Information Technology Reference

In-Depth Information

I
NTRODUCTION

Moore's law describes the trend of computing hardware, in which the performance of the

microprocessor has doubled every two years as shown in Figure 1. But It is widely believed

that Moore's law for microprocessor performance will fail to hold in the next decade due to

the brick wall arising from fundamental physical limitations of the computational process.

Figure 1. Logic gate in the PC (A) and the Moore's law (B).

Instead of conventional computer systems, a quantum computer would store information

as either 1 and 0, or a quantum superposition of the two states. Such a "quantum bit," called a

qubit, allows for far greater flexibility than the binary system of conventional computers.

Specifically, it is considered that a quantum computer would be able to perform calculations

on a far greater order of magnitude than traditional computers.

However, R.Feynman[1986] discussed the possibility of a quantum computer by taking

an example of reversible computing in his paper and he pointed that computational energy

cost versus speed was limited by the energy dissipation during computation. According to

Feynman's idea, the computational speed is limited by minimum energy required to transport

a bit of information irreversibly between two devices, which prevents the speeding up of

quantum computation.

From the assumption that the evanescent photon is a superluminal particle called a

tachyon, the author studies the possibility of realization of a high performance computing

system by utilizing superluminal evanescent photons and he has also studied the possibility

that the microtubular structure of neurons in a human brain is functioning as a quantum

computational system that can attain higher efficient computation compared with

conventional silicon processors.