What is Quantum Computing?
Quantum refers to the discrete, smallest units in which certain physical
properties, such as energy, can exist or be exchanged.
Think of quantum as nature's ultimate Lego bricks. At the microscopic level,
some physical properties don't change continuously; instead, they occur in
specific, discrete amounts.
These tiny quantum systems can possess special properties—such as
superposition and entanglement—that quantum computers harness to
process information in ways that are fundamentally different from standard,
bit-based computers.
Unlike classical computers, which typically use semiconductor transistors to
represent bits, quantum computers can use different physical quantum
systems as qubits. Companies and research groups around the world are
developing several competing approaches.
Some of the important approaches include:
Electrons — Tiny Quantum Magnets
Companies such as Intel are developing spin qubits, where information is
encoded in the spin state of individual electrons confined in silicon.
Carefully controlled electrical and microwave signals can manipulate these
spin states, allowing them to represent and process quantum information.
Photons — Particles of Light
Companies such as PsiQuantum are developing quantum computers based on
photons, or particles of light.
Photons can be generated, manipulated, and sent through tiny optical circuits
to carry quantum information. One advantage of photonic systems is that they
can operate without the extremely low temperatures required by
superconducting qubits.
Superconducting Qubits — Artificial Atoms
Companies such as IBM and Google use superconducting qubits.
These are tiny electrical circuits made from superconducting materials and
fabricated on chips. When cooled to extremely low temperatures, these
circuits exhibit quantum behaviour and can act like artificial atoms, with
controllable quantum states that can be used as qubits.
