Latest news with #quantumphysics
South China Morning Post
6 days ago
- Science
- South China Morning Post
China's new Dawn: Pan Jianwei reveals high-orbit quantum satellite for global network
China is developing the world's first high-orbit quantum communication satellite to enable more efficient, globally accessible quantum networks and lay the groundwork for redefining the international standard of the second, according to Pan Jianwei , the country's 'father of quantum'. Set to launch around 2027, the satellite will operate in geostationary orbit more than 35,000km (21,700 miles) above the Earth, Pan revealed during a pre-recorded keynote speech at a conference in Germany this month to mark the centenary of quantum mechanics. The satellite will carry an optical atomic clock and serve as a new platform for quantum metrology research, including efforts to improve the short-term stability of atomic clocks through global entanglement distribution, and potentially pave the way for a redefinition of the International System of Units (SI) base unit of time – the second. 11:05 Space race elevates Asia in new world order Space race elevates Asia in new world order The satellite – named Dawn – follows Micius , the world's first quantum satellite that was launched into low Earth orbit in 2016 by Pan's team at the University of Science and Technology of China. Pan revealed the satellite's name during a live Q&A session with more than 300 quantum physicists, including four Nobel laureates, who gathered on the island of Helgoland for the week-long meeting. Dawn was designed to extend entanglement distribution distances to over 10,000km, he said. 'A high-orbit satellite is incredibly powerful. It can simultaneously see two locations on Earth that are 10,000km apart,' he told state broadcaster CCTV in May. 'That makes it possible for us to establish key distributions between Beijing and South Africa.' Entanglement distribution from high orbit could also take place around the clock, thanks to the satellite's stationary position over Earth. 'That provides continuous coverage and ensures secure communications 24/7,' Pan told Chinese state broadcaster CCTV. He had previously told Chinese media that long-distance quantum communication through fibre-optic cables was limited by signal loss.
Yahoo
23-06-2025
- Science
- Yahoo
Quantum embezzlement: An entanglement trick once thought impossible exists for real
In quantum physics, entanglement links particles across space in ways that defy logic. However, there's a lesser-known phenomenon that's even more intriguing than entanglement, and it's called quantum embezzlement. It happens when one system quietly supplies entanglement to another system, helping the latter change its state, without being affected itself. It's a bit like quietly borrowing a few grains of sand from a vast beach to build a tiny sandcastle. The beach looks untouched, yet the sand is used. For years, scientists thought such perfectly entangled systems existed only in theory. However, a new study from researchers at Leibniz University Hannover in Germany shows that embezzlement can occur naturally in a class of quantum materials called critical fermion chains. Critical fermion chains are one-dimensional systems made of fermions (a type of subatomic particle) that sit at the transition point between two phases. At this point, they become highly sensitive and exhibit long-range quantum entanglement. The discovery of embezzlement in a real physical system like critical fermion chains is of great importance as it can contribute to the development of robust technologies that rely on entanglement and involve large-scale quantum information transfer. So what makes quantum embezzlement so strange? Well, normally, when you use a resource in quantum physics, like a highly entangled system, you expect its state to change. However, with embezzlement, it's like using a magic battery that powers a process without ever draining. For this to work, the resource must be very entangled, so much so that many scientists doubted such a system could physically exist. It seemed too ideal to be real. Moreover, the embezzlement here is universal, meaning that the resource system can help create any entangled state, not just specific ones. It works in many different situations, not just for one special case. The study authors decided to investigate whether this universal embezzlement could actually occur in real, physical systems. They started by focusing on critical fermion chains, and instead of working with small, manageable systems, the researchers looked directly at infinite systems, using what physicists call the thermodynamic limit. In this setup, they split the system into a left and right half and studied the entanglement between them. Surprisingly, they found that these half-chains satisfied the strict criteria for universal embezzlement that the team had defined in earlier work. In simple terms, the left and right sides were entangled enough to act like perfect embezzlers. The researchers were able to assist in entangling other systems. Even more impressively, the team showed that this effect wasn't just an unusual property of infinite systems. When they looked at large but finite fermion chains, systems that could potentially be built in a lab, scientists still found strong evidence of approximate embezzlement. That means this isn't just a theoretical phenomenon. Real materials might already be doing this under the right conditions. "Finally, we demonstrate that the universal embezzlement property is not exclusive to the thermodynamic limit, but that it already emerges in large but finite fermion systems," Lauritz van Luijk, first author of the study, and a physicist at the Leibniz University Hannover, said. This discovery rewrites the rules about how entanglement can behave in physical systems. It shows that quantum embezzlement is not a fragile or exotic phenomenon, but a robust property occurring in real systems. In the future, this could help scientists discover new ways to transfer entanglement in quantum computers, improve methods of simulating quantum materials, or even new states of matter. However, the work so far is entirely theoretical. "While our work shows that critical spin chains can embezzle entanglement, it does not provide a recipe for how to do so," Luijk said. The research doesn't offer a way to actually perform embezzlement in practice. The study authors are now working on protocols using Gaussian operations, a type of quantum operation that's easier to implement with current technology. They hope these protocols might help them turn embezzlement from theory into something experimentally achievable. The study is published in the journal Nature Physics.
The Independent
11-06-2025
- Science
- The Independent
How physicists made ‘light from darkness' with longheld vacuum theory
Oxford University physicists have simulated how intense laser beams can alter vacuum, recreating a quantum physics phenomenon where vacuum is not empty but full of temporary particle pairs. Classical physics suggests light beams pass through each other undisturbed, but quantum mechanics posits that vacuum is filled with fleeting particles that scatter light. Simulations detailed in Communications Physics recreated a phenomenon where three focused laser pulses alter virtual particles in vacuum, generating a fourth laser beam in a 'light from darkness' process. The simulation used software called OSIRIS to model interactions between laser beams and matter, revealing that intense laser beams can agitate virtual particles and cause light particles to scatter. Physicists aim to conduct real-world laser experiments to confirm this quantum phenomenon, with the simulation potentially paving the way for studying hypothetical dark matter particles like axions and millicharged particles.
The Independent
11-06-2025
- Science
- The Independent
Physicists prove long-held theory light can be made from nothingness of vacuum
Scientists have demonstrated after decades of theorising how light interacts with vacuum, recreating a bizarre phenomenon predicted by quantum physics. Oxford University physicists ran simulations to test how intense laser beams alter vacuum, a state once thought to be empty but predicted by quantum physics to be full of fleeting, temporary particle pairs. Classical physics predicts that light beams pass through each other undisturbed. But quantum mechanics holds that even what we know as vacuum is always brimming with fleeting particles, which pop in and out of existence, causing light to be scattered. The latest simulations, detailed in a study published in Communications Physics, recreated a strange phenomenon predicted by quantum physics. The theory predicts that the combined effect of three focused laser pulses can alter virtual particles in vacuum, generating a fourth laser beam in a 'light from darkness' process. 'This is not just an academic curiosity,' study co-author Peter Norreys said. 'It is a major step towards experimental confirmation of quantum effects that until now have been mostly theoretical.' Physicists used a simulation software package called OSIRIS to model interactions between laser beams and matter, giving them a peek into vacuum-light interactions that were previously out of reach. The simulations revealed that intense laser beams could agitate virtual particles and cause light particles to scatter off one another like billiard balls. They also showed how real-world factors such as imperfect beam alignment could influence the result. 'By applying our model to a three-beam scattering experiment, we were able to capture the full range of quantum signatures, along with detailed insights into the interaction region and key time scales,' said Zixin Zhang, another author of the new study. Physicists now hope to conduct real-world laser experiments to confirm the bizarre quantum phenomenon. The simulation experiment could also pave the way for more in-depth study of a range of theorised quantum effects in vacuum in other laser setups.
BBC News
07-06-2025
- Science
- BBC News
Great Exhibition Road Festival: What is the weirdest thing in the universe?
London's Exhibition Road will close to traffic this weekend as the famous museums and institutions of South Kensington combine for the Great Exhibition Road the series of free events taking place along the street, three researchers affiliated with Imperial College London (ICL) will take to the stage to try to answer one small question - what's the weirdest thing in the universe? For ICL research fellow Mariana Carrillo Gonzalez, the answer is to be found far away from our own planet."My object is black holes," she holes are regions of space where matter has collapsed in on itself, meaning they have such strong gravity that not even light can escape there's a key problem with them for scientists, explains Mariana."We still have no clue how they work."We can't observe them, we just observe the effects of a black hole. We observe the light that goes around the black hole and we observe how it deforms space and how things move... but we really can't see it because there's nothing that can escape from a black hole."We can prove they are there, we just have no idea what's inside," she adds."I think that's just a very weird thing." Nevertheless, Rita Ahmadi argues her research specialism is even more bizarre - "Quantum physics, by which I mean the physics of subatomic particles."They have behaviours that are different from the classical physics that you see around yourself, so the rules are different," the postdoctoral researcher rules include that "they can be observed in two different states at the same time, which is called superposition", while they also have an unusual problem when trying to observe them as "any interaction with a quantum system changes the state of the quantum system".Rita says such peculiarities mean "we know that the mathematics of quantum mechanics work properly so we know that the model works... but still we cannot make sense of that".Even so, quantum science is still seen as hugely important for the future."My research is quantum computing and I'm building devices out of that even without understanding if it makes sense." The other researcher taking part is Fernando Ernesto Rosas De Andraca whose area of expertise is another one full of conundrums."I took human consciousness as the weirdest thing I can think of," he says."Our best guess is that consciousness is somehow generated by the brain but most people would argue that single neurons are not conscious."So you have these little parts that are not conscious, you put them together and they are conscious and that's very strange."He also points to other arguments such as "the only thing you cannot doubt is your consciousness, but at the same time consciousness is this thing that nobody else can see so everybody else can doubt it".Elaborating further, Fernando brings up artificial intelligence (AI), declaring it as something he has become "completely obsessed" with."Most people believe that current AI systems are not conscious... but I think most people agree that there is no fundamental limits to say it will never be conscious so then the question is at one point it might become so," he says."We then get into a different arena that we have to be concerned about things like creating a system that can suffer." The reason for such existential arguments is the festival, which seeks to celebrate science and the arts for people of all ages through activities like insect yoga, quantum discos and robotics."We're always trying to find different and creative ways of exploring some of the topics that we study at Imperial," says James Romero, who is one of the festival organisers for the university."In this case it's challenging the researchers to tweak the public lecture format into a different format and introducing a competitive element into it."Once the three researchers have presented their arguments, a vote will be held with those in the crowd deciding which phenomena should be considered the weirdest in the universe."We thought that the researchers might be too polite to be competitive but clearly that's not necessarily the case," says James, having listened to their arguments."I came from Oxford," replies Rita. "I take debates very seriously."The Weirdest Object in the Universe debate is free to attend and will take place in the Sir Alexander Fleming Building at Imperial College London at 15:30 BST on Saturday.
