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Category: quantum physics – Page 18

Breakthrough could connect quantum computers at 200X the distance

Quantum computers are powerful, lightning-fast and notoriously difficult to connect to one another over long distances.

Previously, the maximum distance two quantum computers could connect through a was a few kilometers. This means that, even if fiber cable were run between them, quantum computers in the University of Chicago’s South Side campus and downtown Chicago’s Willis Tower would be too far apart to communicate with each other.

Research published today in Nature Communications from University of Chicago Pritzker School of Molecular Engineering (UChicago PME) Asst. Prof. Tian Zhong would theoretically extend that maximum to 2,000 km (1,243 miles).

Quantum ‘pinball’ state of matter in electrons allows both conducting and insulating properties, physicists discover

Electricity powers our lives, including our cars, phones, computers, and more, through the movement of electrons within a circuit. While we can’t see these electrons, electric currents moving through a conductor flow like water through a pipe to produce electricity.

Certain materials, however, allow that electron flow to “freeze” into crystallized shapes, triggering a transition in the state of matter that the electrons collectively form. This turns the material from a conductor to an insulator, stopping the flow of electrons and providing a unique window into their complex behavior. This phenomenon makes possible new technologies in quantum computing, advanced superconductivity for energy and medical imaging, lighting, and highly precise atomic clocks.

A team of Florida State University-based physicists, including National High Magnetic Field Laboratory Dirac Postdoctoral Fellow Aman Kumar, Associate Professor Hitesh Changlani and Assistant Professor Cyprian Lewandowski, have shown the conditions necessary to stabilize a phase of matter in which electrons exist in a solid crystalline lattice but can “melt” into a , known as a generalized Wigner crystal. Their work was published in npj Quantum Materials.

Physicists observe key evidence of unconventional superconductivity in magic-angle graphene

Superconductors are like the express trains in a metro system. Any electricity that “boards” a superconducting material can zip through it without stopping and losing energy along the way. As such, superconductors are extremely energy efficient, and are used today to power a variety of applications, from MRI machines to particle accelerators.

But these “conventional” superconductors are somewhat limited in terms of uses because they must be brought down to ultra-low temperatures using elaborate cooling systems to keep them in their superconducting state.

If superconductors could work at higher, room-like temperatures, however, they would enable a new world of technologies, from zero-energy-loss power cables and electricity grids, to practical quantum computing systems. And so, scientists at MIT and elsewhere are studying “unconventional” superconductors—materials that exhibit in ways that are different from and potentially more promising than today’s superconductors.

MIT’s Magic-Angle Graphene Just Changed Superconductivity

MIT researchers uncovered clear evidence of unconventional superconductivity in magic-angle twisted trilayer graphene.

Their new measurement system revealed a sharp, V-shaped superconducting gap — proof of a new pairing mechanism unlike that in traditional superconductors. This breakthrough sheds light on quantum behaviors in ultra-thin materials and could accelerate the quest for room-temperature superconductivity.

Superconductors: Nature’s Perfect Conductors.

Quantum fusion of independent networks based on multi-user entanglement swapping

The quantum fusion of two independent 10-user networks is demonstrated based on multi-user entanglement swapping. Active temporal and wavelength multiplexing schemes are developed to merge the two networks into a larger network with 18 users in the quantum correlation layer.

‘This is easily the most powerful quantum computer on Earth’: Scientists unveil Helios, a record-breaking quantum system

Scientists have built a 98-qubit machine that they say performs better than any other quantum computer in the world. They’ve used it to gain new insights into superconducting physics.

On-chip quantum interference of indistinguishable single photons from integrated independent molecules

Hong–Ou–Mandel experiments on a quantum photonic chip demonstrate on-chip quantum interference of indistinguishable single photons with visibilities exceeding 0.97 for two molecules separately coupled to two waveguides.

Two independent quantum networks successfully fused into one

Many quantum researchers are working toward building technologies that allow for the existence of a global quantum internet, in which any two users on Earth would be able to conduct large-scale quantum computing and communicate securely with the help of quantum entanglement. Although this requires many more technological advancements, a team of researchers at Shanghai Jiao Tong University in China have managed to merge two independent networks, bringing the world a bit closer to realizing a quantum internet.

A true global will require interconnectivity between many networks, and this has proven to be a much more difficult task for than it is for classical networks. While researchers have demonstrated the ability to connect quantum computers within the same network, multi-user fusion remains a major challenge. Fully connected networks using dense wavelength division multiplexing (DWDM) have been achieved, but have scalability and complexity issues.

However, the research team involved in the new study, published in Nature Photonics, has merged two independent networks with 18 different users. All 18 users can communicate securely using -based protocols using this method. This represents the most complex multi-user quantum network to date.

Scientists reveal it is feasible to send quantum signals from Earth to a satellite

Quantum satellites currently beam entangled particles of light from space down to different ground stations for ultra-secure communications. New research shows it is also possible to send these signals upward, from Earth to a satellite; something once thought unfeasible.

This breakthrough overcomes significant barriers to current quantum communications. Ground station transmitters can access more power, are easier to maintain and could generate far stronger signals, enabling future quantum computer networks using satellite relays.

The study, “Quantum entanglement distribution via uplink satellite channels”, by Professor Simon Devitt, Professor Alexander Solntsev and a research team from the University of Technology Sydney (UTS), is published in the journal Physical Review Research.

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