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Researchers who have been working for years to understand electron arrangement and magnetism in certain semimetals have been frustrated by the fact that the materials only display magnetic properties if they are cooled to just a few degrees above absolute zero.

A new MIT study led by Mingda Li, associate professor of nuclear science and engineering, and co-authored by Nathan Drucker, a graduate research assistant in MIT’s Quantum Measurement Group and Ph.D. student in applied physics at Harvard University, along with Thanh Nguyen and Phum Siriviboon, MIT graduate students working in the Quantum Measurement Group, is challenging that conventional wisdom.

The open-access research, published in Nature Communications, for the first time shows evidence that topology can stabilize magnetic ordering, even well above the magnetic transition temperature—the point at which magnetism normally breaks down.

Quantum communications have rapidly progressed toward practical, large-scale networks based on quantum key distributions that spearhead the process. Quantum key distribution systems typically include a sender “Alice,” a receiver “Bob,” who generate a shared secret from quantum measurements for secure communication. Although fiber-based systems are well-suited for metropolitan scale, a suitable fiber infrastructure might not always be in place.

In a new report in npj Quantum Information, Andrej Kržič and a team of scientists developed an entanglement-based, free-space quantum network. The platform offered a practical and efficient alternative for metropolitan applications. The team introduced a free-space quantum key distribution system to demonstrate its use in realistic applications in anticipation of the work to establish free-space networks as a viable solution for metropolitan applications in the future global quantum internet.

Quantum communication typically aims to distribute quantum information between two or more parties. A series of revolutionary applications of quantum networks have provided a roadmap towards engineering a full-blown quantum internet. The proposed invention provides a heterogeneous network of special purpose sub-networks with diverse links and interconnects. The concept of quantum key distribution networks have driven this development to pave the way for other distributed quantum information processing methods to benchmark the technological maturity of quantum networks in general.

A research team led by Prof. Yossi Paltiel at the Hebrew University of Jerusalem with groups from HUJI, Weizmann, and IST Austria recently conducted a study unveiling the significant influence of nuclear spin on biological activities. This discovery challenges long-held assumptions and opens up exciting possibilities for advancements in biotechnology and quantum biology.

Scientists have long believed that nuclear spin had no impact on biological processes. However, recent research has shown that certain isotopes behave differently due to their nuclear spin. The team focused on stable oxygen isotopes (16O, 17O, 18O) and found that nuclear spin significantly affects oxygen dynamics in chiral environments, particularly in its transport.

Researcher show that n-bit integers can be factorized by independently running a quantum circuit with orders of magnitude fewer qubits many times. It then use polynomial-time classical post-processing. The correctness of the algorithm relies on a number-theoretic heuristic assumption reminiscent of those used in subexponential classical factorization algorithms. It is currently not clear if the algorithm can lead to improved physical implementations in practice.

Shor’s celebrated algorithm allows to factorize n-bit integers using a quantum circuit of size O(n^2). For factoring to be feasible in practice, however, it is desirable to reduce this number further. Indeed, all else being equal, the fewer quantum gates there are in a circuit, the likelier it is that it can be implemented without noise and decoherence destroying the quantum effects.

The new algorithm can be thought of as a multidimensional analogue of Shor’s algorithm. At the core of the algorithm is a quantum procedure.

A team of researchers has found a way to speed up the creation of quantum entanglement, a mystifying property of quantum mechanics that Albert Einstein once described as “spooky action at a distance.”

The researchers behind the discovery include Kater Murch, the Charles M. Hohenberg Professor of Physics; Weijian Chen, a postdoctoral research associate in the Department of Physics; and Maryam Abbasi, a postdoctoral research associate in the Department of Chemistry. Their paper was featured on the cover of Physical Review Letters.

Entanglement has baffled researchers—and nearly everyone who has ever read about quantum physics —since Einstein and colleagues first proposed it in the 1930s.

This year’s Nobel Prize in Chemistry recognizes the development of quantum dots, particles whose size controls their color, making them useful for technologies such as displays.

“Using the new quantum ruler to study how the circular orbits vary with magnetic field, we hope to reveal the subtle magnetic properties of these moiré quantum materials”

Graphene, a single-atom-thick sheet of carbon, is renowned for its exceptional electrical conductivity and mechanical strength.

However, when two or more layers of graphene are stacked with a slight misalignment, they become moiré quantum matter, opening the door to a world of exotic possibilities. Depending on the angle of twist, these materials can generate magnetic fields, become superconductors with zero electrical resistance, or transform into perfect insulators.

To listen to more of John Wheeler’s stories, go to the playlist: https://www.youtube.com/playlist?list=PLVV0r6CmEsFzVlqiUh95Q881umWUPjQbB

American physicist, John Wheeler (1911−2008), made seminal contributions to the theories of quantum gravity and nuclear fission, but is best known for coining the term ‘black holes’. A keen teacher and mentor, he was also a key figure in the Manhattan Project. [Listener: Ken Ford]

Continue reading “John Wheeler — Kurt Gödel and the Closed Time-like Line” »

Physicists have used the famous particle smasher to investigate the strange phenomena of quantum entanglement at far higher energies than ever before.

By Alex Wilkins