Quantum computing is a new type of computing that uses the rules of quantum physics to process information in ways that traditional computers can’t.
Classical vs. quantum computers
- Classical computers (laptops, phones) use bits that are either 0 or 1.
- Quantum computers use qubits, which can be 0, 1, or both at the same time (a property called superposition).
Key ideas (in simple terms)
Superposition: A qubit can represent multiple possibilities at once, allowing many calculations to be explored simultaneously. To understand superposition in a simple way, let’s imagine a person on a ladder [ref. 1]; a person further up the ladder would have a higher potential energy than if they were much closer to the ground. However, unlike the person on a ladder example, atoms can possess more than one energy state simultaneously so the atom would behave like a person who is both occupying the ladder closer to the ground and also further up the ladder. Hence, the atom that is in this mixed energy state is known as “quantum superposition”. [see ref. 1]
Fig 1 – shows superposition in the qubit particle (represented by the sphere) [source ref. 1]
Entanglement: Qubits can become linked so that changing one instantly affects another, even if they’re far apart like if one qubit was placed on the Moon and another qubit was placed on Earth [source ref. 1]
Fig 2 – shows quantum entanglement between two qubit particles (each qubit particle represented by a sphere) [see ref. 1]
Quantum interference: The computer amplifies correct answers and cancels out wrong ones through carefully designed operations. Interference arises because of the wave-like properties of quantum particles like electrons and photons (a photon being a packet of energy of electromagnetic radiation, [see ref. 2 and 3]). When a particle is in a superposition of multiple states, these states can interact with each other that can lead to constructive or destructive interference [see ref. 2].
Fig 3 – shows constructive wave interference on the left and destructive wave interference on the right [see ref. 4]
Why this matters
Because of these properties, quantum computers can solve certain problems much faster than classical computers, such as:
- Breaking or analyzing some types of encryption
- Simulating molecules and materials (useful in medicine and chemistry)
- Optimizing complex systems (like logistics or traffic flow)
Important limitations
- Quantum computers are not faster at everything.
- They are very hard to build and control.
- Current quantum computers are experimental and prone to errors.
Simple analogy
If a classical computer checks solutions one at a time, a quantum computer explores many paths at once, then uses physics to guide itself toward the best answer.
Bottom line
Quantum computing doesn’t replace regular computers. Instead, it’s a powerful new tool designed to tackle specific problems that are extremely difficult or impossible for today’s machines.
Reference:
- https://www.nist.gov/quantum-information-science/quantum-computing-explained
- https://quantum.microsoft.com/en-us/insights/education/concepts/interference
- https://www.britannica.com/science/light
- https://kids.britannica.com/students/assembly/view/53869
