The mystery of Quantum entanglement is fading.

[shunyadragon]

Quantum entanglement may now be useful in every aspect computing.
Quantum entanglement used to a mysterious unpredictable phenomenon that lead some to believe in many universes with many possible different constants and laws of nature. Quantum entanglement is becoming increasingly very well understood and likely very useful in computing and communication.

the removal of the shroud of mystery likely began with the ability to image the basic particles of matter, and understand how they function.

Quantum computers are here now, and will likely dominate the future of computing.

Source: Physicists entangle 15 trillion hot atoms | Live Science

Physicists entangle 15 trillion hot atoms
By Tim Childers - Live Science Contributor

Physicists set a new record by linking together a hot soup of 15 trillion atoms in a bizarre phenomenon called quantum entanglement. The finding could be a major breakthrough for creating more accurate sensors to detect ripples in space-time called gravitational waves or even the elusive dark matter thought to pervade the universe.

Entanglement, a quantum phenomena Albert Einstein famously described as "spooky action at a distance," is a process in which two or more particles become linked and any action performed on one instantaneously affects the others regardless of how far apart they are. Entanglement lies at the heart of many emerging technologies, such as quantum computing and cryptography.

Entangled states are infamous for being fragile; their quantum links can be easily broken by the slightest internal vibration or interference from the outside world. For this reason, scientists attempt to reach the coldest temperatures possible in experiments to entangle jittery atoms; the lower the temperature, the less likely atoms are to bounce into each other and break their coherence. For the new study, researchers at the Institute of Photonic Science (ICFO) in Barcelona, Spain, took the opposite approach, heating atoms to millions of times hotter than a typical quantum experiment to see if entanglement could persist in a hot and chaotic environment.

© Copyright Original Source

 

[Brickjectivity]

@shunyadragon I feel a tiny bit of concern that someone will discover a new kind of bomb. Is that likely?

 

[shunyadragon]

@shunyadragon I feel a tiny bit of concern that someone will discover a new kind of bomb. Is that likely?

Our present 'bombs' are very capable of wiping out humanity 10 times over but our knowledge of lasers depends on Quantum mechanics and Quantum properties. Now for future weapons it may be down this alley. Though the unimaginable speed of computing and the potential of quantum circuitry would have military applications.

 

[Brickjectivity]

Our present 'bombs' are very capable of wiping out humanity 10 times over but our knowledge of lasers depends on Quantum mechanics and Quantum properties. Now for future weapons it may be down this alley. Though the unimaginable speed of computing and the potential of quantum circuitry would have military applications.

It would take several bombs to wipe out humanity, but you know that in some way all atoms might be entangled if the big bang theory is correct. We already know that matter appears to be a trick of certain arrangements of quantum particles. What if all matter is like a knitted sweater? Maybe if you pull the strand the whole thing could unravel with no respect for distance? Then suddenly all atoms might simply revert to other forms that don't interact. Is that impossible?

 

[LegionOnomaMoi]

It would take several bombs to wipe out humanity, but you know that in some way all atoms might be entangled if the big bang theory is correct.

Entanglement has little or nothing to do with the big bang. I get (I think) what you mean, i.e., that if there were a common origin to everything in the universe then every "particle" would have previously interacted, but entanglement and quantum coherence more generally is easily broken. In fact, it is extremely difficult not to do so.

What if all matter is like a knitted sweater? Maybe if you pull the strand the whole thing could unravel with no respect for distance? Then suddenly all atoms might simply revert to other forms that don't interact. Is that impossible?

It is impossible. Firstly, whatever it is that correlates observable properties of entangled systems regardless of distance, it cannot be used even to send a signal or information more generally. Secondly, a primary mechanism for the creation of entanglement is in fact the destruction or decay of atoms. Thirdly, were entanglement necessary for general interaction then there would be no interaction (the interaction is only from the outside when examining quantum systems that cannot be factorized into subsystems i.e., in systems that cannot be characterized in terms of joint probability distributions; in such systems knowledge about the probability distribution/density associated with any observable changes the system as a whole). In short, it is better to conceive of entanglement in terms of non-classical probability and the statistical properties of measurement than as something causal, ubiquitous, and/or affecting macroscopic behavior.

 

[LegionOnomaMoi]

Quantum entanglement used to a mysterious unpredictable phenomenon that lead some to believe in many universes with many possible different constants and laws of nature. Quantum entanglement is becoming increasingly very well understood and likely very useful in computing and communication.

the removal of the shroud of mystery likely began with the ability to image the basic particles of matter, and understand how they function.

1) We currently do not have an adequate definition of what constitutes elementary or "basic" particles, partly because we do not understand on a very fundamental how to understand quantum theory as a basic, underlying theory of physics rather than as a statistical scheme which tends to require classical inputs in order to make predictions. Entanglement is problematic at this level not only because of the issues with EFT and renormalization but because of locality principles required of Lorentz and similar invariances necessitated by any relativistic theory.
2) The increases in our ability to use non-classical features of quantum theory does not necessarily come with increased knowledge. Actually, it has tended to increase interest in fundamental questions more than provide any answers. Indeed, a lot of the work and debate in quantum foundations comes from those in quantum information and/or quantum computing because these theorists and experimentalists tend to rely on non-classical features and make use of measurement schemes (non-demolition, weak measurements, entanglement, etc.) without understanding them. According to orthodoxy, QM is a statistical theory that yields predictions of specified kinds for systems of particular types in particular experimental arrangements. This hardly satisfying for anybody working to understand either elementary particles or quantum computing. It is no longer taboo to want to do more than "shut up and calculate", but that doesn't mean we understand e.g., entanglement beyond the mathematics known over 50 years ago.
3) Progress in our experimental and theoretical understanding of nonlocality and entanglement continues to be plagued by issues of interpretation. Bell's theorem was first proved in 1964 and has been proved again and again many times since, while Bohm's reformulation of EPR is from 1951. Yet modern experiments continue to explore various loopholes and to derive more general (and more specific if different) inequalities as well as measurement schemes, not to mention algorithms, all without taking the "mystery" out of any aspect of QM. Indeed, if anything the "mystery" has increased, as greater and greater dissatisfaction with the received orthodoxy of the so-called Copenhagen interpretation has come under more and more fire, in no small part due to the advent of fields like quantum computing and quantum information theory.

 

[Heyo]

Quantum entanglement may now be useful in every aspect computing.
Quantum entanglement used to a mysterious unpredictable phenomenon that lead some to believe in many universes with many possible different constants and laws of nature. Quantum entanglement is becoming increasingly very well understood and likely very useful in computing and communication.

the removal of the shroud of mystery likely began with the ability to image the basic particles of matter, and understand how they function.

Quantum computers are here now, and will likely dominate the future of computing.

Source: Physicists entangle 15 trillion hot atoms | Live Science


Physicists entangle 15 trillion hot atoms
By Tim Childers - Live Science Contributor

Physicists set a new record by linking together a hot soup of 15 trillion atoms in a bizarre phenomenon called quantum entanglement. The finding could be a major breakthrough for creating more accurate sensors to detect ripples in space-time called gravitational waves or even the elusive dark matter thought to pervade the universe.

Entanglement, a quantum phenomena Albert Einstein famously described as "spooky action at a distance," is a process in which two or more particles become linked and any action performed on one instantaneously affects the others regardless of how far apart they are. Entanglement lies at the heart of many emerging technologies, such as quantum computing and cryptography.

Entangled states are infamous for being fragile; their quantum links can be easily broken by the slightest internal vibration or interference from the outside world. For this reason, scientists attempt to reach the coldest temperatures possible in experiments to entangle jittery atoms; the lower the temperature, the less likely atoms are to bounce into each other and break their coherence. For the new study, researchers at the Institute of Photonic Science (ICFO) in Barcelona, Spain, took the opposite approach, heating atoms to millions of times hotter than a typical quantum experiment to see if entanglement could persist in a hot and chaotic environment.

"Entanglement is one of the most remarkable quantum technologies, but it is famously fragile," said Jia Kong, a visiting scientist at ICFO and lead author of the study. "Most entanglement-related quantum technology has to be applied in a low-temperature environment, such as a cold atomic system. This limits the application of entanglement states. [Whether or not] entanglement can survive in a hot and messy environment is an interesting question."

Things get hot and messy
The researchers heated a small glass tube filled with vaporized rubidium and inert nitrogen gas to 350 degrees Fahrenheit (177 degrees Celsius), coincidentally the perfect temperature to bake cookies. At this temperature, the hot cloud of rubidium atoms is in a state of chaos, with thousands of atomic collisions taking place every second. Like billiard balls, the atoms bounce off each other, transferring their energy and spin. But unlike classical billiards, this spin does not represent the physical motion of the atoms.

In quantum mechanics, spin is a fundamental property of particles, just like mass or electric charge, that gives particles an intrinsic angular momentum. In many ways, the spin of a particle is analogous to a spinning planet, having both angular momentum and creating a weak magnetic field, called a magnetic moment. But in the wacky world of quantum mechanics, classical analogies fall apart. The very notion that particles like protons or electrons are rotating solid objects of size and shape doesn't fit the quantum worldview. And when scientists try to measure a particle's spin, they get one of two answers: up or down. There are no in-between in quantum mechanics.

Fortunately, the tiny magnetic fields created by a particle's spin allow scientists to measure spin in a number of unique ways. One of those involves polarized light, or electromagnetic waves that oscillate in a single direction.

The researchers shot a beam of polarized light at the tube of rubidium atoms. Because the atoms' spins act like tiny magnets, the polarization of the light rotates as it passes through the gas and interacts with its magnetic field. This light-atom interaction creates large-scale entanglement between the atoms and the gas. When researchers measure the rotation of the light waves that come out the other side of the glass tube, they can determine the total spin of the gas of atoms, which consequently transfers the entanglement onto the atoms and leaves them in an entangled state.

"The [measurement] we used is based on light-atom interaction," Kong said. "With proper conditions, the interaction will produce correlation between light and atoms, and then if we do correct detection, the correlation will be transferred into atoms, therefore creating entanglement between atoms. The surprising thing is that these random collisions didn't destroy entanglement."

In fact, the "hot and messy" environment inside the glass tube was key to the experiment's success. The atoms were in what physicists call a macroscopic spin singlet state, a collection of pairs of entangled particles' total spin sums to zero. The initially entangled atoms pass their entanglement to each other via collisions in a game of quantum tag, exchanging their spins but keeping the total spin at zero, and allowing the collective entanglement state to persist for at least a millisecond. For instance, particle A is entangled with particle B, but when particle B hits particle C, it links both particles with particle C, and so on.

This "means that 1,000 times per second, a new batch of 15 trillion atoms is being entangled," Kong said in a statement. One millisecond "is a very long time for the atoms, long enough for about 50 random collisions to occur. This clearly shows that the entanglement is not destroyed by these random events. This is maybe the most surprising result of the work."

Because the scientists are only able to understand the collective state of the entangled atoms, the application of their research is limited to special uses. Technologies like quantum computers are likely out of the question, since the state of individually entangled particles needs to be known to store and send information.

However, their results may help to develop ultra-sensitive magnetic field detectors, capable of measuring magnetic fields more than 10 billion times weaker than Earth's magnetic field. Such powerful magnetometers have applications in many fields of science. For example, in the study of neuroscience, magnetoencephalography is used to take images of the brain by detecting the ultra-faint magnetic signals given off by brain activity.

"We hope that this kind of giant entangled state will lead to better sensor performance in applications ranging from brain imaging, to self-driving cars, to searches for dark matter," Morgan Mitchell, a professor of physics and the lab's group leader, said in the statement.

Their results were published online May 15 in the journal Nature Communications.

© Copyright Original Source

Reminds me of research about photosynthesis. (Not this article but a similar one: https://phys.org/news/2018-05-quantum-effects-photosynthesis.html)
Photons are transported down a cellular chain - without loss and without decoherence in a room temperature environment.

 

[shunyadragon]

1) We currently do not have an adequate definition of what constitutes elementary or "basic" particles, partly because we do not understand on a very fundamental how to understand quantum theory as a basic, underlying theory of physics rather than as a statistical scheme which tends to require classical inputs in order to make predictions. Entanglement is problematic at this level not only because of the issues with EFT and renormalization but because of locality principles required of Lorentz and similar invariances necessitated by any relativistic theory.
2) The increases in our ability to use non-classical features of quantum theory does not necessarily come with increased knowledge. Actually, it has tended to increase interest in fundamental questions more than provide any answers. Indeed, a lot of the work and debate in quantum foundations comes from those in quantum information and/or quantum computing because these theorists and experimentalists tend to rely on non-classical features and make use of measurement schemes (non-demolition, weak measurements, entanglement, etc.) without understanding them. According to orthodoxy, QM is a statistical theory that yields predictions of specified kinds for systems of particular types in particular experimental arrangements. This hardly satisfying for anybody working to understand either elementary particles or quantum computing. It is no longer taboo to want to do more than "shut up and calculate", but that doesn't mean we understand e.g., entanglement beyond the mathematics known over 50 years ago.
3) Progress in our experimental and theoretical understanding of nonlocality and entanglement continues to be plagued by issues of interpretation. Bell's theorem was first proved in 1964 and has been proved again and again many times since, while Bohm's reformulation of EPR is from 1951. Yet modern experiments continue to explore various loopholes and to derive more general (and more specific if different) inequalities as well as measurement schemes, not to mention algorithms, all without taking the "mystery" out of any aspect of QM. Indeed, if anything the "mystery" has increased, as greater and greater dissatisfaction with the received orthodoxy of the so-called Copenhagen interpretation has come under more and more fire, in no small part due to the advent of fields like quantum computing and quantum information theory.

Well, ah . . . I seriously disagree with your pessimistic view of the process of research and discoveries concerning the last 50 years. All I can do is continue to cite contemporary research on Quantum Mechanics and it application to very real technology in the modern world.

The fact that we can now image the basic particles of matter greatly contributes to our knowledge of Quantum Mechanics.


No, it is not longer mystery, it is science.

 

[WalterTrull]

I love it when the physical sciences come up with accidental proofs of God.

 

[shunyadragon]

I love it when the physical sciences come up with accidental proofs of God.

Odd neither science nor God (If God exists.} is accidental.

 

[LegionOnomaMoi]

Well, ah . . . I seriously disagree with your pessimistic view of the process of research and discoveries concerning the last 50 years. All I can do is continue to cite contemporary research on Quantum Mechanics and it application to very real technology in the modern world.

And this is irrelevant to the point, or supports mine. My point was that if anything our increasing ability to use quantum mechanics as a statistical theory of measurement processes has been challenged by the technological advances made especially in areas like quantum computing which now contributes greatly to quantum foundations. This is because the older view that QM cannot tell us about the world (the antirealism of the orthodox interpretation) has been called into question in part because our perspective and means of measurement have changed. It is no longer the case that we can simply view QM as a statistical scheme that yields the outcomes of measurements when we require e.g., quantum coherence for quantum computing or spectroscopy. Likewise, foundational questions about quantum (non-classical) probability are no longer philosophical or purely technical when issues of contextuality are key in e.g., determining the extent to which Bell tests serve as certification of randomness.
But the number of differing interpretations has continued to grow with these advances. So too have the number of practitioners (not to mention philosophers of physics) who are no longer content with the FAPP view we adopt in the lab (most of the time). Nothing in recent advances has changed the perspective of the many-world interpretation adherents as you suggest in your original post. Many of the leaders in the field of quantum computing and quantum information subscribe to QBism, which (roughly speaking) holds that QM is best viewed not as a description of physical reality in the traditional sense but rather as a betting scheme yielding the most likely outcomes of physical experiments (Fuchs in particular, or at least in person when we last spoke, was keen on reiterating that he views QBism as realist because he accepts a larger reality). A great deal of theoretical work is now devoted to developing mathematical frameworks to better understand what quantum theory is physically at a basic level. But we still don't have answers, or we'd have a tendency towards agreement rather than the greater divergences we actually find among practicing physicists (and to a lesser extent chemists, engineers, etc.)

No, it is not longer mystery, it is science.

These are not mutually exclusive. There's a reason we distinguish between scientific research and its applications. We do research as scientists because we are looking for answers we don't yet have. I wouldn't enjoy my work very much otherwise, and I would enjoy collaborations (not to mention symposia, conferences, and other areas where we get to discuss work done by others in the field and in related fields) even less so. It is one thing to say that a lot of popular bunk concerning quantum theory is nonsense and shouldn't be justified simply because there remains a great deal we don't know about quantum foundations. It is another to say that because of advancements in technology and work in new fields within quantum physics, the views of those working in these fields as well as the whole of quantum foundations and a good deal of new research is pointless because it is ALL directed at pointing towards remaining mysteries you seem to regard as nonexistent.

 

[shunyadragon]

And this is irrelevant to the point, or supports mine. My point was that if anything our increasing ability to use quantum mechanics as a statistical theory of measurement processes has been challenged by the technological advances made especially in areas like quantum computing which now contributes greatly to quantum foundations. This is because the older view that QM cannot tell us about the world (the antirealism of the orthodox interpretation) has been called into question in part because our perspective and means of measurement have changed. It is no longer the case that we can simply view QM as a statistical scheme that yields the outcomes of measurements when we require e.g., quantum coherence for quantum computing or spectroscopy. Likewise, foundational questions about quantum (non-classical) probability are no longer philosophical or purely technical when issues of contextuality are key in e.g., determining the extent to which Bell tests serve as certification of randomness.
But the number of differing interpretations has continued to grow with these advances. So too have the number of practitioners (not to mention philosophers of physics) who are no longer content with the FAPP view we adopt in the lab (most of the time). Nothing in recent advances has changed the perspective of the many-world interpretation adherents as you suggest in your original post. Many of the leaders in the field of quantum computing and quantum information subscribe to QBism, which (roughly speaking) holds that QM is best viewed not as a description of physical reality in the traditional sense but rather as a betting scheme yielding the most likely outcomes of physical experiments (Fuchs in particular, or at least in person when we last spoke, was keen on reiterating that he views QBism as realist because he accepts a larger reality). A great deal of theoretical work is now devoted to developing mathematical frameworks to better understand what quantum theory is physically at a basic level. But we still don't have answers, or we'd have a tendency towards agreement rather than the greater divergences we actually find among practicing physicists (and to a lesser extent chemists, engineers, etc.)


These are not mutually exclusive. There's a reason we distinguish between scientific research and its applications. We do research as scientists because we are looking for answers we don't yet have. I wouldn't enjoy my work very much otherwise, and I would enjoy collaborations (not to mention symposia, conferences, and other areas where we get to discuss work done by others in the field and in related fields) even less so. It is one thing to say that a lot of popular bunk concerning quantum theory is nonsense and shouldn't be justified simply because there remains a great deal we don't know about quantum foundations. It is another to say that because of advancements in technology and work in new fields within quantum physics, the views of those working in these fields as well as the whole of quantum foundations and a good deal of new research is pointless because it is ALL directed at pointing towards remaining mysteries you seem to regard as nonexistent.

Rambles too much to respond much. Two point the use of Quantum Mechanics in technology, ie Quantum Computers is not just a statistical theory of measurement processes. In this case science and mystery is mutually exclusive.

 

[LegionOnomaMoi]

Rambles too much to respond much. Two point the use of Quantum Mechanics in technology, ie Quantum Computers is not just a statistical theory of measurement processes. In this case science and mystery is mutually exclusive.

1) We don't have quantum computers in any meaningful sense currently
2) Pointing to quantum computing advances as evidence that we better understand the so-called "mystery" or "mysteries" of QM is like claiming that information theory and modern algorithms ensure a better understanding of classical electromagnetism. Quantum computing, like its classical counterpart, involves mostly theoretical work in which the physical systems are of necessity irrelevant. The actual underlying physical processes that will (it is hoped) eventually underlie quantum computers will be advances in the semi-classical physics and engineering underlying current technologies in steering, QND, optics, spectroscopy, and quantum control among others.
3) If you don't have enough of a background in physics to understand the actual physics behind either our current state of knowledge or how much we understood previously of the theoretical nature of quantum physics vs. what we understand now and what the consensus of physics in different relevant fields is, then naturally you would view the difference between your perceptions of pop science articles like the one you linked to and other pop science pieces on quantum "mysteries" as dichotomous and mutually exclusive. I view them as pop science not worth much of my time.

 

[shunyadragon]

1) We don't have quantum computers in any meaningful sense currently
2) Pointing to quantum computing advances as evidence that we better understand the so-called "mystery" or "mysteries" of QM is like claiming that information theory and modern algorithms ensure a better understanding of classical electromagnetism. Quantum computing, like its classical counterpart, involves mostly theoretical work in which the physical systems are of necessity irrelevant. The actual underlying physical processes that will (it is hoped) eventually underlie quantum computers will be advances in the semi-classical physics and engineering underlying current technologies in steering, QND, optics, spectroscopy, and quantum control among others.
3) If you don't have enough of a background in physics to understand the actual physics behind either our current state of knowledge or how much we understood previously of the theoretical nature of quantum physics vs. what we understand now and what the consensus of physics in different relevant fields is, then naturally you would view the difference between your perceptions of pop science articles like the one you linked to and other pop science pieces on quantum "mysteries" as dichotomous and mutually exclusive. I view them as pop science not worth much of my time.

again, no response to your unreasonably negative view. All I can do is post current advances in Quantum Mechanics.

An important point is you have failed to post peer reviewed scientific reference to support your assertions.

 

[shunyadragon]

https://phys.org/news/2020-05-path-quantum-room-temperature.html

Researchers see path to quantum computing at room temperature
by The Army Research Laboratory

Credit: CC0 Public Domain
Army researchers predict quantum computer circuits that will no longer need extremely cold temperatures to function could become a reality after about a decade.

For years, solid-state quantum technology that operates at room temperature seemed remote. While the application of transparent crystals with optical nonlinearities had emerged as the most likely route to this milestone, the plausibility of such a system always remained in question.

Now, Army scientists have officially confirmed the validity of this approach. Dr. Kurt Jacobs, of the U.S. Army Combat Capabilities Development Command's Army Research Laboratory, working alongside Dr. Mikkel Heuck and Prof. Dirk Englund, of the Massachusetts Institute of Technology, became the first to demonstrate the feasibility of a quantum logic gate comprised of photonic circuits and optical crystals.

"If future devices that use quantum technologies will require cooling to very cold temperatures, then this will make them expensive, bulky, and power hungry," Heuck said. "Our research is aimed at developing future photonic circuits that will be able to manipulate the entanglement required for quantum devices at room temperature."

Quantum technology offers a range of future advances in computing, communications and remote sensing.

In order to accomplish any kind of task, traditional classical computers work with information that is fully determined. The information is stored in many bits, each of which can be on or off. A classical computer, when given an input specified by a number of bits, can process this input to produce an answer, which is also given as a number of bits. A classical computer processes one input at a time.

In contrast, quantum computers store information in qubits that can be in a strange state where they are both on and off at the same time. This allows a quantum computer to explore the answers to many inputs at the same time. While it cannot output all the answers at once, it can output relationships between these answers, which allows it to solve some problems much faster than a classical computer.

Unfortunately, one of the major drawbacks of quantum systems is the fragility of the strange states of the qubits. Most prospective hardware for quantum technology must be kept at extremely cold temperatures—close to zero kelvins—to prevent the special states being destroyed by interacting with the computer's environment.

"Any interaction that a qubit has with anything else in its environment will start to distort its quantum state," Jacobs said. "For example, if the environment is a gas of particles, then keeping it very cold keeps the gas molecules moving slowly, so they don't crash into the quantum circuits as much."

Researchers have directed various efforts to resolve this issue, but a definite solution is yet to be found. At the moment, photonic circuits that incorporate nonlinear optical crystals have presently emerged as the sole feasible route to quantum computing with solid-state systems at room temperatures.

"Photonic circuits are a bit like electrical circuits, except they manipulate light instead of electrical signals," Englund said. "For example, we can make channels in a transparent material that photons will travel down, a bit like electrical signals traveling along wires."

Unlike quantum systems that use ions or atoms to store information, quantum systems that use photons can bypass the cold temperature limitation. However, the photons must still interact with other photons to perform logic operations. This is where the nonlinear optical crystals come into play.

Researchers can engineer cavities in the crystals that temporarily trap photons inside. Through this method, the quantum system can establish two different possible states that a qubit can hold: a cavity with a photon (on) and a cavity without a photon (off). These qubits can then form quantum logic gates, which create the framework for the strange states.

In other words, researchers can use the indeterminate state of whether or not a photon is in a crystal cavity to represent a qubit. The logic gates act on two qubits together, and can create "quantum entanglement" between them. This entanglement is automatically generated in a quantum computer, and is required for quantum approaches to applications in sensing.

However, scientists based the idea to make quantum logic gates using nonlinear optical crystals entirely on speculation—up until this point. While it showed immense promise, doubts remained as to whether this method could even lead to practical logic gates.

The application of nonlinear optical crystals had remained in question until researchers at the Army's lab and MIT presented a way to realize a quantum logic gate with this approach using established photonic circuit components.

"The problem was that if one has a photon travelling in a channel, the photon has a 'wave-packet' with a certain shape," Jacobs said. "For a quantum gate, you need the photon wave-packets to remain the same after the operation of the gate. Since nonlinearities distort wave-packets, the question was whether you could load the wave-packet into cavities, have them interact via a nonlinearity, and then emit the photons again so that they have the same wave-packets as they started with."

Once they designed the quantum logic gate, the researchers performed numerous computer simulations of the operation of the gate to demonstrate that it could, in theory, function appropriately. Actual construction of a quantum logic gate with this method will first require significant improvements in the quality of certain photonic components, researchers said.

"Based on the progress made over the last decade, we expect that it will take about ten years for the necessary improvements to be realized," Heuck said. "However, the process of loading and emitting a wave-packet without distortion is something that we should able to realize with current experimental technology, and so that is an experiment that we will be working on next."

Physical Review Letters published the team's findings in a peer-reviewed paper April 20.