Quantum computing is exciting and important—really!

Matt Turlington, Lee E. Sattler, Dante J. Pacella +2 more

Charles Day

Quantum computing, say its champions, promises prodigious power. its basic currency, the qubit, exists in an on/off limbo until it's read out, so if you could operate on kqubits, a potentially vast space of 2kvalues opens up for computation. the fundamental operation on qubits is a rotation. Combine the rotations, and you have logic gates. Combine the logic gates, and you have algorithms. In principle, these algorithms can perform calculations far beyond classical computing's conceivable reach

Ronald de Wolf

Ahmed Banafa

Quantum computing is the area of study focused on developing computer technology based on the principles of quantum theory. The quantum computer, following the laws of quantum physics, would gain enormous processing power through the ability to be in multiple states and to perform tasks using all possible permutations simultaneously. In a quantum computer, a number of elemental particles such as electrons or photons can be used with either their charge or polarization acting as a representation of 0 and/or 1. Each of these particles is known as a quantum bit, or qubit; the nature and behavior of these particles form the basis of quantum computing. The biggest and the most important one is the ability to factorize a very large number into two prime numbers. That is really important because that is what almost all encryptions of internet applications use and can be de-encrypted.

Rajendra Kumar Bera

Hayato Goto, Taro Kanao

Adiabatic quantum computation (AQC), which is particularly useful for combinatorial optimization, becomes more powerful by using excited states, instead of ground states. However, the excited-state AQC is prone to errors due to dissipation. Here we propose the excited-state AQC started with the most stable state, i.e., the vacuum state. This counterintuitive approach becomes possible by using a driven quantum system, or more precisely, a network of Kerr-nonlinear parametric oscillators (KPOs). By numerical simulations, we show that some hard instances, where standard ground-state AQC with KPOs fails to find their optimal solutions, can be solved by the present approach, where nonadiabatic transitions are rather utilized. We also show that the use of the vacuum state as an initial state leads to robustness against errors due to dissipation, as expected, compared to the use of a really excited (nonvacuum) state as an initial state. Thus, the present work offers new possibilities for quantum computation and driven quantum systems.