8 research outputs found
Coherent Processing of a Qubit Using One Squeezed State
We use a single squeezed state to represent a qubit, which can be coherently
processed in a deconvolution picture (DP) in the presence of noise. We avail
ourselves of the fact that when evolution is governed by a quadratic
dissipative equation, there exists a basis of squeezed states that evolves to
another basis of such states in the DP. An operator acts as an impurity filter,
restoring the coherence lost from the inexorable interactions of the qubit with
its surroundings.Comment: Published version includes one new section and some reorganizatio
Positive Quantum Brownian Evolution
Using the independent oscillator model with an arbitrary system potential, we
derive a quantum Brownian equation assuming a correlated total initial state.
Although not of Lindblad form, the equation preserves positivity of the density
operator on a restricted set of initial states