Category Archives: Quantum Physics
What is IBM doing in the race towards quantum computing? – TechHQ
Quantum computing uses electrons rather than transistors, for a much more rapid solution to complex problems. Theres every likelihood that the technology will be able to rapidly reduce current encryptions to dust. The quantum race is largely between China and a handful of western companies.
We may be on the verge of revolutionary AI problem-solving with news of IBMs quantum computing advancements. (We say may in tribute to Werner Heisenberg and his famous principle, and because nothing since has ever been entirely certain in the quantum world).
We are living in a golden age of artificial intelligence, with innovations seemingly bombarding us every day. The trend has continued with IBM announcing advancements in a new kind of computing that is capable of solving extraordinarily complex problems in just a few minutes.
Why is this newsworthy? Surely thats what all computers do?
Yes, but todays supercomputers would need millions of years to solve problems as complex as the ones IBM is making progress with.
Welcome to the wonderful world of quantum.
Quantum computing is a technology being developed by companies like IBM and Google. Operating in a fundamentally different way to classical computing, it relies on quantum bits (qubits) and principles including superposition and entanglement. As the name suggests, quantum physics is an intrinsic part of quantum computing. We may even need a quantum computer to explain how this type of computing works, but this technology is without question changing the world.
Everything we know is pushed to the limits with quantum computing. From science to finances and from AI to computational power, this supercomputer offers the potential for solutions to problems that are currently intractable for classical computers.
The revolutionary nature of quantum computing lies in its potential to transform problem-solving approaches. It has the potential to tackle previously unsolvable problems, and impact many fields worldwide. It presents a paradigm shift akin to the introduction of classical computing, though in comparison, quantum computings possibilities are on a vastly different and exponentially more powerful scale.
IBM director of research Dario Gill believes quantum computing will have a significant impact on the world, but that society is not yet prepared for such changes.
It feels to us like the pioneers of the 1940s and 50s that were building the first digital computers, he said. Its plain to see how much impact digital computers have had on the world since the 1950s, but quantum computing is another kettle of deeply unusual fish.
We are now at a stage where we can do certain calculations with these systems that would take the biggest supercomputers in the world to do, Gill explained. But the potential of this technology is only just being realized. The goal is to continue the expansion of quantum computing capabilities, so that not even a million or a billion of those supercomputers connected together could do the calculations of these future machines.
A quantum computer from IBM the future appears to be agreeably steampunk.
We have already witnessed significant progress in this field of technology, but the difference now is that Dario Gill, and others working in the quantum field, have a clear plan or strategy in place for further advancements. That means the rate of progress is only expected to accelerate possibly at a pace that will surprise the world.
Today, computers process information on transistors, something they have done since the advent of the transistor switch in 1947. Over time, however, the speed and capabilities of computers have increased substantially. This is due to the continuous advancement of technology. This enhancement stems from the strategy of densely integrating an increasing number of transistors onto a single chip, reaching a scale of billions of transistors in todays computer chips.
Computers require billions of transistors because they are in either an on or off state. Known as complementary metal-oxide-semiconductor (CMOS) technology, quantum computing is now presenting alternatives to this hallmark of classic computing.
Rather than using transistors, quantum computing encodes information and data on electrons. These particles, thanks to the rules of quantum mechanics, can exist in multiple states simultaneously, much like a coin spinning in the air. Simultaneously, it shows aspects of both heads and tails. Unlike traditional computing methods, that deal with one bit of data at a time on a transistor, quantum computing uses qubits. These can store and process exponentially more information because of their ability to exist in multiple states at once.
Classical computers require a step-by-step process when finding information or solving problems. Quantum computers, on the other hand, are capable of finding solutions much faster by handling numerous possibilities concurrently.
Like any up-and-coming technology, countries around the world are vying for quantum supremacy. Currently, private free enterprises and state-directed communism are the main competitors. In other words, the race is between China on one side, and IBM, Google, Microsoft, [and] Honeywell, according to physicist Michio Kaku. These are the big boys of quantum computing.
America has approximately 180 private firms researching quantum computing, most of which fund themselves. The US also has a number of government initiatives investing heavily in quantum research. Along with IBM, Google, and Microsoft, institutions including NASA, DARPA, and NIST are at the forefront of quantum computing and technology development.
Quantum computing bringing the sci-fi home.
China has been making substantial investments in quantum development and research for a number of years. For instance, it has several state-backed initiatives and research institutions, including the Chinese Academy of Sciences, all working on quantum technology. Large corporations, including Alibaba and Huawei, are also involved in quantum computing research.
The US government currently spends close to $1 billion a year on quantum research, whereas China has named quantum as a top national priority. New standards for encryption are to be published by the US in 2024, something that will cause waves (or potentially particles) in the quantum field.
If youre looking for revolutions in computing as big as quantum, youre probably looking back to the machine that cracked the Enigma code
The winner of this quantum race will have striking implications, as Kaku believes the nation or company that succeeds will rule the world economy.
Think OpenAI and ChatGPT, but with the potential to crack any code, open any safe, and of course, demand any price.
As we immerse ourselves in quantum computings promising possibilities and how it is a savior to all of humanitys problems, we must not forget the challenges it also faces. For instance, coherence times need to be enhanced and machines require scaling up to operate effectively with quantum computing.
Hartmut Neven, founder and manager of Googles Quantum Artificial Intelligence Lab, believes that small improvements and effective integration of existing pieces are key to building larger quantum systems. We need little improvements here and there. If we have all the pieces together, we just need to integrate them well to build larger and larger systems.
Neven and his team aim to achieve significant progress in quantum computing over the next five or six years. He believes that quantum computing holds the key to solving problems in fields like chemistry, physics, medicine, and engineering that classical computers are currently, and will always, be incapable of. You actually require a different way to represent information and process information. Thats what quantum gives you, he explained.
Further challenges persist due to the delicate nature of qubits, which are prone to errors and interference from the surrounding environment. As James Tyrrell discusses here, efforts to mitigate this noise and enhance the reliability of quantum computers are underway. The expansion of the (Quantum-Computing-as-a-Service) QCaaS ecosystem is expected to shift the focus from technical intricacies to practical applications. This will potentially allow users to harness the power of quantum computing for real-world problem-solving.
The development of quantum computing is accelerating at an exponential rate. Over the next decade or so, Dario Gil sees no reason why quantum computing can expand to thousands of qubits. He believes that systems will be built that will have tens of thousands and even a 100 thousand qubits working with each other. Where quantum technology goes from here is (thank you, Werner!) distinctly uncertain, but if the excitement is anything to go by, it may potentially have the answers to all the worlds problems.
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What is IBM doing in the race towards quantum computing? - TechHQ
Unlocking neutron star rotation anomalies: Insights from quantum simulation – Phys.org
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A collaboration between quantum physicists and astrophysicists, led by Francesca Ferlaino and Massimo Mannarelli, has achieved a significant breakthrough in understanding neutron star glitches. They were able to numerically simulate this enigmatic cosmic phenomenon with ultracold dipolar atoms. This research, now published in Physical Review Letters, establishes a strong link between quantum mechanics and astrophysics and paves the way for quantum simulation of stellar objects from Earth.
Neutron stars have fascinated and puzzled scientists since the first detected signature in 1967. Known for their periodic flashes of light and rapid rotation, neutron stars are among the densest objects in the universe, with a mass comparable to that of the sun but compressed into a sphere only about 20 kilometers in diameter.
These stellar objects exhibit a peculiar behavior known as a "glitch," where the star suddenly speeds up its spin. This phenomenon suggests that neutron stars might be partly superfluid. In a superfluid, rotation is characterized by numerous tiny vortices, each carrying a fraction of angular momentum. A glitch occurs when these vortices escape from the star's inner crust to its solid outer crust, thereby increasing the star's rotational speed.
The key ingredient for this study lies in the concept of a "supersolid"a state that exhibits both crystalline and superfluid propertieswhich is predicted to be a necessary ingredient of neutron star glitches. Quantized vortices nest within the supersolid until they collectively escape and are consequently absorbed by the outer crust of the star, accelerating its rotation. Recently, the supersolid phase has been realized in experiments with ultracold dipolar atoms, providing a unique opportunity to simulate the conditions within a neutron star.
The study by researchers at the University of Innsbruck and the Austrian Academy of Sciences as well as the Laboratori Nazionali del Gran Sasso and the Gran Sasso Science Institute in Italy demonstrates that glitches can occur in ultracold supersolids, serving as versatile analogs for the inside of neutron stars. This groundbreaking approach allows for a detailed exploration of the glitch mechanism, including its dependence on the quality of the supersolid.
"Our research establishes a strong link between quantum mechanics and astrophysics and provides a new perspective on the inner nature of neutron stars," says first author Elena Poli. Glitches provide valuable insights into the internal structure and dynamics of neutron stars. By studying these events, scientists can learn more about the properties of matter under extreme conditions.
"This research shows a new approach to gain insights into the behavior of neutron stars and opens new avenues for the quantum simulation of stellar objects from low-energy Earth laboratories," says Francesca Ferlaino.
More information: Elena Poli et al, Glitches in Rotating Supersolids, Physical Review Letters (2023). DOI: 10.1103/PhysRevLett.131.223401
Journal information: Physical Review Letters
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Unlocking neutron star rotation anomalies: Insights from quantum simulation - Phys.org
‘Wobbly spacetime’ is latest stab at unifying physics – The Register
Since the early 20th century, physicists have struggled to marry theories governing the very big with those for the very small.
Despite the staggering achievements in modern science, the conflict between Einstein's general theory of relativity and quantum mechanics has become a stumbling block in developing a consistent, reliable theory explaining everything.
University College London professor Jonathan Oppenheim proposes to overcome the barrier with the idea of "wobbly spacetime."
Earlier efforts to unify the two main columns of modern physics had gone with the idea that gravity the nature of which is reliably explained by General Relativity should somehow be quantized. That means divided into discrete blocks of magnitude rather than distributed along a continuum that can always be subdivided. Two prominent exponents of the idea are string theory and loop quantum gravity.
But the professor of quantum theory argues that making quantum theory fit relativity would be more fruitful.
In a paper published this week in the journal Physical Review X, Oppenheim proposes to retain the classical nature of gravity but allow for the probabilistic nature of quantum mechanics by inserting certain unpredictable but continuous "wobbles" into spacetime itself.
His approach relies on two separate statistical approaches for the quantum and classical aspects of a system. "In the statistical description of the quantum side, states are described using density operators that evolve as if the system were open that is, susceptible to uncontrolled influences from the environment," an accompanying article explains.
"In the statistical description of the classical side, states are probability distributions on phase space a framework that is often used to model large numbers of particles, where one does not know the individual position and momentum of each particle."
"The rate at which time flows is changing randomly and fluctuating in time," Oppenheim told The Guardian. "It's quite mathematical. Picturing it in your head is quite difficult."
Another paper published in Nature Communications, written by Oppenheim's colleague, PhD student Zach Weller-Davies, proposes approaches to verify or disprove the theory experimentally.
"We have shown that if spacetime doesn't have a quantum nature, then there must be random fluctuations in the curvature of spacetime, which have a particular signature that can be verified experimentally," he told website Physics.org.
"If spacetime is classical, the fluctuations have to be larger than a certain scale, and this scale can be determined by another experiment where we test how long we can put a heavy atom in superposition of being in two different locations."
But this being theoretical physics, not everyone is convinced. Loop theory proponent Carlo Rovelli, an Italian theoretical physicist, told The Guardian: "I think it is good that Oppenheim explores this possibility, even if not very plausible, but big claims about a 'New theory unites Einstein's gravity with quantum mechanics' sounds a bit overblown to me."
Rovelli has signed a 5,000-to-one bet with Oppenheim against the theory being proven correct. So much for unity in physics.
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'Wobbly spacetime' is latest stab at unifying physics - The Register
Physicists May Have Found a Hard Limit on The Performance of Large Quantum Computers – ScienceAlert
A newly discovered trade-off in the way time-keeping devices operate on a fundamental level could set a hard limit on the performance of large-scale quantum computers, according to researchers from the Vienna University of Technology.
While the issue isn't exactly pressing, our ability to grow systems based on quantum operations from backroom prototypes into practical number-crunching behemoths will depend on how well we can reliably dissect the days into ever finer portions. This is a feat the researchers say will become increasingly more challenging.
Whether you're counting the seconds with whispers of Mississippi or dividing them up with the pendulum-swing of an electron in atomic confinement, the measure of time is bound by the limits of physics itself.
One of these limits involves the resolution with which time can be split. Measures of any event shorter than 5.39 x 10-44 seconds, for example, run afoul of theories on the basic functions of the Universe. They just don't make any sense, in other words.
Yet even before we get to that hard line in the sands of time, physicists think there is a toll to be paid that could prevent us from continuing to measure ever smaller units.
Sooner or later, every clock winds down. The pendulum slows, the battery dies, the atomic laser needs resetting. This isn't merely an engineering challenge the march of time itself is a feature of the Universe's progress from a highly ordered state to an entangled, chaotic mess in what is known as entropy.
"Time measurement always has to do with entropy," says senior author Marcus Huber, a systems engineer who leads a research group in the intersection of Quantum Information and Quantum Thermodynamics at the Vienna University of Technology.
In their recently published theorem, Huber and his team lay out the logic that connects entropy as a thermodynamic phenomenon with resolution, demonstrating that unless you've got infinite energy at your fingertips, your fast-ticking clock will eventually run into precision problems.
Or as the study's first author, theoretical physicist Florian Meier puts it, "That means: Either the clock works quickly or it works precisely both are not possible at the same time."
This might not be a major problem if you want to count out seconds that won't deviate over the lifetime of our Universe. But for technologies like quantum computing, which rely on the temperamental nature of particles hovering on the edge of existence, timing is everything.
This isn't a big problem when the number of particles is small. As they increase in number, the risk any one of them could be knocked out of their quantum critical state rises, leaving less and less time to carry out the necessary computations.
Plenty of research has gone into exploring the potential for errors in quantum technology caused by a noisy, imperfect Universe. This appears to be the first time researchers have looked at the physics of timekeeping itself as a potential obstacle.
"Currently, the accuracy of quantum computers is still limited by other factors, for example the precision of the components used or electromagnetic fields," says Huber.
"But our calculations also show that today we are not far from the regime in which the fundamental limits of time measurement play the decisive role."
It's likely other advances in quantum computing will improve stability, reduce errors, and 'buy time' for scaled-up devices to operate in optimal ways. But whether entropy will have the final say on just how powerful quantum computers can get, only time will tell.
This research was published in Physical Review Letters.
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Physicists May Have Found a Hard Limit on The Performance of Large Quantum Computers - ScienceAlert
The race is on for a new internet based on quantum physics – EL PAS USA
In May 2023, Dr Benjamin Lanyon at the University of Innsbruck in Austria took an important step toward creating a new kind of internet: he transferred information along an optical fiber 31 miles (50 kilometers) long using the principles of quantum physics.
Information in quantum physics differs from the units of data binary digits stored and processed by computers that form the core of the current World Wide Web. The quantum physics realm covers the properties and interactions of molecules, atoms and even smaller particles such as electrons and photons.
Quantum bits, or qubits, offer the promise of transmitting information more securely because the particles get changed by the act of observing and measuring them. That means an eavesdropper cant go undetected.
Lanyon said his work makes the quantum internet appear feasible within cities, after which longer intercity distances will be the goal.
You could imagine this being a large-city scale, he said.
His breakthrough was part of an EU research project to bring the goal of a quantum internet closer.
Called the Quantum Internet Alliance, or QIA, the project brings together research institutes and companies across Europe. The initiative is receiving 24 million in EU funding over three and a half years until the end of March 2026.
It is not meant to replace the classical internet, but to work together, said Stephanie Wehner, a German native who coordinates the QIA and is a professor of quantum information at Delft University of Technology in the Netherlands. Were not going to replace Netflix.
A key concept in quantum physics is entanglement. If two particles are entangled, no matter how far apart they are in space, they will possess similar properties for example, both having the same measurement of something called spin, a quantum version of the direction that the particles are spinning.
The spin state of the particles isnt clear until they are observed. Until then, theyre in multiple states called superposition.
But when one is observed, the state of both particles becomes known.
This is useful in secure communications. People hacking a quantum transmission would leave behind an obvious trace of their attempt by causing a change in the state of an observed particle.
We can use the properties of quantum entanglement to achieve a means of secure communication that is provably secure even if the attacker has a quantum computer, said Wehner.
The secure communications afforded by a quantum internet could open up a much broader range of applications that are well beyond the bounds of the classical internet.
In medicine, for example, the physics of entanglement allows for a level of clock synchronization that can improve telesurgery.
If I want to perform surgery on some remote node, I want this to be very precisely timed in order to not make any mistakes, said Wehner.
Astronomy is another potential beneficiary.
Telescopes making distant observations could use a quantum internet to generate entanglement between the sensors to get a much better image of the sky, Wehner said.
A further example might be ATM machines.
At present, were an ATM to crash when a person was withdrawing money, the machine would assume no cash had been delivered while another dispenser would register a money withdrawal. A quantum internet could remove that discrepancy.
Many applications of a quantum internet will likely become apparent only after the technology is created.
It offers a whole range of new possibilities for making precise measurements of space and time and studying how the world and the universe work, said Lanyon.
The trick now is scaling up a quantum internet to use many particles across long distances.
Lanyon and his team have also demonstrated communicating not just between single particles but also trains of particles in this case light particles called photons speeding up the rate of entanglement between quantum nodes.
If you just sent one photon at a time, you have to wait for the travel time, he said. But if you can make trains of many photons at once, this allows you to increase the rate of entanglement between quantum nodes for the distances we want.
The ultimate goal is to extend quantum nodes to much bigger ranges, perhaps 310 miles (500 kilometers), and create a prototype of a quantum internet that can link remote cities much like the classical internet relies on different nodes to create a global internet.
While a quantum internet could exist for specialized applications as soon as 2029, experts are wary of hazarding a guess about when a full version might be available for a wide range of uses.
As the QIA advances the components and systems of the quantum internet, Europe is also working to develop quantum computers themselves.
In June 2023, an EU public-private partnership the European High Performance Computing Joint Undertaking announced that six countries in Europe would host quantum computers. The countries are the Czech Republic, France, Germany, Italy, Poland and Spain.
The aim is to ensure that Europe is at the forefront of the quantum technologies revolution. Quantum computers are expected to have unprecedented calculation power with many uses, including the ability to break the cryptographic algorithms that secure most of the exchanges of the current internet.
With projections that half of the most used cryptographic systems will be broken by the end of the decade, Europe is hardly the only interested party.
China and the US have made advances in quantum computing and the quantum internet in recent years.
Back on the infrastructure front, Europe is taking other steps. Its developing an integrated space and terrestrial infrastructure for secure communications a building block of sorts for the quantum internet.
Im very proud to say we are world-leading in many domains, said Wehner.
While in all interested countries much work remains, the potential benefits signal further advances and breakthroughs before too long.
People are developing new applications of quantum networks at quite a high rate, Lanyon said.
Research in this article was funded by the EU. This article was originally published in Horizon, the EU Research and Innovation magazine.
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The race is on for a new internet based on quantum physics - EL PAS USA
Radical New Theory Could Finally Unite The Two Biggest Frameworks in Physics – ScienceAlert
Some enmities are so powerful, they could never be resolved. Bette and Joan. Batman and the Joker. Hamilton and Burr.
It was starting to look like that list would include general relativity and quantum theory, two mathematical frameworks for describing the Universe that just cannot be made to fit together.
But in new paper, physicist Jonathan Oppenheim of University College London claims to have found a way to resolve their differences.
And it gets better a second paper lays out a way to test it experimentally.
"Quantum theory and Einstein's theory of general relativity are mathematically incompatible with each other, so it's important to understand how this contradiction is resolved," Oppenheim explains.
"Should space-time be quantized, or should we modify quantum theory, or is it something else entirely?"
The Universe doesn't behave in a unified manner across scales, and we have different tools for exploring and describing it. General relativity is the theory that describes gravitational interactions in the large-scale physical Universe, based on the way gravity curves space-time.
It can be used to make predictions about the Universe; general relativity predicted gravitational waves, gravitational lensing, and some behaviors of black holes.
At much smaller scales atomic and subatomic gravity doesn't work the way it does under relativity. A different set of rules is needed to describe the way matter behaves and interacts. This is quantum theory.
For decades, physicists have been trying to figure out how to make the two rulesets work together. The realms of relativity and quantum theory interact in the real world, but scientists haven't been able to figure out how.
The current thought is that gravity can, somehow, be described using quantum theory, or quantized. This is behind theories such as string theory and quantum loop theory.
But in his paper, Oppenheim lays out a completely different alternative. What if space-time can't be quantized, because it is ruled entirely by classical physics?
Imagine reality is your computer or phone screen. You can see the big picture clearly, but if you use a magnifier on the screen, you'll see it's composed of teeny tiny units.
Under quantum theory, this is the Universe. If you zoom in far enough, it's made up of miniscule basic units, or quanta, like the pixels on your screen. If space-time isn't quantum, it doesn't matter how far you zoom in; it will always be smooth.
Under Oppenheim's theory, however, space-time wouldn't just be smooth, it would become sort of wobbly and unpredictable.
Here's where it becomes testable. This wobbliness would result in fluctuations of measurable properties that are larger than the fluctuations predicted by quantum theory.
With the right experiment, physicists could look for those fluctuations.
"We have shown that if space-time doesn't have a quantum nature, then there must be random fluctuations in the curvature of space-time which have a particular signature that can be verified experimentally," says physicist Zach Weller-Davies of University College London.
"In both quantum gravity and classical gravity, space-time must be undergoing violent and random fluctuations all around us, but on a scale which we haven't yet been able to detect. But if space-time is classical, the fluctuations have to be larger than a certain scale, and this scale can be determined by another experiment where we test how long we can put a heavy atom in superposition of being in two different locations."
Now, the problem of relativity and quantum mechanics is a big one. Resolving it is going to require absolutely extraordinary evidence, and we're very far from that.
And Oppenheim's theory certainly has opposition from within the scientific community.
In fact, fellow physicists Carlo Rovelli and Geoff Penington feel so strongly that quantum theory can describe gravity that they have signed a bet against Oppenheim at 5,000:1 odds.
But even finding nothing in an experiment can tell us important somethings, so whichever way the experiment turns out, we can learn something interesting and valuable from it.
"Experiments to test the nature of space-time will take a large-scale effort, but they're of huge importance from the perspective of understanding the fundamental laws of nature," says physicist Sougato Bose of University College London, who was not involved in these papers.
"I believe these experiments are within reach these things are difficult to predict, but perhaps we'll know the answer within the next 20 years."
Oppenheim's theory has been published in Physical Review X. An experiment designed to test it has been described in Nature Communications.
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Radical New Theory Could Finally Unite The Two Biggest Frameworks in Physics - ScienceAlert
Bold New Theory Seeks To Unify Einstein’s Relativity And Quantum Mechanics – IFLScience
Over a century ago, two theories were put forward to explain all of reality: quantum mechanics and general relativity. Both have been refined and improved over decades and extensively tested. They are solid theories. But ultimately, alone, they cant explain everything and together they dont seem to work. For decades, physicists have been looking at the grand unified theory and two main candidates have been put forward, string theory and quantum loop gravity. Now, a group of researchers have proposed a new one.
It took five years of testing and ironing out, but this new idea has now been presented. They are calling it the postquantum theory of classical gravity. The name is certainly not as catchy as the other two contenders, but there is also another major difference. Space-time in this new theory is not quantized.
To bridge the gap between relativity and quantum mechanics, it has been assumed that, ultimately, space-time is made of discrete steps, much smaller than anything that we can measure but discrete nonetheless. In this theory, it is quantum mechanics that changes and this classical space-time leads to a breakdown of predictability once you go to high enough precision.
"Quantum theory and Einstein's theory of general relativity are mathematically incompatible with each other, so it's important to understand how this contradiction is resolved. Should spacetime be quantised, or should we modify quantum theory, or is it something else entirely? Now that we have a consistent fundamental theory in which spacetime does not get quantised, it's anybody's guess," Professor Jonathan Oppenheim, from University College London, said in a statement.
Space-time is expected to have energy fluctuation from which particles and antiparticles come into existence for an instant before disappearing. In the postquantum theory of classical gravity, these fluctuations are even more violent compared to the quantized space-time picture. The good news is that the fluctuations lead to a way to test the theory.
In a second paper, published in Nature Communications, the team highlighted how to test the theory. By measuring the mass and weight of an object with high precision, they should be able to tell if space-time is classical. The fluctuation would change the measured weight over time, and if those tiny changes are not seen then the postquantum theory of classical gravity can be ruled out.
"We have shown that if spacetime doesn't have a quantum nature, then there must be random fluctuations in the curvature of spacetime which have a particular signature that can be verified experimentally, co-author Zach Weller-Davies explained.
"In both quantum gravity and classical gravity, spacetime must be undergoing violent and random fluctuations all around us, but on a scale which we haven't yet been able to detect. But if spacetime is classical, the fluctuations have to be larger than a certain scale, and this scale can be determined by another experiment where we test how long we can put a heavy atom in superposition of being in two different locations."
Testing this is not something we can do tomorrow, but it is equally not something to be tested in a few lifetimes. Some researchers estimate that it could be tested within two decades. And good, because there is a bet going between Professor Oppenheim, Professor Carlo Rovelli, and Dr Geoff Penington, the latter two proponents of quantum loop gravity and string theory respectively. They are betting 5,000 to 1 that space-time is quantized.
The main paper presenting the theory is published in Physical Review X.
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Bold New Theory Seeks To Unify Einstein's Relativity And Quantum Mechanics - IFLScience
Radical new theory finally unites gravity, spacetime, and the quantum realm – Earth.com
In a groundbreaking announcement, physicists from University College London (UCL) have presented a radical theory that unifies the realms of gravity and quantum mechanics while preserving the classical concept of spacetime, as outlined by Einstein.
This innovative approach, detailed in two simultaneously published papers, challenges over a century of scientific consensus and proposes a revolutionary perspective on the fundamental nature of our universe.
Modern physics rests on two contradictory pillars: quantum theory, which rules the microscopic world, and Einsteins theory of general relativity, explaining gravity through spacetime curvature. These theories, despite their individual successes, have remained irreconcilable, creating a significant rift in our understanding of the universe.
Traditionally, scientists have believed that a quantum version of Einsteins theory of gravity was necessary. This belief fueled the development of string theory and loop quantum gravity. However, the new theory from UCL takes a divergent path.
Professor Jonathan Oppenheim of UCL Physics & Astronomy, the lead proponent of this theory, argues for a postquantum theory of classical gravity. This radical idea, as elaborated in his paper in Physical Review X (PRX), suggests that spacetime may remain classical and not subject to quantum mechanics.
Instead of altering spacetime, this theory revises quantum theory itself, predicting unpredictable and significant fluctuations in spacetime. These fluctuations, larger than those anticipated by quantum theory, could render the weight of objects uncertain at precise measurements.
A second paper in Nature Communications, led by Professor Oppenheims former PhD students, proposes an experiment to validate this theory. The experiment involves measuring a mass (like the 1kg standard previously used by the International Bureau of Weights and Measures in France) with extreme precision to detect potential weight fluctuations over time.
Professor Oppenheim, Professor Carlo Rovelli, and Dr. Geoff Penington leading proponents of quantum loop gravity and string theory, respectively have placed a bet with 5000:1 odds on the outcome of the experiment, or any other evidence that might emerge, which would confirm the quantum versus classical nature of spacetime.
For the past five years, the UCL research team has been rigorously examining this theory and its implications. Professor Oppenheim notes the importance of resolving the contradiction between quantum theory and general relativity.
Oppenheim stated, Quantum theory and Einsteins theory of general relativity are mathematically incompatible with each other, so its important to understand how this contradiction is resolved. Should spacetime be quantised, or should we modify quantum theory, or is it something else entirely? Now that we have a consistent fundamental theory in which spacetime does not get quantised, its anybodys guess.
Zach Weller-Davies, a co-author and key contributor to the theory, highlights that this discovery not only challenges our understanding of gravity but also provides a method to probe its potential quantum nature. If spacetime doesnt have a quantum nature, then there must be random fluctuations in the curvature of spacetime with a particular signature that can be verified experimentally, he explains.
We have shown that if spacetime doesnt have a quantum nature, then there must be random fluctuations in the curvature of spacetime which have a particular signature that can be verified experimentally, Weller-Davies continued. In both quantum gravity and classical gravity, spacetime must be undergoing violent and random fluctuations all around us, but on a scale which we havent yet been able to detect.But if spacetime is classical, the fluctuations have to be larger than a certain scale, and this scale can be determined by another experiment where we test how long we can put a heavy atom in superposition* of being in two different locations.
Co-authors Dr. Carlo Sparaciari and Dr. Barbara oda emphasize the significance of these experiments in determining the correct approach to understanding gravity.
Dr oda said, Because gravity is made manifest through the bending of space and time, we can think of the question in terms of whether the rate at which time flows has a quantum nature, or classical nature.And testing this is almost as simple as testing whether the weight of a mass is constant, or appears to fluctuate in a particular way.
Dr Sparaciari elucidated, While the experimental concept is simple, the weighing of the object needs to be carried out with extreme precision.But what I find exciting is that starting from very general assumptions, we can prove a clear relationship between two measurable quantities the scale of the spacetime fluctuations, and how long objects like atoms or apples can be put in quantum superposition of two different locations. We can then determine these two quantities experimentally.
This postquantum theory extends its influence beyond understanding gravity. It negates the need for the problematic measurement postulate in quantum theory. Quantum superpositions would naturally localize due to their interactions with classical spacetime.
Originating from Professor Oppenheims efforts to solve the black hole information problem, this theory allows for the possibility of information destruction, contradicting standard quantum theory but aligning with general relativitys predictions about black holes.
This announcement marks a potential paradigm shift in physics. As Professor Sougato Bose of UCL Physics & Astronomy, not involved in this specific announcement but a pioneer in related research, remarks, Experiments to test the nature of spacetime will take a large-scale effort, but theyre of huge importance from the perspective of understanding the fundamental laws of nature.
Indeed, these efforts could lead to a unified understanding of gravity and quantum mechanics, resolving one of the most profound dilemmas in modern physics. The implications of this theory, if proven correct, are vast, potentially reshaping our understanding of the universe at its most fundamental level.
As mentioned above, Einsteins theory of relativity, a cornerstone of modern physics, revolutionized our understanding of space, time, and gravity. This theory comes in two parts: Special Relativity and General Relativity.
Albert Einstein introduced Special Relativity in 1905. This theory fundamentally changed our perception of space and time. It asserts two key principles:
The Laws of Physics are the Same for All Non-accelerating Observers: No matter how fast an observer is moving, they will measure the same speed of light and observe the same laws of physics.
The Speed of Light is Constant: The speed of light in a vacuum is the same for all observers, regardless of their relative motion or the motion of the light source.
Special Relativity led to several groundbreaking conclusions:
Time Dilation: Time passes slower for objects moving at high speeds compared to those at rest. This effect becomes significant only at speeds close to the speed of light.
Length Contraction: Objects contract in length along the direction of motion as they approach the speed of light.
E=mc: This famous equation relates energy (E) to mass (m) with the speed of light (c) as the constant of proportionality. It implies that energy and mass are interchangeable, laying the groundwork for nuclear energy and weapons.
Ten years later, Einstein expanded on his theory with General Relativity, which addresses gravity and acceleration:
Einstein proposed that gravity is not a force between masses but rather a result of the curvature of spacetime caused by mass and energy. Massive objects like stars and planets warp the space around them, and other objects move along these curves, which we perceive as gravitational attraction.
This principle states that the effects of gravity are indistinguishable from the effects of acceleration. For instance, being in a closed room on Earths surface (where gravity pulls you down) feels the same as being in a room in a spaceship that accelerates upwards.
Light Bending: It predicts that light bends in a gravitational field. Observations during solar eclipses have confirmed this, where stars positions near the sun appear shifted due to the suns gravity bending the light.
Time Dilation Due to Gravity: Clocks run slower in stronger gravitational fields. This effect, tested using precise atomic clocks at different altitudes, is integral for the accuracy of GPS systems.
Gravitational Waves: Predicted by Einstein, these ripples in spacetime, caused by massive accelerating objects (like merging black holes), were directly detected in 2015, confirming a major prediction of General Relativity.
In summary, Einsteins theory of relativity redefined our understanding of the universe. Special Relativity showed that space and time are relative and interconnected, leading to phenomena like time dilation and mass-energy equivalence. General Relativity further advanced this by describing gravity as the curvature of spacetime, profoundly influencing cosmology and astrophysics.
As also discussed above, quantum mechanics, a fundamental theory in physics, describes the behavior of matter and energy at the atomic and subatomic levels. It emerged in the early 20th century as scientists explored phenomena that classical physics couldnt explain. Here are some key aspects of quantum mechanics:
Quantum mechanics introduces the concept of wave-particle duality. Particles, such as electrons and photons, exhibit both particle-like and wave-like properties. For example, electrons can produce interference patterns (a wave property) in a double-slit experiment, while also showing particle characteristics in other contexts.
Werner Heisenberg formulated the Uncertainty Principle, a cornerstone of quantum mechanics. It states that it is impossible to simultaneously know the exact position and momentum of a particle. The more precisely you measure one, the less precise the measurement of the other becomes. This principle challenges the classical notion of determinism.
Quantum Superposition: Quantum particles can exist in multiple states simultaneously, as illustrated by Schrdingers cat thought experiment. A particle in a superposition state doesnt have a specific position, energy, or other physical property until its measured.
Quantum Entanglement: Particles can become entangled, meaning the state of one particle instantly influences the state of another, regardless of the distance separating them. This phenomenon, famously described by Einstein as spooky action at a distance, defies classical ideas of spatial separation and information transfer.
Quantum tunneling occurs when particles pass through barriers that they shouldnt be able to, according to classical physics. This effect is crucial in many modern technologies, such as semiconductors and superconducting devices.
Upon measurement, a quantum system collapses from a superposition of states to a single state. This collapse is instantaneous and is at the heart of many interpretations of quantum mechanics, including the famous Copenhagen interpretation.
Quantum mechanics has led to numerous technological advancements:
Semiconductors: The foundation of modern electronics, including computers and smartphones, relies on quantum mechanics.
Quantum Computing: Quantum computers use quantum bits or qubits, which can be in superpositions of states, offering potentially exponential increases in computing power for certain problems.
Medical Imaging: Techniques like MRI and PET scans depend on principles of quantum mechanics.
In summary, quantum mechanics reveals a strange, counterintuitive world at the smallest scales, fundamentally different from our everyday experiences. Its principles have not only deepened our understanding of the universe but also driven significant technological progress.
The full study was published in the journal Nature Communications.
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Vatican hosts quantum science workshop to spread benefits of technology – Vatican News
As the Pontifical Academy of Sciences hosts a three-day workshop on quantum technology, Dr. Antia Lamas-Linares, a researcher with Amazon Web Services, describes the possibilities of the second quantum revolution.
By Christine Seuss &Stefanie Bross
The Pontifical Academy of Sciences has invited a host of researchers in the field of quantum mechanics for a three-day workshop in the Vatican, which runs from 30 November to 2 December.
According to Joachim von Braun, President of the Pontifical Academy, the goal is to harness technological innovation for the benefit of everyone, not simply developed nations and their citizens.
Around 100 years ago, important members of the Pontifical Academy of Sciences represented the "spearhead of quantum physics," noted Dr. von Braun with reference to Erwin Schrdinger, Max Planck, or Niels Bohr.
Albert Einstein, although not a member himself, also had friendly exchanges with many members of the Academy.
"So, with a certain pride, he said, we commemorate both a remembrance event and a conference that analyzes the achievements of quantum physics and quantum mechanics achieved so far today and illuminates the future prospects of quantum physics.
In the following interview with Vatican News'Stefanie Bross on the sidelines of the workshop, Dr. Antia Lamas-Linares, Lead of the Center for Quantum Networking at Amazon Web Services (AWS), explained that quantum technologies can be used in a wide variety of fields.
Q: Where do we encounter the principles of quantum physics in everyday life?
Quantum information is contained in all kinds of technologies, from computer chips and sensors to GPS, the navigation system in cars.
That said, we are now talking about a second quantum revolution, where some of the more complex and interesting, paradoxical aspects of quantum mechanics are being used to develop new technologies. For example, quantum computing, quantum communication and next-generation quantum sensors.
Q: What is the reason for your participation in the workshop? What brought you here?
I have been working on these topics for more than 20 years and have completed my PhD in quantum technology. I am an experimental physicist in quantum optics and have worked on many aspects of this discipline, both in academia and in national laboratories.
Now I lead the quantum communications division at Amazon, and that's why I'm here. Basically, I'm here as a scientist and also as a representative of the industry, especially the big cloud providers.
Q: How do you see the Church's interest in these technologies?
I was quite surprised when I received the invitation and found it very interesting that the Church is interested in these topics.
I thought it made sense to create a context and perhaps a forum for discussion about where these technologies are going, how they are affecting the world, what we can do, how we can all get involved and how we don't leave certain countries or certain communities behind in these developments.
I think we will see here the impact of the Church taking an interest in this and having these forums.
Q: Could you elaborate on the revolution you are referring to? You spoke of a second quantum revolution. Could you elaborate on what this revolution is and how you think it will affect the future?
We normally talk about this revolution in a scientific and technical sense. We call it a revolution because it concerns certain aspects of quantum mechanics, such as entanglement. This is a quantum effect that is considered paradoxical, that is, it is one of the things that Einstein considered completely impossible and that could not be part of a scientific theory.
And now we don't see them as problems or as philosophical problems, but we see them as resources, in the sense of how we can create them measurably, how we can manipulate them and how we can use them to build better sensors, better computers and so on.
As for your question about whether the revolution will spread to other areas, we don't know, but if, as we believe, quantum computing and quantum communication will have an impact on the development of better chemicals or chemical processes or batteries and things like that, then of course the impact will expand.
Q: What was your first thought when you were invited to this conference?
My first thought was to read the email again. I was surprised that the Pontifical Academy of Sciences was organizing a workshop on a topic that is still pretty deep science.
It is very deep science, and it's not maybe an obvious a topic for this Academy as some others, so I was excited to come and there's an incredible set of participants, so I expect a lot from the following days.
Q: There are a lot of men taking part? What about the women; where are they?
It's dominated by men, but it's changing. But it's an unfortunate reality that most conferences are still vast majority of men.
Again, that is changing, and I think this workshop is skewed towards more senior participants and that makes the imbalance more pronounced.
When you go to conferences that involve more graduate students and some of the younger generations, then you see a more balanced approach.
Still, we're not quite there, but it's progress. It's definitely something the community is working towards.
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Vatican hosts quantum science workshop to spread benefits of technology - Vatican News
Unlocking neutron star rotation anomalies: Insights from quantum simulation – EurekAlert
image:
Ultracold quantum gases made of dipolar atoms form an ideal platform for simulating mechanisms inside neutron stars.
Credit: Elena Poli
Neutron stars have fascinated and puzzled scientists since the first detected signature in 1967. Known for their periodic flashes of light and rapid rotation, neutron stars are among the densest objects in the universe, with a mass comparable to that of the Sun but compressed into a sphere only about 20 kilometers in diameter. These stellar objects exhibit a peculiar behavior known as a glitch, where the star suddenly speeds up its spin. This phenomenon suggests that neutron stars might be partly superfluid. In a superfluid, rotation is characterized by numerous tiny vortices, each carrying a fraction of angular momentum. A glitch occurs when these vortices escape from the star's inner crust to its solid outer crust, thereby increasing the star's rotational speed.
The key ingredient for this study lies in the concept of a supersolid a state that exhibits both crystalline and superfluid properties which is predicted to be a necessary ingredient of neutron star glitches. Quantized vortices nest within the supersolid until they collectively escape and are consequently absorbed by the outer crust of the star, accelerating its rotation. Recently, the supersolid phase has been realized in experiments with ultracold dipolar atoms, providing a unique opportunity to simulate the conditions within a neutron star.
The recent study by researchers at the University of Innsbruck and the Austrian Academy of Sciences as well as the Laboratori Nazionali del Gran Sasso and the Gran Sasso Science Institute in Italy demonstrates that glitches can occur in ultracold supersolids, serving as versatile analogues for the inside of neutron stars. This groundbreaking approach allows for a detailed exploration of the glitch mechanism, including its dependence on the quality of the supersolid. Our research establishes a strong link between quantum mechanics and astrophysics and provides a new perspective on the inner nature of neutron stars, says first author Elena Poli. Glitches provide valuable insights into the internal structure and dynamics of neutron stars. By studying these events, scientists can learn more about the properties of matter under extreme conditions.
This research shows a new approach to gain insights into the behavior of neutron stars and opens new avenues for the quantum simulation of stellar objects from low-energy Earth laboratories, emphasizes Francesca Ferlaino.
The study has been published in Physical Review Letters and was financially supported by the Austrian Science Fund FWF and the European Research Council ERC, among others.
Publication: Glitches in rotating supersolids. Elena Poli, Thomas Bland, Samuel J. M. White, Manfred J. Mark, Francesca Ferlaino, Silvia Trabucco and Massimo Mannarelli. Phys. Rev. Lett. 131, 223401 DOI: 10.1103/PhysRevLett.131.223401 [arXiv: 2306.09698]
Physical Review Letters
Computational simulation/modeling
Glitches in rotating supersolids
29-Nov-2023
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Unlocking neutron star rotation anomalies: Insights from quantum simulation - EurekAlert