Environmentally induced quantum dynamical phase transition in the spin swapping operation

GONZALO A. ÁLVAREZ; ERNESTO P. DANIELI; PATRICIA R. LEVSTEIN; HORACIO M. PASTAWSKI

JOURNAL OF CHEMICAL PHYSICS

American Institute of Physics

Lugar: New York; Año: 2006 vol. 124 p. 1 - 13

0021-9606

-Environmentally induced quantum dynamical phase transition in the spin swapping operation G. A. Álvarez, E. P. Danieli, P. R. Levstein, and H. M. Pastawski The Journal of Chemical Physics 124, 1 (2006) http://arxiv.org/abs/cond-mat/0511639 We introduce a microscopic Hamiltonian model of a two level system with many-body interactions with an environment whose excitation dynamics is fully solved within the Keldysh formalism. If a particle starts in one of the states of the isolated system, the return probability oscillates with the Rabi frequency $omega_{0}$. For weak interactions with the environment $1/ au_{mathrm{SE}}<2omega_{0},$ we find a slower oscillation whose amplitude decays with a decoherence rate $1/ au_{phi}=1/(2 au_{mathrm{SE}% })$. However, beyond a finite critical interaction with the environment, $1/ au_{mathrm{SE}}>2omega_{0}$, the decoherence rate becomes $1/ au_{phi}propto(omega_{0}^{2}) au_{mathrm{SE}}$. The oscillation period diverges showing a emph{quantum dynamical phase transition}to a Quantum Zeno phase.