Topic
Devices that exploit quantum phenomena, including entanglement, to detect weak magnetic, gravitational and electromagnetic signals.
University of Vienna physicists recovered an ultrathin magnet's internal pattern and an 81-nanometer sensor height from external field maps. The authors say other imaging techniques can adopt the principle, though the test used one material and one sensor type.
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UC Berkeley, Austrian Academy of Sciences and Caltech researchers propose a superfluid helium gyrometer to detect Earth's frame-dragging in a lab. The case rests on a new thermal-noise analysis, since random phases can swamp the signal.
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Mark Martirez, a staff research scientist at the Princeton Plasma Physics Laboratory, simulates diamond qubit defects as isolated clusters of 16 to 30 atoms. Simulation turned up boron- and oxygen-based defects that could make useful qubits. They are candidates until someone grows and measures them.
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Researchers used six-nanosecond ultraviolet laser pulses to add new defects to a diamond while its nitrogen-vacancy centers stayed largely unchanged. For teams building diamond quantum sensors, that points to a way of changing one defect without disturbing the centers they depend on, though the evidence comes from one diamond.
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Nanosecond 266-nanometre ultraviolet pulses created new defects in a diamond while its nitrogen-vacancy centres' optical signal stayed largely unchanged. If that holds in more samples, device makers gain a way to change one defect population without disturbing the ones used as qubits.
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Researchers in Tokyo and Glasgow used light to read electron spins inside a metal-organic framework, the first such measurement in this porous material. No chemical has been detected with it yet, and the team says the signal needs to get stronger and work at more practical temperatures before sensors can follow.
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OIST physicists pushed a levitated centimeter-wide diamond with electron spin, an object 8 to 9 orders of magnitude heavier than in earlier spin-mechanical tests. Its motion was classical, so the superposition a quantum-gravity test needs is still ahead of the team.
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EPFL researchers built a chip laser that held its frequency lock from 154 to 300 milliamps of drive current with no active electronic control. It brings mass-producible semiconductor lasers closer to portable clocks and quantum sensors, though only a laboratory device has been shown so far.
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University of Glasgow physicists turned a laser's frequency into the rotation of a camera image, where a 1 MHz shift moves the pattern almost 6 degrees. Its sub-megahertz resolution still trails the kilohertz-level precision of the best existing frequency measurements.
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Quantum jumps were caught in trapped ions in 1986 and in photons in 2007. A resonator that rings for two milliseconds, read out by a superconducting qubit, now shows a single phonon going to zero as it happens.
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A USTC team moved an entangled state off the electron spins of silicon carbide color centers and onto two silicon nuclei, where it survived hundreds of microseconds without cooling, then brought it back to the electron to read out.
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A team led by Mingsheng Zhan compared the freefall of two rubidium isotopes aboard the China Space Station. The 2.8 x 10^-8 uncertainty they report is the best any quantum test has managed. It is also well short of what macroscopic experiments already do.
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Stanford physicists report in Science the first real-time observation of quantum jumps of sound, using a superconducting qubit to check a mechanical resonator hundreds of times during its two milliseconds of vibration.
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A German project measured cardiac magnetism using nitrogen-vacancy centers in a diamond of less than half a cubic millimetre, working at room temperature and off the skin.
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Transition-edge sensors cooled near absolute zero measured the X-ray lines that sit inside the gamma-ray band used to identify nuclear material. Anyone who wants one also has to buy the refrigerator that keeps it cold.
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Sandia's headline number describes the light delivered to the atoms inside a vacuum chamber, and the question for anyone sizing a deployed unit is what the lasers, electronics and pumps around it draw.
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A Stevens-led paper in JOSA B swaps one strong laser pulse for 12 weak ones, each with its own timing, intensity, frequency and phase, keeping the field at every step below where multiphoton pathways open. The work is theoretical.
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Honeywell's sensor read the Earth's crust well enough to navigate an Embraer 170 home over open water, and the notable part is how little of the aircraft had to change. A civil version has no date yet.
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Q-CTRL's trial moves gravity-based navigation from lab result toward shipboard fitting, which means the hard questions now sit with map coverage and with how much error piles up on a long unaided run.
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NIST says it ran a superconducting single-photon wire out to a tenth of a millimeter by fencing it with current-carrying rails. The 98% detection figure still belongs to the narrow devices.
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