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SCIENCE
T
eleportation is a concept that’s familiarto
most people, thanks to the fictional
‘transporter’ in Star Trek. As its name
suggests, the latter is portrayed simply as
another form of transport, getting a person from
A to B as quickly as possible. But if you think
about it, something much weirder is going on.
When someone steps onto the transporter pad,
they’re completely disintegrated – they cease to
exist – and what appears at a remote location
isn’t the original person, but an exact copy of
them. When real-world scientists use the word
teleportation, they’re just as interested in this
copy ing side of the process as the transport one.
In the ever yday world, making a passable
copy of an object isn’t too difficult. But on the
scale of subatomic particles – which is what
we’re ultimately all made of – things are much
harder. This is the world of quantum physics,
and pinning dow n the exact ‘quantum state’ ofa
particle is notoriously difficult. The mere act of
obser v ing it alters it in an unpredictable way. It’s
impossible, in fact, to make an accurate
measurement of all of a quantum particle’s
properties. But around 20 years ago scientistsThe strange phenomenon of quantum entanglement allows
scientists to make exact copies of subatomic particles
Teleportation
in the real world
Words by Andrew MayIBM’sresearchdirectorDarioGilwiththe
Q SystemOnequantumcomputer© Gettydiscovered that, w ithout even looking at a
particle, it’s possible to transfer its properties to
another particle. That’s what they mean by
‘quantum teleportation’.
The secret lies in a strange-sounding quantum
effect called ‘entanglement’, by which t wo
separate particles can share a single quantumstate – not
in the sense
that they’re
both thesame,
but that know ing
somethingaboutone
tells you somethingabout
the other.Theirpropertiesare
quite literallyentangled.Inquantum
teleportation, the particle to be teleported is
brought into contact w ith one half of a pair of
entangled particles. The sender then tells the
receiver, who has the other half of the entangled
pair – even though they may be on the other side
of the world – the result of a simple
measurement. This allows the receiver to put
their particle into an exact duplicate of the
original particle’s state – which, as in a Star Trek
transporter, no longer exists at the sending end.
It may sound like an abstract academic
exercise, but quantum teleportation offers
enormous practical benefits – not as a
revolutionar y means of transport, like its sci-fi
predecessor, but in the world of quantum
computing and quantum communications.Prototype quantum teleportation
equipment made by the Institute for
Experimental Physics in Vienna in 2002© Getty