Understanding quantum computing?Difference between classical computers and quantum computers?quantum computing be used for? Quantum cryptography

 Understanding quantum computing?

Quantum computing holds the promise to solve some of our planet's biggest challenges - in the areas of environment, agriculture, health, energy, climate, materials science, and others we haven't encountered yet. For some of these problems, classical computing is increasingly challenged as the size of the system grows.

Quantum computers are controllable quantum mechanical devices that exploit the properties of quantum physics to perform computations. For some computational tasks, quantum computing provides exponential speedups. These speedups are possible thanks to three phenomena from quantum mechanics: superposition, interference, and entanglement.

Just as bits are the fundamental object of information in classical computing, qubits (quantum bits) are the fundamental object of information in quantum computing. While a bit, or binary digit, can have value either 0 or 1, a qubit can have a value that is either 0, 1 or a quantum superposition of 0 and 1.

difference between classical computers and quantum computers.

A fundamental difference between classical computers and quantum computers is that programs in quantum computers are intrinsically probabilistic, whereas classical computers are usually deterministic. In quantum algorithms each possible result has an associated probability amplitude. After a measurement, one of the possible states is obtained with a certain probability. This fact contrasts with classical computing, where a bit can only be deterministically 0 or 1.

What can quantum computing be used for?

A quantum computer isn't a supercomputer that can do everything faster. One of the goals of quantum computing research is to study which problems can be solved by a quantum computer faster than a classical computer and how large the speedup can be.

Quantum computers do exceptionally well in problems that require calculation of many possible different combinations. These type of problems can be found across many areas.

Quantum cryptography

Cryptography is the technique of concealing confidential information by using physical or mathematical means, such as using a computational difficulty of solving a particular task. Classical cryptography relies on the intractability of problems such as integer factorization or discrete logarithms, many of which can be solved more efficiently using quantum computers.

Quantum computers vs quantum simulators

A quantum computer is a machine that combines the power of classical and quantum computing. The current quantum computers correspond to and hybrid model: a classical computer that controls a quantum processor.

The development of quantum computers is still in the infancy of their development. The quantum hardware and their maintenance are expensive, and most systems are located in universities and research labs. Where classical computers use familiar silicon-based chips, quantum computers use quantum systems such as atoms, ions, photons, or electrons. They use their quantum properties to represent bits that can be prepared in different quantum superpositions of 1 and 0. The technology is advancing, though, and limited public access to some systems is available.