3 research outputs found
Survival Probability of a Ballistic Tracer Particle in the Presence of Diffusing Traps
We calculate the survival probability P_S(t) up to time t of a tracer
particle moving along a deterministic trajectory in a continuous d-dimensional
space in the presence of diffusing but mutually noninteracting traps. In
particular, for a tracer particle moving ballistically with a constant velocity
c, we obtain an exact expression for P_S(t), valid for all t, for d<2. For d
\geq 2, we obtain the leading asymptotic behavior of P_S(t) for large t. In all
cases, P_S(t) decays exponentially for large t, P_S(t) \sim \exp(-\theta t). We
provide an explicit exact expression for the exponent \theta in dimensions d
\leq 2, and for the physically relevant case, d=3, as a function of the system
parameters.Comment: RevTeX, 4 page
Superconductivity from correlated hopping
We consider a chain described by a next-nearest-neighbor hopping combined
with a nearest-neighbor spin flip. In two dimensions this three-body term
arises from a mapping of the three-band Hubbard model for CuO planes to a
generalized model and for large O-O hopping favors resonance-valence-bond
superconductivity of predominantly -wave symmetry. Solving the ground state
and low-energy excitations by analytical and numerical methods we find that the
chain is a Luther-Emery liquid with correlation exponent , where is the particle density.Comment: 10 pages, RevTeX 3.0 + 2 PostScript figs. Accepted for publication in
Phys.Rev.