197 research outputs found
Dimension minimization of a quantum automaton
A new model of a Quantum Automaton (QA), working with qubits is proposed. The
quantum states of the automaton can be pure or mixed and are represented by
density operators. This is the appropriated approach to deal with measurements
and dechorence. The linearity of a QA and of the partial trace super-operator,
combined with the properties of invariant subspaces under unitary
transformations, are used to minimize the dimension of the automaton and,
consequently, the number of its working qubits. The results here developed are
valid wether the state set of the QA is finite or not. There are two main
results in this paper: 1) We show that the dimension reduction is possible
whenever the unitary transformations, associated to each letter of the input
alphabet, obey a set of conditions. 2) We develop an algorithm to find out the
equivalent minimal QA and prove that its complexity is polynomial in its
dimension and in the size of the input alphabet.Comment: 26 page
QED-Cavity model of microtubules implies dissipationless energy transfer and biological quantum teleportation
We refine a QED-cavity model of microtubules (MTs), proposed earlier by two
of the authors (N.E.M. and D.V.N.), and suggest mechanisms for the formation of
biomolecular mesoscopic coherent and/or entangled quantum states, which may
avoid decoherence for times comparable to biological characteristic times. This
refined model predicts dissipationless energy transfer along such "shielded"
macromolecules at near room temperatures as well as quantum teleportation of
states across MTs and perhaps neurons.Comment: 20 pages LATEX, three ps figures incorporate
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