Physicists at the University of Innsbruck in Austria have achieved controlled entanglement of 14 quantum bits (qubits), realizing the largest quantum register ever produced.

The scientists have almost doubled the record for the number of entangled quantum bits realized experimentally. They confined 14 calcium atoms in an ion trap (similar to a quantum computer), and then manipulated them with laser light. The internal states of each atom formed single qubits and a quantum register of 14 qubits.

They discovered that the decay rate of the atoms is not linear, but is proportional to the square of the number of the qubits. When several particles are entangled, the sensitivity of the system increases significantly in a process known as superdecoherence, which has rarely been observed in quantum processing.

Ref.: Rainer Blatt et al., 14-Qubit Entanglement: Creation and Coherence, Physical Review Letters, March 31, 2011