Spin-charge separation in one-dimensional fermion systems beyond the Luttinger liquid theory

We develop a nonperturbative zero-temperature theory for the dynamic response functions of interacting one-dimensional spin-1/2 fermions. In contrast to the conventional Luttinger liquid theory, we take into account the nonlinearity of the fermion dispersion exactly. We calculate the power-law singularities of the spectral function and the charge and spin density structure factors for arbitrary momenta and interaction strengths. The exponents characterizing the singularities are functions of momenta and differ significantly from the predictions of the linear Luttinger liquid theory. We generalize the notion of the spin-charge separation to the nonlinear spectrum. This generalization leads to phenomenological relations between threshold exponents and the threshold energy.Comment: 25 pages, 11 figure

Spectrum of a spin chain with inverse square exchange

The spectrum of a one-dimensional chain of $SU(n)$ spins positioned at the static equilibrium positions of the particles in a corresponding classical Calogero system with an exchange interaction inversely proportional to the square of their distance is studied. As in the translationally invariant Haldane--Shastry model the spectrum is found to exhibit a very simple structure containing highly degenerate ``super-multiplets''. The algebra underlying this structure is identified and several sets of raising and lowering operators are given explicitely. On the basis of this algebra and numerical studies we give the complete spectrum and thermodynamics of the $SU(2)$ system.Comment: 9 pages, late

Exact diagonalisation of 1-d interacting spinless Fermions

We acquire a method of constructing an infinite set of exact eigenfunctions of 1--d interacting spinless Fermionic systems. Creation and annihilation operators for the interacting system are found and thereby the many--body Hamiltonian is diagonalised. The formalism is applied to several examples. One example is the theory of Jack polynomials. For the Calogero-Moser-Sutherland Hamiltonian a direct proof is given that the asymptotic Bethe Ansatz is correct.Comment: 33 page

Scattering of hole excitations in a one-dimensional spinless quantum liquid

Luttinger liquid theory accounts for the low energy boson excitations of one-dimensional quantum liquids, but disregards the high energy excitations. The most important high energy excitations are holes which have infinite lifetime at zero temperature. At finite temperatures they can be scattered by thermally excited bosons. We describe the interaction of the hole with the bosons by treating it as a mobile impurity in a Luttinger liquid. This approach enables us to evaluate the scattering probability at arbitrary interaction strength. In general, the result is expressed in terms of the hole spectrum, its dependence on the density and momentum of the fluid, and the parameters of the Luttinger liquid Hamiltonian. In the special case of Galilean invariant systems the scattering probability is expressed in terms of only the hole spectrum and its dependence on the fluid density. We apply our results to the problem of equilibration of one-dimensional quantum liquids

Implementation of Spin Hamiltonians in Optical Lattices

We propose an optical lattice setup to investigate spin chains and ladders. Electric and magnetic fields allow us to vary at will the coupling constants, producing a variety of quantum phases including the Haldane phase, critical phases, quantum dimers etc. Numerical simulations are presented showing how ground states can be prepared adiabatically. We also propose ways to measure a number of observables, like energy gap, staggered magnetization, end-chain spins effects, spin correlations and the string order parameter

Elementary excitations of the symmetric spin-orbital model: The XY limit

The elementary excitations of the 1D, symmetric, spin-orbital model are investigated by studying two anisotropic versions of the model, the pure XY and the dimerized XXZ case, with analytical and numerical methods. While they preserve the symmetry between spin and orbital degrees of freedom, these models allow for a simple and transparent picture of the low--lying excitations: In the pure XY case, a phase separation takes place between two phases with free--fermion like, gapless excitations, while in the dimerized case, the low-energy effective Hamiltonian reduces to the 1D Ising model with gapped excitations. In both cases, all the elementary excitations involve simultaneous flips of the spin and orbital degrees of freedom, a clear indication of the breakdown of the traditional mean-field theory.Comment: Revtex, two figure

Exact calculation of the ground-state dynamical spin correlation function of a S=1/2 antiferromagnetic Heisenberg chain with free spinons

We calculate the exact dynamical magnetic structure factor S(Q,E) in the ground state of a one-dimensional S=1/2 antiferromagnet with gapless free S=1/2 spinon excitations, the Haldane-Shastry model with inverse-square exchange, which is in the same low-energy universality class as Bethe's nearest-neighbor exchange model. Only two-spinon excited states contribute, and S(Q,E) is found to be a very simple integral over these states.Comment: 11 pages, LaTeX, RevTeX 3.0, cond-mat/930903

Hydrodynamics of cold atomic gases in the limit of weak nonlinearity, dispersion and dissipation

Dynamics of interacting cold atomic gases have recently become a focus of both experimental and theoretical studies. Often cold atom systems show hydrodynamic behavior and support the propagation of nonlinear dispersive waves. Although this propagation depends on many details of the system, a great insight can be obtained in the rather universal limit of weak nonlinearity, dispersion and dissipation (WNDD). In this limit, using a reductive perturbation method we map some of the hydrodynamic models relevant to cold atoms to well known chiral one-dimensional equations such as KdV, Burgers, KdV-Burgers, and Benjamin-Ono equations. These equations have been thoroughly studied in literature. The mapping gives us a simple way to make estimates for original hydrodynamic equations and to study the interplay between nonlinearity, dissipation and dispersion which are the hallmarks of nonlinear hydrodynamics.Comment: 18 pages, 3 figures, 1 tabl

Coagulation factor VIIa binds to herpes simplex virus 1‐encoded glycoprotein C forming a factor X‐enhanced tenase complex oriented on membranes

BackgroundThe cell membrane‐derived initiators of coagulation, tissue factor (TF) and anionic phospholipid (aPL), are constitutive on the herpes simplex virus type 1 (HSV1) surface, bypassing physiological regulation. TF and aPL accelerate proteolytic activation of factor (F) X to FXa by FVIIa to induce clot formation and cell signaling. Thus, infection in vivo is enhanced by virus surface TF. HSV1‐encoded glycoprotein C (gC) is implicated in this tenase activity by providing viral FX binding sites and increasing FVIIa function in solution.ObjectiveTo examine the biochemical influences of gC on FVIIa‐dependent FX activation.MethodsImmunogold electron microscopy (IEM), kinetic chromogenic assays and microscale thermophoresis were used to dissect tenase biochemistry. Recombinant TF and gC were solubilized (s) by substituting the transmembrane domain with poly‐histidine, which could be orientated on synthetic unilamellar vesicles containing Ni‐chelating lipid (Ni‐aPL). These constructs were compared to purified HSV1 TF±/gC ± variants.ResultsIEM confirmed that gC, TF, and aPL are simultaneously expressed on a single HSV1 particle where the contribution of gC to tenase activity required the availability of viral TF. Unlike viral tenase activity, the cofactor effects of sTF and sgC on FVIIa was additive when bound to Ni‐aPL. FVIIa was found to bind to sgC and this was enhanced by FX. Orientation of sgC on a lipid membrane was critical for FVIIa‐dependent FX activation.ConclusionsThe assembly of gC with FVIIa/FX parallels that of TF and may involve other constituents on the HSV1 envelope with implications in virus infection and pathology.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155933/1/jth14790-sup-0001-Supinfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155933/2/jth14790.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155933/3/jth14790_am.pd