| • Science | • People | • Locations | • Timeline |
These hypothetical computing machines can be viewed as idealised analog computers which operate on real numbers and are differential, whereas digital computers are limited to computable numbers and are algebraic.
This means that idealised analog computers have a larger information dimension rate (see Information Theory), or potential computing domain, than do digital computers. This in theory enables analog computers to solve problems that are inextricable on digital computers.
Computer theorists often refer to these idealised analog computers as real computers (so called because they operate on the set of real numbers), in order to avoid confusion with real-world analog computers.
Real-world analog computers are far from attaining this ideal, with noise and other errors completely swamping any hypothetical computation-theoretic advantages.
Even assuming perfect Newtonian physics, the atomic nature of matter makes all mechanical linkages highly irregular at small scales. Unless the apparatus is at absolute zero, it will be perturbed by its own thermal vibrations, which are impossible to remove. Similarly, the discrete nature of classical electric charge makes perfectly accurate analog electronic computers impossible, even in the absence of the usual sources of noise such as shot noise and 1/f noiseSignal processing Digital signal processing 1/f noise is a signal or process with a frequency spectrum such that the spectral energy density is proportional to the reciprocal of the frequency. 1/f noise, sometimes pronounced as one over f noise is also ca.
Moving beyond classical physics, quantum physics effects such as the HeisenbergWerner Karl Heisenberg ( December 5, 1901 February 1, 1976) was a celebrated physicist and Nobel laureate, one of the founders of quantum mechanics. He was born in Wurzburg, Germany and died in Munich. Heisenberg was the head of Nazi Germany's nuclear ene uncertainty principleIn quantum physics, the Heisenberg uncertainty principle expresses a limitation on accuracy of (nearly) simultaneous measurement of observables such as the position and the momentum of a particle. It furthermore precisely quantifies the imprecision by pro and zero-point energyIn a quantum mechanical system such as the particle in a box or the quantum harmonic oscillator, the lowest possible energy is called the zero-point energy . Existence Does electromagnetic zero-point energy exist, and if so, are there any practical applic present even more problems for building a real computer, making it difficult or impossible to set up real-valued inputs and read out real-valued results.
Some physical theories such as loop quantum gravityLoop quantum gravity (LQG also known as loop gravity quantum geometry and canonical quantum general relativity, is a proposed quantum theory of spacetime which attempts to blend together the seemingly incompatible theories of quantum mechanics and general hypothesize that space and time themselves are quantized: this would also present major problems for building a "real computer".