Here’s what you’ll learn when you read this story:
- Imaginary time is a wonky concept for our time-bound brains, but in quantum theory and mathematics, it’s a useful tool for exploring radiation’s interaction with materials.
- A new study from scientists at the University of Maryland has now captured how microwave radiation interacts with imaginary time delay.
- This could improve not only sensing and storage devices, but also help probe how information becomes corrupted as light travels through a material.
To our temporally embedded minds, the idea of “imaginary time” is a strange one. But in quantum field theory, this isn’t imaginary, not in the sense that the tooth fairy is imaginary. Instead, “imaginary time” is defined as a length of time that can be multiplied by the square root of -1, an imaginary number represented by the number i.
Obviously, we don’t encounter these numbers in the natural world, hence the term “imaginary,” but they are particularly useful in quantum and cosmological calculations. Scientists already see “imaginary time” as a helpful mathematical quirk, but a new study from the University of Maryland (UMD) found a way to actually measure imaginary time in a lab. The results of the study were published in the journal Physical Review Letters.
When a beam of radiation—in this case microwaves—travels through a material, they can experience a time delay, which scientists in 2016 previously determined could be imaginary. Fast-forward nearly a decade later, UMD scientists Isabella Giovannelli and Steven Anlage discovered that if you send a pulse through coaxial cables that form a ring shape, close analysis of the microwave pulse using an oscilloscope as it exits the experimental setup shows that imaginary time can appear as one very small physical change, according to New Scientist.
“It’s sort of like a hidden degree of freedom that people ignored,” Anlage, a co-author of the study, told New Scientist. “I think what we’ve done is bring it out and give it a physical meaning.”
This change occurs due to a slightly shifting frequency as the microwave passes through the material. But the imaginary time delays are incredibly small, presenting an observational challenge. Giovannelli tells New Scientist that they only had a chance at discovering this behavior because they happened to be using the very best oscilloscopes in the world.
Of course, a small behavior in a pulse of radiation in a material may seem inconsequential, but for nanoscience applications, it’s immensely important. Scientists have previously studied the non-imaginary components of this interaction, so the world’s first observation of light experiencing imaginary time helps complete the picture. Understanding how light experiences imaginary time can improve sensing devices, along with storage platforms that rely on light.
“It’s like a hammer that we’ve invented, and now we can find nails,” says Anlage.
One of the first nails, the authors tell New Scientist, will be to look at how information-carrying pulses used in communications are corrupted as they travel through materials, and if they too are related to the imaginary time delays.
Darren lives in Portland, has a cat, and writes/edits about sci-fi and how our world works. You can find his previous stuff at Gizmodo and Paste if you look hard enough.
