All posts tagged: quantum sensing

New prototype quantum sensor expedites search for dark matter and gravitational waves

New prototype quantum sensor expedites search for dark matter and gravitational waves

Published by Jenni Sidey

The trouble with listening for the faintest events in the universe is that your own instrument often drowns them out. However, physicists at Imperial College London have now shown that a prototype quantum sensor can still pull out a real signal. This happens even when noise appears to erase each measurement. That result, reported in Nature, tackles one of the central technical problems facing a new class of detectors known as long-baseline atom interferometers. These devices are being developed to search for gravitational waves in a frequency range current observatories cannot reach. Moreover, they aim to look for signs of ultralight dark matter. Instead of using mirrors and laser beams in the usual way, atom interferometers use lasers to split and recombine the wave-like motion of atoms. Tiny changes in that motion can reveal equally tiny disturbances in space, time, or the atoms themselves. The promise is huge. So is the noise. Building a quantum sensor requires light with precisely controlled frequency, polarization, and intensity. In this image, a red laser’s frequency is adjusted before …

Oxford physicists create a new kind of Schrödinger’s cat

Oxford physicists create a new kind of Schrödinger’s cat

Published by Jenni Sidey

Quantum mechanics is full of states that seem to defy ordinary sense, but one of its strangest ideas has usually been built from fairly familiar pieces. At the University of Oxford, physicists have now shown they can assemble Schrödinger’s cat-like superpositions from far more exotic quantum ingredients. This produces a new class of states in the motion of a single trapped ion. That matters because the usual picture of a quantum superposition, a qubit that is both 0 and 1, is only the beginning. Many quantum systems are not limited to two possibilities. A harmonic oscillator is the mathematical model used for systems such as light, vibrations, and the motion of trapped particles. It can occupy many energy levels and support much richer forms of quantum behavior. The Oxford team used that larger playground to build superpositions that go beyond the standard “cat state,” where two coherent wave packets sit in opposition. Instead, they made superpositions from components that were already strongly nonclassical. These included squeezed, trisqueezed, and quadsqueezed motional states. “This approach gave us …

University of Chicago team proposes flexible new platform to produce entangled quantum states

University of Chicago team proposes flexible new platform to produce entangled quantum states

Published by Jenni Sidey

Entanglement sits at the heart of quantum technology, but it is rarely easy to make. The most powerful states often demand delicate hardware, custom-built controls, and a long list of moving parts. That is why a new proposal from the University of Chicago is drawing attention. It suggests that a much simpler setup may be able to produce a surprisingly wide range of complex quantum states. This includes some that could improve sensors and help physicists study exotic forms of matter. The work, published in Physical Review X, lays out a theoretical method for generating and controlling entangled states in cavity quantum electrodynamics, or cavity QED, a platform already familiar in many quantum labs. The idea begins with atoms placed inside an optical cavity. There, light bounces between two mirrors and interacts with the atoms. In standard cavity QED, all the atoms usually couple to the light in the same way. That sameness is useful, but it also imposes limits. “We wanted to take simple ingredients that you find in a lot of physical platforms …

New optical trick pulls hidden quantum signals out of background noise

New optical trick pulls hidden quantum signals out of background noise

Published by Jenni Sidey

Bright background light can do more than clutter a quantum experiment. It can wash out the very features that make quantum systems useful in the first place. That is the problem a team at the Institut national de la recherche scientifique, or INRS, set out to tackle. Working with light particles called photons, the researchers built a way to sift out meaningful quantum signals even when those signals are buried under heavy optical noise. Their results, published in Science Advances, point to a simpler and more energy-efficient route for keeping quantum information intact in messy, real-world conditions. The work came from the group of Professor José Azaña, in collaboration with Professor Roberto Morandotti’s team. It was carried out by Benjamin Crockett during his PhD at the INRS Énergie Matériaux Télécommunications Research Centre. Crockett has since moved to the University of British Columbia as a Banting postdoctoral fellow. Quantum technologies depend on detecting the properties carried by single photons. That sounds manageable in a carefully controlled lab. It becomes much harder when the photon you care …

Scientists unlock scalable entanglement for next-generation quantum computing

Scientists unlock scalable entanglement for next-generation quantum computing

Published by Jenni Sidey

Light moving through a tiny silicon structure does not look dramatic. It slips down narrow waveguides etched onto a chip, guided by geometry too small to see with the naked eye. Yet in those channels, researchers at the University of Central Florida say they have found a way to build more complex quantum states of light without making the system itself more cumbersome. Their study, published in Science, centers on a problem that has lingered in quantum photonics. Entangled states of light can help power quantum computing and quantum sensing, but making those states both scalable and resistant to imperfections has been difficult. Andrea Blanco-Redondo, an optics and photonics professor at CREOL, the College of Optics and Photonics, said her group has now shown a method for entangling multiple topologically protected modes of light in silicon photonic superlattices. CREOL doctoral student Javad Zakeri while performing the photonic quantum experiments at UCF’s College of Optics and Photonics. (CREDIT: UCF) Where the robustness comes from Topological modes are unusual because they depend on the overall structure of …