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Einstein was WRONG: 'Spooky' quantum experiment shows that the measurement of a photon affects its location
- Previous experiments have shown entanglement with two particles
- But this is the first to show the entanglement of a photon with itself
- The study reveals how when a light photon is observed it changes state
- Einstein didn't believe this could happen as it violates theory of relativity
Albert
Einstein may have been a genius, but even he could get it wrong sometimes.
In
the 1920s and 1930s, Einstein said he couldn't back the strange theory that the
measurement of a particle actually affects its location.
Now
a team of scientists from Japan and Australia have proven that this 'spooky
action at a distance' takes place in a photon.
Professor
Howard Wiseman at Griffiths University, who worked with the University of
Tokyo, made measurements to show what Einstein did not believe to be real -
namely the non-local collapse of a particle's 'wave function'.
According
to quantum mechanics, a single particle can be described by a wave function
that spreads over large distances, but is never detected in two or more places.
This
phenomenon is explained in quantum theory by what Einstein disparaged in 1927
as 'spooky action at a distance.'
This
is the instantaneous collapse of the wave function to wherever the particle is
detected.
It
happens because physicists believe the universe behaves like a little
probability wave.
Particles
are in many places at once, each with some probability.
This
means if an electron was fired through two slits at a screen, it would go
through both of them.
But if you set up a pair of cameras to monitor the
slit, the wave function collapses.
As
a result it only goes through on of the slits, rather than both.
Einstein
didn't believe the phenomenon existed because it violates the theory of
relativity which states that the speed of light is a limit on how fast any
information can travel.
Almost
90 years later, by splitting a single photon between two laboratories,
scientists have used homodyne detectors - which measure wave-like properties -
to show the collapse of the wave function is a real effect.
According
to Live Science, the paradox was resolved years later,
when experiments showed that even though the interaction between two quantum
particles happens faster than light, it is impossible use it to send
information.
The
report adds that while other experiments have shown entanglement with two
particles, the new study entangles a photon with itself.
This
phenomenon is the strongest yet proof of the entanglement of a single particle,
an unusual form of quantum entanglement that is being increasingly explored for
quantum communication and computation.
'Einstein
never accepted orthodox quantum mechanics and the original basis of his contention
was this single-particle argument,' said Professor Wiseman.
'This
is why it is important to demonstrate non-local wave function collapse with a
single particle.
'Einstein's
view was that the detection of the particle only ever at one point could be
much better explained by the hypothesis that the particle is only ever at one
point, without invoking the instantaneous collapse of the wave function to
nothing at all other points.
By splitting a single photon between two laboratories, scientists have used homodyne detectors - which measure wave-like properties - to show the collapse of the wave function is a real effect
'However,
rather than simply detecting the presence or absence of the particle, we used
homodyne measurements enabling one party to make different measurements and the
other, using quantum tomography, to test the effect of those choices.'
'Through
these different measurements, you see the wave function collapse in different ways,
thus proving its existence and showing that Einstein was wrong.'
Charles Krauthammer: "It means that Einstein’s relativity — a theory of uncommon beauty upon
which all of physics has been built for 100 years — is wrong. Not just
inaccurate. Not just flawed. But deeply, fundamentally, indescribably
wrong."
Washington Post:Gone in 60 nanoseconds
Washington Post:Gone in 60 nanoseconds
