2,098 research outputs found
Time optimal simultaneous control of two level quantum systems
In this paper, we solve the problem of simultaneously driving in minimum time
to arbitrary final conditions, N two level quantum systems subject to
independent controls. The solution of this problem is obtained via an explicit
description of the reachable set of the associated control system on SU(2). The
treatment generalizes previous results on the time optimal control of two level
quantum systems and suggests that similar techniques could be used to solve the
minimum time control problem for a larger class of right invariant systems on
Lie groups
Non-stationary quantum walks on the cycle
We consider quantum walks on the cycle in the non-stationary case where the
`coin' operation is allowed to change at each time step. We characterize, in
algebraic terms, the set of possible state transfers and prove that, as opposed
to the stationary case, it is possible to asymnptotically reach a uniform
distribution among the nodes of the associated graph.Comment: Revised version with minor change
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