On a method of solving SAT efficiently using the quantum Turing machine
Takashi Mihara, T. Nishino · 2002
In this paper, under an assumption that superposed physical states can be observed without collapsing the superposition, we show that the satisfiability problem (SAT, for short) can be solved by a quantum Turing machine in O(2/sup n/4/) time. This assumption is not widely accepted among physicists, however, (Aharonov et al., 1993) conjecture that a physical state actually exists as a superposition and can be observed without collapsing the superposition.>