Abstract
Computational capabilities are reaching their limits with the current technology. Quantum computing is the answer to this limitation. It has unraveled new possibilities of solving the unsolvable and computationally hard problems within a feasible time frame. In this chapter, the authors have discussed the basics of quantum computing, which include the need for quantum computers and how it internally works without getting into too much mathematics for an introductory understanding. The authors have also discussed different technologies in which the scientific communities and industries are working to make these computers feasibly work and the different programming techniques and tools available to implement the algorithms in these computers and the testbeds available to common people for testing the feasibilities of their programs.
TopFrom Classical Computers To Quantum Computers
Whenever we are talking about computers, the basic understanding of computation is based on the concept of the electrical signals passed through the computer system poising high and low voltage signals which are interpreted as 1 and 0 respectively. This whole concept of computing is based on the classical understanding of information in the form of these values known as bits. The classical bits are the energy states that are used to communicate with the computer system and the same is stored in some media in the form of magnetic charge or optical information which is translated to the electrical signals for any kind of computation.
Key Terms in this Chapter
Photonic Gate: In photonic quantum computing, the qubits are properties related to photons. That may be the presence of the photon itself or the uncertainty in a particular state of the photon.
Ion Trap: In ion traps, the qubits are atoms that are missing some electrons and therefore have a net positive charge. We can then trap these ions in electromagnetic fields, and use lasers to move them around and entangle them. Such ion traps are comparable in the size to the qubit chips. They also need to be cooled but not quite as much, “only” to temperatures of the few Kelvins.
Topological Quantum Computing: In topological quantum computers, information will be stored in conserved properties of “quasi-particles,” which are collective motions of particles. The great thing about this is that this information would be very robust to decoherence.
Nitrogen-Vacancy System: In the nitrogen-vacancy system, the qubits are placed in the structures of a carbon crystal where a carbon atom is replaced by a nitrogen atom.
Superconducting Gate: Superconducting qubits are the most widely used and most advanced type of qubits. They are basically small currents on a chip. The two-state qubits can be physically realized either by the distribution of the charge or by the flux of the current.
Semiconducting Qubits: Semiconducting qubits are very similar to superconducting qubits, but here the qubits are either the spin or charge of a single electron.
Quantum Annealing: Quantum annealing is the process of finding the minimum energy state of something where instead of focusing on trying to find the minimum energy state, a sample from any low energy state is taken and try and characterize the shape of the energy landscape. This is useful for applications like machine learning where we try to build a probabilistic representation of the world and these samples give us information about what the model looks like now and these models can be used over time.
Quantum Entanglement: Quantum entanglement comes into play when there is more than one particle is participating in the computation. When the quantum particles are in an entangled state, they are linked in the strongest possible way even if they are far apart from each other. once they are entangled, an invisible link is generated among them irrespective of how far apart they are. The entanglement among these quantum particles gives rise to the enormous number of possibilities of states for quantum communication.