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 […]