A research team from the American Institute of Physics (AIP) has discovered that quantum entities can evolve from gravitational wave experiments.
In AVS Quantum Science, co-published by AIP Publishing and AVS, researchers from Hamburg University, Germany, review research on gravitational wave detectors as a historical example of quantum technologies and examine the fundamental research on the connection between quantum entities and gravity. Gravitational wave astronomy requires unprecedented sensitivities for measuring the tiny space-time oscillations at audio-band frequencies and below.
How have scientists observed this quantum entity evolution?
Physical experiments exploring quantum entities include a focus on the motion of macroscopic and heavy bodies under gravitational forces, which require protection from any environmental noise and highly efficient sensing.
An ideal system is a highly reflecting mirror whose motion is sensed by monochromatic light, which is photoelectrically detected with high quantum efficiency.
A quantum optomechanical experiment is achieved if the quantum uncertainties of light and mirror motion influence each other, ultimately leading to the observation of entanglement between optical and motional degrees of freedom.
What did the experiments reveal?
The team examined recent gravitational wave experiments, demonstrating that it is possible to shield large objects, such as a 40-kilogram quartz glass mirror reflecting 200 kilowatts of laser light, from strong influences from the thermal and seismic environment to allow them to evolve as one quantum object.
“The mirror perceives only the light, and the light only the mirror. The environment is basically not there for the two of them,” explained Roman Schnabel, lead author. “Their joint evolution is described by the Schrödinger equation.”
This decoupling from the environment, which is central to all quantum technologies, such as the quantum computer, enables measurement sensitivities that would otherwise be impossible. The researchers review intersects with Nobel laureate, Roger Penrose’s work on exploring the quantum behaviour of massive objects.
What were Penrose’s theories on this?
Penrose sought to better understand the connection between quantum physics and gravity, which remains an uncertain topic in the scientific community.
Penrose thought of an experiment in which light would be coupled to a mechanical device utilising radiation pressure. In their review, the researchers demonstrate that while these very fundamental questions in physics remain unresolved, the highly shielded coupling of massive devices that reflect laser light is beginning to improve sensor technology.
In the future, researchers will likely explore further decoupling gravitational wave detectors from influences of the environment.
Additionally, on a broader scale, the decoupling of quantum devices from any thermal energy exchange with the environment is key. It is required for quantum measurement devices as well as quantum computers.
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