Phys.org May 10, 2022 Finding convincing evidence that quantum spin liquids exist in actual physical materials has been a decades-long challenge. In a 2019 study led by Rice university found the first evidence that cerium zirconium pyrochlore was a quantum spin liquid. To build a convincing case, an international team of researchers (USA – Florida State University, National High Magnetic Field Laboratory, UCLA, Rice University, Germany) developed a model and tested it against thermodynamic, neutron-scattering and magnetization results from previously published experimental studies of cerium zirconium pyrochlore. They matched three different pieces of evidence: that a version of monopoles does […]
Tag Archives: Quantum science
On-chip circuit produces up to six microwave photons at the same time
Phys.org May 10, 2022 An international team of researchers (France, Germany) built a on-chip circuit which is a simple battery-biased superconducting tunnel junction in series with a microwave resonator. At discrete values of the battery voltage, a dc current flows through the circuit, with the emission of several photons at the resonator frequency for each superconducting pair of electrons that tunnels across the junction. They measured the total microwave power emitted and characterized the granularity of the emission both of which were good agreement with a simple theoretical model. In particular, at a small transparency of the tunnel junction, they […]
Making a ‘sandwich’ out of magnets and topological insulators, potential for lossless electronics
Nanowerk April 3, 2022 Inducing magnetic order in topological insulators via proximity to a magnetic material offers a promising pathway towards achieving quantum anomalous Hall (QAH) effect at higher temperatures for lossless transport applications. An international team of researchers (Australia, Singapore, USA – UC Berkeley) demonstrated the growth of a MnBi2Te4 / Bi2Te3 /MnBi2Te4 heterostructure via molecular beam epitaxy and probed the structure’s electronic structure using angle resolved photoelectron spectroscopy. They observed strong hexagonally warped massive Dirac fermions and a bandgap of 75 ± 15 meV. The 2D MnBi2Te4 ferromagnets induced magnetic order in the ultra-thin topological insulator Bi2Te3 via […]
Quantum ‘shock absorbers’ allow perovskite to exhibit superfluorescence at room temperature
Phys.org March 31, 2022 While analyzing the structure and optical properties of a common lead-halide hybrid perovskite an international team of researchers (USA – North Caroline State University, France) noticed the formation of polarons in these materials. Their analysis showed that formation of large polarons creates a thermal vibrational noise filter mechanism that they called ‘Quantum Analog of Vibration Isolation,’ or QAVI, which is like a shock absorber protecting the dipoles. When they are protected by the shock absorbers, the dipoles can synchronize and exhibit superfluorescence. According to the researchers, QAVI is an intrinsic property that exists in certain materials, […]
Qubits: Developing long-distance quantum telecommunications networks
Science Daily March 22, 2022 An international team of researchers (Switzerland, France) has stored a qubit for 20 milliseconds in crystals doped with europium capable of absorbing light and then re-emitting it. They managed to reach the 100-millisecond mark with a small loss of fidelity. The crystals were kept at -273,15°C, because beyond 10°C above this temperature, the thermal agitation of the crystal destroys the entanglement of the atoms. In theory, it would be enough to increase the duration of exposure of the crystal to radio frequencies, but for the time being, technical obstacles to their implementation over a longer […]
New materials for quantum technologies
Phys.org December 22, 2021 To advance spintronics devices and quantum information technology using materials with non-trivial topological properties, three key challenges are still unresolved – the identification of topological band degeneracies located at the Fermi level, the ability to easily control such topological degeneracies., and the identification of generic topological degeneracies in large, multisheeted Fermi surfaces. Researchers in Germany have shown that the non-symmorphic symmetries in chiral, ferromagnetic manganese silicide (MnSi) generate nodal planes (NPs) which enforce topological protectorates (TPs) with substantial Berry curvatures at the intersection of the NPs with the Fermi surface (FS) regardless of the complexity of […]
Tapping into magnets to clamp down on noise in quantum information
Phys.org September 3, 2021 Building on their earlier efforts to create a superconducting circuit integrated with magnetic elements, a team of researchers in the US (Argonne National Laboratory, University of Illinois) is investigating whether magnons could partner with microwave photons to ensure that microwaves can only travel in one direction, thereby essentially eliminating noise. They will be testing known and new material systems to find candidates that can handle an ultracold environment and operate in a real quantum device. According to the researchers if they are successful, it is possible to have magnetic structures directly integrated with quantum circuitry. The […]
Nanoscale systems for generating various forms of light
Science Daily August 30, 2021 Stimulated by experimental work in the possibility of preserving nonclassical correlations in light-matter interactions mediated by scattering of photons and plasmons, it has been assumed that similar dynamics underlie the conservation of the quantum fluctuations that define the nature of light sources. An international team of researchers (Usa – State University of Louisiana, University of Alabama, Mexico) demonstrated that the quantum statistics of multiparticle systems are not always preserved in plasmonic platforms and report the observation of their modification. They showed that optical near fields provide additional scattering paths that can induce complex multiparticle interactions. […]
A quantum step to a heat switch with no moving parts
Science Daily June 7, 2021 Based on foundational theory a team of researchers in the US (Iowa State University, University of Ohio, University of Chicago) engineered an alloy with the elements bismuth and antimony at precise ranges. In this material electrons move like massless photons, a phenomenon theoretically predicted to exist. Under the influence of an external magnetic field some of the electrons generate energy, while others absorb energy, effectively turning the material into an energy pump resulting in 300% increase in its thermal conductivity. The mechanism is turned off if the magnet is taken away. This property, and the […]
New evidence for electron’s dual nature found in a quantum spin liquid
EurekAlert May 13, 2021 In spin liquid materials, the spins are constantly changing in a tightly coordinated, entangled choreography resulting in one of the most entangled quantum states. A team of researchers in the US (Princeton University, University of Tennessee, Oak Ridge National Laboratory, Purdue University) proposed that in the quantum regime an electron may be regarded as composed of two particles, one bearing the electron’s negative charge and the other containing its spin they called it spinon. They searched for signs of the spinon in a spin liquid composed of ruthenium and chlorine atoms. The measurements demanded an extraordinarily […]