Determining the role of initial conditions in late time evolution is a key issue for theory nonequilibrium dynamics isolated quantum systems. Here we extend quenches to case which before quench system an excited state. In particular, show perturbatively size (and arbitrarily strong interactions among quasiparticles) that persistent oscillations one-point functions require presence one-quasipart...

A model describing the dynamics of crystal exciton states on a hexagonal lattice has been studied in [1]. The hamiltonian includes terms describing the movement of the exciton throughout the crystal. Here we generalize the hamiltonian by including first order couplings of such terms to the lattice phonon fields. A discussion of the ground state configuration of the exciton field as a function o...

A generalization of the Lieb-Schultz-Mattis theorem to higher dimensional spin systems is shown. The physical motivation for the result is that such spin systems typically either have long-range order, in which case there are gapless modes, or have only short-range correlations, in which case there are topological excitations. The result uses a set of loop operators, analogous to those used in ...

The scattering off a potential of finite rank (a sum of a finite number of separable potentials) is studied thoroughly in the neighborhood of infinity of potential strength; for this purpose we introduce the "strong coupling representation" by means of a canonical transformation. The same K matrix as for the infinitely strong repulsion is derived for the infinitely strong attraction. The differ...

We analyze the achievable precision for single-qubit gates that are based on Raman transitions between two near-degenerate ground states via a virtually excited state. In particular, we study the errors due to non-perfect adiabaticity and due to spontaneous emission from the excited state. For the case of non-adabaticity, we calculate the error as a function of the dimensionless parameter χ = ∆...