Despiteitsmuchsmallerscale,quantumteleportationbasically
functionslikeaStarTrektransporter.It createsa copyofa particleata
distantlocation,anderasestheoriginalparticle’sstate.Humanbeings
arejustlargecollectionsofparticles,sointheoryit shouldbepossible
toteleportthemtoo.Butthereareinsurmountabledifficulties.The
numberofparticlesinvolvedis over4 tredecillion– fourwith 42 zeros
afterit.There’snowaytohandlethatamountofdata quiteapartfrom
thetechnical
challengeofcreating
allthoseentangled
pairsofparticles.Eve
if it wasphysically
possible,the
philosopherDerek
Parfithasargued
thata teleported
copywouldn’tbe
thesameasthe
originalperson.
aytohandlethatamountofdata,quiteapartfrom
g
en
http://www.howitworksdaily.com
DID YOU KNOW? It would take 1he entire UK electricity grid a million years to power the teleportation of a single human
An exact copy of the particle being
teleported appears at the receiving end
How quantum
teleportation works
1
Teleportation’sorigins
Theword‘teleportation’wasn’t
formallyuseduntilthe20th
century,althoughtheconceptof
objectsdisappearingfromone
placeandappearingintheother
hasbeendocumentedsince1878.
2
Einsteincalled
entanglement“spooky”
Notbecausehefoundit scary– he
justdidn’tbelieveinit.Hesaid
“physicsshouldrepresenta reality
intimeandspace,freefrom
spookyactionata distance”.
3
TheAspectexperiment
Proofthatentanglementis real
cameintheearly1980switha
groundbreaking experimental
demonstration by French physicist
Alain Aspect.
4
Mainstream use
The word ‘teleportation’ was
first used in a serious scientific
context in 1993 in a theoretical
paper written by Charles Bennett
and his team.
5
Long-distance teleportation
In June 2017, Chinese scientists
teleported a quantum state from a
ground-based lab to a satellite in
orbit, 300 miles away.
TELEPORTATION
© Getty
Why is teleportation important?
At first sight, being able to copythequantumstateofa particlemaynotlookexciting
- but it’s hugely significant for theviabilityofquantumcomputers.Inplaceof
electronic components that arealwaysinoneoftwostates,representingbinarydigit
zero or one, these employ quantumparticlesthatcanbeinanysuperpositionofthese
states. The result, called a ‘qubit’,makesquantumcomputingmuchmoreefficientat
number-crunching tasks like code-breakingandequation-solving.
There’s a catch though. Qubits,likeallquantumstates,aredestroyedbyany
attempt to measure them. It’s herethatteleportationcomestotherescue,byallowin
information to be extracted – andeventransmittedtodistantlocations– without
disturbing the system. It’s an intrinsicallysecureprocess,too– becauseonceagain
you can’t observe a quantum particlewithoutchangingitsstate.Tryingtoeavesdrop
on a ‘teleported’ communicationwilldestroythemessage.
g
ts
e
ng
Conceptualillustrationof
single-atomqubits,shownin
red,ina quantumcomputer
© National Institute of Standards and Technology
Teleporting humans
Star Trek’s
transporter is a great
sci-fi gimmick, but
totally impractical in
the real world
© Getty
Symbolic representation of a pair of
quantum particles in an entangled state
© NASA
Photon Entangled
photons
Transformation
Classical
signal
Bell-state
analyser
SENDER RECEIVER
Sender
ThesenderhasparticleX
- tobeteleported– as
wellasparticleA,onehalf
ofanentangledpair.
pho
Entangledparticlepair
Thekeytoteleportationis thefactthatA andB,although
widelyseparated,arein a sharedquantumstate.
Resultofanalysis
Theanalyserequipment
transmitsa singlenumber
- notthefullquantumstate
- totheremotereceiver.
Receiver
Thereceiverhas
theotherentangled
particle,B,which
willbetransformed
intoa copyofX.
Quantumstateanalyser
ThesenderputsX,theparticletobe
teleported,intothisgadgetwiththeir
halfoftheentangledpair,A.
Makinga copy
Thereceiverusesthenumber
providedbytheanalysertotransform
particleB intoanexactcopyofX.