Comment: 57 pages, 13 figures; revised content; added URL to manuscript with higher-quality image

Few-Body States in Fermi-Systems and Condensation Phenomena

Residual interactions in many particle systems lead to strong correlations. A multitude of spectacular phenomenae in many particle systems are connected to correlation effects in such systems, e.g. pairing, superconductivity, superfluidity, Bose-Einstein condensation etc. Here we focus on few-body bound states in a many-body surrounding.Comment: 10 pages, proceedings 1st Asian-Pacific Few-Body Conference, needs fbssuppl.sty of Few-Body System

Dynamics of few-body states in a medium

Strongly interacting matter such as nuclear or quark matter leads to few-body bound states and correlations of the constituents. As a consequence quantum chromodynamics has a rich phase structure with spontaneous symmetry breaking, superconductivity, condensates of different kinds. All this appears in many astrophysical scenarios. Among them is the formation of hadrns during the early stage of the Universe, the structure of a neutron star, the formation of nuclei during a supernova explosion. Some of these extreme conditions can be simulated in heavy ion colliders. To treat such a hot and dense system we use the Green function formalism of many-body theory. It turns out that a systematic Dyson expansion of the Green functions leads to modified few-body equations that are capable to describe phase transitions, condensates, cluster formation and more. These equations include self energy corrections and Pauli blocking. We apply this method to nonrelativistic and relativistic matter. The latter one is treated on the light front. Because of the medium and the inevitable truncation of space, the few-body dynamics and states depend on the thermodynamic parameters of the medium.Comment: 3 pages, 2 figures, talk presented at the 19th European Conference on Few-Body System

Spontaneous generation of spin-orbit coupling in magnetic dipolar Fermi gases

The stability of an unpolarized two-component dipolar Fermi gas is studied within mean-field theory. Besides the known instability towards spontaneous magnetization with Fermi sphere deformation, another instability towards spontaneous formation of a spin-orbit coupled phase with a Rashba-like spin texture is found. A phase diagram is presented and consequences are briefly discussed