A new interpretation of quantum mechanics suggests that reality does not depend on the person measuring it

Phys.org October 6, 2020 According to the traditional interpretation of the Heisenberg principle, location and momentum cannot be determined simultaneously to an arbitrary degree of precision, as the person conducting the measurement always affects the values. In their study researchers in Finland used stochastic optimal control theory to conclude that the correlation between a location and momentum, i.e., their relationship, is fixed. In other words, reality is an object that does not depend on the person measuring it. In their theory’s frame of reference, Heisenberg’s uncertainty principle is a manifestation of thermodynamic equilibrium, in which correlations of random variables do […]

Glass blowing inspires new class of quantum sensors

Nanowerk  August 12, 2020 By embedding micron-scale diamond particles at an annular interface within the cross section of a silicate glass fiber, researchers in Australia demonstrated a robust fiber material capable of sensing magnetic fields. NV centers in the diamond microcrystals are well preserved throughout the fiber drawing process. The hybrid fiber presents a low propagation loss of ∼4.0 dB/m in the NV emission spectral window, permitting remote monitoring of the optically detected magnetic resonance signals. They demonstrated NV-spin magnetic resonance readout through 50 cm of fiber. The study paves a way for the scalable fabrication of fiber-based diamond sensors […]

Quantum entanglement offers unprecedented precision for GPS, imaging and beyond

Science Daily  April 20, 2020 To date, almost all quantum-metrology demonstrations are restricted to improving the measurement performance at a single sensor. A team of researchers in the US (University of Arizona, industry) has demonstrated an entangled sensor network, empowered by continuous-variable (CV) multipartite entanglement, which is composed of three sensor nodes each equipped with an electro-optic transducer for the detection of radio-frequency (RF) signals. By properly tailoring the CV multipartite entangled states, the network can be reconfigured to maximize the quantum advantage in distributed RF sensing problems such as measuring the angle of arrival of an RF field. The […]

Physicists count sound particles with quantum microphone

Phys.org  July 27, 2019 Researchers at Stanford University built a hybrid platform that integrates nanomechanical piezoelectric resonators with a microwave superconducting qubit on the same chip. They excited the phonons with resonant pulses and probed the resulting excitation spectrum of the qubit to observe phonon-number-dependent frequency shifts that are about five times larger than the qubit linewidth. The result demonstrated a fully integrated platform for quantum acoustics that combines large couplings, considerable coherence times and excellent control over the mechanical mode structure. With modest experimental improvements, the approach could enable quantum nondemolition measurements of phonons and will lead to quantum […]

Quantum-enhanced sensing of magnetic fields

Science Daily  July 2, 2018 Transmon qubit is currently one of the leading candidates for a building block of large-scale quantum computers. An international team of researchers (Finland, Switzerland, Russia) has constructed an artificial atom with an intrinsic magnetic moment that is around 100’000 times larger than that of natural atoms or ions. The coupling of large moment to an external magnetic field makes it possible to accurately measure the strength of the field. The combination of harnessing quantum hardware and quantum algorithms in the context of quantum sensing provides an appealing route towards novel devices that, ultimately, promise to […]