Regular computers, also known as classical or digital computers, use simple information units called bits, which can be either 1 or 0, like a light switch turned on or off.
To perform calculations, a quantum computer employs more sophisticated units known as qubits. These qubits can store more complex information states.
A qubit, like physicist Erwin Schrödinger's famous thought experiment about a cat being both dead and alive, can exist in a superposition of being both 1 and 0.
This unique property of qubits enables quantum computers to perform multiple calculations at the same time, whereas regular computers must do them one at a time.
Quantum computers have the potential to solve large and complex problems in fields such as chemistry and materials science that are currently intractable.
There is another disadvantage to quantum computers. Certain algorithms they can employ may endanger privacy by breaching the safeguards used to secure passwords and encrypted communications.