Phys.org September 3, 2021 The photoluminescence and the contrast of the optically detected magnetic resonance (ODMR) of hexagonal boron nitride (hBN) spin defects are relatively low so far, which limits their sensitivity. An international team of researchers (USA – Purdue University, Australia) used a gold film to increase the brightness of spin qubits by up to 17-fold. The gold film supports the surface plasmon that can speed up photon emission and hence more signals. They improved the contrast of their magnetic resonance signal by a factor of 10 by optimizing the design of a microwave waveguide substantially improving the sensitivity […]
Tag Archives: Quantum sensing
Quantum sensing: Odd angles make for strong spin-spin coupling
Science Daily May 25, 2021 Exotic quantum vacuum phenomena are predicted in cavity quantum electrodynamics systems with ultra-strong light-matter interactions. However, such predictions have not been realized because antiresonant interactions are typically negligible compared to resonant interactions in light-matter systems. An international team of researchers (USA – Rice University, Japan, Germany, China) reports an unusual, ultra-strongly coupled matter-matter system of magnons that is analytically described by a unique Hamiltonian in which the relative importance of resonant and antiresonant interactions can be easily tuned and the latter can be made vastly dominant. They found a regime where vacuum Bloch-Siegert shifts, the […]
A speed limit also applies in the quantum world
Science Daily February 19, 2021 In two-level systems, the quantum brachistochrone solutions are long known but they are not applicable to larger systems, especially when the target state cannot be reached through a local transformation. An international team of researchers (Germany, USA – MIT, Italy) has demonstrated fast coherent transport of an atomic wave packet over 15 times its size, a case of quantum processes going beyond the two-level system. The measurements of the transport fidelity revealed the existence of a minimum duration—a quantum speed limit—for the coherent splitting and recombination of matter waves. They obtained physical insight into this […]
Machine learning paves the way for next-level quantum sensing
Phys.org May 2, 2019 An international team of researchers (UK, Germany, USA – industry, University of Washington) show how machine learning can process the noisy readout of a single NV center at room temperature, requiring on average only one photon per algorithm step, to sense magnetic-field strength with a precision comparable to those reported for cryogenic experiments. The findings could lead to a new generation of MRI scanners as well as further potential uses in biology and material science…read more. TECHNICAL ARTICLE
Novel approach to coherent control of a three-level quantum system
Science Daily August 8, 2018 Researchers in Switzerland combined a quantum system with a mechanical oscillator employing electrons trapped in nitrogen-vacancy centers and embedded these spins in single-crystalline mechanical resonators made from diamond. The nitrogen-vacancy spins possess three eigenstates, which can be described as “up,” “down” and “zero.” The researchers showed complete quantum control over such a three-level system, in a way not possible before. They showed that if the three eigenstates are coupled to each other the coherence time can be significantly extended. Research could have application in quantum sensing or quantum information processing… read more. Open Access TECHNICAL […]