We present an optimal asymmetric 1 → 4 quantum cloner. Our derivation generalizes the constructions of optimal asymmetric 1 → 2 and 1 → 3 quantum cloners in [Quantum Inf. Comput 5, 583 (2005)]. We ...

Scientists in China have produced a theory for a quantum cloning machine able to produce several copies of the state of a particle at atomic or sub-atomic scale, or quantum state. The advance could ...

Time travel is often a way to change history in science fiction such as "Back to the Future" and "Looper." Now researchers suggest a certain kind of time machine could also possess another powerful ...

In some cases, machine breakdowns are more than just inconveniences -- in the military, they can spell disaster on the battlefield. Software is quickly eliminating those rude surprises, however. NASA ...