Eight basic components of memory of an electronic computer can be in 256
states: 00000000, 00000001, 00000010, ..., 11111111, and the best a
single CPU electronic computer can do is to process
them one by one. By contrast, eight basic components
of memory of a quantum computer can be in a "superposition" of
all these states, and all these states can be processed at the same time.
There is even no restriction to 8 components with 256
states; the same will work for 64 components and their
18446744073709551616 states! Quantum computing promises
massively parallel computations, often with an exponential speedup
comparing to classical computers. A quantum computer
running Shor's factorization algorithm (discovered in
1994) could easily break the encryption currently used for
various "secure" transactions over the Internet; on the other hand
quantum phenomena offer new ways of securing
information. There are also suggestions that these new
tremendously powerful computers could run on as little energy as
an electronic watch.
Quantum computing is an area of active research in academic centers and
military and national security research institutes around the world.
Basic principles behind quantum computing (such as
existence of superposition) have been confirmed but a
technology needs to be developed to construct anything
beyond toy systems which exist today. Simultaneously, research continues on
developing quantum algorithms for practical applications, because
classical algorithms are not easily adaptable for more
efficient execution in the new paradigm.
March 2009