A qubit in quantum computing is the basic fundamental unit. It is similar to a bit in a classical computer or the current computers that are in use extensively. Qubits provide exceptional power to quantum computation, making them more capable than traditional computing devices.
Importance of a qubit in Quantum Computing:
However, qubits exhibit unique features that enable them to perform extremely complex calculations that are difficult for even classical computers to accomplish.
Furthermore, these quantum computers, due to the presence of qubits as the basic unit of information, can perform specific calculations in a fraction of a second, which otherwise takes thousands of years with classical computers.
Let’s consider a real-world example to understand the concept better. For instance, if there is a challenge to distinguish a popular face from a multitude of unknown faces. In such cases, classical computers check each individual one by one, taking very long; in contrast, quantum computers can check all at once.
Some Salient Features of Quantum Computers:
Superposition:
Generally, computers in use today employ bits that encode information as either 0s or 1s. In contrast, quantum computers do not use bits but use qubits or quantum bits, a phenomenon from quantum mechanics. Qubits are exceptional because instead of existing in 0 or 1 form, can exists in combination, meaning can stay in 0 or 1 states simultaneously. Such existence widens the capabilities of quantum computers to process multiple tasks simultaneously while increasing the speed of computation, especially for specific issues.
Entanglement:
Qubits can entangle with one another. It means that a particular qubit state determines the state of another qubit as it is related directly, despite the distance gap between the two qubits. Due to this feature, it allows powerful correlation and exhibits speed and parallelism. The correlation widens the quantum computing application to quantum cryptography, quantum error correction, and quantum teleportation. It is another essential feature of a qubit in quantum computing.
Measurement:
Qubits are fragile. Hence, measuring them makes them cease to exist in superposition and allows them to occupy a definite value. It stays in a definite state until it is acted upon again. Though measuring a qubit disturbs its delicate quantum state, it aids in extracting the information from a qubit, delivering the classical result.
As a result, measuring helps humans to fetch the necessary classical result, which helps attain a definite answer that is easy to understand. Another importance of measuring is that it eases the difficulty of measuring the reading of qubits during superposition. Hence, it is the last step in quantum computation, enabling the extraction of meaningful results of the quantum state. Any computation needs a meaningful result, and measurement helps in that.
Quantum Gates:
To understand precisely, we can compare quantum gates in quantum computers with logic gates such as AND, NOT, OR in traditional computers. They primarily involve manipulating qubits that aid in changing their states while being cautious in not destroying the qubit and facilitating the running of quantum algorithms. Importantly, they help preserve the basic properties of qubits, such as superposition and entanglement. Finally, they can perform computations in a quantum algorithm.
Difference between Conventional Computers and Quantum Computers:
Conventional computers use either 0s or 1s, making them answer questions sequentially. While a qubit in quantum computing exists in superposition, giving them the capability to process and to exist in 2ⁿstates simultaneously. It widens the processing capabilities of qubits to perform parallel computation. With traditional computers trying many combinations for the perfect solution, it can take millions of years to solve a problem. On the contrary, qubits combining entanglement with quantum interference can compute the correct solutions much more quickly.
Because of all these features, quantum computers might introduce revolutionary changes in the field of computing, offering to explore new solutions across various specific fields, including large-scale simulations, drug discovery, and cryptography.