Basic Facts about Quantum Computing

Quantum computers employ the laws of quantum mechanics to process data. Quantum mechanics in itself is the study of matter and light on the atomic and subatomic scale. Quantum material behaves according to the laws of quantum mechanics. At the quantum level laws of classical physics largely don’t apply instead concepts such as probabilistic computation, superposition, and entanglement play a key role. These concepts provide the foundation for quantum algorithms that utilize the power of quantum computing to solve complex problems.

Classical computers use bits i.e. a stream of electrical or optical pulses representing 1s and 0s; that is, they are either a zero or one (two state) whereas quantum computers uses quantum bits or qubits which aren’t limited to two states; they can exist in superposition – two (or more) quantum states. Qubits represent atoms, ions, photons or electrons and their respective control devices that are working together to behave as a computer memory and a processor. Since a quantum computer can contain multiple states simultaneously, it has the potential to be more powerful than today’s most powerful supercomputers.

Let’s look at the three properties of quantum computing which are:

• Superposition
• Entanglement
• Interference

Superposition

As indicated above, qubits can represent numerous combinations or 1 and 0 at the same time the ability to simultaneously be in multiple sates which is referred to as superposition. To place qubits into superposition, researchers control them using either microwave beams or precision lasers.

Entanglement

This is the ability of two or more quantum particles to become entangled to each other i.e. they form a single system such that the quantum state of any one particle cannot be depicted independently of the quantum state of the other particles. This happens even if they are separated by very long distances. This implies that whatever input or operation you can apply to one particle correlates to other particles as well. To make a practical quantum computer, researchers have to device ways of making measurements indirectly to preserve the system’s integrity, and entanglement provides a potential answer.

Interference

This property of quantum computing can be used to control states and amplify the signals that are leading towards the right answer, while cancelling those signals that are leading to the wrong answer.

Quantum Decoherence

Although quantum computing is promising in terms of being able to deliver high computing power, they have some limitations that require more work and research in order to be able to utilize them. For example, they are extremely sensitive to noise and environmental effects.

The interaction of qubits with the environment can cause their quantum behaviour to decay and eventually disappear in what is called decoherence. Their quantum state is extremely delicate; any slightest change in temperature or vibration i.e. noise can cause them to spill out of superposition before they can perform their intended task hence scientists work to protect qubits from the outside world using either vacuum chambers and supercooled fridges.

You can also read: Electromagnetism and Its Applications

Knowing in advance how long quantum information will last before it is out of coherence is crucial to quantum computing.