First International Conference on Unconventional Models of Computation UMC'98. An Unconventional Review
Review of the First International Conference on Unconventional Models of Computation UMC'98, Auckland, New Zealand, 5-9 January, 1998
quant-ph↗
arXiv subjects
Karl Svozil
Publications and source records attributed to Karl Svozil.
The Church-Turing thesis as a guiding principle for physics
Two aspects of the physical side of the Church-Turing thesis are discussed. The first issue is a variant of the Eleatic argument against motion, dealing with Zeno squeezed time cycles of computers. The second argument reviews the issue of one-to-one computation, that is, the bijective (unique and reversible) evolution of computations and its relation to the measurement process.
quant-ph↗
Experimental realization of any discrete operator
A straightforward argument shows that, by allowing counterfactual elements of physical reality, any arbitrary discrete finite-dimensional operator corresponds to an observable.
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Undecidability everywhere?
We discuss the question of if and how undecidability might be translatable into physics, in particular with respect to prediction and description, as well as to complementarity games.
chao-dyn↗
Quantum algorithmic information theory
The agenda of quantum algorithmic information theory, ordered `top-down,' is the quantum halting amplitude, followed by the quantum algorithmic information content, which in turn requires the theory of quantum computation. The fundamental atoms processed by quantum computation are the quantum bits which are dealt with in quantum information theory. The theory of quantum computation will be based upon a model of universal quantum computer whose elementary unit is a two-port interferometer capable of arbitrary $U(2)$ transformations. Basic to all these considerations is quantum theory, in particular Hilbert space quantum mechanics.
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Stronger-than-quantum correlations
After an elementary derivation of Bell's inequality, several forms of expectation functions for two-valued observables are discussed. Special emphasis is given to hypothetical stronger-than quantum expectation functions which give rise to a maximal violation of Bell's inequality.
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Consistent use of paradoxes in deriving constraints on the dynamics of physical systems and of no-go-theorems
The classical methods used by recursion theory and formal logic to block paradoxes do not work in quantum information theory. Since quantum information can exist as a coherent superposition of the classical ``yes'' and ``no'' states, certain tasks which are not conceivable in the classical setting can be performed in the quantum setting. Classical logical inconsistencies do not arise, since there exist fixed point states of the diagonalization operator. In particular, closed timelike curves need not be eliminated in the quantum setting, since they would not lead to any paradoxical outcome controllability. Quantum information theory can also be subjected to the treatment of inconsistent information in databases and expert systems. It is suggested that any two pieces of contradicting information are stored and processed as coherent superposition. In order to be tractable, this strategy requires quantum computation.
quant-ph↗
Quantum electrodynamics in the squeezed vacuum state: Feynman rules and corrections to the electron mass and anomalous magnetic moment
Due to the nonvanishing average photon population of the squeezed vacuum state, finite corrections to the scattering matrix are obtained. The lowest order contribution to the electron mass shift for a one mode squeezed vacuum state is given by $δm(Ω,s)/m=α(2/π)(Ω/m)^2\sinh^2(s)$, where $Ω$ and $s$ stand for the mode frequency and the squeeze parameter and $α$ for the fine structure constant, respectively. The correction to the anomalous magnetic moment of the electron is $δa_e(s)=-(4α/π)\sinh^2(s)$.
hep-ph↗