Dephasing with strings attached
Leonid Pryadko, University of California, Riverside
Is there a difference between the quantum dynamics of a "real" particle and a collective excitation, like that in a spin ice, which creates a measurable gauge field? I will argue that in the presence of weak dephasing, the answer depends on the quantity measured. Namely, compare quantum dynamics in the presence of weak Markovian dephasing for a particle hopping on a chain and for an Ising domain wall whose motion leaves behind a string of flipped spins. Exact solutions show that the two models on long chains have near identical transport responses to a uniform driving field. On the other hand, on finite-length chains, the broadening of discrete spectral lines is much more noticeable in the case of a domain wall.
This is joint work with Claudio Castelnovo, Mark I. Dykman, Roderich Moessner, and Vadim N. Smelyanskiy.