Physics News and Discussions

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First direct imaging of tiny noble gas clusters at room temperature
https://phys.org/news/2024-01-imaging-t ... sters.html
by University of Vienna

For the first time, a research team has succeeded in stabilizing and directly imaging small clusters of noble gas atoms at room temperature. This achievement opens exciting possibilities for condensed matter physics and applications in quantum information technology.

The key to this breakthrough, achieved by researchers at the University of Vienna in collaboration with colleagues at the University of Helsinki, was the inclusion of noble gas atoms between two graphene layers. This overcomes the difficulty that noble gases do not form stable structures under experimental conditions at room temperature.

Details of the method and the first electron microscopic images of noble gas structures (krypton and xenon) have now been published in Nature Materials .

Jani Kotakoski's group at the University of Vienna was studying the use of ion irradiation to change the properties of graphene and other two-dimensional materials when they noticed something unusual: When noble gases are used for irradiation, they can become trapped between two graphene layers. This happens when the noble gas ions are fast enough to penetrate the first but not the second graphene layer.

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Scientists build mass-producible miniature quantum memory element
https://phys.org/news/2024-01-scientist ... emory.html
by University of Basel

Researchers at the University of Basel have built a quantum memory element based on atoms in a tiny glass cell. In the future, such quantum memories could be mass-produced on a wafer.

It is hard to imagine our lives without networks such as the internet or mobile phone networks. In the future, similar networks are planned for quantum technologies that will enable the tap-proof transmission of messages using quantum cryptography and make it possible to connect quantum computers to each other.

Like their conventional counterparts, such quantum networks require memory elements in which information can be temporarily stored and routed as needed. A team of researchers at the University of Basel led by Professor Philipp Treutlein has now developed such a memory element, which can be micro-fabricated and is, therefore, suitable for mass production. Their results were published in Physical Review Letters.

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Research reveals quantum topological potential in material
https://phys.org/news/2024-01-reveals-q ... erial.html
by Los Alamos National Laboratory

New research into topological phases of matter may spur advances in innovative quantum devices. As described in a new paper published in the journal Nature Communications, a research team including Los Alamos National Laboratory scientists used a novel strain engineering approach to convert the material hafnium pentatelluride (HfTe5) to a strong topological insulator phase, increasing its bulk electrical resistance while lowering it at the surface, a key to unlocking its quantum potential.

"I'm excited that our team was able to show that the elusive and much-sought-after topological surface states can be made to become a predominant electrical conduction pathway," said Michael Pettes, scientist with the Center for Integrated Nanotechnologies (CINT) at the Laboratory.

"This is promising for the development of types of quantum optoelectronic devices, dark matter detectors and topologically protected devices such as quantum computers. And the methodology we demonstrate is compatible for experimentation on other quantum materials."

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Rare decay of the Higgs boson may point to physics beyond the Standard Model

Particle physicists have detected a novel decay of the Higgs boson for the first time, revealing a slight discrepancy in the predictions of the Standard Model and perhaps pointing to new physics beyond it. The findings are published in the journal Physical Review Letters.

The Higgs boson, predicted theoretically since the 1960s, was finally detected in 2012 at the CERN laboratory in Europe. As a quantum field it permeates all of space, through which other particles move, acquiring mass via their interaction with the Higgs field that can be roughly envisioned as a kind of resistance to their motion.

Many properties of the Higgs boson, including how it interacts with other particle and their associated fields, have already been measured to be consistent with predictions of the Standard Model.

But one Higgs decay mode that had yet to be investigated was a theoretical prediction that a Higgs boson would occasionally decay and produce a photon, the quantum of light, and a Z boson, which is an uncharged particle that together with the two W bosons conveys the weak force.

https://phys.org/news/2024-01-rare-deca ... ysics.html

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Room-temperature long-range ferromagnetic order realized in a confined molecular monolayer
https://phys.org/news/2024-01-room-temp ... fined.html
by University of Science and Technology of China

How can we manipulate intermolecular exchange interaction to achieve long-range spin ordering? The answer to this question is of great importance in understanding and modulating magnetic behavior at the microscopic scale and in developing new macroscopic magnetic materials and devices.

However, temperature and environment play a decisive role in molecular magnetic behavior and spin ordering. At high temperatures, thermal uplift disrupts the spin ordering and disables intermolecular exchange interactions.

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Research team takes a fundamental step toward a functioning quantum internet
https://phys.org/news/2024-02-team-fund ... ernet.html
by Stony Brook University

Research with quantum computing and quantum networks is taking place around the world in the hopes of developing a quantum internet in the future. A quantum internet would be a network of quantum computers, sensors, and communication devices that will create, process, and transmit quantum states and entanglement and is anticipated to enhance society's internet system and provide certain services and securities that the current internet does not have.

A team of Stony Brook University physicists and their collaborators have taken a significant step toward the building of a quantum internet testbed by demonstrating a foundational quantum network measurement that employs room-temperature quantum memories. Their findings are described in a paper published in npj Quantum Information.

The field of quantum information essentially combines aspects of physics, mathematics, and classical computing to use quantum mechanics to solve complex problems much faster than classical computing and to transmit information in an unhackable manner.

While the vision of a quantum internet system is growing and the field has seen a surge in interest from researchers and the public at large, accompanied by a steep increase in the capital invested, an actual quantum internet prototype has not been built.

According to the Stony Brook research team, the key hurdle to achieve the potential of making communication networks more secure, measurement systems more precise, and algorithms for certain scientific analyses more powerful, relies on developing systems capable of bringing quantum information and entanglement across many nodes and over long distances. These systems are called quantum repeaters and are one of the more complex challenges in current physics research.

The researchers have advanced quantum repeater capacities in their latest experimentation. They built and characterized quantum memories that operate at room temperature and demonstrated that these memories have identical performance, an essential feature when the goal is to build large-scale quantum repeater networks that will comprise several of these memories.

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Quantum materials: A new state of matter with chiral properties
https://phys.org/news/2024-02-quantum-m ... rties.html
by Ca' Foscari University of Venice

An international research group has discovered a new state of matter characterized by the existence of a quantum phenomenon called chiral current. These currents are generated on an atomic scale by a cooperative movement of electrons, unlike conventional magnetic materials whose properties originate from the quantum characteristic of an electron known as spin and their ordering in the crystal.

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Flowermon: A superconducting qubit based on twisted cuprate van der Waals heterostructures
https://phys.org/news/2024-02-flowermon ... prate.html
by Ingrid Fadelli , Phys.org

Quantum technology could outperform conventional computers on some advanced optimization and computational tasks. In recent years, physicists have been working to identify new strategies to create quantum systems and promising qubits (i.e., basic units of information in quantum computers).

Researchers at the Institute for Complex Systems of CNR (Consiglio Nazionale delle Ricerche), Max Planck Institute for Chemical Physics of Solids, and other institutes worldwide have recently introduced a new superconducting and capacitively shunted qubit, which they dubbed "flowermon." This qubit, introduced in Physical Review Letters, is based on twisted cuprate van der Waals heterostructures.

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Scientists report first look at electrons moving in real-time in liquid water
https://phys.org/news/2024-02-scientist ... iquid.html
by Pacific Northwest National Laboratory

In an experiment akin to stop-motion photography, scientists have isolated the energetic movement of an electron while "freezing" the motion of the much larger atom it orbits in a sample of liquid water.

The findings, reported in the journal Science, provide a new window into the electronic structure of molecules in the liquid phase on a timescale previously unattainable with X-rays. The new technique reveals the immediate electronic response when a target is hit with an X-ray, an important step in understanding the effects of radiation exposure on objects and people.

"The chemical reactions induced by radiation that we want to study are the result of the electronic response of the target that happens on the attosecond timescale," said Linda Young, a senior author of the research and Distinguished Fellow at Argonne National Laboratory.

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Diamond quantum memory with Germanium vacancy exceeds coherence time of 20 ms
https://phys.org/news/2024-02-diamond-q ... cancy.html
by Ingrid Fadelli , Phys.org

The color centers of diamond are the focus of an increasing number of research studies, due to their potential for developing quantum technologies. Some works have particularly explored the use of negatively-charged group-IV diamond defects, which exhibit an efficient spin-photon interface, as the nodes of quantum networks.

Researchers at Ulm University in Germany recently leveraged a Germanium vacancy (GeV) center in diamond to realize a quantum memory. The resulting quantum memory, presented in a Physical Review Letters paper, was found to exhibit a promising coherence time of more than 20 ms.

"Our research group's primary focus is the exploration of diamond color centers for quantum applications," Katharina Senkalla, co-author of the paper, told Phys.org. "The most popular defect of diamond so far has been the nitrogen-vacancy center, but, recently, other color centers have also become a focus of research. These consist of an element from the IV column of the periodic table—Si, Ge, Sn or Pb, and a lattice vacancy (i.e., missing next-neighbor carbon atom)."