So far, LIGO has successfully detected 90 gravitational waves. However, scientists are eager for more which means enhancing the sensitivity of the experiment. This is a huge undertaking since increasing the sensitivity of these detectors can complicate matters, according to Lisa Barsotti, an MIT physicist.
Despite the challenges, Barsotti and her team developed an innovative device designed to allow LIGO’s detectors to capture more occurrences of black hole mergers and neutron star collisions. Their invention is part of a growing body of instruments that utilize quantum squeezing, a technique that allows researchers to manipulate the elusive laws of quantum physics to their benefit.
In the quantum world, objects are defined by probabilities. An electron, for instance, isn’t fixed in one location but has an unpredictable chance of being anywhere until its properties are measured. Quantum squeezing allows the manipulation of these probabilities, giving researchers more control over measurements and significantly enhancing the precision of quantum sensors including the LIGO experiment.
“In applications where the detection of tiny signals is crucial, quantum squeezing can be a game-changer,” explains Mark Kasevich, a physicist at Stanford University who applies this technique to produce more accurate magnetometers, gyroscopes, and clocks for navigation purposes. Some commercial and military technology creators have also started exploring this technique. For instance, Xanadu, a Canadian startup uses it in its quantum computers, and last fall, DARPA revealed Inspired, a project for developing quantum squeezing technology on a chip. Two examples where quantum squeezing is currently exploiting the capabilities of quantum systems will be demonstrated.
Understanding and grasping control of uncertainty lies at the heart of quantum squeezing, linked to Heisenberg’s uncertainty principle. This principle dictates the level of precision in measurement of an object’s properties in a quantum system, suggesting an inherent trade-off. To precisely track a particle’s speed, one must concede precision in determining its position and vice versa. It imposes limits-based physics to experiments, particularly those associated with precision measurement, according to John Robinson, a physicist at the quantum computing startup QuEra.
However, scientists can achieve higher precision in the property they aim to measure by ‘squeezing’ uncertainty into properties they are not measuring. This concept of squeezing in measurement was proposed by theorists as early as the 1980s and has been continually developed by experimental physicists ever since. Over the last 15 years, they have grown from sprawling tabletop prototypes to practical devices. The essential query today revolves around identifying the applications that stand to benefit from this ‘squeezed’ state. “We are trying to comprehend the potential of this technology,” says Kasevich, “then hopefully, we will be able to envisage broader applications.”
