ua nt - p h / 01 02 09 2 v 3 2 5 Ju n 20 02 The quantum absolute phase observable

ua nt - p h / 01 01 02 8 v 1 5 J an 2 00 1 QUANTUM LOGICS

ua nt - p h / 01 07 09 0 v 1 1 8 Ju l 2 00 1 QUANTUM MEASUREMENT , INFORMATION , AND COMPLETELY POSITIVE MAPS

Axiomatic approach to measurement theory is developed. All the possible statistical properties of apparatuses measuring an observable with nondegenerate spectrum allowed in standard quantum mechanics are characterized.

ua nt - p h / 02 06 14 4 v 3 2 4 Ju n 20 02 General Qubit Errors Cannot Be Corrected Subhash Kak

Error correction in the standard meaning of the term implies the ability to correct all small analog errors and some large errors. Examining assumptions at the basis of the recently proposed quantum error-correcting codes, it is pointed out that these codes can correct only a subset of errors, and are unable to correct small phase errors which can have disastrous consequences for a quantum comp...

ua nt - p h / 01 01 02 8 v 2 6 J an 2 00 1 QUANTUM LOGICS

ar X iv : q ua nt - p h / 02 07 04 4 v 3 2 9 Ju l 2 00 8 Shouldn ’ t there be an antithesis to quantization ? ∗

We raise the possibility of developing a theory of constructing quantum dynamical observables independent from quantization and deriving classical dynamical observables from pure quantum mechanical consideration. We do so by giving a detailed quantum mechanical derivation of the classical time of arrival at arbitrary arrival points for a particle in one dimension.