MOSCOW, July 12 - RIA Novosti. Physicists from Shanghai announced the success of the first “space” quantum teleportation, transferring information about the state of a particle from the Mo Tzu quantum satellite to a tracking station on Earth, according to an article posted in the electronic library arXiv.org

“We announce the first quantum teleportation of single photons from an observatory on Earth to a satellite in low-Earth orbit, 1,400 kilometers away from it. The successful implementation of this task opens the way to ultra-long-range teleportation and is the first step towards the creation of a quantum Internet,” Jian writes -Wei Pan (Jian-Wei Pan) from the University of Shanghai and his colleagues.

The phenomenon of quantum entanglement is the basis of modern quantum technologies. This phenomenon, in particular, plays an important role in secure quantum communication systems - such systems completely eliminate the possibility of unnoticed “wiretapping” due to the fact that the laws of quantum mechanics prohibit “cloning” the state of light particles. Currently, quantum communication systems are being actively developed in Europe, China, and the USA.

In recent years, scientists from Russia and foreign countries have created dozens of quantum communication systems, the nodes of which can exchange data over fairly large distances, amounting to about 200-300 kilometers. All attempts to expand these networks internationally and intercontinentally have encountered insurmountable difficulties related to the way light fades as it travels through fiber optics.

For this reason, many teams of scientists are thinking about moving quantum communication systems to the “cosmic” level, exchanging information via satellite, allowing them to restore or strengthen the “invisible connection” between entangled photons. The first spacecraft of this kind is already present in orbit - it is the Chinese Mo Tzu satellite, launched into space in August 2016.

This week, Pan and his colleagues described the first successful quantum teleportation experiments carried out on board the Mo-Zu and at a communications station in the town of Ngari in Tibet, built at an altitude of four kilometers to exchange information with the first quantum satellite.

Quantum teleportation was first described at a theoretical level in 1993 by a group of physicists led by Charles Bennett. According to their idea, atoms or photons can exchange information at any distance if they were “entangled” at the quantum level.

To carry out this process, a regular communication channel is required, without which we cannot read the state of entangled particles, which is why such “teleportation” cannot be used to transmit data over astronomical distances. Despite this limitation, quantum teleportation is of great interest to physicists and engineers because it can be used to transmit data in quantum computers and to encrypt data.

Guided by this idea, the scientists entangled two pairs of photons in the laboratory in Ngari, and transmitted one of the four "entangled" particles aboard the Mo-Tzu using a laser. The satellite simultaneously measured the state of both this particle and another photon that was on board at that moment, as a result of which information about the properties of the second particle was instantly "teleported" to the Earth, changing the behavior of the "ground" photon entangled with the first particle.

In total, as Chinese physicists say, they managed to “entangle” and teleport over 900 photons, which confirmed the correctness of the “Mo-Zu” work and proved that two-way “orbital” quantum teleportation is possible in principle. In a similar way, as scientists note, it is possible to transmit not only photons, but also qubits, memory cells of a quantum computer, and other objects of the quantum world.

Numerous blockbusters of recent years, most of them film adaptations of comic books, have firmly implanted the image of a superhero in the consciousness of modern people. A superhero is most often an ordinary-looking person who has supernatural powers and is often forced to lead a secretive lifestyle because of this. These films are so popular, colorful and numerous that for some people the concept of "superhero" becomes commonplace. The idea of ​​the reality of such heroes visits people more and more often - therefore, such plots as teleportation in China appear and are very popular.

Superman on the roadway

In the fall of 2012, one of the main hits of the World Wide Web was a video that allegedly showed more than just teleportation person, but a very dramatic teleportation of two people at once. The video posted on YouTube video hosting has a duration of about a minute and looks like shooting from a street surveillance camera. The time of events, judging by the timing in the upper left corner, is just after midnight on May 9, 2012. The location of the events is one of the urban or suburban intersections of China. There are three main characters. The first is a truck driver with a white van, the second is a cyclist. The third is a mysterious stranger, whose face is not visible because of the wide hood. In terms of physique, this clearly young man could be either a boy or a girl.

The events in the video unfold as follows. After several cars have passed, a truck appears in the background, gradually picking up speed. As he approaches, a cyclist appears from a darkened area on the side road on the left. The trajectories and speeds of the truck and the cyclist are such that a collision seems inevitable, and the consequences for the driver of a lighter vehicle promise to be fatal. But here, in the right darkened area of ​​the screen, some movement is noted: a rapid blurred silhouette is approaching the site of the impending collision. At the last moment, the silhouette is outlined more clearly and the viewer sees a man who grabs the cyclist almost under the very wheels of the car. After this, the stranger, the cyclist and the bicycle literally disappear, and the truck begins to brake. The car has not yet completely stopped when a group of two people and a bicycle appears on the far right side of the screen, just on the illuminated part of the road. The stranger lets go of the rescued man, while his hands glow brightly. He throws his hood over his head and quickly moves out of the way. At this time, the clearly shocked cyclist sits down exhausted on the curb, and a truck driver comes out and finds nothing on the roadway.

It is easy to deceive those who are happy to be deceived

Human teleportation in China, especially recorded on video and in addition under such cinematic circumstances, very quickly became known and gained millions of views on video hosting. Immediately, lively discussions began about whether the video was real or whether it was a hoax by some visual effects specialists. It is curious that there were quite a lot of supporters of the reality of the teleportation observed on the set. Even original “fan fiction” arose immediately - stories began to be invented designed to create the story of a female superhero (the female gender of the character seemed more intriguing and impressive to most audiences), to reveal the reasons that prompted her to hide her superpowers, and the like.

But there were also a lot of skeptic critics, and they literally broke down the video to its bones. Many rational arguments were given in favor of the fact that the plot is staged, bears obvious traces of the use of software for converting video material, and also has obvious logical flaws. First of all, the very occurrence of a potentially fatal accident was alarming: contrary to usual, the truck, when approaching the intersection, began to pick up speed rather than slow down, as if creating the conditions for a dramatic scene. The cyclist’s suspicion is also suspicious: he surprisingly calmly rode directly under the wheels, without changing speed and without even turning his head when crossing the main road, where he should give way to traffic priority. Not everything is all right with the truck driver - the footage clearly shows that the man who got out of the cab is wearing a bright white T-shirt or shirt. But in a fairly well-lit cabin during braking, not only is nothing bright visible, the driver is not visible there at all.

As for the mysterious man with the ability to teleport himself and teleport others, he is also not so “pure”. Firstly, there are obvious traces of video editing in his “energy trail” during his super-fast dash onto the road. His silhouette at the moment of grabbing the cyclist is very clear, while the blurry silhouette of his movement still remains. Secondly, the choice of teleportation end point looks very strange. The laws of geometry, physics and simply logic say that the simplest and most natural thing would be for the rescued cyclist to move in the direction of the stranger’s movement - that is, to the left side of the screen, away from the road. But teleportation occurs with a reverse vector, to the right - it turns out that the stranger made a kind of loop during teleportation, which has no explanation. Secondly, a vague doubt creeps in that the appearance of two teleporting people and a bicycle on the right side of the road is explained, so to speak, by stage necessity. It is this part that is the most illuminated in the entire scene, so it is best suited for achieving the greatest drama, for observing the shock state of the rescued, the luminous hands of the savior and his retreat into the darkness. The totality of all these observations and reasoning leads to the conclusion that this teleportation is quite creative, but still a hoax.

Alexander Babitsky

MOSCOW, July 12 - RIA Novosti. Physicists from Shanghai announced the success of the first “space” quantum teleportation, transferring information about the state of a particle from the Mo Tzu quantum satellite to a tracking station on Earth, according to an article posted in the electronic library arXiv.org

“We announce the first quantum teleportation of single photons from an observatory on Earth to a satellite in low-Earth orbit, 1,400 kilometers away from it. The successful implementation of this task opens the way to ultra-long-range teleportation and is the first step towards the creation of a quantum Internet,” Jian writes -Wei Pan (Jian-Wei Pan) from the University of Shanghai and his colleagues.

The phenomenon of quantum entanglement is the basis of modern quantum technologies. This phenomenon, in particular, plays an important role in secure quantum communication systems - such systems completely eliminate the possibility of unnoticed “wiretapping” due to the fact that the laws of quantum mechanics prohibit “cloning” the state of light particles. Currently, quantum communication systems are being actively developed in Europe, China, and the USA.

In recent years, scientists from Russia and foreign countries have created dozens of quantum communication systems, the nodes of which can exchange data over fairly large distances, amounting to about 200-300 kilometers. All attempts to expand these networks internationally and intercontinentally have encountered insurmountable difficulties related to the way light fades as it travels through fiber optics.

For this reason, many teams of scientists are thinking about moving quantum communication systems to the “cosmic” level, exchanging information via satellite, allowing them to restore or strengthen the “invisible connection” between entangled photons. The first spacecraft of this kind is already present in orbit - it is the Chinese Mo Tzu satellite, launched into space in August 2016.

This week, Pan and his colleagues described the first successful quantum teleportation experiments carried out on board the Mo-Zu and at a communications station in the town of Ngari in Tibet, built at an altitude of four kilometers to exchange information with the first quantum satellite.

Quantum teleportation was first described at a theoretical level in 1993 by a group of physicists led by Charles Bennett. According to their idea, atoms or photons can exchange information at any distance if they were “entangled” at the quantum level.

To carry out this process, a regular communication channel is required, without which we cannot read the state of entangled particles, which is why such “teleportation” cannot be used to transmit data over astronomical distances. Despite this limitation, quantum teleportation is of great interest to physicists and engineers because it can be used to transmit data in quantum computers and to encrypt data.

Guided by this idea, the scientists entangled two pairs of photons in the laboratory in Ngari, and transmitted one of the four "entangled" particles aboard the Mo-Tzu using a laser. The satellite simultaneously measured the state of both this particle and another photon that was on board at that moment, as a result of which information about the properties of the second particle was instantly "teleported" to the Earth, changing the behavior of the "ground" photon entangled with the first particle.

In total, as Chinese physicists say, they managed to “entangle” and teleport over 900 photons, which confirmed the correctness of the “Mo-Zu” work and proved that two-way “orbital” quantum teleportation is possible in principle. In a similar way, as scientists note, it is possible to transmit not only photons, but also qubits, memory cells of a quantum computer, and other objects of the quantum world.

Years ago, Albert Einstein called quantum entanglement “spooky action at a distance.” This is a truly counterintuitive concept that at first glance defies common sense. Two objects may be at a great distance from each other, but they maintain a “connection” with each other through their quantum states. By destroying the state of one object (by measuring it), we thereby find out the state of the object entangled with it, no matter at what distance it may be. That is, the quantum state of the first object at the moment of measurement, as it were, passes to the second object; this is figuratively called quantum teleportation.

Now a group of Chinese physicists has, for the first time in the world, carried out quantum teleportation of an object from Earth to orbit. The results of the “spooky action at a distance” experiment were published on July 4, 2017 on the preprint website arXiv.org (arXiv:1707.00934).

Especially for this experiment, the Chinese launched the Micius scientific satellite into a sun-synchronous orbit last year. Every day it passes over the same point on the Earth at the same time, which makes it possible to carefully prepare the experiment and carry it out at any time under constant conditions, and also repeat it if necessary under the same conditions. The Micius satellite is equipped with a highly sensitive photon detector and equipment to determine the quantum state of individual photons sent from Earth.

During the experiment, quantum teleportation was carried out with varying degrees of reliability (see diagram) at a distance of 500-1400 km from the transmitter to the satellite, which is a new world record for the range of quantum teleportation. Previously, such experiments were carried out only on Earth, and the maximum distance to test quantum entanglement was about 100 km. In a vacuum, photons are transmitted more reliably, they react less with surrounding objects and retain entanglement better.


The Ngari station with the transmitter for the experiment was built in the mountains of Tibet at an altitude of more than 4000 m. The station generated entangled pairs of photons at a speed of 4000 per second. Half of them were sent to an orbital station, and there they checked whether quantum entanglement was preserved after transmission. The second half of the photons remained on Earth.

To improve transmission quality, researchers have developed a number of innovative techniques and special instruments, including a compact ultra-bright multiphoton entanglement source, equipment to reduce beam divergence, and a high-speed and high-precision APT (acquiring, pointing, tracking) system.

Measurements showed that some photons, upon arrival at the satellite, actually remained entangled with their terrestrial “partners.” In particular, over 32 days of transmission, out of several million sent photons, 911 remained entangled. The transmission accuracy was 0.80 ± 0.01, which significantly exceeds the classical limit (see diagram below).

Photons with identical quantum states are identical photons from a physical point of view. Thus, it can be stated that for the first time in history, scientists teleported an object from the Earth’s surface into orbit. Well, in a practical sense, this is the first working uplink for the reliable transmission of quantum information over very long distances - from Earth to a satellite. The authors believe that this is an important step towards creating a quantum internet on a global scale.

Theoretically, there is no maximum distance limit for measuring entanglement, i.e. quantum teleportation. In practice, the quantum state of photons is very fragile and is destroyed as a result of reaction with the environment, so it is very important to develop technologies for reliable transmission of entangled photons over long distances.

Quantum teleportation could find applications in a variety of fields: “Long-distance teleportation is considered a fundamental element in protocols such as large-scale quantum networks and distributed quantum computing,” a group of Chinese scientists writes in the abstract of the scientific paper. - To create a “quantum Internet” on a global scale, it is necessary to significantly expand the distance for transmitting information. A promising technology for this is the use of a satellite platform and satellite communication link, which can conveniently link two remotely located points on Earth with relatively little signal loss because photons travel most of the way in a vacuum.

It will now be difficult for other countries to break China's record for quantum teleportation range, because neither the European Union nor the United States planned to launch satellites with photodetectors specifically for such an experiment in space, and maintaining quantum entanglement on Earth in a 1,400 km long optical fiber is incredibly difficult.

System for preparing entangled states and transmitted states for teleportation

The QUESS Quantum Communications Satellite (aka Mo Tzu) mission team reported the first successes in teleporting photons from the Earth's surface into orbit. As part of a month-long experiment, physicists managed to teleport 911 photons over a distance of 500 to 1,400 kilometers. These are record distances for quantum teleportation. A preprint of the study was published on the arXiv.org server, and MIT Technology Review briefly reported on it.

Quantum teleportation involves transferring the quantum state of one particle to another particle without directly transferring the first particle in space. To teleport, for example, the polarization of a photon would require a pair of quantum entangled particles. One of the entangled particles must be kept by the sender of the quantum state, and the second by the recipient. The sender then makes a measurement simultaneously on the transmitted particle and one of the particles of the entangled pair. Quantum entanglement is designed in such a way that two particles behave as a single system - the entangled particle at the recipient feels that a measurement has been taken with its pair and changes its state. Knowing the measurement result on the sender's side (it can be sent via a regular channel), you can receive an exact copy of the sent particle - directly from the recipient. You can read more about this in our material on the quantum alphabet: "".

Previously, the distance for teleportation was limited to tens of kilometers - in 2012, Austrian physicists teleported photon states between La Palma and Tenerife (143 kilometers). The new work overcomes this milestone and improves it several times.

One of the main problems for teleportation - the distribution of entangled photons between the sender (on Earth) and the recipient (satellite) - has already been solved by physicists. The work on creating an entangled pair separated by 1200 kilometers was published a month ago in the magazine Science. Using these pairs, all that remained was to experimentally demonstrate teleportation itself.

Experimental design

Ji-Gang Ren et al. / arXiv.org, 2017

In the new work, the authors used an entangled photon generator installed not on a satellite, but on Earth, at the Ngari Observatory (Tibet). It created over four thousand entangled pairs per second, one photon from each being sent by a laser beam to a satellite that flew over the generator every midnight. First, scientists showed that quantum entanglement persists between the Earth and the satellite, and then they teleported the polarization of a photon. In reality, to reliably test teleportation, scientists needed to create not one, but two entangled pairs of photons.

The greatest losses were associated with turbulence and heterogeneity of the Earth's atmosphere. These effects lead to a broadening of the beam of entangled photons and their scattering - which means fewer particles reach the satellite.

In total, 911 particles were successfully teleported - and during the entire experiment, millions of photon pairs were prepared and transmitted. The authors note that teleportation accuracy reaches 80 percent, and losses range from 41 to 52 decibels (one photon in 100 thousand flies). If you transmit a similar signal over a 1200-kilometer optical fiber with a loss level of 0.2 decibels per kilometer, then the transmission of even one photon will take 20 times longer than the lifetime of the Universe.

Quantum teleportation is one of the important data transmission techniques in quantum telecommunications. It is necessary when developing a global “quantum Internet” with ideally protected communication channels (at the level of physical laws prohibiting the cloning of quantum states). Last year, quantum teleportation protocols for physics on urban fiber optic lines.

Vladimir Korolev