Physicists at the
University
of Michigan have demonstrated how two separate atoms can communicate with a
sort of 'quantum intuition' which
Albert
Einstein referred to as "spooky".
In doing so, the researchers have made an advance towards super-fast quantum
computing and even a quantum internet.
The scientists used light to establish an "entanglement" between two atoms,
which were trapped one metre apart in separate enclosures.
"This link between remote atoms could be the fundamental piece of a radically
new quantum computer architecture," said Professor Christopher Monroe, the
principal investigator on the project who is now at the
University
of Maryland.
"Now that the technique has been demonstrated, it should be possible to scale
it up to networks of many interconnected components that will eventually be
necessary for quantum information processing."
David Moehring, the lead author of the paper who performed the research as a
University of Michigan graduate student, explained that the most important
aspect of the experiment is the distance between the two atoms.
"The separation of the quantum bits [qubits] in our entangled state is the
most important feature," he said.
"Localised entanglement has been performed in ion trap qubits in the past,
but to build a scalable quantum computer network (or a quantum internet) the
creation of entanglement schemes between remotely entangled qubit memories is
necessary."
The researchers used two atoms to function as qubits storing a piece of
information in their electron configuration. They then excited each atom,
inducing electrons to fall into a lower energy state and emit one photon, or one
particle of light, in the process.
The atoms, which were actually ions of the rare-earth element
ytterbium,
are capable of emitting two different types of photons of different wavelengths.
The type of photon released by each atom indicates the particular state of
the atom. Because of this, each photon was entangled with its atom.
By manipulating the photons emitted from each of the two atoms and guiding
them to interact along a fibre-optic thread, the researchers were able to detect
the resulting photon clicks and entangle the atoms.
Professor Monroe explained that the fibre-optic thread was necessary to
establish entanglement of the atoms. But the fibre could be severed and the two
atoms would remain entangled, even if one were "carefully taken to Jupiter".
Do you agree?
Have your say on this article