Count with 14 quantum bits: Quantum Computer - Physicists Move limit of the previously possible

A new world record was reached Innsbruck quantum physicists: They have 14 quantum controlled entangle with each other and thus create the largest ever built quantum register. The experiment is not only an important step on the way to a future quantum computer, it also provides surprising insights into the phenomenon of quantum entanglement.

The concept of entanglement in 1935 by the Austrian Nobel laureate Erwin Schrodinger coined and describes a quantum mechanical phenomenon that can be clearly demonstrated in the experiment, but which is still not fully understood. Entangled particles can not be described as particles with defined conditions, but only as a single system. The entanglement of individual qubits with quantum computers can solve certain problems much faster than classical computers. "It is particularly difficult to understand entanglement, if many particles are in play," Thomas Monz, says a team of young researchers Rainer Blatt at the Institute of Experimental Physics, University of Innsbruck. "Our experiments provide us with many particles here new insights," added Journal.

World record: 14 quantum bits

The physicist Rainer Blatt to hold since 2005, the record for the number of entangled quantum bits, which were realized in an experiment. To date, there is no one succeeded in other things, fold to eight particles in a controlled manner and thus produce a "quantum byte". Now the Innsbruck researchers have that record again nearly doubled. In an ion trap they have 14 calcium atoms trapped, which they manipulate a quantum processor the same, with laser light. Internal states of each atom are looking at individual quantum bits together creates a quantum register with 14 processing units. This is the core of a future quantum computer. Physicists at the University of Innsbruck presented but also notes that with them the fault sensitivity is not linear but as is usually assumed by the number of particles increases quadratically. If several particles are entangled, so the sensitivity increases sharply. "This is called Superdekoharenz," says Thomas Monz. "In the quantum information of this phenomenon was hardly realized." It has not only for the construction of quantum computers significance, but also in the construction of highly accurate atomic clocks and quantum simulations.

Number of entangled particles to expand

The experimental physicist in the Innsbruck laboratory do it now, up to 64 to catch particles in ion traps. "We still can not fold this large number of ions," says Thomas Monz. "These results allow, however, a better understanding of the behavior of many entangled particles." Thus, perhaps soon even more particles are entangled.

A few weeks ago, researchers led by Rainer Blatt in the journal "Nature" also the first time demonstrated that ions could be crossed by means of electromagnetic coupling. Thus many small quantum register of a microchip efficiently linked together. Is Rainer Blatt, of the Research Directors at the Institute for Quantum Optics and Quantum Information of the Austrian Academy of Science (AAS) "This all important steps on the way to daily use for quantum information processing technologies are" convinced.

Publication:
Thomas Monz, Philipp Schindler, Julio T. Barreiro, Michael Chwalla, Daniel Nigg, William A. Coish, Maximilian Harlander, Wolfgang Hansel, Markus Hennrich, Rainer Journal: 14-Qubit Entanglement: Creation and Coherence. Physical Review Letters 106, 130 506 (2011). doi: 10.1103/PhysRevLett.106.130506

Source: Austrian Academy of Science