. It is described by a state vector in a 2-level
Physical representation
Any two-level system can be used as a qubit
Multilevel systems can
be used as well, if they possess two states that can be effectively
decoupled from the rest (e.g., ground state and first excited state of
a nonlinear oscillator).
There are various proposals. Several physical
implementations which approximate two-level systems to various degrees
were successfully realized.
Similarly to a classical bit where the
state of a transistor in a processor, the magnetization of a surface in
a hard disk and the presence of current in a cable can all be used to
represent bits in the same computer, an eventual quantum computer is
likely to use various combinations of qubits in its design.
Variations of the qubit
Similar to the qubit, a qurit is a unit of quantum information in a 3-level quantum system.
This is analogous to the unit of classical information trit. The term "qudit" is used to denote
a unit of quantum information in a d-level quantum system. A quiet qubit refers to a qubit
that can be efficiently decoupled from the environment.
A Quantum computer could be a billion times faster than a Pentium lll computer.
The dream of someday performing complicated algorithms more
efficiently and faster using advanced quantum mechanical properties, is
not yet a reality, but the teams of physicists are taking a
step-by-step approach, finding success in small accomplishments in a
qubit that lasts only a microsecond.
Previous qubits or artificial atoms were only able to maintain a
quantum state for a mere nanosecond, so the researchers were able
to create a quantum bit that lasts a thousand times longer.
Each qubit is made up of a billion aluminum atoms, which performs
like a single atom that can occupy two different energy states. A
standard computer holds single bits of memory in a single state, with
each bit only capable of storing either a one or a zero.
Scientists can use super qubits in a “superposition” of multiple
states at the same time, which can store more information and powerful
processing functions. The two mechanical qubits solve problems by
communicating with one another through connecting wires, transmitting
photons on a “quantum bus.”
Although, the two connected qubits can only process basic
algorithms, researchers have great hopes to create and link up
additional qubits in the future. Researchers also plan to develop
qubits that can last longer than the current microsecond.
Qubit Operation
Two beam splitters, B1 and
B2, are in one plane. The mirrors, M1 and M2, are opposite to each
other.
There are two Photon Detectors - one on the top and the other on
the right side.
A photon is incident from the left side.
RESOURCE LINKS
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DR VACCARO
CODE PROJECT
ATOMIC QC
SCIENCEWISE
OVERVIEW
As the computer industry continues increasing the density of
transistors on silicon chips a scale will be reached where quantum
mechanical effects will introduce fundamental randomness into the
chip's logic operations. This scale represents the ultimate limit for
classical computing technology. These quantum effects whilst presenting
a barrier, also provide a way forward.
Quantum computing attempts to
control and exploit quantum effects not as a means to cram more bits
into silicon, but to support a new kind of computation with
qualitatively different algorithms based on quantum principles.
The potentially awesome power of quantum computing is due to the
numerous parameters needed to define the state of a quantum system.
''By the year 2030 or sooner quantum computers will make our present computers seem stone age in comparison for processing and capabilities.'' - Site author
