  In this paper the authors extend [1] and provide more details of how the
brain may act like a quantum computer. In particular, positing the difference
between voltages on two axons as the environment for ions undergoing spatial
superposition, we argue that evolution in the presence of metric perturbations
will differ from that in the absence of these waves. This differential state
evolution will then encode the information being processed by the tract due to
the interaction of the quantum state of the ions at the nodes with the
`controlling' potential. Upon decoherence, which is equal to a measurement, the
final spatial state of the ions is decided and it also gets reset by the next
impulse initiation time. Under synchronization, several tracts undergo such
processes in synchrony and therefore the picture of a quantum computing circuit
is complete. Under this model, based on the number of axons in the corpus
callosum alone [2], we estimate that upwards of 15 million quantum states might
be prepared and evolved every millisecond in this white matter tract, far
greater processing than any present quantum computer can accomplish.
