What is quantum technology and what are its applications?

For thousands of years, humans have relied on their innate intuition to understand how nature works. Although this approach has led us astray in many ways, for example, we were once convinced that the earth was flat. But overall, the truth and knowledge we have gained far outweighs the error. It is in this slow but effective but very positive accumulation process that people gradually explore and summarize knowledge such as the laws of motion and thermodynamic principles, and the world they live in becomes less mysterious. As a result, the value of intuition is even more affirmed. But all this ended with the emergence of quantum mechanics.

Quantum origin

This is a subject described by Einstein and Bohr as "God plays dice with the universe". It is also a physics that studies "matter in the extremely microscopic realm" Branch, it has brought many shocking conclusions - scientists have discovered that the behavior of electrons has the dual characteristics of both waves and particles (wave-particle duality), but they only added human observation activities , enough to instantly change their properties; in addition, particles thousands of miles apart can communicate instantaneously (quantum entanglement): uncertain photons can go in two directions at the same time (Heisenberg Uncertainty Principle); not to mention the theoretical hypothesis The cat is both dead and alive (Schr?dinger's cat)...

Such research results are often subversive because they basically go against people's accustomed logical thinking. So much so that Einstein had to lament: "The more successful quantum mechanics becomes, the more absurd it becomes."

Now, compared with a century ago when humans first set foot in the quantum field, Einstein's views seem to have gained wider support. The more mathematically perfect quantum mechanics continues to score, the more crude our instinctive intuition becomes. People have to admit that although it still seems strange and unfamiliar, quantum mechanics has brought many revolutionary inventions to mankind in the past one hundred years. As James Kakaglios said in the introduction to the book "The Amazing Story of Quantum Mechanics": "Where is quantum mechanics? Aren't you immersed in it?"

Strange quantum, no The unfamiliar transistor

One of the major applications of quantum mechanics in the real world given by the online version of the American "Discover" magazine is the transistor that is no longer unfamiliar to people.

In the fall of 1945, the U.S. military successfully manufactured the world's first vacuum tube computer, ENIAC. According to records at the time, this behemoth weighed more than 30 tons, covered an area close to a small residence, and cost as much as $1 million. Such a huge investment destined vacuum tubes, a large consumer of energy and space, to be just a passer-by in the history of computer development. Because at that time, scientists at Bell Labs were already stepping up their efforts to develop a new invention that could replace the vacuum tube-the transistor.

The advantage of a transistor is its ability to act as both an electronic signal amplifier and a converter. This is almost the most basic functional requirement of all modern electronic devices. But the first thing we must thank for the emergence of transistors is quantum mechanics.

It was breakthroughs in the basic research field of quantum mechanics that allowed Stanford University researcher Eugene Wagner and his student Friedrich Seitz to discover the properties of semiconductors in 1930 - and at the same time as exist as conductors and insulators. Applying voltage to the transistor can realize the function of the gate and control the conduction or interruption of the current in the tube. Using this principle, the information can be encoded, so that a language of 1 and 0 can be written to operate them.

Over the next 10 years, Bell Labs scientists produced and improved the world's first transistor. In 1954, the U.S. military successfully manufactured the world's first transistor computer, TRIDAC. Compared with previous unreliable vacuum tube computer predecessors that were often as bloated as buildings, TRIDAC was only 3 cubic feet in size and powered no more than 100 watts. Today, billions of microprocessors can be placed on cutting-edge chips from Intel and AMD. And all this must be attributed to quantum mechanics.

Quantum interference "gets" energy recovery

No matter how respectful we are, it is not easy for us to connect the theory represented by quantum mechanics with the results it brings. Together, because they sound like two completely unrelated things. And "energy recovery" is an example.

Every time we travel by car, people inevitably do one negative thing - waste energy. Because when the engine ignites the fuel to generate the driving force to propel the body forward, a considerable amount of energy is lost in the form of heat, or to put it bluntly, wasted in the air. For this situation, researchers at the University of Arizona tried to solve this problem with the help of the quantum interference principle in quantum mechanics.

Quantum interference describes the superposition of several different states of the same quantum system into a pure state. This sounds completely confusing, but researchers have used it to develop a molecular thermoelectric material. Can effectively convert heat into electrical energy. What's more, the material is only a millionth of an inch thick, requires no external moving parts and does not produce any pollution when it works. The research team says that if a car's exhaust system is wrapped in this material, the vehicle will receive enough electricity to light up 200 100-watt light bulbs - although the theory is confusing, this number is clearly visible.

The team is therefore confident in the future of the new material and has determined that the material can also play a role in converting thermal energy into electricity in other areas where heat loss exists, such as photovoltaic solar panels. And all we need to know is that this is all "done" by quantum interference.

Uncertain quantum, extremely certain clock

As ordinary people, generally they don’t mind if their watch is half a minute too fast or ten seconds too slow. However, if you are responsible for a country's time like the U.S. Naval Meteorological Observatory, then errors of half a minute and half a second are not allowed. Fortunately, these important organizational units can rely on atomic clocks to keep time accurate. These atomic clocks are more accurate than any clock that has ever existed before. The most powerful of them is a cesium atomic clock, which can still maintain an error of no more than 1 second after 20 million years.

After seeing this kind of precise and confusing clock, you may wonder if anyone or what occasion would really use them? The answer is yes, there are people who do. For example, when aerospace engineers calculate the flight trajectory of a spacecraft, they must clearly understand the location of the destination. Whether they are stars or asteroids, they are always in motion. Distance is also a factor that must be considered. Once we fly out of the range of our galaxy in the future, the margin of error will become smaller and smaller.

So, what does quantum mechanics have to do with these? For these extremely accurate atomic clocks, the biggest enemy causing errors is quantum noise. They can reduce the ability of atomic clocks to measure atomic vibrations. Now, two researchers from a German university have developed a way to suppress the level of quantum noise by adjusting the energy levels of cesium atoms. They are currently trying to apply this method to all atomic clocks. After all, the more advanced technology is, the higher the demand for punctuality.

The battle of quantum cryptography is invincible

The Spartans have always been famous for their bravery and ferocity in battle, but people cannot underestimate their talents in strategy. To prevent their enemies from learning about their military operations in advance, the Spartans used something called a cipher stick to encrypt and decrypt confidential information. They would wrap a piece of parchment around a column, write a message on it, and then remove the parchment. In this way, Spartan officers were able to issue an order that seemed incoherent to the enemy. Your own personnel only need to wrap the parchment around a column of the same size again to read the real order.

The simple skills of the Spartans were just the beginning of a long history of cryptography. Today, quantum cryptography, which relies on some strange properties of microscopic matter, has publicly declared that it has no solution. It is a new information transmission method based on single photon polarization state that utilizes the quantum entanglement effect. Its safety lies in that whenever someone breaks into the transmission network, the photon beam will be disordered, and the detectors at each node will point out the increase in error levels, thereby issuing an attack alarm; both the sending and receiving parties will also randomly select A subset of the key values ??are compared, and only if all match, it is considered that no one is eavesdropping. In other words, a hacker cannot break into a quantum system without leaving a trace of interference, because the mere act of trying to decode it will cause the quantum cryptographic system to change its own state.

Correspondingly, even if a hacker successfully intercepts and obtains the decoding key for a set of cryptographic information, the key will be changed at the same time as he completes this action. Therefore, when the legitimate recipient of the information checks the key, he will easily find the clues and replace the key with a new one.

The emergence of quantum cryptography has always been regarded as the return of "absolute security". However, there is no airtight wall in the world. The Norwegians, who own the Viking Age pirate history more than 1,000 years ago, have broken the myth that quantum cryptography has no solution. Using devices that mislead users into reading cryptographic information, they obtained the information without trying to decode it. But they admit that this is just exploiting a loophole in existing technology, which can be avoided after quantum cryptography is perfected.

Random number generator: God’s “quantum dice”

The so-called random number generator is not the fantasy and mysterious stuff in old-school soap operas. They use quantum mechanics to conjure truly random numbers. However, why do scientists go to the trouble of delving into the quantum world to find random numbers, instead of simply tossing a coin and rolling a dice? The answer is: true randomness only exists at the quantum level. In fact, once scientists gather enough information about a die roll, they can predict the outcome in advance. This is true for roulette, lotteries, and even computer-generated lottery results.

However, in the quantum world, everything is absolutely unpredictable. Researchers at Max Planck University's Institute of Optical Physics took advantage of this unpredictability to create a "quantum dice." They first generated quantum noise by creating fluctuations in the vacuum, and then measured the random levels generated by the noise to obtain truly random numbers that can be used for information encryption, weather forecasting, etc. It is worth mentioning that this kind of dice is installed on a solid-state chip and can meet a variety of different use needs.

We almost missed the mark with lasers

Similar to the experience of quantum mechanics, lasers were also considered "theoretical giants, practical application dwarfs" in the early days. But today, whether it is a home CD player or a "missile defense system," lasers have occupied a core position in contemporary human social life. However, if it were not for quantum mechanics, our story with lasers would probably end in a "passing by".

The principle of a laser is to first impact the electrons rotating around the atoms, causing them to burst out photons when they return to a low energy level. These photons then cause the surrounding atoms to undergo the same change, emitting photons. Eventually, guided by the laser, these photons form a stable, concentrated beam that we see as laser light. Of course, people can't know this without the theoretical physicist Max Planck and the principles of quantum mechanics he discovered. Planck pointed out that the energy levels of atoms are not continuous, but dispersed and incoherent. When atoms emit energy, they do so in the smallest fundamental units of discrete values ??called quanta. The working principle of a laser is actually to excite a specific quantum to emit energy.

An ultra-precision thermometer designed to challenge extremes

If you use an ordinary medical thermometer to measure a temperature that is one percent lower than absolute zero, you can imagine the fate of this thermometer. . So how to deal with such extreme temperatures? Researchers at Yale University have invented a magical thermometer that can handle just such situations. Not only does it remain strong in extreme environments, it also provides extremely accurate values.

In order to make this kind of thermometer, the research team had to reorganize the design ideas of the thermometer. For example, how to obtain accurate numerical values. Fortunately, in the pursuit of precision, scientists have used quantum tunnels to get the answers they want. Like drilling into a mountain instead of climbing up and down its surface, particles create quantum noise as they cross potential barriers. Using the research team's quantum thermometer to measure these noises, the temperature of the experimental object can be accurately obtained.

Although this kind of thermometer does not have much significance for ordinary people's daily life, it can be used in scientific laboratories, especially those materials laboratories that require extremely low temperature environments. Now, researchers are still working hard to improve the accuracy of the thermometer through various means, and hope that as its application range expands, more extreme scientific research environments can benefit from it.

Quantum energy conversion technology loaded with standing waves

Quantum energy conversion technology loaded with standing waves. The main principle is to rely on high-tech quantum energy capsules. After the product enters the cabin, energy is implanted through physical intervention methods such as "sound, light, electricity, and magnetism."

Moreover, implanting standing waves at the molecular level of matter will not change the original molecular structure and properties of the matter. Products after quantum implantation have no half-life in theory. The existing quantum products in the laboratory are currently 17 years old and still maintain saturated quantum energy.

Everyone loves quantum computers

In a paper published in 1965, Intel co-founder Gordon Moore made some predictions about the future development of computer technology. A crude but profound prediction. The most important of these is what will become known as Moore's Law: the number of transistors per square foot of integrated circuits will double every 18 months. This law has had a profound impact on the development of computer technology, but now, Moore's Law seems to have come to an end, because by 2020, silicon chips will reach their physical limits, and as the size of transistors continues to shrink, they will begin to Follow various laws of the quantum world.

Compared with being "hostile" to the laws of the quantum world, adapting to the quantum era may be people's best choice. Today, scientists working on quantum computers are doing exactly that. Compared with traditional computers, quantum computers have an unparalleled advantage: parallel processing. With the power of parallel processing, quantum computers can handle multiple tasks at the same time, rather than having to prioritize tasks like traditional computers. This characteristic of quantum computers is destined to surpass traditional computers at an exponential rate in the future.

However, scientists still need to overcome some difficult challenges before quantum computing can become a reality. For example, quantum computers use qubits that have much higher storage capabilities than traditional bits. Unfortunately, qubits are very difficult to create because they require a variety of particles to form a network simultaneously. Until now, scientists have only been able to entangle 12 types of particles at once. If quantum computers are to be commercialized, this number needs to be increased by at least dozens or even hundreds of times.

Teleportation from science fiction to reality

Science fiction movies, especially those with space themes, love teleportation the most: a huge person disappears mysteriously in a place without any need for anything. The carrying of the carrier appears instantly in another place.

Long-distance transmission is quantum state teleportation, which is the "entangled" motion state of quantum in the extremely strange quantum world. Photons in this state are like "telepathy", which can make the quantum state that needs to be transmitted "travel through time and space", disappear mysteriously in one place without any carrier, and appear instantly in another place. In "time and space travel", what it transmits is no longer classical information, but quantum information carried by quantum states. These quantum information are the components of future quantum communication networks.

Previously, six engineers from the IBM team proved that long-distance transmission is completely achievable, at least in theory. But it must be noted that the "original object" will disappear during this process - because long-distance transmission is not a "fax machine", your original "document" will be destroyed by it. It seems to be a process of "copying" the original object, but it is actually a change of the original object.

In 2009, scientists at the Joint Quantum Institute of Maryland State University in the United States conducted a "quantum information processing" experiment and successfully realized the transmission from one atom to another atom in a container 1 meter away. Quantum teleportation. Although one atom is transformed into another atom in the experiment, and the second atom plays the role of the first atom, which is different from the concept of "original transmission", the atom-to-atom transmission is very important for the development of ultra-dense ultrasonic technology. Fast quantum computers and quantum communications are of great significance.

Yes, long-distance transmission is not only valuable for the purpose of transmitting objects. Before reaching this goal, various research leading to the "sacred realm" has also been proven to be useful in multiple other fields. Much promise. The same applies to all quantum mechanics research, and even all human scientific activities.

Do you want to know what real instantaneous communication is?

The achievements that quantum mechanics has brought to people in the past years are precious, but scientists have reason to believe that it will Will give more.

Nowadays, when you are wandering between mobile phones, text messages, emails, MSN, Fetion and other communication tools, you may think that you have been covered by the so-called "instantaneous communication". In fact, the sounds, words, and images you send out will take some time to reach the destination, whether it is long or short. The communication methods that people can use daily today require extremely short time, but in the far future, communication between people will not be limited to continents, but may need to span galaxies. This greatly increases the communication time - for example, on August 6 this year, when the "Curiosity" rover landed on Mars, there was a delay of more than ten minutes for the signal returned to reach the earth. But this is only the distance between the Earth and Mars in the solar system. If the distance is extended further, scientists believe that only quantum mechanics has the ability to truly achieve "instant" communication, no matter how far away it is.

The key to making instantaneous communication a reality lies in a quantum mechanical phenomenon known as quantum entanglement—what Einstein called "spooky action at a distance," referring to two entangled particles. Even if they are far apart, they maintain a special correlation. Operations on one particle will affect another particle. To put it simply, when one of the particles is measured or observed, the state of the other particle will change accordingly in an instant. This kind of coordinated action, which is like "telepathy", has gone beyond the scope of explanation of the rules of classical physics, so it was regarded as a ghost by Einstein. But using quantum entanglement, we can manipulate one of the particles to cause immediate and corresponding changes in the corresponding particle, thereby completing the action of sending and receiving "cosmic mail".