Keeping it together: Protecting entanglement from decoherence and sudden death
(PhysOrg.com) -- Decoherence can be metaphorically seen as a quantum fall from grace: When quantum bits, or qubits, are in superposition such as a single qubit simultaneously having both 1 and 0 values theyre said to be in a state of coherence. Any coupling with the environment whether intentional (as in an observation or measurement) or accidental causes the superposition to collapse into a state of decoherence in which only one of all possible coherent states exists. When two or more objects be they subatomic particles, atoms, molecules, or even small but macroscopic diamonds are in a state of entanglement, a change in a property of one instantaneously appears as the inverse change in the same property of the other, and does so instantaneously i.e., no time elapses regardless of the distance between the two entangled objects. Since entanglement is critical factor...