Quantum teleportation was just achieved with over 90% accuracy over a 44 km distance.
Imagine visiting Mars and coming back to a laboratory on earth after collecting samples
from the red planet. Well it looks like something like that would be possible with quantum teleportation
but not the way we want it because teleportation as we want it might only exist in science
fiction. In the quantum world, teleportation involves the transportation of information
rather than transportation of physical objects.
A team of Chinese physicists already made some serious progress in the field of quantum
mechanics as they were able to measure the speed of quantum entanglement, something referred
to as spooky action at a distance by Einstein himself. But what exactly are all these? Well
keep watching till the end to find out more about quantum teleportation.
Picture a world where the journey from the UK to Dubai would be done in the blink of
an eye. Well that is teleportation! By now we are all aware of the concept of teleportation,
all thanks to the works of science fiction where a physical object or even a human being
can be instantly transported to a faraway location with the help of highly sophisticated
teleportation machines.
Most people believe that teleportation of matter is extremely unlikely. This is because
a Star Trek-like transporter must do three things. It needs to pin down the position
and type of every atom in a person's body and then transmit that information, presumably
at the speed of light or even faster, to a remote location, and finally use that information
to assemble atoms the exact same way. Yes all of this sounds extremely complicated,
and it is.
Until very recently, such a thing was almost impossible because according to quantum theory,
it's impossible to know everything about an atom with 100% certainty. There is also a
cosmic speed limit that applies to every object which means no object can ever exceed the
speed of light. Over the years researchers have developed several clever schemes to circumvent
this limit and finally, they have introduced tachyons as hypothetical particles that could
exceed the speed of light. But tachyons are also required to have imaginary masses, and
they do not exist physically.
But physicists have found a new trick known as quantum teleportation, which allows one
to ingeniously create a perfect copy of a quantum particle at a remote location. Not
only that, scientists can now achieve this feat at multiple locations, and this is known
as quantum telecloning.
A team of Chinese physicists were also able to make some serious progress in the field
of quantum mechanics, as the team very recently measured the speed of quantum entanglement
or the spooky action at a distance like Einstein called it.
But what exactly is quantum entanglement? Well, in simple terms, two or more particles
are entangled, which means they share the same waveform. The more technical definition
for quantum entanglement would be something that occurs when particles such as photons,
electrons, molecules as large as buckyballs, and even small diamonds interact physically
and then become separated; the type of interaction is such that each resulting member of a pair
is properly described by the same quantum mechanical description or state, which is
indefinite in terms of important factors such as position, momentum, spin, polarization,
etc.
In order to measure the speed of light, Chinese physicists entangled pairs of photons and
then transmitted half of the pair to receiving units. These receiving units were named Alice
and Bob for reasons that we don't know, and they were positioned about 15.3 kilometers
or 9.5 miles apart in an east West orientation. The receivers were oriented in this fashion
in order to minimize the interference from Earth's rotation, which is an extremely significant
factor considering the scale of operation.
The team then observed the very first half of the entangled pair and waited to see how
quickly the other half assumed the same state. They repeated the process for 12 hours to
confirm the accuracy of their measurements.
So what were their results? Well, the team reported that quantum entanglement transfers
information at 3 trillion meters per second, or four orders of magnitude faster than light.
This is a lower speed limit, which means as we collect more precise data, you can expect
the number to be a lot larger.
So how exactly does quantum teleportation work?
One of the very first scientific articles to investigate quantum teleportation is “Teleporting
an unknown quantum state via dual classical and Einstein Podolsky Rosen channels” published
by C. H. Bennett, G. Brassard, C. Crépeau, R. Jozsa, A. Peres, and W. K. Wootters in
1993, in which they used dual communication methods to send/receive quantum information.
It was experimentally realized in 1997 by two research groups, led by Sandu Popescu
and Anton Zeilinger, respectively.
The experimental determinations of quantum teleportation have been made in information
content including atoms, electrons, photons and superconducting circuits, as well as distance
with 1400 kilometer, or 870 miles, which is by far the longest distance of successful
teleportation by group of Jian-Wei Pan using the Micius satellite for space-based quantum
teleportation.
Just in 2019, scientists confirmed that the information could be passed between photons
on computer chips, even when the photons were not physically linked. According to the National
Science Foundation, funded research by University of Rochester and Purdue University scientists,
teleportation may also be possible between electrons, which changes everything that we
know so far making this science fiction concept a reality someday in the future.
In a paper published in Nature Communications and another one in Physical Review X, the
researchers including Rochester physicists John Nichol and Andrew Jordan explore new
ways of creating quantum mechanical interactions between distant electrons.
This research is extremely important in understanding the way quantum computing works and also improving
the same. According to scientists this has the potential to revolutionize medicine, science
and technology by providing faster and more efficient processes and sensors.
Quantum teleportation is simply the technique for transferring quantum information from
a sender from one location to a receiver some distance away. Teleportation is already commonly
portrayed in science fiction as a means to physically transfer objects from one location
to another. But quantum teleportation only transfers quantum information. The sender
does not have to know the particular quantum state being transferred. The location of the
recipient can also be unknown, but to complete quantum teleportation, classical information
needs to be sent from the sender to receiver because quantum teleportation cannot occur
faster than speed of light.
Quantum teleportation involves two distant entangled particles in which the state of
a third particle instantly teleports its state to the two entangled particles.
To understand more about how Quantum teleportation works, you need to understand what quantum
states are. Consider a single photon which is a fundamental bit of an electromagnetic
wave, so it can be polarized so that its electric field points vertically or horizontally.
The photons can also be in both states at once all thanks to how weird quantum mechanics
can be. So the photons can literally be polarized both vertically and horizontally at the same
time.
The amounts of vertical and horizontal help define the state of a photon. Things get even
more complicated than that. In addition to the mixture of vertical and horizontal, the
photon’s state is also defined by another parameter which is an angle known as phase.
So the actual state of a photon consists of the mixture of vertical and horizontal and
the phase.
It can be visualized with the help of an abstract sphere or globe on which the North Pole stands
for the pure vertical state and the South Pole stands for the horizontal late state.
The precise state of a photon is then a point on the globe with the latitude giving the
balance of vertical and horizontal in the state and longitude giving the phase.
Thus every point on the equator stands for a state in which the photon is in an equal
mixture of vertical and horizontal but in which the face which can be probed in certain
more complicated measurements is different.
Quantum teleportation instantly transfers the condition or state of one quantum particle
to another distant one without sending the particle itself. It's more like transferring
the reading on one clock to a distant one.
So you could say that quantum teleportation is doing something that is less ambitious
and more subtle because the quantum teleportation that we have right now is very different to
what is already depicted in television shows like Star Trek and several other science fiction
stories.
Such a teleportation generally involves disintegrating a material object somehow, beaming the contents
through space, instantly and perfectly reassembling the object in some distant location. Nothing
is disintegrated and reassembled in quantum teleportation and no matter travels anywhere.
The process only works at the level of individual quantum particles like photons, electrons,
atoms and so on which means quantum teleportation and the teleportation that we know is not
the same.
Ultimately, quantum technology and the research surrounding the same is opening new doors
to all kinds of new opportunities and possibilities. Quantum teleportation will drastically improve
the speed of communication if they can travel faster than the speed of light.
Research still continues on the subject and some physicists believe that faster than light
communications might be possible with some intricate manipulation of these entangled
particles. For now we know that the interaction between entangled quantum particles is a lot
faster than the speed of light. We know that quantum entanglement can be used to realize
quantum teleportation experimentally, and we also know that entanglement has applications
in several emerging technologies of quantum computing and quantum cryptography.
At this point we are extremely confident that quantum computers will be able to do revolutionary
things which involve solving complex problems infinitely faster than the computers of today.
This technology will have huge applications in a wide range of fields, from weather predictions
to medical research and also the development of artificial intelligence.
It can also improve cyber security and might also give us the ability to break current
encryption methods.
But the question is, can quantum communication be faster than the speed of light?
If the answer is yes then the door will open to even more possibilities like communications
in space, especially considering the newly found interest in space exploration, all thanks
to the space race between private companies like Blue Origin and SpaceX.