1 7 Ju n 19 99 Persistence in the Zero - Temperature Dynamics of the Disordered Ising Model

Zero Temperature Dynamics of the Weakly-disordered Ising Model

The Glauber dynamics of the pure and weakly-disordered random-bond 2d Ising model is studied at zero-temperature. The coarsening length scale, L(t), is extracted from the equal time correlation function. In the pure case, the persistence probability decreases algebraically with L(t). In the disordered case, three distinct regimes are identified: a short time regime where the behaviour is pure-l...

Blocking and Persistence in the Zero-Temperature Dynamics of Homogeneous and Disordered Ising Models

Blocking and Persistence in the Zero-Temperature Dynamics of Homogeneous and Disordered Ising Models

A “persistence” exponent θ has been extensively used to describe the nonequilibrium dynamics of spin systems following a deep quench: for zero-temperature homogeneous Ising models on the d-dimensional cubic lattice Zd, the fraction p(t) of spins not flipped by time t decays to zero like t−θ(d) for low d; for high d, p(t) may decay to p(∞) > 0, because of “blocking” (but perhaps still like a pow...

A pr 2 00 0 Scaling and Persistence in the Two - Dimensional Ising Model

The spatial distribution of persistent spins at zero-temperature in the pure two-dimensional Ising model is investigated numerically. A persistence correlation length, ξ(t) ∼ t Z is identified such that for length scales r << ξ(t) the persistent spins form a fractal with dimension d f ; for length scales r >> ξ(t) the distribution of persistent spins is homogeneous. The zero-temperature persist...

ua nt - p h / 99 06 10 9 v 1 2 8 Ju n 19 99 Influence of Non - Resonant Effects on the Dynamics of Quantum Logic Gates at Room Temperature

We study numerically the influence of non-resonant effects on the dynamics of a single π-pulse quantum CONTROL-NOT (CN) gate in a macroscopic ensemble of four-spin molecules at room temperature. The four nuclear spins in each molecule represent a four-qubit register. The qubits are " labeled " by the characteristic frequencies, ω k , (k = 0 to 3) due to the Zeeman interaction of the nuclear spi...