Scientists turn the faint quantum “glow” of empty space into a measurable flash
Researchers from Stockholm University and the Indian Institute of Science Education and Research (IISER) Mohali have reported a practical way to spot one of physics’ strangest predictions: the Unruh effect, which says that an object speeding up (accelerating) would perceive empty space as faintly warm. But, trying to heat something up by accelerating it unimaginably fast is a non-starter in the lab. The team shows how to convert that tiny effect into a clear, timestamped flash of light.
AI illustration of the proposed experiment - Time-Resolved and Superradiantly Amplified Unruh Effect
Here’s the simple picture. Imagine a group of atoms between two parallel mirrors. The mirrors can either speed up or slow down light emission from the atoms. When these atoms cooperate, they can emit together like a choir — much louder than solo singers. This collective outburst is called superradiance. The new study explains how the acceleration-induced warmth of empty space, if experienced by the atoms, quietly nudges them so that the choir’s burst happens earlier than it would for atoms sitting still. That earlier-than-expected flash becomes a clean, easy-to-spot signature of the Unruh effect.
“We’ve found a way to turn the Unruh effect’s whisper into a shout,” said Akhil Deswal, a PhD student at IISER Mohali. “By using carefully spaced high-quality mirrors, we make ordinary background signals quieter while the acceleration-seeded burst comes out early and clean.”
Crucially, the proposal demands significantly lower acceleration compared to the requirement in the absence of high-quality mirrors.
“Timing is the key,” added Navdeep Arya, a postdoctoral researcher at Stockholm University. “The choir of atoms is not only louder but also shouts earlier if they feel the faint Unruh effect-related warmth of empty space. That simple clock-like marker can make it easier to separate the Unruh signal from everyday noise.”
By theoretically addressing a decades-old detection challenge, the idea opens a bridge between available laboratory devices and phenomena usually linked to extreme conditions. Because acceleration and gravity are closely related, similar timing tricks might one day help researchers probe subtle, gravity-driven quantum effects — right on the lab bench.
The work, co-authored with Kinjalk Lochan and Sandeep K. Goyal of IISER Mohali, is now published in Physical Review Letters.
We are interested in various aspects of theoretical quantum mechanics. Currently, our main focus is on quantum simulations using quantum optical systems and the theory of open quantum systems.
Semiconductor devices and non-linear processes can generate a wide spectrum of quantum states of light that can be employed in tasks of communication, simulation, and sensing. We use best tools and methods available to modern science to generate quantum light, harness its unique properties, and bring it closer to real-world application.
Our research is focused on the field of quantum optics and quantum information. This include tests of quantum theory foundations, quantum communication, quantum encryption, quantum sensing, photonic-based quantum processor, and topological photonics.
The Bergholtz group explores the world of quantum and complex systems — what it is and what it could be — from the perspective of mathematics and theoretical physics.
Due to a significant technical progress and precise engineering, we are nowadays able to manipulate individual quantum systems, like single atoms, with a precision that has been unthinkable a few decades ago.
