A theoretical description of one- and two-color photon echo peak shifts (PEPS) and two-dimensional (2D) photon echo spectrum (PES) of a coupled chromophore system are presented. The effects of population relaxation in the one-exciton states on both the PEPS and the 2D PES are investigated. For values of time T shorter than the population relaxation time, a finite two-color peak shift magnitude ...

Flexible polymer knots with strict topological constraint of no segment crossing are studied by Monte Carlo simulations. The nonequilibrium relaxation time of an equilibrated polymer knot cut at one point to relax to a linear chain is measured. Prime knots up to 20 essential crossings from the groups (3(1),5(1),7(1),...), (4(1),6(1),8(1),...) and (5(2),7(2),9(2),...), (6(2),8(2),10(2),...) are ...

Recent advances have enabled a new wave of biomechanics measurements, and have renewed interest in selecting appropriate rheological models for soft tissues such as the liver, thyroid, and prostate. The microchannel flow model was recently introduced to describe the linear response of tissue to stimuli such as stress relaxation or shear wave propagation. This model postulates a power law relaxa...

We discuss the mass transport of a degenerate Fermi liquid ^{3}He film over a rough surface, and the film momentum relaxation time, in the framework of theoretical predictions. In the mesoscopic regime, the anomalous temperature dependence of the relaxation time is explained in terms of the interference between elastic boundary scattering and inelastic quasiparticle-quasiparticle scattering wit...

the thermally stimulated discharge (tsdc) current is studied for acrylonitrile butadiene rubber (nbr) loaded with different high abrasion furnace carbon black (haf). tsdc peak appears only for higher haf contents > 60phr (70 and 80phr of haf contents), the tsdc spectra consist of a sharp peak corresponding to a peak temperature tm which is slightly shifted to higher temperature for 70phr ...

We investigate the close connection between metastability of the reversible diffusion process X defined by the stochastic differential equation dXt =−∇F (Xt)dt+ √ 2εdWt, ε > 0, and the spectrum near zero of its generator −Lε ≡ ε∆−∇F ·∇, where F :R → R and W denotes Brownian motion on R. For generic F to each local minimum of F there corresponds a metastable state. We prove that the distribution...

Molecular dynamics simulations are employed to study the static and dynamic properties of macromolecules in dilute and semidilute solutions of a good solvent. The results are compared with dielectric spectroscopy experiments. Crossover concentrations, r*, that demarcate the dilute and semidilute regimes are identified. The shift from self-avoiding-walk to random-walk behavior is also studied. A...

The LH-1 antenna of the purple bacterium Rhodopseudomonas Viridis has been investigated using femtosecond pump-probe spectroscopy. We find that qualitatively the relaxation processes are comparable to those in Rhodobacter sphaeroides and Rhodospirillum rubrum. Both the spectral relaxation and depolarization take place in approximately 150 fs, which suggests that the excitations in the LH-1 ring...

We discuss the mass transport of a degenerate Fermi liquid He film over a rough surface, and the film momentum relaxation time, in the framework of theoretical predictions. In the mesoscopic regime, the anomalous temperature dependence of the relaxation time is explained in terms of the interference between elastic boundary scattering and inelastic quasiparticle-quasiparticle scattering within ...

We have exactly solved the relaxational dynamics of a model protein which possesses a kinetically perfect funnel-like energy landscape. We find that the dependence of the relaxation time, τ , on the density of states (DOS) and the energy level spacing distributions of the model displays several main types of behavior depending on the temperature T . This allows us to identify possible generic f...