Is teleportation possible? Yes, in the quantum world
Quantum teleportation is an important step in improving quantum computing


Date:
June 19, 2020
Source:
University of Rochester
Summary:
Researchers are exploring new ways of creating quantum-mechanical
interactions between distant electrons. The research marks an
important advance in quantum computing.



FULL STORY ========================================================================== "Beam me up" is one of the most famous catchphrases from the Star
Trek series.

It is the command issued when a character wishes to teleport from a
remote location back to the Starship Enterprise.


========================================================================== While human teleportation exists only in science fiction, teleportation
is possible in the subatomic world of quantum mechanics -- albeit not
in the way typically depicted on TV. In the quantum world, teleportation involves the transportation of information, rather than the transportation
of matter.

Last year scientists confirmed that information could be passed between
photons on computer chips even when the photons were not physically
linked.

Now, according to new research from the University of Rochester and
Purdue University, teleportation may also be possible between electrons.

In a paper published in Nature Communications and one to appear in
Physical Review X, the researchers, including John Nichol, an assistant professor of physics at Rochester, and Andrew Jordan, a professor of
physics at Rochester, explore new ways of creating quantum-mechanical interactions between distant electrons. The research is an important
step in improving quantum computing, which, in turn, has the potential
to revolutionize technology, medicine, and science by providing faster
and more efficient processors and sensors.

'SPOOKY ACTION AT A DISTANCE' Quantum teleportation is a demonstration
of what Albert Einstein famously called "spooky action at a distance" --
also known as quantum entanglement. In entanglement -- one of the basic
of concepts of quantum physics -- the properties of one particle affect
the properties of another, even when the particles are separated by a
large distance. Quantum teleportation involves two distant, entangled
particles in which the state of a third particle instantly "teleports"
its state to the two entangled particles.



========================================================================== Quantum teleportation is an important means for transmitting information
in quantum computing. While a typical computer consists of billions of transistors, called bits, quantum computers encode information in quantum
bits, or qubits. A bit has a single binary value, which can be either
"0" or "1," but qubits can be both "0" and "1" at the same time. The
ability for individual qubits to simultaneously occupy multiple states underlies the great potential power of quantum computers.

Scientists have recently demonstrated quantum teleportation by using electromagnetic photons to create remotely entangled pairs of qubits.

Qubits made from individual electrons, however, are also promising for transmitting information in semiconductors.

"Individual electrons are promising qubits because they interact very
easily with each other, and individual electron qubits in semiconductors
are also scalable," Nichol says. "Reliably creating long-distance
interactions between electrons is essential for quantum computing."
Creating entangled pairs of electron qubits that span long distances,
which is required for teleportation, has proved challenging, though:
while photons naturally propagate over long distances, electrons usually
are confined to one place.



========================================================================== ENTANGLED PAIRS OF ELECTRONS In order to demonstrate quantum teleportation using electrons, the researchers harnessed a recently developed technique
based on the principles of Heisenberg exchange coupling. An individual
electron is like a bar magnet with a north pole and a south pole that can
point either up or down. The direction of the pole -- whether the north
pole is pointing up or down, for instance -- is known as the electron's magnetic moment or quantum spin state. If certain kinds of particles
have the same magnetic moment, they cannot be in the same place at the
same time. That is, two electrons in the same quantum state cannot sit
on top of each other. If they did, their states would swap back and
forth in time.

The researchers used the technique to distribute entangled pairs of
electrons and teleport their spin states.

"We provide evidence for 'entanglement swapping,' in which we create entanglement between two electrons even though the particles never
interact, and 'quantum gate teleportation,' a potentially useful technique
for quantum computing using teleportation," Nichol says. "Our work shows
that this can be done even without photons." The results pave the way
for future research on quantum teleportation involving spin states of all matter, not just photons, and provide more evidence for the surprisingly
useful capabilities of individual electrons in qubit semiconductors.


========================================================================== Story Source: Materials provided by University_of_Rochester. Original
written by Lindsey Valich. Note: Content may be edited for style and
length.


========================================================================== Journal References:
1. Haifeng Qiao, Yadav P. Kandel, Sreenath K. Manikandan, Andrew
N. Jordan,
Saeed Fallahi, Geoffrey C. Gardner, Michael J. Manfra, John
M. Nichol.

Conditional teleportation of quantum-dot spin states. Nature
Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-16745-0
2. Haifeng Qiao, Yadav P. Kandel, Kuangyin Deng, Saeed Fallahi,
Geoffrey C.

Gardner, Michael J. Manfra, Edwin Barnes, John M. Nichol. Coherent
multi- spin exchange in a quantum-dot spin chain. Physical Review X,
2020 [link] ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200619115707.htm

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