Scientists in Wales have built the world\u2019s most sensitive table-top interferometer, which is a miniature, ultra-precise instrument capable of measuring distortions in space-time smaller than a trillionth of a human hair.<\/p>\n
The research team at Cardiff University took a bold step toward understanding the quantum nature of gravity by setting new limits on the existence of very high-frequency gravitational waves.<\/p>\n
The experiment, also known as the Quantum Enhanced Space-Time measurement (QUEST), was developed at Cardiff University\u2019s School of Physics and Astronomy.<\/p>\n
According to the team, QUEST can measure changes in length 100 trillion times smaller than the width of a human hair. It set a new record for sensitivity in just a three-hour experiment. The results are expected to help scientists study new physics about space-time, gravity, and the existence of dark matter.<\/p>\n
Unlocking quantum gravity<\/p>\n
Gravitational waves<\/a>, which are ripples in the fabric of space-time first predicted by Einstein, are typically detected at low frequencies by observatories like LIGO and Virgo, which listen for signals from events such as black hole collisions. <\/p>\n But waves at much higher frequencies, produced by phenomena like primordial black holes<\/a> or processes in the early universe, have remained elusive. <\/p>\n To tackle the challenge, the team employed advanced interferometry, a technique that merges laser light reflections from mirrors to detect infinitesimal distance changes. They then used it to probe the faintest fluctuations in space-time.<\/p>\n<\/p>\n \u201cOur experiment is trying to answer the question of whether space-time is \u2018quantized\u2019,\u201d Abhinav Patra, MSc, a doctoral student in the university\u2019s Gravity Exploration Institute and lead author of the study, stated. \u201cModern physics treats space and time not as two separate things, but as a single physical entity.\u201d<\/p>\n By correlating data from two independent interferometers, the team ruled out certain high-frequency gravitational waves that might be predicted by quantum theories of gravity. <\/p>\n This correlation method allowed them to isolate potential signals from random noise and effectively filter out local disturbances like seismic vibrations<\/a> or thermal fluctuations.<\/p>\n Measuring the impossible<\/p>\n Hartmut Grote, PhD, a physics professor at the university and co-author of the study, stated that the results demonstrate just how powerful compact instruments can be in exploring the frontier between quantum mechanics and relativity.<\/p>\n \u201cQuantum theories of gravity can manifest themselves as fluctuations in space-time, which interferometers excel at measuring,\u201d he revealed. \u201cQUEST is an interferometric approach to the problem of quantum gravity.\u201d<\/p>\n According to Grote, the QUEST experiment took the team four years to design, install and commission.<\/p>\n<\/p>\n \u201cSo, it employs all the lessons learned from the technological developments made for the interferometric detection of gravitational waves to study quantum gravity,\u201d Grote concluded in a press release<\/a>.<\/p>\n Now that the team has proven the setup\u2019s sensitivity, the next phase will involve months-long observation runs to push the detection threshold even further.<\/p>\n These future tests could help uncover space-time fluctuations predicted by some quantum gravity models and shed light on the interplay between dark matter, vacuum energy, and gravitational fields.<\/p>\n