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

Phase space deformation of a trapped dipolar Fermi gas

We consider a system of quantum degenerate spin polarized fermions in a harmonic trap at zero temperature, interacting via dipole-dipole forces. We introduce a variational Wigner function to describe the deformation and compression of the Fermi gas in phase space and use it to examine the stability of the system. We emphasize the important roles played by the Fock exchange term of the dipolar interaction which results in a non-spherical Fermi surface.Comment: 5 pages, 5 figure

Critical Temperature for α\alpha-Particle Condensation within a Momentum Projected Mean Field Approach

Alpha-particle (quartet) condensation in homogeneous spin-isospin symmetric nuclear matter is investigated. The usual Thouless criterion for the critical temperature is extended to the quartet case. The in-medium four-body problem is strongly simplified by the use of a momentum projected mean field ansatz for the quartet. The self-consistent single particle wave functions are shown and discussed for various values of the density at the critical temperature

Density wave instability in a 2D dipolar Fermi gas

We consider a uniform dipolar Fermi gas in two-dimensions (2D) where the dipole moments of fermions are aligned by an orientable external field. We obtain the ground state of the gas in Hartree-Fock approximation and investigate RPA stability against density fluctuations of finite momentum. It is shown that the density wave instability takes place in a broad region where the system is stable against collapse. We also find that the critical temperature can be a significant fraction of Fermi temperature for a realistic system of polar molecules.Comment: 10 figure

Dynamical properties of dipolar Fermi gases

We investigate dynamical properties of a one-component Fermi gas with dipole-dipole interaction between particles. Using a variational function based on the Thomas-Fermi density distribution in phase space representation, the total energy is described by a function of deformation parameters in both real and momentum space. Various thermodynamic quantities of a uniform dipolar Fermi gas are derived, and then instability of this system is discussed. For a trapped dipolar Fermi gas, the collective oscillation frequencies are derived with the energy-weighted sum rule method. The frequencies for the monopole and quadrupole modes are calculated, and softening against collapse is shown as the dipolar strength approaches the critical value. Finally, we investigate the effects of the dipolar interaction on the expansion dynamics of the Fermi gas and show how the dipolar effects manifest in an expanded cloud.Comment: 14 pages, 8 figures, submitted to New J. Phy

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

Excited states nonlinear integral equations for an integrable anisotropic spin 1 chain

We propose a set of nonlinear integral equations to describe on the excited states of an integrable the spin 1 chain with anisotropy. The scaling dimensions, evaluated numerically in previous studies, are recovered analytically by using the equations. This result may be relevant to the study on the supersymmetric sine-Gordon model.Comment: 15 pages, 2 Figures, typos correcte

Explicit formulas for the generalized Hermite polynomials in superspace

We provide explicit formulas for the orthogonal eigenfunctions of the supersymmetric extension of the rational Calogero-Moser-Sutherland model with harmonic confinement, i.e., the generalized Hermite (or Hi-Jack) polynomials in superspace. The construction relies on the triangular action of the Hamiltonian on the supermonomial basis. This translates into determinantal expressions for the Hamiltonian's eigenfunctions.Comment: 19 pages. This is a recasting of the second part of the first version of hep-th/0305038 which has been splitted in two articles. In this revised version, the introduction has been rewritten and a new appendix has been added. To appear in JP

Gaps and forks in DNA replication: Rediscovering old models

Most current models for replication past damaged lesions envisage that translesion synthesis occurs at the replication fork. However older models suggested that gaps were left opposite lesions to allow the replication fork to proceed, and these gaps were subsequently sealed behind the replication fork. Two recent articles lend support to the idea that bypass of the damage occurs behind the fork. In the first paper, electron micrographs of DNA replicated in UV-irradiated yeast cells show regions of single-stranded DNA both at the replication forks and behind the fork, the latter being consistent with the presence of gaps in the daughter-strands opposite lesions. The second paper describes an in vitro DNA replication system reconstituted from purified bacterial proteins. Repriming of synthesis downstream from a blocked fork occurred not only on the lagging strand as expected, but also on the leading strand, demonstrating that contrary to widely accepted beliefs, leading strand synthesis does not need to be continuous