Although quantum entanglement was formerly thought of as the "freaky kid" of physics, it has gone a very far way since Einstein dismissed it as "spooky activity at a distance."
In a recent experiment, researchers successfully sent
entangled photons over 1,200 kilometres from a satellite to Earth (750 miles).
The previous record for entanglement dispersion, which only extended up to 100
kilometres, is shattered by this.
As stated in the study's principal author Juan Yin's statement, "We have shown the distribution of two entangled photons from a satellite to two ground stations that are 1,203 kilometres apart." Juan Yin is a physicist at the Science and Technology University of China in Shanghai.
"Quantum networks and their theories must be tested
across long distances," says the author.
Quantum entanglement is a weird phenomena that happens when
two or more particles join up and instantly impact each other, regardless of
how far away they are. Einstein once laughed it off.
Quantum entanglement states that if we, for instance, cause
one particle to spin in a clockwise manner, the other particle, whether it be
one centimetre away or at the other end of the cosmos, will spin in an
anti-clockwise direction.
While quantum entanglement has become a crucial tool for
examining how information may be conveyed over great distances, Einstein was
not so confident that such strange particle behaviour was truly taking place in
the real-life Universe.
This is already useful for applications in supercomputing and
hacker-proof banking.
However, scientists have only been able to disperse entangled
particles up to a hundred kilometres away. The challenge with long-distance
entanglement is that the particles frequently wander off as they move over open
spaces or through optical fibres.
There are a few approaches physicists might take to solve
this issue. Breaking the transmission line into smaller pieces and swapping,
purifying, and storing the quantum information along the optical fibre are two
methods of enhancing particle dispersal.
This is all well and good, but when information needs to be
kept for a long time and accessed rapidly, getting all of these components to
operate together flawlessly is still a challenge.
Fortunately, utilising laser beams and satellite technology, Yin
and his team have now revealed a superior method for building worldwide quantum
networks.
The researchers set out to connect with three ground stations
around China using entangled photons with the aid of Micius, the first
quantum-enabled satellite deployed last year (light particles).
The distance between each station and the orbiting satellite
ranged from 500 to 2,000 kilometres. The stations were each around 1,200
kilometres apart.
They divided the satellite's laser beam into two separate
polarised states using a beam splitter. The entangled photons were sent using
one of these split beams, and received using the other.
The photons kept their entanglement throughout the lengthy
round-trip and were successfully received by the ground stations, which were
more than a thousand kilometres distant.
The team says in its report, "The result again verifies
the nonlocal aspect of entanglement and rejects the models of reality that
depend on the ideas of locality and realism."
The connection effectiveness of our satellite-based strategy
is 12 and 17 orders of magnitude greater than the prior way of entanglement
distribution by direct transmission of the identical two-photon source, according
to the research.
The fundamental advantage of this strategy is that two
Earth-based sites that are thousands of kilometres apart may be readily covered
by satellites. There is essentially little loss of particles since the majority
of the transmission line is in a vacuum.
The team claims that its satellite-based approach would still
be four to eight orders of magnitude more effective even if ideal optical
fibres were created in the future.
These new discoveries bring up a whole new universe of real-world applications, from improved communication networks to secure payment systems, even if quantum entanglement will always screw with our thoughts.
We can only hope that this record will be broken soon.
Science has published the research.
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