Physicists propose new quantum device to measure how Earth twists space-time
Scientists have proposed a new tabletop device to detect the subtle way Earth's daily spin on its axis twists the space-time around it — an effect predicted by Einstein's general relativity.
Key points
- They tracked how the twisting of space-time slowly shifts spinning gyroscopes or the paths of satellites.
- (Image credit: NASA) Einstein's theory of general relativity predicts that a massive, spinning object drags the fabric of space-time along with it, just like a spoon twirling in honey.
- A quantum loop The new device is a loop of superfluid helium-4 — helium chilled until it flows without friction and behaves like a single, giant quantum object.
As Earth spins and drags space-time, it nudges the quantum state of the helium flowing through the junction.
If built, the sensor could measure the quantum effect known as frame dragging with the same precision as the best satellite experiments, but in minutes instead of years, the researchers proposed in a new study.
Additional details
- Researchers also had to account for the fact that Earth bulges at the equator and its mass is spread unevenly, which gives the planet’s gravity small irregularities that tug on satellites far more strongly than frame dragging does.
- This device measured Earth's frame-dragging from space, confirming Einstein's predictions with an 18% margin of error.
- Instead, the team calculated how the device would behave at a few thousandths of a degree above absolute zero.
- One key finding in the new paper is the result of the team's thermal noise analysis, which showed how sensitive these devices could be at millikelvin temperatures, Elles said.
- "It is impossible to synchronize that collection of clocks when you're in a rotating frame," Kai-Isaak Ellers, a physics graduate student at the University of California, Berkeley (UC Berkeley) and first author of the study, told Live Science.
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