Archive for the ‘quantum physics’ category

May 17, 2024

Scientists Test for Quantum Gravity

Posted by in categories: engineering, particle physics, quantum physics

The tension between quantum mechanics and relativity has long been a central split in modern-day physics. Developing a theory of quantum gravity remains one of the great outstanding challenges of the discipline. And yet, no one has yet been able to do it. But as we collect more data, it shines more light on the potential solution, even if some of that data happens to show negative results.

That happened recently with a review of data collected at IceCube, a neutrino detector located in the Antarctic ice sheet, and compiled by researchers at the University of Texas at Arlington. They looked for signs that gravity could vary even a minuscule amount based on quantum mechanical fluctuations. And, to put it bluntly, they didn’t find any evidence of that happening.

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May 17, 2024

UK completes world’s first flights for quantum navigation that could replace GPS

Posted by in categories: government, military, quantum physics

A British consortium with funding from the UK government has successfully tested what it calls “un-jammable” quantum navigation tech in flight.

Geopolitical tensions and warfare have introduced GPS jamming as a means of messing with enemy communication and navigation. This can cause disturbances for both military and civilian transportation and location services.

The quantum-based navigation system is called Positioning, Navigation, and Timing (PNT). Its developers are quantum technology firm Infleqtion’s UK subsidiary in collaboration with aerospace company BAE Systems and defence tech contractor QinetiQ, among others.

May 17, 2024

Scientists Step Toward Quantum Internet With Experiment Under the Streets of Boston

Posted by in categories: computing, finance, internet, quantum physics, security

A quantum internet would essentially be unhackable. In the future, sensitive information—financial or national security data, for instance, as opposed to memes and cat pictures—would travel through such a network in parallel to a more traditional internet.

Of course, building and scaling systems for quantum communications is no easy task. Scientists have been steadily chipping away at the problem for years. A Harvard team recently took another noteworthy step in the right direction. In a paper published this week in Nature, the team says they’ve sent entangled photons between two quantum memory nodes 22 miles (35 kilometers) apart on existing fiber optic infrastructure under the busy streets of Boston.

“Showing that quantum network nodes can be entangled in the real-world environment of a very busy urban area is an important step toward practical networking between quantum computers,” Mikhail Lukin, who led the project and is a physics professor at Harvard, said in a press release.

May 17, 2024

What is ‘time’ for quantum particles?

Posted by in categories: particle physics, quantum physics

In an amazing phenomenon of quantum physics known as tunneling, particles appear to move faster than the speed of light. However, physicists from Darmstadt believe that the time it takes for particles to tunnel has been measured incorrectly until now. They propose a new method to stop the speed of quantum particles.

In classical physics, there are hard rules that cannot be circumvented. For example, if a rolling ball does not have enough energy, it will not get over a hill, but will turn around before reaching the top and reverse its direction. In quantum physics, this principle is not quite so strict: a particle may pass a barrier, even if it does not have enough energy to go over it. It acts as if it is slipping through a tunnel, which is why the phenomenon is also known as quantum tunneling. What sounds magical has tangible technical applications, for example in flash memory drives.

In the past, experiments in which particles tunneled faster than light drew some attention. After all, Einstein’s theory of relativity prohibits faster-than-light velocities. The question is therefore whether the time required for tunneling was “stopped” correctly in these experiments. Physicists Patrik Schach and Enno Giese from TU Darmstadt follow a new approach to define “time” for a tunneling particle. They have now proposed a new method of measuring this time. In their experiment, they measure it in a way that they believe is better suited to the quantum nature of tunneling.

May 16, 2024

Scientists demonstrate the survival of quantum coherence in a chemical reaction involving ultracold molecules

Posted by in categories: chemistry, particle physics, quantum physics

If you zoom in on a chemical reaction to the quantum level, you’ll notice that particles behave like waves that can ripple and collide. Scientists have long sought to understand quantum coherence, the ability of particles to maintain phase relationships and exist in multiple states simultaneously; this is akin to all parts of a wave being synchronized. It has been an open question whether quantum coherence can persist through a chemical reaction where bonds dynamically break and form.

May 16, 2024

Researchers call for a new measurement of time for tunneling particles

Posted by in categories: particle physics, quantum physics

In an amazing phenomenon of quantum physics known as tunneling, particles appear to move faster than the speed of light. However, physicists from Darmstadt believe that the time it takes for particles to tunnel has been measured incorrectly. They propose a new method to stop the speed of quantum particles.

May 16, 2024

Quantum experts review major techniques for isolating Majoranas

Posted by in categories: computing, quantum physics

Named after an Italian theoretical physicist, Majoranas are complex quasiparticles that could be the key to building next-generation quantum computing systems.

May 16, 2024

World’s Purest Silicon Paves the Way for Next-Gen Quantum Computers

Posted by in categories: computing, particle physics, quantum physics

A major breakthrough in quantum computing has been achieved with the development of ultra-pure silicon, setting the stage for the creation of powerful, scalable quantum computers.

More than 100 years ago, scientists at The University of Manchester changed the world when they discovered the nucleus in atoms, marking the birth of nuclear physics.

Fast forward to today, and history repeats itself, this time in quantum computing.

May 16, 2024

Wavefunction matching for solving quantum many-body problems

Posted by in categories: chemistry, particle physics, quantum physics

Strongly interacting systems play an important role in quantum physics and quantum chemistry. Stochastic methods such as Monte Carlo simulations are a proven method for investigating such systems. However, these methods reach their limits when so-called sign oscillations occur. This problem has now been solved by an international team of researchers from Germany, Turkey, the USA, China, South Korea and France using the new method of wavefunction matching. As an example, the masses and radii of all nuclei up to mass number 50 were calculated using this method. The results agree with the measurements, the researchers now report in the journal “Nature.”

All matter on Earth consists of tiny particles known as atoms. Each atom contains even smaller particles: protons, neutrons and electrons. Each of these particles follows the rules of quantum mechanics. Quantum mechanics forms the basis of quantum many-body theory, which describes systems with many particles, such as atomic nuclei.

One class of methods used by nuclear physicists to study atomic nuclei is the ab initio approach. It describes complex systems by starting from a description of their elementary components and their interactions. In the case of nuclear physics, the elementary components are protons and neutrons. Some key questions that ab initio calculations can help answer are the binding energies and properties of atomic nuclei and the link between nuclear structure and the underlying interactions between protons and neutrons.

May 16, 2024

Why China, the U.S., and Big Tech Are Racing to Harness Quantum Computing and AI

Posted by in categories: economics, encryption, military, quantum physics, robotics/AI

Micius is considered quantum’s “Sputnik” moment, prompting American policymakers to funnel hundreds of millions of dollars into quantum information science via the National Quantum Initiative. Bills such as the Innovation and Competition Act of 2021 have provided $1.5 billion for communications research, including quantum technology. The Biden Administration’s proposed 2024 budget includes $25 billion for “emerging technologies” including AI and quantum. Ultimately, quantum’s awesome computing power will soon render all existing cryptography obsolete, presenting a security migraine for governments and corporations everywhere.

Quantum’s potential to turbocharge AI also applies to the simmering technology competition between the world’s superpowers. In 2021, the U.S. Commerce Department added eight Chinese quantum computing organizations to its Entity List, claiming they “support the military modernization of the People’s Liberation Army” and adopt American technologies to develop “counter-stealth and counter-submarine applications, and the ability to break encryption.”

These restrictions dovetail with a raft of measures targeting China’s AI ambitions, including last year blocking Nvida from selling AI chips to Chinese firms. The question is whether competition between the world’s top two economies stymies overall progress on AI and quantum—or pushes each nation to accelerate these technologies. The answer could have far-reaching consequences.

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