Physics – Quantum Physics
Scientific paper
1996-11-17
Physics
Quantum Physics
12 pages
Scientific paper
We define formally decohered quantum computers (using density matrices), and present a simulation of them by a probabalistic classical Turing Machine. We study the slowdown of the simulation for two cases: (1) sequential quantum computers, or quantum Turing machines(QTM), and (2) parallel quantum computers, or quantum circuits. This paper shows that the computational power of decohered quantum computers depends strongly on the amount of parallelism in the computation. The expected slowdown of the simulation of a QTM is polynomial in time and space of the quantum computation, for any non zero decoherence rate. This means that a QTM subjected to any amount of noise is worthless. For decohered quantum circuits, the situation is more subtle and depends on the decoherence rate, eta. We find that our simulation is efficient for circuits with decoherence rate higher than some constant, but exponential for general circuits with decoherence rate lower than some other constant. Using computer experiments, we show that the transition from exponential cost to polynomial cost happens in a short range of decoherence rates, and exhibit the phase transitions in various quantum circuits.
Aharonov Dorit
Ben-Or Michael
No associations
LandOfFree
Polynomial Simulations of Decohered Quantum Computers does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Polynomial Simulations of Decohered Quantum Computers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Polynomial Simulations of Decohered Quantum Computers will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-649122