Quantum entanglement, information and signal
We have long been transmitting signals using various storage media. We used signal bonfires, drums, pigeons, electricity. And in the end they came to light again - to transmit information on optics. And now we study coupled photons. We all know that a key can be transmitted directly through quantum interlinking, but not other information. And if not directly, but with the help? Who cares, welcome under cat.
To begin with, I will try to explain the effect of quantum coupling:
There are a pair of socks. Immediately after the creation of the clutch, each sock of the pair is placed in a separate box and sent to its addressee. At the moment when one of the addressees opens the parcel, he sees the right (or left) sock and immediately receives information about what kind of sock the second addressee, no matter how far he is. And in advance to accurately predict whether the toe is right or left, it is impossible. And the most important thing is what makes quantum physics so different from classical physics: until the socks are opened, they themselves “do not know” which one is right and which one is left. But as soon as one of the socks was observed and “determined”, the second at the same time acquires a strictly opposite property. In more detail, with proof, you can find out at the request "Bell's Theorem".
As you can see, it is impossible to transfer meaningful information directly through this property. But there is a workaround.
')
So, the QUESS quantum communication satellite was able to transmit entangled photons between pairs of observatories located up to 1203 kilometers away. Scientists have confirmed the ratio: one event of a successful transmission to six million photon pairs sent. The signal-to-noise ratio, it would seem, does not cause optimism, but the very fact of the success of the transfer translates the task of working with such a carrier from the impossible to the engineering task of combating redundancy and noise.
Hopefully, over time, we will come up with many ways to use quantum coupling. I will describe one of, in my opinion, possible.
The first stage: the device separates the coupled pairs and transmits the entangled photons by a sequential chain to the towers “A” (future conditional transmitter) and “B” (future conditional receiver) for storage. Media has been transferred.
The second stage: tower “A” measures (monitors) the first photon in the chain, determining the start of the message transmission, starts the timer “T”, during which it measures those photons in the chain that are conventional units and does not affect those photons will be conditional zero; by means of a weak measurement, the hardware of tower “B” determines the change in the state of the first photon and starts the timer “T”.
The third stage: at the end of the specified time "T", the tower equipment "B" fixes the state of the photons in the chain through weak interaction, where the photons that have lost cohesion are 1, the remaining ones are coupled is 0.
Also, for example, the trigger of the start and end of the observation chain can be a timer synchronized in advance time.
Thus, we are not interested in what exactly a photon is in a pair. We are interested in the fact itself: clutch preserved or not. Signal transmitted.
This is a concept from an ideal world, where not a single photon was lost, the chain was assembled correctly, and so on. The problems of the real world are the problems of combating redundancy and noise, as well as the difficulty in creating storage systems, impact, and particle control.
But the main thing is the fundamental possibility of transmitting a signal by means of quantum coupling.
The very possibility of such a way of working with a signal allows us to look at the information from a new angle. It turns out that at the moment of transfer of the information carrier (chain of coupled particles) within the framework of current laws, not faster than the speed of light, we transmit all possible information that can be encoded in this way.
I will give an analogy: you ordered a book in the library, you meet a courier, and behind him are all the books from the library that are invisible to you, whether you know about them or not. You name the author and title, pick up your one book, and the rest are immediately destroyed.
Until the next courier from the library.
Another analogy: I write the word "spit" and you have images in your brain that can be initiated by this information carrier. However, for signal transmission requires specification: "light brown" or "wooden" or "sandy." In other languages, this combination of symbols "spit" may mean something else, and the information is contained in the carrier, regardless of whether we know it. We simply do not have a specifying trigger and memory for the desired signal.
So with the chain of particles: at the moment of transmission to the towers, we transmitted all possible information (possible variants), remaining within the framework of familiar physics, not faster than the speed of light, and the fact of measurement only made a clarification.
In general, we are waiting for a fascinating time in an attempt to explain (and understand) that a conditional spy, dragging a pair of entangled particles at an object and pressing a button at a certain time (or not pressing, leaving particles hooked together) did not transmit information through headquarters faster than the speed of light. He penned his piece of information like a snail on his hump. And the button just clarified, chose, concretized. We still have to figure out what he did. But the military will like it. Like the mine, which can not be shielded from the team, and without control wires. You will like the opportunity to give an order to any distance, through any jammers, to a receiver with a container of particles taken in advance. I think that they, again, will move the technology.
Or the surgeon, for whom the towers around the world accumulated data carriers (tangled particles) at different ends of the planet all over the world with all due respect to the speed of light, will do the operation and see the instantaneous reactions of the surgical robot tens of thousands of kilometers away from its office. He will then say in an interview that everything happened instantly. And the physicist reading this will grumble that all the information about all possible actions of the surgeon was transmitted at night (from the point of view of physics), at a normal speed. And the surgeon only “clarified” with his actions exactly how he operated on.
Or interaction of information and, for example, the properties of the locality of the world. This property means that an event at one point, say, a planet, cannot instantly affect the physical reality at another point on the planet. Then, if the conditional pressing of a button through the effect of quantum entanglement instantly lights a light bulb on the other side of the planet, then information about the influencing event was contained in the information carrier before the influencing event occurred.
It turns out that we are on the threshold of the next step of signal evolution. With the help of the quantum world, we separate the speed of passage of a signal and the speed of propagation of a storage medium. By providing a supply of coupled pairs at normal speed, at the moment when the critical signal is transmitted almost instantly, we can, albeit theoretically, do this.
Quantum coupling
To begin with, I will try to explain the effect of quantum coupling:
There are a pair of socks. Immediately after the creation of the clutch, each sock of the pair is placed in a separate box and sent to its addressee. At the moment when one of the addressees opens the parcel, he sees the right (or left) sock and immediately receives information about what kind of sock the second addressee, no matter how far he is. And in advance to accurately predict whether the toe is right or left, it is impossible. And the most important thing is what makes quantum physics so different from classical physics: until the socks are opened, they themselves “do not know” which one is right and which one is left. But as soon as one of the socks was observed and “determined”, the second at the same time acquires a strictly opposite property. In more detail, with proof, you can find out at the request "Bell's Theorem".
As you can see, it is impossible to transfer meaningful information directly through this property. But there is a workaround.
')
The principle of transmission of the information carrier and signal
So, the QUESS quantum communication satellite was able to transmit entangled photons between pairs of observatories located up to 1203 kilometers away. Scientists have confirmed the ratio: one event of a successful transmission to six million photon pairs sent. The signal-to-noise ratio, it would seem, does not cause optimism, but the very fact of the success of the transfer translates the task of working with such a carrier from the impossible to the engineering task of combating redundancy and noise.
Hopefully, over time, we will come up with many ways to use quantum coupling. I will describe one of, in my opinion, possible.
The first stage: the device separates the coupled pairs and transmits the entangled photons by a sequential chain to the towers “A” (future conditional transmitter) and “B” (future conditional receiver) for storage. Media has been transferred.
The second stage: tower “A” measures (monitors) the first photon in the chain, determining the start of the message transmission, starts the timer “T”, during which it measures those photons in the chain that are conventional units and does not affect those photons will be conditional zero; by means of a weak measurement, the hardware of tower “B” determines the change in the state of the first photon and starts the timer “T”.
The third stage: at the end of the specified time "T", the tower equipment "B" fixes the state of the photons in the chain through weak interaction, where the photons that have lost cohesion are 1, the remaining ones are coupled is 0.
Also, for example, the trigger of the start and end of the observation chain can be a timer synchronized in advance time.
Thus, we are not interested in what exactly a photon is in a pair. We are interested in the fact itself: clutch preserved or not. Signal transmitted.
This is a concept from an ideal world, where not a single photon was lost, the chain was assembled correctly, and so on. The problems of the real world are the problems of combating redundancy and noise, as well as the difficulty in creating storage systems, impact, and particle control.
But the main thing is the fundamental possibility of transmitting a signal by means of quantum coupling.
The relationship of media and signal
The very possibility of such a way of working with a signal allows us to look at the information from a new angle. It turns out that at the moment of transfer of the information carrier (chain of coupled particles) within the framework of current laws, not faster than the speed of light, we transmit all possible information that can be encoded in this way.
I will give an analogy: you ordered a book in the library, you meet a courier, and behind him are all the books from the library that are invisible to you, whether you know about them or not. You name the author and title, pick up your one book, and the rest are immediately destroyed.
Until the next courier from the library.
Another analogy: I write the word "spit" and you have images in your brain that can be initiated by this information carrier. However, for signal transmission requires specification: "light brown" or "wooden" or "sandy." In other languages, this combination of symbols "spit" may mean something else, and the information is contained in the carrier, regardless of whether we know it. We simply do not have a specifying trigger and memory for the desired signal.
So with the chain of particles: at the moment of transmission to the towers, we transmitted all possible information (possible variants), remaining within the framework of familiar physics, not faster than the speed of light, and the fact of measurement only made a clarification.
In general, we are waiting for a fascinating time in an attempt to explain (and understand) that a conditional spy, dragging a pair of entangled particles at an object and pressing a button at a certain time (or not pressing, leaving particles hooked together) did not transmit information through headquarters faster than the speed of light. He penned his piece of information like a snail on his hump. And the button just clarified, chose, concretized. We still have to figure out what he did. But the military will like it. Like the mine, which can not be shielded from the team, and without control wires. You will like the opportunity to give an order to any distance, through any jammers, to a receiver with a container of particles taken in advance. I think that they, again, will move the technology.
Or the surgeon, for whom the towers around the world accumulated data carriers (tangled particles) at different ends of the planet all over the world with all due respect to the speed of light, will do the operation and see the instantaneous reactions of the surgical robot tens of thousands of kilometers away from its office. He will then say in an interview that everything happened instantly. And the physicist reading this will grumble that all the information about all possible actions of the surgeon was transmitted at night (from the point of view of physics), at a normal speed. And the surgeon only “clarified” with his actions exactly how he operated on.
Or interaction of information and, for example, the properties of the locality of the world. This property means that an event at one point, say, a planet, cannot instantly affect the physical reality at another point on the planet. Then, if the conditional pressing of a button through the effect of quantum entanglement instantly lights a light bulb on the other side of the planet, then information about the influencing event was contained in the information carrier before the influencing event occurred.
It turns out that we are on the threshold of the next step of signal evolution. With the help of the quantum world, we separate the speed of passage of a signal and the speed of propagation of a storage medium. By providing a supply of coupled pairs at normal speed, at the moment when the critical signal is transmitted almost instantly, we can, albeit theoretically, do this.
Source: https://habr.com/ru/post/370703/
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