In 1797, English scientist Henry Cavendish measured the strength of gravity with a contraption made of lead spheres, wooden rods and wire. In the 21st century, scientists are doing something very similar with rather more sophisticated tools: atoms.

Gravity might be an early subject in introductory physics classes, but that doesn’t mean scientists aren’t still trying to measure it with ever-increasing precision. Now, a group of physicists has done it using the effects of time dilation—the slowing of time caused by increased velocity or gravitational force—on atoms. In a paper published online today (Jan. 13) in the journal Science, the researchers announce that they’ve been able to measure the curvature of space-time.

The experiment is part of an area of science called atom interferometry. It takes advantage of a principle of quantum mechanics: just as a light wave can be represented as a particle, a particle (such as an atom) can be represented as a “wave packet.” And just as light waves can overlap and create interference, so too can matter wave packets.

In particular, if an atom’s wave packet is split in two, allowed to do something, and then recombined, the waves might not line up anymore—in other words, their phases have changed.

“One tries to extract useful information from this phase shift,” Albert Roura, a physicist at the Institute of Quantum Technologies in Ulm, Germany, who was not involved in the new study, told Space.com. Roura wrote a “Perspectives” piece about the new research, which was published online in the same issue of Science today.

Gravitational wave detectors work via a similar principle. By studying particles in this way, scientists can fine-tune the numbers behind some of the key workings of the universe, such as how electrons behave and how strong gravity really is—and how it subtly changes over even relatively small distances.

It’s that last effect that Chris Overstreet of Stanford University and his colleagues measured in the new study. To do this, they created an “atomic fountain,” consisting of a vacuum tube 33 feet (10 meters) tall ornamented with a ring around the very top.

www.scientificamerican.com/article/in-a-first-an-atomic-fountain-has-measured-the-curvature-of-spacetime

Spiny Norman said:

In 1797, English scientist Henry Cavendish measured the strength of gravity with a contraption made of lead spheres, wooden rods and wire. In the 21st century, scientists are doing something very similar with rather more sophisticated tools: atoms.

Gravity might be an early subject in introductory physics classes, but that doesn’t mean scientists aren’t still trying to measure it with ever-increasing precision. Now, a group of physicists has done it using the effects of time dilation—the slowing of time caused by increased velocity or gravitational force—on atoms. In a paper published online today (Jan. 13) in the journal Science, the researchers announce that they’ve been able to measure the curvature of space-time.

The experiment is part of an area of science called atom interferometry. It takes advantage of a principle of quantum mechanics: just as a light wave can be represented as a particle, a particle (such as an atom) can be represented as a “wave packet.” And just as light waves can overlap and create interference, so too can matter wave packets.

In particular, if an atom’s wave packet is split in two, allowed to do something, and then recombined, the waves might not line up anymore—in other words, their phases have changed.

“One tries to extract useful information from this phase shift,” Albert Roura, a physicist at the Institute of Quantum Technologies in Ulm, Germany, who was not involved in the new study, told Space.com. Roura wrote a “Perspectives” piece about the new research, which was published online in the same issue of Science today.

Gravitational wave detectors work via a similar principle. By studying particles in this way, scientists can fine-tune the numbers behind some of the key workings of the universe, such as how electrons behave and how strong gravity really is—and how it subtly changes over even relatively small distances.

It’s that last effect that Chris Overstreet of Stanford University and his colleagues measured in the new study. To do this, they created an “atomic fountain,” consisting of a vacuum tube 33 feet (10 meters) tall ornamented with a ring around the very top.

www.scientificamerican.com/article/in-a-first-an-atomic-fountain-has-measured-the-curvature-of-spacetime

To be fair to Mr Cavendish, his device used lots of atoms too.

Spiny Norman said:

In 1797, English scientist Henry Cavendish measured the strength of gravity with a contraption made of lead spheres, wooden rods and wire. In the 21st century, scientists are doing something very similar with rather more sophisticated tools: atoms.

Gravity might be an early subject in introductory physics classes, but that doesn’t mean scientists aren’t still trying to measure it with ever-increasing precision. Now, a group of physicists has done it using the effects of time dilation—the slowing of time caused by increased velocity or gravitational force—on atoms. In a paper published online today (Jan. 13) in the journal Science, the researchers announce that they’ve been able to measure the curvature of space-time.

The experiment is part of an area of science called atom interferometry. It takes advantage of a principle of quantum mechanics: just as a light wave can be represented as a particle, a particle (such as an atom) can be represented as a “wave packet.” And just as light waves can overlap and create interference, so too can matter wave packets.

In particular, if an atom’s wave packet is split in two, allowed to do something, and then recombined, the waves might not line up anymore—in other words, their phases have changed.

“One tries to extract useful information from this phase shift,” Albert Roura, a physicist at the Institute of Quantum Technologies in Ulm, Germany, who was not involved in the new study, told Space.com. Roura wrote a “Perspectives” piece about the new research, which was published online in the same issue of Science today.

Gravitational wave detectors work via a similar principle. By studying particles in this way, scientists can fine-tune the numbers behind some of the key workings of the universe, such as how electrons behave and how strong gravity really is—and how it subtly changes over even relatively small distances.

It’s that last effect that Chris Overstreet of Stanford University and his colleagues measured in the new study. To do this, they created an “atomic fountain,” consisting of a vacuum tube 33 feet (10 meters) tall ornamented with a ring around the very top.

www.scientificamerican.com/article/in-a-first-an-atomic-fountain-has-measured-the-curvature-of-spacetime

> Henry Cavendish measured the strength of gravity with a contraption made of lead spheres

Yep.

> a group of physicists has done it using the effects of time dilation

Interesting.

As a side note. The gravitational constant is the fundamental physical constant known to the worst precision. Which is why improving the accuracy is most important.

Back in 1937 it was only known as 6.664±0.002 in metric units. That’s 100 times less accurate than the velocity of light was known.

By 1986 it was known as 6.67259 with an error of 128 ppm. That’s 200 times less accurate than the Planck constant.

> Atomic fountain

These are the most accurate clocks, by which I mean accurate over a smallish period of time, seconds to minutes, streching to hours.

> In a paper published online today (Jan. 13) in the journal Science

Not found on the website for the journal Science.

https://www.science.org/

Papers published 13 Jan are:
“Isospin magnetism and spin-polarized superconductivity in Bernal bilayer graphene”
and
“Antibodies elicited by SARS-CoV-2 infection or mRNA vaccines have reduced neutralizing activity against Beta and Omicron pseudoviruses”
and
“Epstein-Barr virus and multiple sclerosis”
and
“When hyping technology is a crime”

“India’s pandemic toll far exceeds official count”

“Artificial intelligence unmasks anonymous chess players”

“Mapping where HIV hides suggests cure strategy”

“Indonesia’s research reform triggers layoffs and protests”

“Omicron leads to fresh wave of meeting cancellations”

“Study of soldiers implicates common virus as MS trigger”

“Cloning goes wild” about the cloning of a ferrett.

“Quantum probe of space-time curvature”

Aha, found it. https://www.science.org/doi/10.1126/science.abm6854.
“time dilation can affect the oscillation phase of quantum waves and give rise to a measurable effect in interference experiments. On page 226 of this issue, “C. Overstreet et al., Science 375, 226 (2022)”. present an atom interferometry experiment in which this effect has been measured for gravitational time dilation. In addition to the importance of the results for fundamental physics, the methods used can lead to more accurate measurements of Newton’s gravitational constant”

“Observation of a gravitational Aharonov-Bohm effect”
“The Aharonov-Bohm effect is a quantum mechanical effect in which a magnetic field affects the phase of an electron wave as it propagates along a wire. Atom interferometry exploits the wave characteristic of atoms to measure tiny differences in phase as they take different paths through the arms of an interferometer. Overstreet et al. split a cloud of cold rubidium atoms into two atomic wave packets about 25 centimeters apart and subjected one of the wave packets to gravitational interaction with a large mass (see the Perspective by Roura). The authors state that the observed phase shift is consistent with a gravitational Aharonov-Bohm effect.”

“We measure the gravitational phase shift induced in a matter-wave interferometer by a kilogram-scale source mass close to one of the wave packets. Deflections of each interferometer arm due to the source mass are independently measured. The phase shift deviates from the deflection-induced phase contribution, as predicted by quantum mechanics. In addition, the observed scaling of the phase shift is consistent with Heisenberg’s error-disturbance relation. These results show that gravity creates Aharonov-Bohm phase shifts analogous to those produced by electromagnetic interactions.”

https://en.wikipedia.org/wiki/Aharonov%E2%80%93Bohm_effect

“The Aharonov–Bohm effect is a quantum mechanical phenomenon in which an electrically charged particle is affected by an electromagnetic potential (φ, A), despite being confined to a region in which both the magnetic field B and electric field E are zero.”

Brooks, Michael (May 5, 2010). “Seven wonders of the quantum world”. New Scientist.
the Aharonov–Bohm effect was chosen by the New Scientist magazine as one of the “seven wonders of the quantum world”

“Gravitational effect
The Aharonov–Bohm phase shift due to the gravitational potential should also be possible to observe in theory and in 2022 an experiment was carried to observe it based on a experimental design from 2012 but multiple other tests have been proposed. In it ultra-cold rubidium atoms in superposition were launched vertically inside a vacuum tube and split with a laser so that one part would go higher than the other and then recombined back, outside of the chamber at the top sits an axially symmetric mass that changes the gravitational potential so that the part that goes higher should experience a greater change which manifests as interference pattern when recombining the wave packets resulting in a measurable phase shift, evidence of a match between the measurements and the predictions was found by the team.