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Category: quantum physics – Page 168

Twisted trilayer graphene shows high kinetic inductance and quantum coherence

Superconductivity is an advantageous physical phenomenon observed in some materials, which entails an electrical resistance of zero below specific critical temperatures. This phenomenon is known to arise following the formation of so-called Cooper pairs (i.e., pairs of electrons).

There are two known types of superconductivity, known as conventional and unconventional superconductivity. In , the formation of Cooper pairs is mediated by the interaction between electrons and phonons (i.e., vibrations in a crystal’s lattice), as explained by Bardeen-Cooper-Schrieffer (BCS) theory.

Unconventional superconductors, on the other hand, are materials that exhibit a superconductivity that is not prompted by electron–phonon interactions. While many past studies have tried to shed light on the mechanisms underpinning unconventional superconductivity, its underlying physics remains poorly understood.

Magnetic chains on superconductors: New heterostructure design advances quantum technology

Magnetic-superconducting hybrid systems are key to unlocking topological superconductivity, a state that could host Majorana modes with potential applications in fault-tolerant quantum computing. However, creating stable, controllable interfaces between magnetic and superconducting materials remains a challenge.

Traditional systems often struggle with lattice mismatches, complex interfacial interactions, and disorder, which can obscure the signatures of topological states or mimic them with trivial phenomena. Achieving over at the atomic scale has been a long-standing challenge in this field.

Published in Materials Futures, the researchers developed a novel sub-monolayer CrTe2/NbSe2 heterostructure. By carefully depositing Cr and Te on NbSe2 substrate, they observed a two-stage growth process: an initial compressed Cr-Te layer forms with a lattice constant of 0.35 nm, followed by the formation of an atomically flat CrTe2 monolayer with a lattice constant of 0.39 nm. Annealing the Cr-Te layer can trigger stress-relief reconstruction, which creates stripe-like patterns with edges that host localized , effectively forming one-dimensional magnetic chains.

Researcher discusses trapping single atoms and putting them to work in emerging quantum technologies

Blink and you might miss it, but if you keep your eye on the monitors in professor Sebastian Will’s lab, you’ll catch a series of single-second flashes that light up the screen. Each flash is an atom of strontium, a naturally occurring alkaline-earth metal, being briefly captured and held in place by “tweezers” made of laser light. “We can see single atoms,” says graduate student Aaron Holman. “Seeing those never gets old.”

The lab saw its first atom at the end of 2022, after two years of constructing the experimental setup—a complicated and carefully calibrated series of atomic sources, vacuum chambers, magnets, electronics, and lasers that trap and place them into custom arrangements—from scratch.

Holman, currently a 5th-year Ph.D. student in Physics, helped build the “TweeSr” project, as it’s referred to in the lab, from the ground up. A pure atomic, molecular, and optical (AMO) physicist at heart, he’s now working on ways to turn fundamental research on how atoms, molecules, and light interact into new technologies with collaborators at Columbia Engineering. He’s also heading toward bigger scales as part of a that is currently under construction.

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