Reality doesn’t exist, quantum experiment confirms

 

Reality doesn't exist

Reality doesn’t exist

Australian scientists have recreated a famous experiment and confirmed quantum physics’s bizarre predictions about the nature of reality, by proving that reality doesn’t actually exist until we measure it – at least, not on the very small scale.

That all sounds a little mind-meltingly complex, but the experiment poses a pretty simple question: if you have an object that can either act like a particle or a wave, at what point does that object ‘decide’?

Our general logic would assume that the object is either wave-like or particle-like by its very nature, and our measurements will have nothing to do with the answer. But quantum theory predicts that the result all depends on how the object is measured at the end of its journey. And that’s exactly what a team from the Australian National University has now found.

“It proves that measurement is everything. At the quantum level, reality does not exist if you are not looking at it,” lead researcher and physicist Andrew Truscott said in a press release.

Known as John Wheeler’s delayed-choice thought experiment, the experiment was first proposed back in 1978 using light beams bounced by mirrors, but back then, the technology needed was pretty much impossible. Now, almost 40 years later, the Australian team has managed to recreate the experiment using helium atoms scattered by laser light.

“Quantum physics predictions about interference seem odd enough when applied to light, which seems more like a wave, but to have done the experiment with atoms, which are complicated things that have mass and interact with electric fields and so on, adds to the weirdness,” said Roman Khakimov, a PhD student who worked on the experiment.

To successfully recreate the experiment, the team trapped a bunch of helium atoms in a suspended state known as a Bose-Einstein condensate, and then ejected them all until there was only a single atom left.

This chosen atom was then dropped through a pair of laser beams, which made a grating pattern that acted as a crossroads that would scatter the path of the atom, much like a solid grating would scatter light.

They then randomly added a second grating that recombined the paths, but only after the atom had already passed the first grating.

When this second grating was added, it led to constructive or destructive interference, which is what you’d expect if the atom had travelled both paths, like a wave would. But when the second grating was not added, no interference was observed, as if the atom chose only one path.

The fact that this second grating was only added after the atom passed through the first crossroads suggests that the atom hadn’t yet determined its nature before being measured a second time.

So if you believe that the atom did take a particular path or paths at the first crossroad, this means that a future measurement was affecting the atom’s path, explained Truscott. “The atoms did not travel from A to B. It was only when they were measured at the end of the journey that their wave-like or particle-like behaviour was brought into existence,” he said.

Although this all sounds incredibly weird, it’s actually just a validation for the quantum theory that already governs the world of the very small. Using this theory, we’ve managed to develop things like LEDs, lasers and computer chips, but up until now, it’s been hard to confirm that it actually works with a lovely, pure demonstration such as this one.

Source:  Sciencedaily.com

Quantum systems can have hot and cold temperatures at once

quantum chip Hot and cold at the same time

quantum chip Hot and cold at the same time

Quantum systems can have several temperatures at once.

Temperature is a very useful physical quantity. It allows us to make a simple statistical statement about the energy of particles swirling around on complicated paths without having to know the specific details of the system. Scientists from the Vienna University of Technology together with colleagues from Heidelberg University have now investigated, how quantum particles reach such a state where statistical statements are possible. The result is surprising: a cloud of atoms can have several temperatures at once. This is an important step towards a deeper understanding of large quantum systems and their exotic properties.

 Statistics Helps where Things get Complicated

The air around us consists of countless molecules, moving around randomly. It would be utterly impossible to track them all and to describe all their trajectories. But for many purposes, this is not necessary. Properties of the gas can be found which describe the collective behaviour of all the molecules, such as the air pressure or the temperature, which results from the particles’ energy. On a hot summer’s day, the molecules move at about 430 meters per second, in winter, it is a bit less.

This statistical view (which was developed by the Viennese physicist Ludwig Boltzmann) has proved to be extremely successful and describes many different physical systems, from pots of boiling water to phase transitions in liquid crystals in LCD-displays. However, in spite of huge efforts, open questions have remained, especially with regard to quantum systems. How the well-known laws of statistical physics emerge from many small quantum parts of a system remains one of the big open questions in physics.

Hot and Cold at the Same Time

Scientists at the Vienna University of Technology have now succeeded in studying the behaviour of a quantum physical multi-particle system in order to understand the emergence of statistical properties. The team of Professor Jörg Schmiedmayer used a special kind of microchip to catch a cloud of several thousand atoms and cool them close to absolute zero at -273°C, where their quantum properties become visible.

The experiment showed remarkable results: When the external conditions on the chip were changed abruptly, the quantum gas could take on different temperatures at once. It can be hot and cold at the same time. The number of temperatures depends on how exactly the scientists manipulate the gas. “With our microchip we can control the complex quantum systems very well and measure their behaviour,” says Tim Langen, leading author of the paper published in “Science.” There had already been theoretical calculations predicting this effect, but it has never been possible to observe it and to produce it in a controlled environment.

The experiment helps scientists to understand the fundamental laws of quantum physics and their relationship with the statistical laws of thermodynamics. This is relevant for many different quantum systems, maybe even for technological applications. Finally, the results shed some light on the way our classical macroscopic world emerges from the strange world of tiny quantum objects.

Source:  sciencedaily.com

First photograph of light as a particle and a wave

Quantum mechanics tells us that light can behave simultaneously as a particle or a wave. However, there has never been an experiment able to capture both natures of light at the same time; the closest we have come is seeing either wave or particle, but always at different times. Taking a radically different experimental approach, EPFL scientists have now been able to take the first ever snapshot of light behaving both as a wave and as a particle. The breakthrough work is published in Nature Communications.

When UV light hits a metal surface, it causes an emission of electrons. Albert Einstein explained this “photoelectric” effect by proposing that light – thought to only be a wave – is also a stream of particles. Even though a variety of experiments have successfully observed both the particle- and wave-like behaviors of light, they have never been able to observe both at the same time.

A new approach on a classic effect

A research team led by Fabrizio Carbone at EPFL has now carried out an experiment with a clever twist: using electrons to image light. The researchers have captured, for the first time ever, a single snapshot of light behaving simultaneously as both a wave and a stream of particles particle.

The experiment is set up like this: A pulse of laser light is fired at a tiny metallic nanowire. The laser adds energy to the charged particles in the nanowire, causing them to vibrate. Light travels along this tiny wire in two possible directions, like cars on a highway. When waves traveling in opposite directions meet each other they form a new wave that looks like it is standing in place. Here, this standing wave becomes the source of light for the experiment, radiating around the nanowire.

This is where the experiment’s trick comes in: The scientists shot a stream of electrons close to the nanowire, using them to image the standing wave of light. As the electrons interacted with the confined light on the nanowire, they either sped up or slowed down. Using the ultrafast microscope to image the position where this change in speed occurred, Carbone’s team could now visualize the standing wave, which acts as a fingerprint of the wave-nature of light.

While this phenomenon shows the wave-like nature of light, it simultaneously demonstrated its particle aspect as well. As the electrons pass close to the standing wave of light, they “hit” the light’s particles, the photons. As mentioned above, this affects their speed, making them move faster or slower. This change in speed appears as an exchange of energy “packets” (quanta) between electrons and photons. The very occurrence of these energy packets shows that the light on the nanowire behaves as a particle.

“This experiment demonstrates that, for the first time ever, we can film quantum mechanics – and its paradoxical nature – directly,” says Fabrizio Carbone. In addition, the importance of this pioneering work can extend beyond fundamental science and to future technologies. As Carbone explains: “Being able to image and control quantum phenomena at the nanometer scale like this opens up a new route towards quantum computing.”

 

Source:  eurekalert.org

Plants Energy Through Quantum Entanglement

Plants Energy Through Quantum Entanglement:

Plants Energy Through Quantum Entanglement

Plants Energy Through Quantum Entanglement

 

Biophysical theorize that plants exploit the mysterious world of quantum entanglement in photosynthesis . The evidence to date has been purely circumstantial, but now scientists have discovered a characteristic of plants that can not be explained by classical physics .

They are like mini -computers, quantum capable of scanning all possible options in order to choose the most efficient paths or solutions . For plants, this means the ability to make the most of the energy they receive and then deliver that energy from leaves with almost perfect efficiency.

The theory is that plants have light collection macromolecules in cells that can transfer their energy through molecular vibrations – vibrations that have no equivalent in classical physics .

In the new study , researchers at UCL identified a specific feature in biological systems that can only be predicted by quantum physics. The team learned that the energy transfer in light-harvesting macromolecules is facilitated by specific vibrational motions of the chromophore . Quantum effects improve the efficiency of plant photosynthesis in a way that classical physics can not afford.

Life does not end and it can last forever

Quantum Theory Proves Consciousness Moves To Another Universe At Death:

 

Scientists Claim That Quantum Theory Proves Consciousness Moves To Another Universe At Death

Scientists Claim That Quantum Theory Proves Consciousness Moves To Another Universe At Death

Lance is an expert in regenerative medicine and chief scientific officer of Advanced Cell Technology Company. Before he was known for his extensive research that deals with stem cells, was also famous for several successful experiments in animal cloning endangered species .

But not long ago , the scientist involved with physics, quantum mechanics and astrophysics. This explosive mixture has given birth to the new theory of biocentrism , the teacher has been preaching since. Biocentrism teaches that life and consciousness are fundamental to the universe. It is consciousness that creates the material universe , and not vice versa .

Spear points to the structure of the universe and the laws , forces and constants of the universe seem finely tuned for life , which means the existing intelligence before importing. It also states that space and time are not objects or things, but rather the tools of our animal understanding. Lanza said that we time and space around us ” like turtles with shells . ” Which means that when the projectile leaves (space and time ) , we still exist .

The theory implies that there simply is not the death of consciousness. It only exists as a thought, because people identify with his body. They believe that the body will sooner or later die, thinking that your conscience will also disappear. If the body generates consciousness, then consciousness dies when the body dies . But if the body receives consciousness in the same way that a cable satellite signals , and then , of course , consciousness does not end with the death of the physical vehicle. Indeed , consciousness exists outside the constraints of time and space. It can be anywhere : in the human body and beyond . In other words, is not local in the sense that quantum objects are not local.

Lanza also believes that there may be multiple universes simultaneously. In a universe , the body may be dead. And in another continues to exist , consciousness , who emigrated to this universe absorbing . This means that a dead person while traveling through the same tunnel ends not in hell or in heaven , but in a similar world that he or she once inhabited , but this time with life. And so on , ad infinitum . It’s almost like an effect beyond the cosmic Russian doll.
multiple worlds

This instilling hope, but highly controversial theory Lanza has many supporters unconscious , not just mere mortals who want to live forever, but also some renowned scientists . These are physicists and astrophysicists tend to agree with the existence of parallel worlds and suggest the possibility of multiple universes. Multiverse ( multiverse ) is a scientific concept of the call, which they defend. They believe that there are no physical laws that prohibit the existence of parallel worlds.

The first was a science fiction writer HG Wells , who proclaimed in 1895 , in his story ” The Door in the Wall” . And after 62 years , this idea was developed by Dr. Hugh Everett in his graduate thesis at Princeton University . Basically states that at one point the universe is divided into innumerable similar cases. And the next moment, these universes ” newborn ” was divided in a similar manner. In some of these worlds may be present : reading this article in a universe, or watch TV in another.

The trigger for these multiplyingworlds factor is our actions, Everett said . If we make some choices , instant universe is divided into two with different versions of the results.

In the 1980s , Andrei Linde, scientist at the Institute of Physics of the Lebedev developed the theory of multiple universes. He is currently a professor at Stanford University . Linde said : Space is inflation in many areas , leading to similar areas , and these , in turn , produce more areas , and so on to infinity. In the universe , which are separated from each other . They are not aware of each other’s existence . But they represent parts of the same physical universe.

The fact that our universe is not only based on data received from the Planck space telescope. The use of data , scientists have created the most accurate map of the microwave background , the so-called background radiation of the relic, which has been maintained since the beginning of our universe. They also found that the universe has a lot of dark corners represented by some large holes and gaps.

Theoretical physicist Laura Mersini – Houghton of the University of North Carolina with his colleagues argue, there are anomalies of the microwave background due to the fact that our universe is influenced by other nearby existing universes . And the holes and gaps are a direct result of the attacks against us by neighboring universes.
soul

Therefore, there are plenty of places or other universes where our souls could migrate after death , according to the theory of neo – biocentrism . But is there a soul? Is there any scientific theory of consciousness that could accommodate such a statement ? According to Dr. Stuart Hameroff , a near death happens when the quantum information that lives in the nervous system leaves the body and is dissipated in the universe experience. Contrary to materialist accounts of consciousness , Dr. Hameroff offers an alternative explanation of consciousness that may perhaps appeal to both the rational scientific mind and personal insights.

Consciousness resides , according to Stuart and British physicist Sir Roger Penrose, microtubules in brain cells , which are the primary sites of quantum processing. On death, this information is released from your body , which means your consciousness goes with it. They have argued that our experience of consciousness is the result of quantum gravity effects in these microtubules , a theory called orchestrated objective reduction ( Orch – O) .

Consciousness, or at least proto – consciousness is theorized by them as a fundamental property of the universe, present even in the beginning of the universe during the Big Bang. ” In one such scheme proto- conscious experience is a basic property of physical reality accessible to a quantum process associated with brain activity . ”

Our souls are in fact constructed from the very fabric of the universe – and may have existed since the beginning of time . Our brains are just receivers and amplifiers for proto – awareness that is intrinsic to the structure of spacetime . So is there really a part of your consciousness that is not material and will live after the death of his physical body?

Dr. Hameroff said Science Channel documentary through the Wormhole . ” Say the heart stops beating , the blood stops flowing , microtubules lose their quantum state Quantum information microtubules is not destroyed , not may be destroyed, only distributes and dissipates to the universe at large. ” Robert Lanza add here that not only exists in the universe , there is perhaps another universe.

If the patient is resuscitated , revived , this quantum information can return to microtubules and the patient says “I had a near-death experience ” ‘

He adds: ” If you are not revived , and the patient dies , it is possible that this quantum information can exist outside the body, perhaps indefinitely , as a soul . ”

This explanation of quantum consciousness explains things like near-death experiences , astral projection , out of body experiences , reincarnation and even without appeal to religious ideology. The energy of your consciousness potentially recycled back into a different body, at some point, and in the mean time that exists outside the physical body at some other level of reality, and possibly in another universe .

Largest quantum circuit board

Scientists make largest ever quantum circuit board:

Scientists make largest ever quantum circuit board

Scientists make largest ever quantum circuit board

A team of international researchers has been able to create the largest quantum circuit board ever, taking a big step toward truly useful quantum computers. Before this work, the largest number of quantum systems ever strung together in a single component was 14 — the record is now 10,000. Scientists working on the project likened this breakthrough to the move from vacuum tubes to transistors.

This system is not technically a “board” in the strictest sense of the word. Rather, the researchers employed a split laser that contained all 10,000 individually addressable quantum wave packets — photons, essentially. Each photon in the system has an entangled partner in the other half of the beam, which makes it theoretically easier to take measurements. This experimental setup allowed the team to more easily entangle large numbers of quantum bits, which is one of the necessary elements of a quantum computer.

The transistors in a traditional computer are only capable of being a 1 or a 0 at any given time. The big leap made by quantum computers is that a single bit (or qubit) exists in every theoretically possible state at once. When one particle — in this case a photon — is observed, the waveform collapses and we can ascertain its state. This act of observation makes the entangled particle take on the opposite state, even if it’s nowhere near the first one. This is known as quantum superposition, and it’s what makes the potential of quantum computing so alluring to scientists.

BeamsScalability and control of many quantum simultaneous systems have long held back quantum computing, but maybe not for long. The team, made up of researchers from the University of Tokyo and the Australian National University, has shown that a laser light quantum system is scalable — the previous record used captured ions as the matrix of the quantum system.

The authors of the study do, however, admit that the massive scale of the quantum board has made control of the model tricky. Actually making use of such a large light-based quantum computer requires more work. The method currently being proposed for running calculations through this giant quantum computer is based on sequential quantum teleportation, but improved precision is needed. This is the next step for the researchers, who still have some problems to work out before this method becomes the transistor of the quantum computing era.

‘Rare’ Atom May Advance Quantum Computers

‘Rare’ Atom Finding May Advance Quantum Computers:

'Rare' Atom Finding May Advance Quantum Computers

‘Rare’ Atom Finding May Advance Quantum Computers

 

 

Quantum computers could crack codes and run more complex simulations than current machines, but actually building one is hard to do. The bits that store this complex data don’t last long, because they are made of single atoms that get knocked around by stray electrons and photons in the environment.

Enter a team of physicists at Germany’s Karlsruhe Institute of Technology. They found a way to get the bits to last long enough to do computations with, using the magnetic properties of a rare earth element called holmium and the symmetry of platinum. The experiment, detailed in tomorrow’s (Nov. 14) issue of the journal Nature, is an important step in creating quantum computers and making quantum memory useful.

What makes quantum computers powerful is the nature of the bit. Ordinary computers have bits that are 1 or 0, stored in the current in a circuit or the alignment of magnetic fields on a disk. Due to the weirdness of quantum physics, quantum bits, called qubits, can be both 0 and 1 at the same time. That means a quantum computer can do certain kinds of calculations much, much faster. [Wacky Physics: The Coolest Quantum Particles Explained]

One way for qubits to store information in the so-called spin magnetic moments of atoms. Elementary particles such as electrons can have spins that are either up or down. The total spins of the electrons — each has a spin of one-half — will induce the magnetic moment, which is a way of measuring how much torque a magnetic field might exert on a loop of wire. In atoms, the moment has a direction, just like the spins, and it is either up or down.

Magnetic moments

In the study, led by Toshio Miyamachi, the researchers placed a single atom of holmium on a sheet of platinum with a scanning tunneling microscope. The holmium atom’s moments were in a certain state, either up or down. That up or down state represented a bit of information, a 1 or 0 that makes up the language of computers. [Facts About Rare Earth Elements (Infographic)]

To cut down on the chances that a stray photon or electron would interact with the holmium atom, the whole apparatus operates at near absolute zero temperatures.

Ordinarily they would have expected the holmium’s magnetic moment state to last a few milliseconds at most. Physicist Wulf Wulfhekel, whose lab did the work, told LiveScience that other research groups have managed that. But his lab group managed to keep the holmium in a given state for about 10 minutes. To a computer, that’s a long time.

“One of the main problems with quantum computers is that the quantum bit loses its information rather quickly… In our case, you would have 10 minutes time to perform the calculation,” Wulfhekel wrote in an email.

The key to the long-lasting spin magnetic moment state was the arrangement of atoms in the platinum. Atoms’ spin states get upset because in any metal, a few electrons are always on the move. So when a holmium (or any other) atom is on top of the platinum layer, the spin state of a passing electron will link to that of the holmium atom storing the bit and flip the magnetic moment, ruining the quantum state.

The platinum atoms, though, were in a pattern that had three-fold symmetry, which means that an object rotated one-third of the way around looks the same as when you start. If you were the size of a holmium atom and standing on the platinum, you’d see the same pattern turning 120 degrees, like a set of hexagonal or triangular tiles on a floor, Wulfhekel said.

The total spin of the holmium’s inner electrons adds up to 8 — and that number isn’t evenly divisible by three, which is the symmetry of the platinum. That means the holmium atoms are “invisible” to the electrons moving through the platinum.

“This is really a beautiful result,” said Michael Flatté, a professor of physics at the University of Iowa and an expert on spintronics. Flatté, who was not involved in the research, said the paper is likely to be influential because it shows another approach to stabilizing spin states using the structure of the material itself.

Better than diamond?

Even so, there’s still some way to go. Flatté noted that there are other materials that show this phenomenon — one of them is diamond, and it doesn’t need to be kept at cryogenic temperatures. But the problem is that for a computer to be useful one has to be able to manipulate the bits. Bigger atoms, like heavy metals, are easier to work with because it’s possible to move them around with electric or magnetic fields.

That’s one reason this work is important, Flatté said. Miyamachi and Wulfhekel found a way around the trade-off between atoms that are easy to interact with, but at the same time can hang on to their quantum states.

“This is an appealing system,” he said. “They still have a ways to go to challenge diamond.”

Wulfhekel said his experiment only involved a single atom, and to be useful as a real computer it would require more, something that will be the focus of future work.

The team will also look at other elements. Praseodymium is a possibility, though Wulfhekel said he hasn’t tried it yet. The bit-storing atoms have to have spins that have a non-integral relationship to the symmetry of the atoms around them, so that limits the number of elements available.

quantum-computer

New spin on Single-Atom quantum computer

Researchers create single-atom silicon-based quantum computer:

Researchers create single-atom silicon-based quantum computer

Researchers create single-atom silicon-based quantum computer

A team of Australian engineers is claiming it has made the first working quantum bit (qubit) fashioned out of a single phosphorous atom, embedded on a conventional silicon chip. This breakthrough stems all the way back to 1998, when Bruce Kane — then a University of New South Wales (UNSW) professor — published a research paper on the possibility of phosphorous atoms, suspended in ultra-pure silicon, being used as qubits. For 14 years, UNSW has been working on the approach — and today, it has finally turned theory into practice. To create this quantum computer chip, the Australian engineers created a silicon transistor so small that “electrons have to travel along it one after the other.” A single phosphorous atom is then implanted into the silicon substrate, right next to the transistor. The transistor only allows electricity to flow through it if one electron from the phosphorus atom jumps to an “island” in the middle of the transistor. This is the key point: by controlling the phosphorus’s electrons, the engineers can control the flow of electricity across the transistor.

An artist's rendition of the single phosphorous atom (red circle) surrounded by its electron cloud

 

A team of Australian engineers is claiming it has made the first working quantum bit (qubit) fashioned out of a single phosphorous atom, embedded on a conventional silicon chip. This breakthrough stems all the way back to 1998, when Bruce Kane — then a University of New South Wales (UNSW) professor — published a research paper on the possibility of phosphorous atoms, suspended in ultra-pure silicon, being used as qubits. For 14 years, UNSW has been working on the approach — and today, it has finally turned theory into practice. To create this quantum computer chip, the Australian engineers created a silicon transistor so small that “electrons have to travel along it one after the other.” A single phosphorous atom is then implanted into the silicon substrate, right next to the transistor. The transistor only allows electricity to flow through it if one electron from the phosphorus atom jumps to an “island” in the middle of the transistor. This is the key point: by controlling the phosphorus’s electrons, the engineers can control the flow of electricity across the transistor. At this point, I would strongly recommend that you watch this excellent video that walks you through UNSW’s landmark discovery — but if you can’t watch it, just carry on reading. To control the phosphorus atom’s electrons, you must change their spin, which in this case is done by a small burst of microwave radiation. In essence, when the phosphorus atom is in its base state, the transistor is off; it has a value of 0 — but when a small burst of radiation is applied, the electrons change orientation, one of them pops into the transistor, it turns on; it has a value of 1. For more on electron spin and how it might impact computing. Now, we’ve written about quantum computers before — the University of Southern California has created a quantum computer inside a diamond, for example — but the key breakthrough here is that UNSW’s quantum transistor has been fashioned using conventional silicon processes. Rather than beating its own path, UNSW is effectively riding on the back of 60 years and trillions of dollars of silicon-based electronics R&D, which makes this a much more exciting prospect than usual. It is now quite reasonable to believe that there will be readily available, commercial quantum computers in the next few years.

 

Physicists Quantum Teleport Photons Over 88 Miles

 

Physicists Quantum Teleport Photons Over 88 Miles:

Physicists Quantum Teleport Photons Over 88 Miles

Physicists Quantum Teleport Photons Over 88 Miles

Last May, European researchers reported successfully teleporting photons over a distance of 143 km – a little over 88 miles- between two Canary Islands. The researchers’ findings have been reviewed and published in Nature. The previous record of 97 kilometers by a team of researchers in China was published in Nature earlier this month. Those researchers, who are affiliated with the Austrian Academy of Sciences and other European organizations, used lasers to teleport a photon from one Canary Island to the other. This was a process that required several key innovations, because the most common teleportation solution – using optical fiber – wasn’t an option due to signal degradation. Xiao-song Ma, one of the scientists involved in the experiment, said in a press release that “The realization of quantum teleportation over a distance of 143 km has been a huge technological challenge.” That’s putting it mildly. When researchers quantum teleport a photon, they aren’t making it disappear and reappear like on Star Trek. Instead, the information contained in the photon’s quantum state is transmitted from one photon to another through quantum entanglement – without actually travelling the intervening distance.  Unfortunately, this doesn’t mean that information is travelling instantaneously. That’s because the transfer of information occurs when the sender measures the quantum state of their photon. That causes the receiver’s entangled photon to instantly change. However, in order to understand the information, the receiver has to know what the original measurement was, along with some other instructions. Those instructions are sent via normal communications, which are limited to being no faster than the speed of light. To all of this complexity, now add weather – over a large body of water, no less. You start to see the problem, because even the most focused lasers can experience a loss of signal when it passes through water, water vapor, etc. And right now, quantum teleportation is an extremely delicate process. Which makes both the Chinese and European researchers’ work – which use different methods – all the more impressive. The European experiment took place over the ocean, and the Chinese experiment crossed a lake. While quantum teleportation doesn’t lead to instantaneous communication, what it does lead to is incredibly secure communications. That’s because no matter what instructions the sender sends over normal communications channels, those instructions are completely useless without the receiver’s entangled photon. And the sender doesn’t have to know the location of the receiver’s entangled photon. It could be anywhere – there’s no way to track it. Of course, there’s still a long way to go – decades, perhaps – before this produces any kind of practical communications device. These researchers, however, are eager to move on to the next step – quantum teleportation between the Earth’s surface and a satellite. “Our experiment shows how mature ‘quantum technologies’ are today, and how useful they can be for practical applications,” said physicist Anton Zeilinger in a press release. “The next step is satellite-based quantum teleportation, which should enable quantum communication on a global scale. We have now taken a major step in this direction and will use our know-how in an international cooperation, which involves our colleagues at the Chinese Academy of Sciences. The goal is to launch a ‘quantum satellite mission’.” If that mission is successful, then we might start seeing the backbone of a satellite-based, secure, quantum Internet. The applications could be quite fascinating.

 

 

Quantum encryption Unbreakable

With quantum encryption, in which a message gets encoded in bits represented by particles in different states, a secret message can remain secure even if the system is compromised by a malicious hacker.

Cryptography

Cryptography

 

No matter how complex they are, most  secret codes turn out to be breakable. Producing the ultimate secure code may require encoding a secret message inside the quantum relationship between atoms, scientists say.  Now cryptographers have taken “quantum encryption” a step further by showing how a secret message can remain secure even if the system is compromised by a malicious hacker.Artur Ekert, director of the Center for Quantum Technologies at the National University of Singapore, presented the new findings here at the annual meeting of the American Association for the Advancement of Science.  Ekert, speaking Saturday (Feb. 18), described how  decoders can adjust for a compromised encryption device, as long as they know the degree of compromise.  The subject of subatomic particles is a large step away from the use of papyrus, the ancient writing material employed in the first known cryptographic device. That device, called a scytale, was used in 400 B.C. by Spartan military commanders to send coded messages to one another. The commanders would wrap strips of papyrus around a wooden baton and write the message across the strips so that it could be read only when the strips were wrapped around a baton of matching size. Later, the technique of substitution was developed, in which the entire alphabet would be shifted, say, three characters to the right, so than an “a” would be replaced by “d,” and “b” replaced by “e,” and so on. Only someone who knew the substitution rule could read the message. Julius Caesar employed such a cipher scheme in the first century B.C.  Over time, ciphers became more and more complicated, so that they were harder and harder to crack. Harder, but not impossible.  “When you look at the history of cryptography, you come up with a system, and sooner or later someone else comes up with a way of breaking the system,” Ekert said. “You may ask yourself: Is it going to be like this forever? Is there such a thing as the perfect cipher?”  The closest thing to a perfect cipher involves what’s called a one-time pad.  “You just write your message as a sequence of bits and you then add those bits to a key and obtain a cryptogram,” Ekert said.”If you take the cryptogram and add it to the key, you get plain text. In fact, one can prove that if the keys are random and as long as the messages, then the system offers perfect security.”  “If the keys are as long as the message, then you need a secure way to distribute the key,” Ekert said.  The nature of physics known as quantum mechanics seems to offer the best hope of knowing whether a key is secure.  Quantum mechanics says that certain properties of subatomic particles can’t be measured without disturbing the particles and changing the outcome. In essence, a particle exists in a state of indecision until a measurement is made, forcing it to choose one state or another. Thus, if someone made a measurement of the particle, it would irrevocably change the particle.  If an encryption key were encoded in bits represented by particles in different states, it would be immediately obvious when a key was not secure because the measurement made to hack the key would have changed the key.  This, of course, still depends on the ability of the two parties sending and receiving the message to be able to independently choose what to measure, using a truly random number generator — in other words, exercising free will — and using devices they trust.   But what if a hacker were controlling one of the parties, or tampering with the encryption device?  Ekert and his colleagues showed that even in this case, if the messaging parties still have some free will, their code could remain secure as long as they know to what degree they are compromised.  In other words, a random number generator that is not truly random can still be used to send an undecipherable secret message, as long as the sender knows how random it is and adjusts for that fact.  “Even if they are manipulated, as long as they are not stupid and have a little bit of free will, they can still do it,”.