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BOULDER, Colo. Your morning coffee is playing an important role in the world of quantum physics. Adding cream to a cup of joe can cause mesmerizing swirls, but imagine if it was for an indefinite period of time instead of a few seconds. Researchers at the University of Colorado-Boulder are now drawing a parallel between this tasty event and the potential advancements of quantum computing.

They have made a theoretical breakthrough, suggesting that quantum computer chips could be engineered to maintain information in a constant state, much like unending swirls in a coffee cup. This discovery could revolutionize how we approach data storage in quantum computers.

What Are Quantum Computers?

Quantum computers, unlike traditional computers, operate on qubits instead of bits. While bits represent data as zeros or ones, qubits, due to the peculiarities of quantum physics, can exist as zero, one, or both simultaneously. This unique capability allows quantum computers to perform complex computations at unprecedented speeds. However, qubits are notoriously susceptible to becoming jumbled, leading to disorganized and unusable data a challenge akin to the settling of coffee swirls into a uniform brown liquid.

Scientists have proposed a solution to this instability. By arranging qubits in specific patterns, similar to a checkerboard, and bringing them in close proximity, they can influence each other in a way that preserves their initial state. This arrangement, the researchers suggest, could create a form of quantum memory, resistant to disturbances like magnetic fields.

This could be a way of storing information, says study author Rahul Nandkishore, an associate professor of physics at CU Boulder, in a university release. You would write information into these patterns, and the information couldnt be degraded.

The study used mathematical models to envision an array of hundreds to thousands of qubits in tight configurations. In such a setup, individual qubits can affect their neighbors, preventing them from flipping states randomly. This concept, Nandkishore explains, is akin to squeezing people into a telephone booth, where movement is highly restricted.

Beyond quantum computers, this research touches on fundamental principles of physics. It challenges the concept of thermal equilibrium, where systems like a cup of coffee or an ice cube in water eventually reach a uniform state. Nandkishores work suggests that in certain conditions, systems can resist this equilibrium, potentially defying long-standing physical laws.

The wonderful thing about this study is that we discovered that we could understand this fundamental phenomenon through what is almost simple geometry, says Nandkishore.

While further experimental validation is required, the research teams findings offer a promising avenue for developing more stable and efficient quantum computers, potentially leading to significant advancements in the field.

Were not going to have to redo our math for ice and water, concludes Nandkishore. The field of mathematics that we call statistical physics is incredibly successful for describing things we encounter in everyday life. But there are settings where maybe it doesnt apply.

The study is published in the journal Physical Review Letters.

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Coffee With Cream Is Revolutionizing Quantum Physics - Study Finds

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Electrons that spin to the right and the left at the same time. Particles that change their states together, even though they are separated by enormous distances. Intriguing phenomena like these are completely commonplace in the world of quantum physics. Researchers at the TUM Garching campus are using them to build quantum computers, high-sensitivity sensors and the internet of the future.

"We cool the chip down to only a few thousandths of a degree above absolute zerocolder than in outer space," says Rudolf Gross, Professor of Technical Physics and Scientific Director of the Walther Meissner Institute (WMI) at the Garching research campus. He's standing in front of a delicate-looking device with gold-colored disks connected by cables: The cooling system for a special chip that utilizes the bizarre laws of quantum physics.

For about twenty years now, researchers at WMI have been working on quantum computers, a technology based on a scientific revolution that occurred 100 years ago when quantum physics introduced a new way of looking at physics. Today it serves as the foundation for a "new era of technology," as Prof. Gross calls it.

To shape this emerging era, researchers at Garching are investigating ways to utilize the rules of quantum physics, as well as the associated risks and the potential benefits of quantum technology to society.

"We encounter quantum physics every day," says Gross. For example, when we see a stovetop burner element glowing red. In 1900 Max Planck found the formula for the radiation that bodies of different temperatures emit. This meant that he had to assume that the emitted light consists of tiny energy parcels, referred to as quanta. Quantum physics continued to develop in the years that followed, fundamentally changing our understanding of the microcosmos. New technologies exploited the special properties of atoms and electrons, for example, the laser, the magnetic resonance tomograph and the computer chip.

The technologies of this first quantum revolution control large quantities of particles. In the meantime, physicists can also manipulate individual atoms and photons and can produce objects that obey the laws of quantum physics. "Today we can create tailor-made quantum systems," says Gross. The principles of quantum physics, for which there as yet hardly any technological realizations, can be used in this so-called second quantum revolution.

The first of these principles is superposition: A quantum object can assume parallel states, which are mutually exclusive in the classic frame of reference. For example, an electron can rotate both to the right and to the left at the same time. The superposed states can also mutually interact, similar to intersecting waves which either reinforce one another or cancel out one anotherthis is the second principle: Quantum interference.

The third phenomenon is entanglement. Two particles can have a joint quantum state, even if they are located kilometers away from one another. For example, if we measure the polarization of a given photon, then the measurement result for the entangled partner is instantaneously ascertained as if the space between the two photons did not exist.

As exotic as these concepts may sound, they're equally important for technical progress. Classical computers have a drawback: They process information sequentially, one step at a time. "Not even supercomputers which are constantly growing faster will be able to master all the tasks at hand," says Gross, since the complexity of some tasks can increase drastically.

For example, the number of possible travel routes between several cities increases with each potential stop. There are six possible routes between four cities, while for 15 cities the number is more than 40 billion. Thus, the task of finding the shortest route very quickly becomes overwhelmingly complex, even unsolvable, using classical computers within a viable amount of time.

The principle of superposition makes the task much easier for the quantum computer: It uses quantum bits, or qubits, which can process the bit values 0 and 1 simultaneously instead of sequentially. A large number of qubits, linked with one another by quantum interference or entanglement, can process an inconceivably large number of combinations in parallel and can thus solve highly complex tasks very quickly.

Back to WMI: Here we find silver vacuum chambers in which metal atoms are precisely deposited on hand-sized silicon wafers. The highly pure metal layers forming on these wafers form the basis for tiny circuits. When supercooling makes the circuits superconductive, the electricity they carry oscillates at various frequencies corresponding to different energy levels. The two lowest levels serve as the qubit values 0 and 1. The chip in one of these cooling systems contains six qubits, sufficient for research purposes.

However, quantum computers need several hundred qubits in order to solve practical problems. In addition, each one of the qubits should be able to perform as many computational steps as possible in order to realize algorithms that are relevant for practical purposes. But qubits lose their superposition very quickly, even after the slightest disturbance, such as material defects or electrosmog"an enormous problem," says Gross.

Complex correction procedures must then be used to correct these errors, but these processes will require thousands of additional qubits. Experts expect that this will take many years to achieve. Nevertheless, initial applications could already be functional when the number of qubit errors is reduced, if not eliminated.

"One important error source is unwanted mutual interaction between qubits," says Dr. Kirill Fedorov of the WMI. His remedy: Distributing qubits across several chips and entangling them with one another. In the basement of the WMI Fedorov points to a tube with the diameter of a tree branch leading from one quantum computer to the next. The tubes contain microwave conductors which put the qubits into mutual interaction with one another. This approach could make it possible for thousands of qubits to work together in the future.

Eva Weig, Professor of Nano and Quantum Sensor Technology, has a different perspective on this lack of perfection. "The fact that quantum states react so sensitively to everything can also be an advantage," she says. Even the most minute magnetic fields, pressure variations or temperature fluctuations can measurably change a quantum state. "This can make sensors more sensitive and more precise and make them capable of better spatial resolution," says Weig.

She wants to use relatively large objects as mechanical quantum sensors. Even nanostructures consisting of millions of atoms can be put into their quantum ground state, as researchers at the University of California first demonstrated in 2010. Eva Weig is building on the finding. "I want to construct easily controlled nanosystems in order to measure the smallest forces."

In the laboratory, the physicist presents a chip her team made in its own cleanroom. On it are what she calls "nano-guitars," invisible to the naked eye: Tiny strings, 1,000 times thinner than a human hair, which vibrate at radio frequency. Weig's team is attempting to put these nano-oscillators into a defined quantum state. Then the strings could be used as quantum sensors, for example in measuring the forces existing between individual cells.

Professor of Quantum Networks Andreas Reiserer wants to use another aspect of quantum systems in order to facilitate a quantum internet: The quantum state of a particle is destroyed when it is measured, meaning that the information it contains can only be read out once. Thus any attempt at interception would inevitably leave behind traces. If there are no such traces, a communication can then be trusted. "Quantum cryptography is cost-effective and can already support interception-proof communication today," he says.

But the scope of this technology still remains limited. According to Reiserer, fiber optic elements are ideal for transporting quantum information using light. But the glass absorbs some of the light in every kilometer it travels. After about 100 kilometers, communication is no longer possible.

Reiserer's team is therefore conducting research into what are called quantum repeaters, storage units for quantum information which are to be spaced out along the fiber optical network approximately every 100 kilometers. If it is possible to entangle each of the quantum repeaters with its immediate neighbor, then information sent can be passed on without any loss. "This way we hope to be able to traverse global-scale distances," Reiserer says. "Then it could be possible to link devices everywhere around the world to form a 'quantum supercomputer.'"

The Munich-based team wants to miniaturize quantum repeaters, to simplify them and make them suitable for mass production by putting them onto a computer chip. The chip contains an optical fiber in which erbium atoms have been embedded. These atoms serve as qubits which can buffer the information. However, Reiserer admits, this requires cooling to as little as four degrees Kelvin (i.e., approximately -269C) and adds that a lot more research will be necessary before practical viability is achieved.

The arrival of quantum technologies in everyday life also entails some risks. An error-corrected quantum computer could crack today's conventional encryption procedures and could for example compromise online banking security. "The good news is that there are already new encryption procedures which are secure against quantum computer attacks," says Urs Gasser, Professor of Public Policy, Governance and Innovative Technology and head of the "Quantum Social Lab" at TUM. Gasser, a legal scholar, adds that the transition will take several years, making it necessary to get started now.

"The cost of arriving too late could even outstrip the cost of being late on Artificial Intelligence," Gasser warns. The Quantum Social Lab focuses on the ethical, legal and societal impacts of emerging quantum technologies. This includes for example the question of how to integrate people in the debate surrounding the new technology, or whether or not only wealthy countries should be able to better plan their cities thanks to quantum optimization.

"The second quantum revolution is a paradigm shift which will have a far-reaching social, political and economic impact," says Prof. Gasser. "We have to shape this revolution in the best interests of society."

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Shaping the dawn of the quantum age - Phys.org

Researchers at EPFL make significant advances in quantum physics by exposing a peculiar and enigmatic behavior in a quantum magnetic material and providing hints about potential future technological developments.

Image Credit:ArtemisDiana/Shutterstock.com

The world of quantum materials is a mysterious place where things do not always behave as expected. These materials can perform tasks in ways that traditional materials cannot, such as conducting electricity without loss or having magnetic properties that may prove useful in advanced technologies. These unique properties are governed by the laws of quantum mechanics.

Certain quantum materials have minute magnetic waves, known as magnons, circulating through them. These waves exhibit peculiar behaviors. Gaining an understanding of magnons is essential for deciphering the microscopic workings of magnets, which will be important for the development of next-generation computers and electronics.

Up until recently, researchers believed they understood what to expect from the studies of these magnons behavior in strong magnetic fields. Researchers at EPFL, led by Henrik Rnnow and Frdric Mila, have revealed a new and unexpected behavior in strontium copper borate (SrCu2(BO3)2), a quantum material. Although the study casts doubt on what is already known about quantum physics, it also raises intriguing possibilities for next-generation technologies.

But why this particular content? SrCu2(BO3)2 is significant in the field of quantum materials, though the specifics are highly technical. This is because it is the only known real-world example of the Shastry-Sutherland model, a theoretical framework for comprehending structures where atoms' interactions and arrangement prevent them from settling into a simple, ordered state.

Known as highly frustrated lattices, these structures frequently endow the quantum material with complex, peculiar behaviors and characteristics. Therefore, SrCu2(BO3)2 is a perfect candidate to study intricate quantum phenomena and transitions due to its unique structure.

Neutron scattering is a method that the scientists used to study the magnons in SrCu2(BO3)2. In essence, they exposed the material to neutrons and measured how many of them deflected off of it. Since neutrons have no charge and can therefore analyze magnetism without being affected by the charge of the materials electrons or nuclei, neutron scattering is especially useful in the study of magnetic materials.

This work was done at the Helmholtz-Zentrum Berlin's high-field neutron scattering facility, which could probe fields as high as 25.9 Tesla. This level of magnetic field study was unprecedented and allowed the scientists to see the behavior of the magnons up close.

Subsequently, the scientists integrated the data with cylinder matrix-product-states computations, an effective computational technique that supported the experimental findings from the neutron scattering and clarified the two-dimensional quantum behaviors of the material.

The novel method disclosed a startling finding: the material's magnons were forming bound states, or pairing up to dance, rather than acting as single, independent unities as would have been predicted.

The spin-nematic phase, a novel and unexpected quantum state with ramifications for the materials properties, is the result of this peculiar pairing. Imagine it like this: unlike regular magnets on a fridge, which point either way (that is their spin), the focus of this new phase is on how the magnets align with one another to form a distinctive pattern rather than on their direction of orientation.

This is a fascinating finding. It exposes a previously unseen behavior in magnetic materials. This discovery of a hidden law of quantum mechanics may open our minds to previously unconsidered uses of magnetic materials in quantum technologies.

The research was funded by the European Research Council (ERC) Synergy network HERO, the

Swiss National Science Foundation (SNSF), and the Qatar Foundation.

More from AZoQuantum: Quantum-Inspired Noise-Resistant Phase Imaging

Fogh, E., et al. (2024) Field-induced bound-state condensation and spin-nematic phase in SrCu2(BO3)2 revealed by neutron scattering up to 25.9 T. Nature Communications. doi.org/10.1038/s41467-023-44115-z

Source: https://www.epfl.ch/en/

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Unexpected Pairing Paves the Way for Computing Devices - AZoQuantum

At New Scientist last week, science writer and editor George Musser talked about the way a theory of consciousness that sees the brain as a quantum system is now under reluctant consideration. Musser, author of Putting Ourselves Back in the Equation (Farrar, Straus and Giroux, 2023) went to visit anesthesiologist Stuart Hameroff, who with theoretical physicist Roger Penrose advances the quantum-based Orch Or Theory (orchestrated objective reduction of the quantum state).

Do quantum phenomena create conscious experience?

Musser explains the basic idea of the Orch Or Theory (OOT), that conscious experience arises from quantum phenomena in the brain. The theory gained little traction in the past because it was difficult to test but Musser thinks that the use of anesthetics on brain organoids (lumps of brain tissue grown in a medium), along with other new methods may enable the theory to be tested:

Such ideas have existed, in various guises, on the fringes of mainstream consciousness research for decades. They have never come in from the cold because, as their critics argue, there is no solid experimental evidence that quantum effects occur in the brain, never mind a clear idea of how they would give rise to consciousness.

What, more specifically, is the Orch Or theory?

In short, it says that consciousness arises when gravitational instabilities in the fundamental structure of space-time collapse quantum wave functions in tiny structures called microtubules that are found inside neurons and, in fact, in all complex cells.

In quantum theory, a particle does not really exist as a tiny bit of matter located somewhere but rather as a cloud of probabilities. If observed, it collapses into the state in which it was observed. Penrose has postulated that each time a quantum wave function collapses in this way in the brain, it gives rise to a moment of conscious experience.

Hameroff has been studying proteins known as tubulins inside the microtubules of neurons. He postulates that microtubules inside neurons could be exploiting quantum effects, somehow translating gravitationally induced wave function collapse into consciousness, as Penrose had suggested. Thus was born a collaboration, though their seminal 1996 paper failed to gain much traction.

Of course, the Nineties was the decade of the Astonishing Hypothesis, (Scribner, 1994), wherein Nobel laureate Francis Crick (19162004) proclaimed, Youre nothing but a pack of neurons. In those days, many thought that materialism had already won and no more sophisticated analysis was needed.

Quantum processing in bird brains

Musser tells us, recent research suggests that some kind of quantum processing does occur in the brain. One suggested example is the way a birds internal compass includes radicals with an odd, unpaired electron:

When these radicals eventually react, the outcome will depend on the strength and orientation of the magnetic field. The thinking is that the bird is sensitive to this in a way that allows it to tell north from south. The process is highly quantum as the radical pair electrons are entangled, which means that they act as a single quantum object, even though they are some distance apart.

If thats correct, we already know of at least one quantum process in a nervous system. Linking that up to human consciousness is still a stretch but, he says, scientists are more willing now to at least consider it.

And other research?

Musser seems to be on to something. In 2022, for example, researchers at Trinity College in Dublin did experiments that suggest our brains do quantum computation. They think that their finding may help solve a mystery:

Quantum brain processes could explain why we can still outperform supercomputers when it comes to unforeseen circumstances, decision making, or learning something new. Our experiments, performed only 50 meters away from the lecture theater where Schrdinger presented his famous thoughts about life, may shed light on the mysteries of biology, and on consciousness which scientifically is even harder to grasp.

Likewise, Dorje C. Brody, Professor of Mathematics at the University of Surrey, hopes that quantum processes can shed light on human behavior. For example, the order in which questions are asked is important in quantum physics but not in classical physics. But in that respect, the human mind often behaves more in a quantum way, he says:

For example, in a study published 20 years ago about the effects that question order has on respondents answers, subjects were asked whether they thought the previous US president, Bill Clinton, was honest. They were then asked if his vice president, Al Gore, seemed honest.

When the questions were delivered in this order, a respective 50% and 60% of respondents answered that they were honest. But when the researchers asked respondents about Gore first and then Clinton, a respective 68% and 60% responded that they were honest.

He sees the human response as more like a quantum system.

How trying to understand human consciousness or behavior via quantum processes will work out is anyones guess but heres a prediction: It wont help the cause of materialism much.

You may also wish to read: Why many researchers now see the brain as a quantum system. The hypothesis is that the brain relies on quantum physics, not classical physics, to power thinking processes. Quantum processes are helpful to know about when we hear a gimcrack new theory that dismisses or explains away consciousness. We know it cant be that simple.

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The Theory That Consciousness Is a Quantum System Gains Support - Walter Bradley Center for Natural and Artificial Intelligence